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Avian Coccidiosis.
AVIAN COCCIDIOSIS. W. T. JOHNSON Veterinary Division, Western Washington Experiment Station, Puyallup, Washington Downloaded from http://ps.oxfordjournals.org/ at University of South Dakota and School of Medicine on April 8, 2015
Avian coceidiosis is undoubtedly one of the most destructive and widespread diseases known to commercial poultry raising— chicken rearing in particular. More than usual difficulty is encountered in attempting to solve this problem, which situation is perhaps largely responsible for the widely divergent views held in regard to this infection. Much yet remains to be done to unify our conceptions of this disease. "Wherever poultry is handled under "intensive" conditions, that is, with large numbers of fowls and limited acreage, we And very favorable circumstances for the development of a parasitic disease such as coceidiosis, which emphasizes the importance of this problem to the commercial poultryman. The term "coceidiosis" applies to infection with any organism belonging to the order Cocciddidea. As commonly used in connection with poultry this term refers to infection with the species Eimeria avium. Although different forms ^, ^, ^, *, of coceidiosis are thought to have been recognized in various species of animals, including fowls, circumstances make it necessary to deal only with the intestinal form at the present time. "When studying this parasite and only a few of the stages of the coccidium are taken into consideration it is well to note that the organism assumes such a variety of forms and structure in the different stages of development that it is an easy matter, in the case of some of its forms to mistake other parasitic or non-parasitic bodies as being this organism. It is probable that this situation has resulted in some conditions being diagnosed as coceidiosis when they were not. Intestinal coceidiosis, however, has been so well· demonstrated that there can be no question about its existence. The Cause of Avian Coceidiosis is regarded by Hadley and Fantham as being Eimeria avium and yet there seems to be some difïerêlïee in>-Certain stages of the organism described-by'these investigators. The orgahisiii observed by the writer does Wot in all i-espects agree wjth either of their descriptions. These dif-
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ferences, however, may be more apparent than real. The name Eimeria avium will be used in this paper except for a few in stances to be noted later.
Hadley' claims to have infected chicks of the domestic fowl with "cyst-containing material from the intestines of sparrows * * * * * with the result that coccidiosis appeared. In a similar manner cyst-containing material from poultry was fed
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Eimeria avitcm and Various Hosts. Fantham writes °, that Eimeria avium infects "fowls, turkeys, pigeons, geese, ducks, pheasants, partridges and grouse." Hadley states* that " i n any locality visited by the parasite it will usually be found not in turkeys and fowls alone, but to a less degree in all the domestic birds associated with them in the same yards. At the Rhode Island Station in the poultry yards which are infected with the organism, it has been found as a pathogenic agent in guinea fowls, ducks, pheasants, quail, grouse, pigeons and sparrows, though the degree of susceptibility to the parasite varies greatly in these different species." Again Hadley writes' " A study of the morphology of the coceidium of the span*ow demonstrated that it was identical with the coceidium of blackhead in turkeys, and of eoccidial white diarrhea of chicks. ' ' Our work does not bear out the above statements with reference to sparrows, tur keys and ducks. Turkey and duck coccidiosis, however, have been investigated here only to a very limited extent. Examination of the common sparrow (Passer domesticus) at the Western Washington Experiment Station revealed the pres ence of oocysts in thé intestines of the majority of these birds, and which were similar in morphology to those found by Hadley in sparrows, but upon providing conditions which resulted in completion of the sporogonous cycle it was found that these forms were not those of Eimeria avium but an entirely different species which develops by the production of two sporocysts instead of four as found in the genus Eimeria. Since eoccidia are classified chiefly according to the number of sporocysts formed in the oocyst and the number of sporozoites formed in each sporocyst it is evident that a coceidium of a different genus is present in the sparrow of Washington than that in the chicken. According to Doflein® and Biitschlii^ this coceidium must be placed in the genus Cyelospora.
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caged sparrows, several of which subsequently developed eoccidiosis after an incubation period of 13 days." The writer has been unable by repeated attempts to show such transmission, and in each instance sporozoite formation in the ingested material has been complete. Repeated examinations of the fecal material from sparrows given oocysts (containing sporozoites) of Eimeria avium taken from the chicken revealed no coccidium or only the one belonging to the genus Cyclospora. This same coccidium has also been demonstrated to be the only one present in all other sparrows examined here. To date seventy-four sparrows have been ex amined. In every instance, at this Station, where the coccidium of the chicken has been sporulated it has shown four sporocysts and not two. Eimeria avium does sometimes show a massing of the content into two spherical areas, but two complete sporo cysts have not been noted. It is interesting to note that the above sparrows were trapped immediately above yards used for chickens. Blackbirds (Euphagus cyanocephalus) were also found to harbor a cocciditiin apparently identical with that found in spar rows. This coccidium of the blackbird did not prove infective to the chicken or vice versa. Also, in the case of the blackbirds as with sparroΛvs no other coccidium was demonstrated. Further, Hadley" states that "birds, including both turkeys and fowls, died of blackhead subsequent to ingesting cyst-con taining material taken from a rabbit, which had died of coccidiosis · " Fantham"' writes that the coccidium of the rab bit—Eimeria-stiedae is not transmissible to birds. Our infection experiments with feeding the common coccidium of the rabbit showing oocysts with sporozoites fully developed, did not result in the production of eoocidiosis even when young chicks were used. Regarding the coccidium of the turkey, it may be stated that while this organism may be infective for the chicken or vice versa, our cases of coccidiosis in this fowl have revealed an or ganism of the genus Eimeria in which the shape-index of the oocyst approaches nearer to zero than that found in chickens, and which in this respect is quite similar to Eimeria stiedâe (common rabbit coccidium). One attempt to inoculate a seven-
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Life Cycle and Nature of the Disease; A'general knowledge of the life cycle and nature of Bimeria avium is essential to a comprehensive understanding of the disease. The • following description of the parasite is therefore given':: ; • Resistant forms known as oo;cysts are discharged in the droppings of infected fowls after due time has elapsed following infection. Outside of the body and there only during; the life of the host, under favorable conditions ; of ; moisture . aïict air chiefly, those oocysts whicli; have ..been fertilized, develop by the granular content dividing to -form ifour sporoblasts, which then form into four spqrocysts, that each;.finally, contain two slender bodies known as sporozoites; together::with; a small centrally located granular structure qallçd the residual body. The change brought about in producing the spofozpites is known &\ sporogony. After sporogony has ta,ken place and entrance to the fowl brought about through ingestion the oocysts and sporocysts are affected by the action of intestinal juices, which results in liberation of motile sporozoites. The :Spprpzoites then penetrate , the intestinal epithelium and develop;:bodies known as schizonts containing merozoites.:::!|lhe. process of. merozoite formation is known as schizogony or asexual reproduction. The merozoite is motile and moves with : a doubling movement in which the body becomes curved to a greater degree a,t one end and in straightening out shows a quick and vigorous movement. The merozpites also attack the epithelium or develop subepithelial schizonts. This formation of merozoites ,is repeated a number of times, resulting in the intestiixal, tract becoming riddled by the parasite in severe cases. Finally the, merozoites differentiate, some developing into macrogametocytes or the female mother cells and others into microgametocytes, or the male
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months turkey with the eoccidium from the chicken resulted in no oocysts being formed, as judged by examination of the dropr pings. Our turkey cases have been comparatiyeljr few, and tiie above evidence is therefore merely offered for; what it is worth. Results: similar to that.in the above turkey were also obtained in attempting to inoculate two four months old ducks with sporulated oocysts from the chicken.: It is possible that age was the determining factor in the above ducks and turkey not developing coccidial oocysts.
