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Pigeon Therapeutics
THERAPEUTICS
1094-9194/00 $8.00 + .00
PIGEON THERAPEUTICS Roger W. Harlin, DVM
The association of humans with pigeons and doves dates back to as early as 3000 to 5000 BC. Other birds were bred for meat and egg production, but pigeons are thought to have been fept to aid agriculture. Their ability to fly long distances, select the richest nutrients, and then return to the same nesting place, made their droppings an easily collect ible source of rich fertilizer for growing crops in arid climates and on infertile land. As time went on, humans found more uses for pigeons. Best known is the part they played in communication during wartime before the invention