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mother cells, which contain the female or male elements, respectively, necessary for the completion of the life cycle. The formation of the male and female stages leading to the development of the oocyst is known as gametogony or sexual development. A male and female fuse to produce a fertile oocyst or zygote, which later is expelled with the feces. The oocyst is so constructed that it can withstand considerable adversity, which it encounters outside of the body. The merozoite stage or schizogony results in the greatest injury to the host and when at this stage the organism is very susceptible to unfavorable conditions; in fact, merozoites usually show movement for a comparatively short time after being removed from the body of the host or after the death of the host. Most merozoites show no motility in smears prepared immediately after the death of the fowl. Even a moderate lowering of the temperature, such as to room temperature, very soon results in cessation of movement in the merozoite. Starting with the oocyst as we find it in feces which have just been passed we note under laboratory conditions that it usually takes several days before the oocyst reaches the stage at which it is infective. The shortest time in which the writer has noted this to take place is between two and three days. The infective stage is frequently reached in four or five days in the laboratory when favorable, conditions are provided. In experimental cases of coecidiosis the shortest time in which marked symptoms have developed and with which coccidian forms were definitely recognized at autopsy has been six days. These chicks were eighteen days old when symptoms developed. At the time of autopsy no oocystal development was demonstrated. I t is problematical how much longer it would have taken before this stage would have developed, probably within several days. An important point to bear in mind in connection with the life history is that the infection runs a self-limited course. The various stages of development are gone through and finally the organism is eliminated from the body by being discharged with the feces and the fowl remains free from the parasite unless reinfection from an external source takes place again. I n this respect coecidiosis differs distinctly from the bacterial diseases. ' Transmission of the Disease. So far as the investigations here
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The accompanying illustration shows the common infection cycle of the parasite. Numbers 1 and 2 oocysts represent common oocystal forms discharged in the droppings. No further development of the organism than this takes place within the body of the living host. These forms cannot produce disease, but when provided with proper conditions, chiefly those of air and moisture, they develop into number 3 oocystal form which when ingested liberates sporozoites that produce disease in any age fowl—as a rule to a very limited extent in mature fowls. The reading of some literature leads to confusion in connection with sporozoite formation of coccidia. To exemplify: Dobell*" illustrates oocysts with completely formed sporozoites, and in the description of this plate states : ' ' The oocysts are shown as they usually appear in freshly passed human feces—those of the Bimeria containing fully formed s p o r e s * * * * " . "While this may be true of Bimeria Wenyon and Bmeria oxyspora of man it certainly is not true of the coccidia found by the writer in chickens, sparrows, blackbirds, cattle and rabbits. Then
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go to show, infection, takes place only as a result of the ingestion of sporulated oocysts. The feeding of fresh, infected intestines or fresh feces at this Station has not been demonstrated to produce eoccidiosis, while untreated young chickens ingesting oocysts containing sporozoites have in every instance developed the disease. Fowls fed such material and in which infection was definitely checked by post mortem examination have ranged in age from a few days to forty days. In view of results claimed to have been obtained by others it is necessary to do further work in order to determine definitely whether or not ingestion of fresh feces or intestines infected with the coccidium in the various stages of development (excepting sporulated oocysts), particularly free merozoites or sporozoites, results in the development of eoccidiosis. This much can be said without fear of contradiction : That the most important cause for the spread of eoccidiosis in our flocks is ingestion of oocysts showing sporocystal development and this usually means a necessary lapse of about two or more days between expulsion and ingestion of the oocysts. It seems probable that future experiments will demonstrate conclusively that this is the only serious means of spreading the disease.
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* Estimated, records not kept.
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again, Fantham" illustrates coccidial forms which are supposed to have been found in "feces of a fowl chick infected with cpccidiosis * * * * * "^ but he makes no mention as to whether or not they have just been passed or are old feces. In this illustration he shows the common adult oocyst and oocysts at the sporoblast and completely developed sporocystal stages. It might appear from Fantham's illustration and description that oocysts with sporozoites are commonly found in feces Just passed and that serious eoccidiosis could be readily produced by ingestion of such material. A number of other instances could also be cited to show that this point is not made clear, so that an incorrect im pression is readily obtained. Had oocysts with complete sporozoite development (highly im probable) been found by Fantham in feces just expelled he was dealing with a different coccidium, since oocysts with complete sporoblast formation even have not been noted in our work in connection with feces just passed. The nearest approach to these forms has been a comparatively few oocysts showing a slight massing of the granular content into four areas, possibly indi cating beginning sporoblast formation. At this Station at least 1500* fowls infected with eoccidiosis have been autopsied and 3000* smears made of feces and material from all parts of the intestinal tract and in no instance were oocysts with sporozoites demonstrated in feces just passed or in material just taken from the intestinal tract. In other words, conditions ΛVithin the host are not favorable to sporozoite formation, at least until the oocyst has first been exposed to external conditions. Fantham claims that the parasite may pass through the intes^ tinal tract of sparrows or flies unchanged and without impair ment of vitality. This affords a means of distributing the disease over the country. Mature fowls in particular may be harboring some eoccidia and be distributing oocysts in the droppings and not show any symptoms of disease. Such individuals are sometimes permitted to run over ground to be used for growing stock and the soil be comes contaminated, so that the young fowls given access to such yards develop eoccidiosis and show marked symptoms of the
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disease. To date, however, our records show that fowls which are mature usually harbor oocysts to a much less degree than young, both as to percentage of fowls affected and degree of infestation. One investigator^^ has stated that in a certain state close to 90 per cent of the poultry yards probably show coccidian contamination, which emphasizes its wide distribution. Transmission of coceidiosis through the egg is being given credence by a number of writers. Quoting from one author^^ we have: " I t has also been shown that fowls' eggs may become contaminated by excreta containing coccidia as they are being laid, and thus young chicks may and do become infected very soon after being hatched, even in the incubator". Another'^' writes: " I t is stated that coccidia may be present in the albumin of eggs derived from infected hens, the parasite gaining access before the egg reaches the shell forming portion of the oviduct. Such instances may account for the mortality among brooderreared chicks, when other means of infection are remote or cannot be accounted for". I t is probable that Eimeria avium would remain in the egg in a dormant state for an indefinite perioH, since our experiments indicate that as long as either yolk or white of eggs mixed with coceidial oocysts have not undergone too great a change, probably induced by bacteria, the oocysts remain intact and probably viable. A high percentage sporoeystal development was demonstrated in a yolk culture, but in an egg white culture no development took place. Development in the yolk culture occurred with considerable putrefaction present, showing also that the oocyst is very resistant to some putrefactive products. While it is possible for infection with Eimeria avium to take place through the medium of the egg it seems highly improbable that this is a very common occurrence, or a serious means of transmission, because of the susceptibility of this organism to dryness, particularly before sporoeystal development, its need for moisture and air before it is enabled to develop to the sporozoite stage, the necessity of being ingested before intestinal coceidiosis can take place and the infrequeney with which oocysts occur in fowls having attained maturity. We must recognize the fact, however, that contamination of the egg shell can be brought about in fowls discharging oocysts as the egg passes through the cloaca and to the external. The
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The term, "White Diarrhea,"^* has been used to denote coceidian infection, but in oui experience the term "bloody diarrhea" would be more appropriate. Distinctly bloody drop-
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probabilities are that the danger of transmission through the eggs being contaminated is of secondary importance to mechanical distribution, such as carrying the organism on the shoes, coeeidia-laden dust, etc. Present knowledge, therefore, does not permit us to reject eggs from infected fowls for hatching. Observation of a large number of flocks indicates that the chief source of infection is contaminated soil, since the noticeable outbreaks most often take place after the flock has been turned out on the ground. Judging from the results we have obtained in artificially infecting young chicks it is reasonable to assume that a chick infected at hatching time by the ingestion of infectiA^e oocysts would develop the disease in a week or less. If the infection were severe a fatal hemorrhage should take place in about this time. This we have not noted. However, it is reasonable to expect that if infection did take place at hatching time, because of an infected egg it would be slight and might readily escape notice until later when re-infection from some other source, such as the soil, would be brought about as a result of the primary infection from the egg. Diagnosis of eoecidiosis can not be definitely determined without the microscope. Further, satisfactory diagnosis frequently depends upon the recognition of other forms than the oocyst. Bloody diarrhea is not a positive indication of eoecidiosis as is thought by some. I t is merely suggestive. Passing of considerable blood from the digestive tract of growing fowls and collection of considerable quantities in any part of the intestines is very indicative. The tendency toward hemorrhage decreases as the fowls grow older. Thickening of the intestine, particularly the duodenum, apparently occurs in fowls chronically affected with intestinal eoecidiosis. A caseated content of the ceea in growing fowls is frequently found, but it is not characteristic or necessarily associated with the disease. Emaciation is common with severe infection, especially chronic infection. Chronic cases, particularly growing fowls, frequently become so emaciated that the breast region is practically devoid of muscular tissue.
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Frequently flocks of young chickens are met with which show very good developnient and activity up to several weeks of age, but which suddenly break down with severe coceidiosis without anything unusual in regard to feeding and general care, im mediately preceding the development of the disease. The most vigorous as well as weaker fowls suffer—it does not seem to at tack particularly the weaker appearing ones. Coceidiosis has been produced experimentally at will in ap proximately one hundred young White Leghorn fowls of highproducing strains, thus they were representative of the fowl commonly found in connection with our commercial flocks. The fowls were from different sources, of varying ages and infected with material from different flocks. None of the fowls here referred to was older than forty days. In each instance inocula tion has been bv the mouth—the natural channel of infection.
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pmgs, however, have been noted by the Avriter only in eases of a very severe infection in fowls which had not yet attained matut·ity. Serious infection may exist without the droppings beiiii? bloodj' and in such cases they tend to be "watery." Effect of Vigor on -the Development of Coceidiosis. The im pression seems to have gained ground that devitalization or low ered vigor must precede coccidial invasion. Evidence on this point is certainly of much value and is therefore given here. On January 23, 1922, four White Leghorn chicks, twelve days old and which showed everj^ external indication of vigor, were placed in a cage. Three of these were each given, by the month, approximately 14 gram of cecal content taken from a four months old pullet July 19, 1921: The inoculation material con tained numerous oocysts with sporozoites. No. 1 inoculated chick was found dead on the morning of January 29, No. 2 and No. 3 died about 11 A. M. January 30. Autopsy showed in each case the rectum and ceca filled with blood and very noticeable hemorrhagic areas in these organs. Microscopic examination showed merozoites and schizonts present in large numbei-s. This is a typical example of Λvhat occurred to other vigorous youngchickens inoculated in a similar manner. The post mortem con dition noted in these fowls was identical with what has been found in many brought to the laboratory and which developed the disease naturally.
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Effect, of Moisture and Dryness on the Oocyst. Tests were made to determine the effect of moisture and dryness. Smears prepared by adding material containing oocysts freshly removed from the digestive organs to a drop of water will show a slight collapsing of many oocysts as soon as the excess moisture has evaporated at room temperature. After twenty-foui hours has elapsed many of the oocysts will show a distinct collapsing. Several days after preparing the smear many of the oocysts appear to hâve degenerated to the point of death. A small percentage appear to be unchanged, even after a number of days. These are of the early oocystal type which show the gra:nular content scattered throughout the cell and not in a contracted state. No sporulation takes place under such conditions of dryness, but it has been noted after days of drying that sporulation does take place in at least part of the oocysts if moisture, together with air, is supplied in proper amounts. Fecal material containing sporulated oocysts if permitted to dry at room temperature will show a considerable decrease in the percentage of definitely recognizable oocysts, but some appear to resist drying to a considerable extent and show but a slight collapsing of the oocystal wall and with sporocysts and sporozoites clearly visible. Such oocysts can be found in fecal material which has dried to such an extent that the material has become brittle. From this we can conclude that drying does have an effect in destroying coccidial oocysts, but that the action is somewhat delayed and that in tlie case of a small per-
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From the above it is safe to conclude that coccidiosis can be consistently produced in young White Leghorn fowls of high producing strains. I t is worthy of note that variable results have followed feeding contaminated material to older fowls, even fowls considerably under the age of maturity. It is reasonable to assume that devitalization brought about in various ways exer^ cises an influence on the development of coccidiosis, but it has not been demonstrated that this is necessary for the production of the disease, at least in very young fowls. We must therefore take cognizarice of the fact that we are dealing with an organism which possesses disease-producing power to a high degree, severity of the disease depending largely upon the amount of infective material ingested and the age of the fowl.
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centage of the oocysts it is questionable whether or not drying at room temperature has any appreciable effect, even after a prolonged period. Slides prepared by adding fresh oocystal material to a drop of water, covering this with a coverglass and sealing the edge of the coverglass to the slide with petrolatum will result in no change in the oocyst for a number of days— neither development nor discernible degeneration taking place. I n time, however, bubbles appear in the oocysts, indicatiijg degeneration. Oocysts exposed to the air for a time and then placed under a sealed coverglass do not cease developing as soon as placed under the sealed coverglass. Effect of Disinfectants. In an effort to determine the ef fects of some disinfectants upon Eimeria avium, fresh unsporulated oocysts were placed in 5%, 2.5% and 1% solutions of lye (Eagle brand) in water, others in 5% and 1% creolin in water and still others in lime water. Sporozoite formation took place to a very noticeable extent in all three lye dilutions. A fair percentage of the oocysts in the lime water showed sporo zoite formation and yet there was a noticeable destructive effect detected in many oocysts in which sporozoite formation was pre vented. Not a single oocyst in either of the creolin solutions was noted to show even sporozoite formation. Water was added to the 5% creolin tube and the mixture thoroughly shaken. This was then permitted to stand and settle for a time. The greater portion of the solution was then drained off. More wat er was added, the tube shaken and again permitted to settle. This fluid was then almost entirely removed and the " c u l t u r e " allowed to stand. No sporulation took place, indicating that the oocysts were dead, but still intact. I t is questionable wheth er or not creolin would be as effective or effective at all in the event of applying it to sporulated oocysts. TΛventy-four hours exposure of a culture of sporulated oocysts to a one per cent so lution of creolin did not result in destruction of virulence, as fatal coccidiosis (cecal hemorrhage) was produced in two threeweeks-old chicks on the sixth day following ingestion of such ma terial. Similarly a culture of sporulated oocysts exposed to lime water for twenty-four hours produced fatal hemorrhage in two three-weeks-old chicks, six days after being ingested. Avian Coccidiosis and So-called Blackhead in Turkeys.
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Coccidiosis Control. Sanitation is the foundation of eoc cidiosis control. Without adequate sanitation it is doubtful that the disease will ever be satisfactorily controlled for any consid erable period of time. The salient points to be considered in making provision for sanitary measures are: range, cultiva tion of the soil, change of yards and the maintenance of dry ness as much as possible. The inauguration of sanitary measures on an economic basis can not be expected to totally eliminate coccidian infection, but they should result in holding infection down to a low degree and permit of successful rearing. Further, we must remember that the same sanitary measures applied to control coccidiosis should also assist in overcoming other common intestinal infec tions. Treatment. In the light of present knowledge it seems improbable that any treatment alone can be relied upon to con trol coccidiosis satisfactorily. This does not mean to say that treatments are of no value, since we know some do assist in over coming the disease. Treatment is hopeless in chronic cases as sociated with emaciation. These cases are frequently unrecog nized until they are about of laying age and then their slow de velopment attracts attention. The condition of such fowls often is not readily determined by observation—one must handle them to fully appreciate it. Pullets of laying age showing emaciation
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Fantham^ makes the statement that "The disease (referring to eoccidiosis) in turkeys is known as blackhead" and some years ago Hadley'' was of the opinion that so-called blackhead in turkeys was a coccidian disease. More recently Hadley^^,^" has expressed himself as believing that it is not eoccidiosis but trich omoniasis. In examining turkeys at this Station some were found showing typical lesions of blackhead without any coccidial forms being observed upon microscopic examination of the in testinal content. In each instance, however, large numbers of both motile and encysted stages of a trichomonas have been noted. It can not be doubted that turkeys suffer with eoccidiosis pro duced by a species of the genus Bimeria and that a coccidium is frequently found associated with blackhead, but it seems im probable that the coccidium has a direct relationship to the pro duction of blackhead.
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should be culled. Those which are comparatively free at this ag» usually escape serious coccidiosis if given reasonable care and sanitary conditions, as they should by this time be quite resist ant to the infection, resistance developing Avith age. A number of drugs have been recommended as being effec tive or of value in controlling coccidiosis in poultry. No data have been noted in the literature which definitely establish the value of any of them. In the year 1912, Meyer and Crooker made an effort to determine the effect of some drugs which have been used for coccidiosis control. These were, namely : Turpen tine mixed with castor oil, potassium permanganate; a mixture of iron sulphate and glycerine ; suphocarbolates ; methylene blue and calomel. The above mentioned writers concluded, " t h a t calomel and methylene blue are undoubtedly capable of prolong ing life, ' ' and also that ' ' a specific chemo-therapeutic action can, in our opinion, be excluded. " Fatham (1915)," and Beach (1917)," claimed that sour skimmed milk or buttermilk given in cases of coccidiosis are of value in controlling the disease. The writer's experience has shown that some flocks given no water and only sour skimmed milk or buttermilk to drink together wdth mixed grains and with or without mash have not responded to treatment and also have actually developed the disease when such a feeding plan was in effect. In an attempt to obtain further evidence relative to the ef fect of sour skimmed milk on Bimeria avium in the chicken, four vigorous White Leghorn chicks (3 cockerels and 1 pullet) hatched January 1, 1922, were placed in a cage on February 2, 1922 and given nothing but sour skimmed milk to drink and chick grain. February 3, 1922, 4:00 P. M. three of the chicks (2 cockerels and the pullet) were each inoculated by the mouth with approximate ly 1/4 gram of cecal content taken from a four months old pullet autopsied July 19, 1921. This material showed large numbers of oocysts with spores at this time. February 9, 1922, 8:00 A. M., considerable blood was noted in the cage. Pure blood was being discharged from the intestinal tract. No droopiness was noted at this time. At 10:30 A. M., February 9, all three in fected chicks showed slight droopiness. Uninfected chick looked well. Number 1 died night of February 9, number 2 at 1:00 Ρ
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One should not conclude from the above that sour skimmed milk is of no value until further work has been done. Certainly its use is of limited value in controlling this disease. It might be stated that flocks so fed seem to show some improvement as a result of such treatment. " Since Epsom salts^* have also been recommended as a cure for coccidiosis the following was undertaken to note what effect the drug might have : On May 3, 1922, nine White Leghorn chicks which had just been hatched in an incubator were placed in a cage. The feed consisted of chick grain, mash composed of purified bran (2 parts), red dog flour (§4 part) and corn feed meal (1 part). The mash was fed moistened. Sour skimmed milk and water were supplied at all times. At 4:30 P. M., May 10, three of these chicks were each given, by the mouth, approximately 1/15 of a gram of a culture prepared March 13, 1922, by using the cecal content of a pullet six weeks of age. Oocysts with spores were present in ' fair numbers. Three chicks were left as checks and three were used for other inoculation work. At 5:00 P . M., May 10, all the chicks were given a wet mash made by dissolving 6.0 grams of epsom salts in water and this used to moisten the mash. This amount of epsom salts was considered to be a fairly heavy dose. No. 1 (infected cockerel) was killed at 9:00 A. M., May 22.. A smear from the cecal mucosa showed coccidial forms in large numbers, including 500 oocysts, under an 18 millimeter cover glass. No. 2, (infected cockerel) was killed 9:30 A. M., May 22. A smear from the cecal mucosa resulted in finding approximately 3,000 oocysts under an 18 millimeter cover glass. In one microscopic field approximately 500 oocysts were noted under the 16 millimeter ob-
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M., February 10. In both cases the rectum and ceca were filled Avith blood. Microscopic examination of the cecal mucosa and content revealed asexual and sexual forms of Eimeria avium, including many trophozoites and myriads of merozoites. Number 3 infected chick was very droopy and unable to stand most of the time February 10. This chick was considerably improved. 4:00 P. M., February 11. Number 3 was killed February 18 and showed numerous early stages of gametogony and a few oocysts. It is doubtful that chick number 3 would have lived and developed properly.
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1 Schultz, C. H. (1915). Observations among dairy cattle. Article read at the Annual Convention of the Wash. State Dairymen's Assn. 2 Idem. (1915). Coccidiosis in Cattle and Caraboas. Reprint from The Jour, of Infect. Dis. Vol. 17, No. 1. 3 Saunders, Charles G. (1919). Coccidiosis in Rabbits. Amer. Jour, of Vet. Med. Vol. 14. No. 9. * Meyer, K. F. and Crocker, W. J. (1913). Some Experiments on Medicinal Treatment of Coccidiosis in Chickens. Amer. Vet. Review. 5 Fantham, H. B. (1915). Coccidiosis in Poultry and Game Birds. Jour, of the Board of Agri. London, Vol. 21, No. 10. β Hadley, P. B. (1910). Blackhead in Turkeys: A study in Avian Coccidiosis, Rhode Island Sta. Bui. 141. 7 Idem. (1910). Studies in Avian Coccidiosis. 3. Coccidiosis in the English Sparrow and Other Wild Birds. Reprint from Abdruck aus dem Centralblatt fur Bakteriologie, Parasitenkunde und Infektionskrankheiten, 56 Band. 8 Doflein. (1911). Lehrbuck Der Protozoenkunde. 3rd Ed. 9 Butschlii. 1880-82). Protozoen. Vol.1. loDobell; C. A. (1919): Revision of the Coccidia Parasitic in Man. Parasitology. Loiidpn, Vol. 11, No. 2. 11 Chandler, W. L. (1919). Coccidiosis. Mich. Ag. College Quarterly Bui. Vol. 2, No. 1.
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jective. No. 3 killed May 22, showed approximately 5,000 oocysts under an 18 millimeter cover glass, about 500 being seen under the 16 millimeter objective in one field. To date the most effective treatment^ in our hands, as determined by placing chicks in cages, starting treatment and then infecting them, by the mouth, has been the use of crude catechu in the amount of % to one gram of the drug to each gallon of drinking water for a period of ten to fourteen days. The drug is best added to a small quantity of water first. Such water is as readily consumed as the unmedicated. The present retail price of this drug is about fifty cents a pound. Prescribing it in the above amounts two thirds to one ounce makes thirty gallons of medicated water. I t is not advisable to continue the use of this drug for long periods, since it has a slightly constipating action. In conclusion, it is only fair to state that the purpose of this paper has been to present a few important points bearing on coccidiosis in poultry and to serve as an aid toward establishing our knowledge of this problem on a firmer foundation than has existed in the past.
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i2podd, Sydney. (1917). Coccidiosis in Poultry. The Agri. Gazette of New South Wales. Sydney, Par.t 12. i3Reid, H. A. (1920). Coccidiosis of Poultry. The New Zealand Jour, of Agri. Wellington. Vol. 11, No. 6. "Morse, Geo. Byron (1908). White Diarrhea of Chicks with notes on Coccidiosis in birds. U. S. Dept. of Agri., B. A. I. Cir. 128. isHadley, P. B., (1916). The avenue and development of tissueinfection in intestinal Trichomoniasis. Rhode Island Sta. Bui. 168. leidem. (1916). The role of the Flagellated Protozoa in Infective Processes of the Intestines and Liver. Rhode Island Sta. Bui. 166. "Beach, J. R. (1917). Bacillary Wlhite Diarrhea or Fatal Septicemia of Chicks and Coccidiosis or Coccidial Enteritis of Chicks. Calif. Sta. Cir. 162. 18 Charles, T. B. (1921-22). Practical Experiences in the Control of Coccidiosis in Young Chicks. Poultry Science. Vol. 1, No. 2.
Avian coceidiosis is undoubtedly one of the most destructive and widespread diseases known to commercial poultry raising— chicken rearing in particular. More than usual difficulty is encountered in attempting to solve this problem, which situation is perhaps largely responsible for the widely divergent views held in regard to this infection. Much yet remains to be done to unify our conceptions of this disease. "Wherever poultry is handled under "intensive" conditions, that is, with large numbers of fowls and limited acreage, we And very favorable circumstances for the development of a parasitic disease such as coceidiosis, which emphasizes the importance of this problem to the commercial poultryman. The term "coceidiosis" applies to infection with any organism belonging to the order Cocciddidea. As commonly used in connection with poultry this term refers to infection with the species Eimeria avium. Although different forms ^, ^, ^, *, of coceidiosis are thought to have been recognized in various species of animals, including fowls, circumstances make it necessary to deal only with the intestinal form at the present time. "When studying this parasite and only a few of the stages of the coccidium are taken into consideration it is well to note that the organism assumes such a variety of forms and structure in the different stages of development that it is an easy matter, in the case of some of its forms to mistake other parasitic or non-parasitic bodies as being this organism. It is probable that this situation has resulted in some conditions being diagnosed as coceidiosis when they were not. Intestinal coceidiosis, however, has been so well· demonstrated that there can be no question about its existence. The Cause of Avian Coceidiosis is regarded by Hadley and Fantham as being Eimeria avium and yet there seems to be some difïerêlïee in>-Certain stages of the organism described-by'these investigators. The orgahisiii observed by the writer does Wot in all i-espects agree wjth either of their descriptions. These dif-
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ferences, however, may be more apparent than real. The name Eimeria avium will be used in this paper except for a few in stances to be noted later.
Hadley' claims to have infected chicks of the domestic fowl with "cyst-containing material from the intestines of sparrows * * * * * with the result that coccidiosis appeared. In a similar manner cyst-containing material from poultry was fed
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Eimeria avitcm and Various Hosts. Fantham writes °, that Eimeria avium infects "fowls, turkeys, pigeons, geese, ducks, pheasants, partridges and grouse." Hadley states* that " i n any locality visited by the parasite it will usually be found not in turkeys and fowls alone, but to a less degree in all the domestic birds associated with them in the same yards. At the Rhode Island Station in the poultry yards which are infected with the organism, it has been found as a pathogenic agent in guinea fowls, ducks, pheasants, quail, grouse, pigeons and sparrows, though the degree of susceptibility to the parasite varies greatly in these different species." Again Hadley writes' " A study of the morphology of the coceidium of the span*ow demonstrated that it was identical with the coceidium of blackhead in turkeys, and of eoccidial white diarrhea of chicks. ' ' Our work does not bear out the above statements with reference to sparrows, tur keys and ducks. Turkey and duck coccidiosis, however, have been investigated here only to a very limited extent. Examination of the common sparrow (Passer domesticus) at the Western Washington Experiment Station revealed the pres ence of oocysts in thé intestines of the majority of these birds, and which were similar in morphology to those found by Hadley in sparrows, but upon providing conditions which resulted in completion of the sporogonous cycle it was found that these forms were not those of Eimeria avium but an entirely different species which develops by the production of two sporocysts instead of four as found in the genus Eimeria. Since eoccidia are classified chiefly according to the number of sporocysts formed in the oocyst and the number of sporozoites formed in each sporocyst it is evident that a coceidium of a different genus is present in the sparrow of Washington than that in the chicken. According to Doflein® and Biitschlii^ this coceidium must be placed in the genus Cyelospora.
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caged sparrows, several of which subsequently developed eoccidiosis after an incubation period of 13 days." The writer has been unable by repeated attempts to show such transmission, and in each instance sporozoite formation in the ingested material has been complete. Repeated examinations of the fecal material from sparrows given oocysts (containing sporozoites) of Eimeria avium taken from the chicken revealed no coccidium or only the one belonging to the genus Cyclospora. This same coccidium has also been demonstrated to be the only one present in all other sparrows examined here. To date seventy-four sparrows have been ex amined. In every instance, at this Station, where the coccidium of the chicken has been sporulated it has shown four sporocysts and not two. Eimeria avium does sometimes show a massing of the content into two spherical areas, but two complete sporo cysts have not been noted. It is interesting to note that the above sparrows were trapped immediately above yards used for chickens. Blackbirds (Euphagus cyanocephalus) were also found to harbor a cocciditiin apparently identical with that found in spar rows. This coccidium of the blackbird did not prove infective to the chicken or vice versa. Also, in the case of the blackbirds as with sparroΛvs no other coccidium was demonstrated. Further, Hadley" states that "birds, including both turkeys and fowls, died of blackhead subsequent to ingesting cyst-con taining material taken from a rabbit, which had died of coccidiosis · " Fantham"' writes that the coccidium of the rab bit—Eimeria-stiedae is not transmissible to birds. Our infection experiments with feeding the common coccidium of the rabbit showing oocysts with sporozoites fully developed, did not result in the production of eoocidiosis even when young chicks were used. Regarding the coccidium of the turkey, it may be stated that while this organism may be infective for the chicken or vice versa, our cases of coccidiosis in this fowl have revealed an or ganism of the genus Eimeria in which the shape-index of the oocyst approaches nearer to zero than that found in chickens, and which in this respect is quite similar to Eimeria stiedâe (common rabbit coccidium). One attempt to inoculate a seven-
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Life Cycle and Nature of the Disease; A'general knowledge of the life cycle and nature of Bimeria avium is essential to a comprehensive understanding of the disease. The • following description of the parasite is therefore given':: ; • Resistant forms known as oo;cysts are discharged in the droppings of infected fowls after due time has elapsed following infection. Outside of the body and there only during; the life of the host, under favorable conditions ; of ; moisture . aïict air chiefly, those oocysts whicli; have ..been fertilized, develop by the granular content dividing to -form ifour sporoblasts, which then form into four spqrocysts, that each;.finally, contain two slender bodies known as sporozoites; together::with; a small centrally located granular structure qallçd the residual body. The change brought about in producing the spofozpites is known &\ sporogony. After sporogony has ta,ken place and entrance to the fowl brought about through ingestion the oocysts and sporocysts are affected by the action of intestinal juices, which results in liberation of motile sporozoites. The :Spprpzoites then penetrate , the intestinal epithelium and develop;:bodies known as schizonts containing merozoites.:::!|lhe. process of. merozoite formation is known as schizogony or asexual reproduction. The merozoite is motile and moves with : a doubling movement in which the body becomes curved to a greater degree a,t one end and in straightening out shows a quick and vigorous movement. The merozpites also attack the epithelium or develop subepithelial schizonts. This formation of merozoites ,is repeated a number of times, resulting in the intestiixal, tract becoming riddled by the parasite in severe cases. Finally the, merozoites differentiate, some developing into macrogametocytes or the female mother cells and others into microgametocytes, or the male
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months turkey with the eoccidium from the chicken resulted in no oocysts being formed, as judged by examination of the dropr pings. Our turkey cases have been comparatiyeljr few, and tiie above evidence is therefore merely offered for; what it is worth. Results: similar to that.in the above turkey were also obtained in attempting to inoculate two four months old ducks with sporulated oocysts from the chicken.: It is possible that age was the determining factor in the above ducks and turkey not developing coccidial oocysts.
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mother cells, which contain the female or male elements, respectively, necessary for the completion of the life cycle. The formation of the male and female stages leading to the development of the oocyst is known as gametogony or sexual development. A male and female fuse to produce a fertile oocyst or zygote, which later is expelled with the feces. The oocyst is so constructed that it can withstand considerable adversity, which it encounters outside of the body. The merozoite stage or schizogony results in the greatest injury to the host and when at this stage the organism is very susceptible to unfavorable conditions; in fact, merozoites usually show movement for a comparatively short time after being removed from the body of the host or after the death of the host. Most merozoites show no motility in smears prepared immediately after the death of the fowl. Even a moderate lowering of the temperature, such as to room temperature, very soon results in cessation of movement in the merozoite. Starting with the oocyst as we find it in feces which have just been passed we note under laboratory conditions that it usually takes several days before the oocyst reaches the stage at which it is infective. The shortest time in which the writer has noted this to take place is between two and three days. The infective stage is frequently reached in four or five days in the laboratory when favorable, conditions are provided. In experimental cases of coecidiosis the shortest time in which marked symptoms have developed and with which coccidian forms were definitely recognized at autopsy has been six days. These chicks were eighteen days old when symptoms developed. At the time of autopsy no oocystal development was demonstrated. I t is problematical how much longer it would have taken before this stage would have developed, probably within several days. An important point to bear in mind in connection with the life history is that the infection runs a self-limited course. The various stages of development are gone through and finally the organism is eliminated from the body by being discharged with the feces and the fowl remains free from the parasite unless reinfection from an external source takes place again. I n this respect coecidiosis differs distinctly from the bacterial diseases. ' Transmission of the Disease. So far as the investigations here
AVIAN GOCCIDIOBIS
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The accompanying illustration shows the common infection cycle of the parasite. Numbers 1 and 2 oocysts represent common oocystal forms discharged in the droppings. No further development of the organism than this takes place within the body of the living host. These forms cannot produce disease, but when provided with proper conditions, chiefly those of air and moisture, they develop into number 3 oocystal form which when ingested liberates sporozoites that produce disease in any age fowl—as a rule to a very limited extent in mature fowls. The reading of some literature leads to confusion in connection with sporozoite formation of coccidia. To exemplify: Dobell*" illustrates oocysts with completely formed sporozoites, and in the description of this plate states : ' ' The oocysts are shown as they usually appear in freshly passed human feces—those of the Bimeria containing fully formed s p o r e s * * * * " . "While this may be true of Bimeria Wenyon and Bmeria oxyspora of man it certainly is not true of the coccidia found by the writer in chickens, sparrows, blackbirds, cattle and rabbits. Then
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go to show, infection, takes place only as a result of the ingestion of sporulated oocysts. The feeding of fresh, infected intestines or fresh feces at this Station has not been demonstrated to produce eoccidiosis, while untreated young chickens ingesting oocysts containing sporozoites have in every instance developed the disease. Fowls fed such material and in which infection was definitely checked by post mortem examination have ranged in age from a few days to forty days. In view of results claimed to have been obtained by others it is necessary to do further work in order to determine definitely whether or not ingestion of fresh feces or intestines infected with the coccidium in the various stages of development (excepting sporulated oocysts), particularly free merozoites or sporozoites, results in the development of eoccidiosis. This much can be said without fear of contradiction : That the most important cause for the spread of eoccidiosis in our flocks is ingestion of oocysts showing sporocystal development and this usually means a necessary lapse of about two or more days between expulsion and ingestion of the oocysts. It seems probable that future experiments will demonstrate conclusively that this is the only serious means of spreading the disease.
I
Γ* ) — \
oc
maTuCe f o w l
One Τα seveKu-i weeks aj^ter ûocysîal inciesTîon oKobbif^O'i beqin ίο Contain oocysts.
^
;jiick
ScKizoqony.—> Cja ni eTo qoay.
D/ies+lœ 0^~ns.
Fig.—Common (possibly only means of transniissioii) Transmission Cycle of Binicria avium.
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* Estimated, records not kept.
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again, Fantham" illustrates coccidial forms which are supposed to have been found in "feces of a fowl chick infected with cpccidiosis * * * * * "^ but he makes no mention as to whether or not they have just been passed or are old feces. In this illustration he shows the common adult oocyst and oocysts at the sporoblast and completely developed sporocystal stages. It might appear from Fantham's illustration and description that oocysts with sporozoites are commonly found in feces Just passed and that serious eoccidiosis could be readily produced by ingestion of such material. A number of other instances could also be cited to show that this point is not made clear, so that an incorrect im pression is readily obtained. Had oocysts with complete sporozoite development (highly im probable) been found by Fantham in feces just expelled he was dealing with a different coccidium, since oocysts with complete sporoblast formation even have not been noted in our work in connection with feces just passed. The nearest approach to these forms has been a comparatively few oocysts showing a slight massing of the granular content into four areas, possibly indi cating beginning sporoblast formation. At this Station at least 1500* fowls infected with eoccidiosis have been autopsied and 3000* smears made of feces and material from all parts of the intestinal tract and in no instance were oocysts with sporozoites demonstrated in feces just passed or in material just taken from the intestinal tract. In other words, conditions ΛVithin the host are not favorable to sporozoite formation, at least until the oocyst has first been exposed to external conditions. Fantham claims that the parasite may pass through the intes^ tinal tract of sparrows or flies unchanged and without impair ment of vitality. This affords a means of distributing the disease over the country. Mature fowls in particular may be harboring some eoccidia and be distributing oocysts in the droppings and not show any symptoms of disease. Such individuals are sometimes permitted to run over ground to be used for growing stock and the soil be comes contaminated, so that the young fowls given access to such yards develop eoccidiosis and show marked symptoms of the
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disease. To date, however, our records show that fowls which are mature usually harbor oocysts to a much less degree than young, both as to percentage of fowls affected and degree of infestation. One investigator^^ has stated that in a certain state close to 90 per cent of the poultry yards probably show coccidian contamination, which emphasizes its wide distribution. Transmission of coceidiosis through the egg is being given credence by a number of writers. Quoting from one author^^ we have: " I t has also been shown that fowls' eggs may become contaminated by excreta containing coccidia as they are being laid, and thus young chicks may and do become infected very soon after being hatched, even in the incubator". Another'^' writes: " I t is stated that coccidia may be present in the albumin of eggs derived from infected hens, the parasite gaining access before the egg reaches the shell forming portion of the oviduct. Such instances may account for the mortality among brooderreared chicks, when other means of infection are remote or cannot be accounted for". I t is probable that Eimeria avium would remain in the egg in a dormant state for an indefinite perioH, since our experiments indicate that as long as either yolk or white of eggs mixed with coceidial oocysts have not undergone too great a change, probably induced by bacteria, the oocysts remain intact and probably viable. A high percentage sporoeystal development was demonstrated in a yolk culture, but in an egg white culture no development took place. Development in the yolk culture occurred with considerable putrefaction present, showing also that the oocyst is very resistant to some putrefactive products. While it is possible for infection with Eimeria avium to take place through the medium of the egg it seems highly improbable that this is a very common occurrence, or a serious means of transmission, because of the susceptibility of this organism to dryness, particularly before sporoeystal development, its need for moisture and air before it is enabled to develop to the sporozoite stage, the necessity of being ingested before intestinal coceidiosis can take place and the infrequeney with which oocysts occur in fowls having attained maturity. We must recognize the fact, however, that contamination of the egg shell can be brought about in fowls discharging oocysts as the egg passes through the cloaca and to the external. The
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The term, "White Diarrhea,"^* has been used to denote coceidian infection, but in oui experience the term "bloody diarrhea" would be more appropriate. Distinctly bloody drop-
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probabilities are that the danger of transmission through the eggs being contaminated is of secondary importance to mechanical distribution, such as carrying the organism on the shoes, coeeidia-laden dust, etc. Present knowledge, therefore, does not permit us to reject eggs from infected fowls for hatching. Observation of a large number of flocks indicates that the chief source of infection is contaminated soil, since the noticeable outbreaks most often take place after the flock has been turned out on the ground. Judging from the results we have obtained in artificially infecting young chicks it is reasonable to assume that a chick infected at hatching time by the ingestion of infectiA^e oocysts would develop the disease in a week or less. If the infection were severe a fatal hemorrhage should take place in about this time. This we have not noted. However, it is reasonable to expect that if infection did take place at hatching time, because of an infected egg it would be slight and might readily escape notice until later when re-infection from some other source, such as the soil, would be brought about as a result of the primary infection from the egg. Diagnosis of eoecidiosis can not be definitely determined without the microscope. Further, satisfactory diagnosis frequently depends upon the recognition of other forms than the oocyst. Bloody diarrhea is not a positive indication of eoecidiosis as is thought by some. I t is merely suggestive. Passing of considerable blood from the digestive tract of growing fowls and collection of considerable quantities in any part of the intestines is very indicative. The tendency toward hemorrhage decreases as the fowls grow older. Thickening of the intestine, particularly the duodenum, apparently occurs in fowls chronically affected with intestinal eoecidiosis. A caseated content of the ceea in growing fowls is frequently found, but it is not characteristic or necessarily associated with the disease. Emaciation is common with severe infection, especially chronic infection. Chronic cases, particularly growing fowls, frequently become so emaciated that the breast region is practically devoid of muscular tissue.
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Frequently flocks of young chickens are met with which show very good developnient and activity up to several weeks of age, but which suddenly break down with severe coceidiosis without anything unusual in regard to feeding and general care, im mediately preceding the development of the disease. The most vigorous as well as weaker fowls suffer—it does not seem to at tack particularly the weaker appearing ones. Coceidiosis has been produced experimentally at will in ap proximately one hundred young White Leghorn fowls of highproducing strains, thus they were representative of the fowl commonly found in connection with our commercial flocks. The fowls were from different sources, of varying ages and infected with material from different flocks. None of the fowls here referred to was older than forty days. In each instance inocula tion has been bv the mouth—the natural channel of infection.
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pmgs, however, have been noted by the Avriter only in eases of a very severe infection in fowls which had not yet attained matut·ity. Serious infection may exist without the droppings beiiii? bloodj' and in such cases they tend to be "watery." Effect of Vigor on -the Development of Coceidiosis. The im pression seems to have gained ground that devitalization or low ered vigor must precede coccidial invasion. Evidence on this point is certainly of much value and is therefore given here. On January 23, 1922, four White Leghorn chicks, twelve days old and which showed everj^ external indication of vigor, were placed in a cage. Three of these were each given, by the month, approximately 14 gram of cecal content taken from a four months old pullet July 19, 1921: The inoculation material con tained numerous oocysts with sporozoites. No. 1 inoculated chick was found dead on the morning of January 29, No. 2 and No. 3 died about 11 A. M. January 30. Autopsy showed in each case the rectum and ceca filled with blood and very noticeable hemorrhagic areas in these organs. Microscopic examination showed merozoites and schizonts present in large numbei-s. This is a typical example of Λvhat occurred to other vigorous youngchickens inoculated in a similar manner. The post mortem con dition noted in these fowls was identical with what has been found in many brought to the laboratory and which developed the disease naturally.
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Effect, of Moisture and Dryness on the Oocyst. Tests were made to determine the effect of moisture and dryness. Smears prepared by adding material containing oocysts freshly removed from the digestive organs to a drop of water will show a slight collapsing of many oocysts as soon as the excess moisture has evaporated at room temperature. After twenty-foui hours has elapsed many of the oocysts will show a distinct collapsing. Several days after preparing the smear many of the oocysts appear to hâve degenerated to the point of death. A small percentage appear to be unchanged, even after a number of days. These are of the early oocystal type which show the gra:nular content scattered throughout the cell and not in a contracted state. No sporulation takes place under such conditions of dryness, but it has been noted after days of drying that sporulation does take place in at least part of the oocysts if moisture, together with air, is supplied in proper amounts. Fecal material containing sporulated oocysts if permitted to dry at room temperature will show a considerable decrease in the percentage of definitely recognizable oocysts, but some appear to resist drying to a considerable extent and show but a slight collapsing of the oocystal wall and with sporocysts and sporozoites clearly visible. Such oocysts can be found in fecal material which has dried to such an extent that the material has become brittle. From this we can conclude that drying does have an effect in destroying coccidial oocysts, but that the action is somewhat delayed and that in tlie case of a small per-
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From the above it is safe to conclude that coccidiosis can be consistently produced in young White Leghorn fowls of high producing strains. I t is worthy of note that variable results have followed feeding contaminated material to older fowls, even fowls considerably under the age of maturity. It is reasonable to assume that devitalization brought about in various ways exer^ cises an influence on the development of coccidiosis, but it has not been demonstrated that this is necessary for the production of the disease, at least in very young fowls. We must therefore take cognizarice of the fact that we are dealing with an organism which possesses disease-producing power to a high degree, severity of the disease depending largely upon the amount of infective material ingested and the age of the fowl.
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centage of the oocysts it is questionable whether or not drying at room temperature has any appreciable effect, even after a prolonged period. Slides prepared by adding fresh oocystal material to a drop of water, covering this with a coverglass and sealing the edge of the coverglass to the slide with petrolatum will result in no change in the oocyst for a number of days— neither development nor discernible degeneration taking place. I n time, however, bubbles appear in the oocysts, indicatiijg degeneration. Oocysts exposed to the air for a time and then placed under a sealed coverglass do not cease developing as soon as placed under the sealed coverglass. Effect of Disinfectants. In an effort to determine the ef fects of some disinfectants upon Eimeria avium, fresh unsporulated oocysts were placed in 5%, 2.5% and 1% solutions of lye (Eagle brand) in water, others in 5% and 1% creolin in water and still others in lime water. Sporozoite formation took place to a very noticeable extent in all three lye dilutions. A fair percentage of the oocysts in the lime water showed sporo zoite formation and yet there was a noticeable destructive effect detected in many oocysts in which sporozoite formation was pre vented. Not a single oocyst in either of the creolin solutions was noted to show even sporozoite formation. Water was added to the 5% creolin tube and the mixture thoroughly shaken. This was then permitted to stand and settle for a time. The greater portion of the solution was then drained off. More wat er was added, the tube shaken and again permitted to settle. This fluid was then almost entirely removed and the " c u l t u r e " allowed to stand. No sporulation took place, indicating that the oocysts were dead, but still intact. I t is questionable wheth er or not creolin would be as effective or effective at all in the event of applying it to sporulated oocysts. TΛventy-four hours exposure of a culture of sporulated oocysts to a one per cent so lution of creolin did not result in destruction of virulence, as fatal coccidiosis (cecal hemorrhage) was produced in two threeweeks-old chicks on the sixth day following ingestion of such ma terial. Similarly a culture of sporulated oocysts exposed to lime water for twenty-four hours produced fatal hemorrhage in two three-weeks-old chicks, six days after being ingested. Avian Coccidiosis and So-called Blackhead in Turkeys.
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Coccidiosis Control. Sanitation is the foundation of eoc cidiosis control. Without adequate sanitation it is doubtful that the disease will ever be satisfactorily controlled for any consid erable period of time. The salient points to be considered in making provision for sanitary measures are: range, cultiva tion of the soil, change of yards and the maintenance of dry ness as much as possible. The inauguration of sanitary measures on an economic basis can not be expected to totally eliminate coccidian infection, but they should result in holding infection down to a low degree and permit of successful rearing. Further, we must remember that the same sanitary measures applied to control coccidiosis should also assist in overcoming other common intestinal infec tions. Treatment. In the light of present knowledge it seems improbable that any treatment alone can be relied upon to con trol coccidiosis satisfactorily. This does not mean to say that treatments are of no value, since we know some do assist in over coming the disease. Treatment is hopeless in chronic cases as sociated with emaciation. These cases are frequently unrecog nized until they are about of laying age and then their slow de velopment attracts attention. The condition of such fowls often is not readily determined by observation—one must handle them to fully appreciate it. Pullets of laying age showing emaciation
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Fantham^ makes the statement that "The disease (referring to eoccidiosis) in turkeys is known as blackhead" and some years ago Hadley'' was of the opinion that so-called blackhead in turkeys was a coccidian disease. More recently Hadley^^,^" has expressed himself as believing that it is not eoccidiosis but trich omoniasis. In examining turkeys at this Station some were found showing typical lesions of blackhead without any coccidial forms being observed upon microscopic examination of the in testinal content. In each instance, however, large numbers of both motile and encysted stages of a trichomonas have been noted. It can not be doubted that turkeys suffer with eoccidiosis pro duced by a species of the genus Bimeria and that a coccidium is frequently found associated with blackhead, but it seems im probable that the coccidium has a direct relationship to the pro duction of blackhead.
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should be culled. Those which are comparatively free at this ag» usually escape serious coccidiosis if given reasonable care and sanitary conditions, as they should by this time be quite resist ant to the infection, resistance developing Avith age. A number of drugs have been recommended as being effec tive or of value in controlling coccidiosis in poultry. No data have been noted in the literature which definitely establish the value of any of them. In the year 1912, Meyer and Crooker made an effort to determine the effect of some drugs which have been used for coccidiosis control. These were, namely : Turpen tine mixed with castor oil, potassium permanganate; a mixture of iron sulphate and glycerine ; suphocarbolates ; methylene blue and calomel. The above mentioned writers concluded, " t h a t calomel and methylene blue are undoubtedly capable of prolong ing life, ' ' and also that ' ' a specific chemo-therapeutic action can, in our opinion, be excluded. " Fatham (1915)," and Beach (1917)," claimed that sour skimmed milk or buttermilk given in cases of coccidiosis are of value in controlling the disease. The writer's experience has shown that some flocks given no water and only sour skimmed milk or buttermilk to drink together wdth mixed grains and with or without mash have not responded to treatment and also have actually developed the disease when such a feeding plan was in effect. In an attempt to obtain further evidence relative to the ef fect of sour skimmed milk on Bimeria avium in the chicken, four vigorous White Leghorn chicks (3 cockerels and 1 pullet) hatched January 1, 1922, were placed in a cage on February 2, 1922 and given nothing but sour skimmed milk to drink and chick grain. February 3, 1922, 4:00 P. M. three of the chicks (2 cockerels and the pullet) were each inoculated by the mouth with approximate ly 1/4 gram of cecal content taken from a four months old pullet autopsied July 19, 1921. This material showed large numbers of oocysts with spores at this time. February 9, 1922, 8:00 A. M., considerable blood was noted in the cage. Pure blood was being discharged from the intestinal tract. No droopiness was noted at this time. At 10:30 A. M., February 9, all three in fected chicks showed slight droopiness. Uninfected chick looked well. Number 1 died night of February 9, number 2 at 1:00 Ρ
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One should not conclude from the above that sour skimmed milk is of no value until further work has been done. Certainly its use is of limited value in controlling this disease. It might be stated that flocks so fed seem to show some improvement as a result of such treatment. " Since Epsom salts^* have also been recommended as a cure for coccidiosis the following was undertaken to note what effect the drug might have : On May 3, 1922, nine White Leghorn chicks which had just been hatched in an incubator were placed in a cage. The feed consisted of chick grain, mash composed of purified bran (2 parts), red dog flour (§4 part) and corn feed meal (1 part). The mash was fed moistened. Sour skimmed milk and water were supplied at all times. At 4:30 P. M., May 10, three of these chicks were each given, by the mouth, approximately 1/15 of a gram of a culture prepared March 13, 1922, by using the cecal content of a pullet six weeks of age. Oocysts with spores were present in ' fair numbers. Three chicks were left as checks and three were used for other inoculation work. At 5:00 P . M., May 10, all the chicks were given a wet mash made by dissolving 6.0 grams of epsom salts in water and this used to moisten the mash. This amount of epsom salts was considered to be a fairly heavy dose. No. 1 (infected cockerel) was killed at 9:00 A. M., May 22.. A smear from the cecal mucosa showed coccidial forms in large numbers, including 500 oocysts, under an 18 millimeter cover glass. No. 2, (infected cockerel) was killed 9:30 A. M., May 22. A smear from the cecal mucosa resulted in finding approximately 3,000 oocysts under an 18 millimeter cover glass. In one microscopic field approximately 500 oocysts were noted under the 16 millimeter ob-
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M., February 10. In both cases the rectum and ceca were filled Avith blood. Microscopic examination of the cecal mucosa and content revealed asexual and sexual forms of Eimeria avium, including many trophozoites and myriads of merozoites. Number 3 infected chick was very droopy and unable to stand most of the time February 10. This chick was considerably improved. 4:00 P. M., February 11. Number 3 was killed February 18 and showed numerous early stages of gametogony and a few oocysts. It is doubtful that chick number 3 would have lived and developed properly.
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1 Schultz, C. H. (1915). Observations among dairy cattle. Article read at the Annual Convention of the Wash. State Dairymen's Assn. 2 Idem. (1915). Coccidiosis in Cattle and Caraboas. Reprint from The Jour, of Infect. Dis. Vol. 17, No. 1. 3 Saunders, Charles G. (1919). Coccidiosis in Rabbits. Amer. Jour, of Vet. Med. Vol. 14. No. 9. * Meyer, K. F. and Crocker, W. J. (1913). Some Experiments on Medicinal Treatment of Coccidiosis in Chickens. Amer. Vet. Review. 5 Fantham, H. B. (1915). Coccidiosis in Poultry and Game Birds. Jour, of the Board of Agri. London, Vol. 21, No. 10. β Hadley, P. B. (1910). Blackhead in Turkeys: A study in Avian Coccidiosis, Rhode Island Sta. Bui. 141. 7 Idem. (1910). Studies in Avian Coccidiosis. 3. Coccidiosis in the English Sparrow and Other Wild Birds. Reprint from Abdruck aus dem Centralblatt fur Bakteriologie, Parasitenkunde und Infektionskrankheiten, 56 Band. 8 Doflein. (1911). Lehrbuck Der Protozoenkunde. 3rd Ed. 9 Butschlii. 1880-82). Protozoen. Vol.1. loDobell; C. A. (1919): Revision of the Coccidia Parasitic in Man. Parasitology. Loiidpn, Vol. 11, No. 2. 11 Chandler, W. L. (1919). Coccidiosis. Mich. Ag. College Quarterly Bui. Vol. 2, No. 1.
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jective. No. 3 killed May 22, showed approximately 5,000 oocysts under an 18 millimeter cover glass, about 500 being seen under the 16 millimeter objective in one field. To date the most effective treatment^ in our hands, as determined by placing chicks in cages, starting treatment and then infecting them, by the mouth, has been the use of crude catechu in the amount of % to one gram of the drug to each gallon of drinking water for a period of ten to fourteen days. The drug is best added to a small quantity of water first. Such water is as readily consumed as the unmedicated. The present retail price of this drug is about fifty cents a pound. Prescribing it in the above amounts two thirds to one ounce makes thirty gallons of medicated water. I t is not advisable to continue the use of this drug for long periods, since it has a slightly constipating action. In conclusion, it is only fair to state that the purpose of this paper has been to present a few important points bearing on coccidiosis in poultry and to serve as an aid toward establishing our knowledge of this problem on a firmer foundation than has existed in the past.
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i2podd, Sydney. (1917). Coccidiosis in Poultry. The Agri. Gazette of New South Wales. Sydney, Par.t 12. i3Reid, H. A. (1920). Coccidiosis of Poultry. The New Zealand Jour, of Agri. Wellington. Vol. 11, No. 6. "Morse, Geo. Byron (1908). White Diarrhea of Chicks with notes on Coccidiosis in birds. U. S. Dept. of Agri., B. A. I. Cir. 128. isHadley, P. B., (1916). The avenue and development of tissueinfection in intestinal Trichomoniasis. Rhode Island Sta. Bui. 168. leidem. (1916). The role of the Flagellated Protozoa in Infective Processes of the Intestines and Liver. Rhode Island Sta. Bui. 166. "Beach, J. R. (1917). Bacillary Wlhite Diarrhea or Fatal Septicemia of Chicks and Coccidiosis or Coccidial Enteritis of Chicks. Calif. Sta. Cir. 162. 18 Charles, T. B. (1921-22). Practical Experiences in the Control of Coccidiosis in Young Chicks. Poultry Science. Vol. 1, No. 2.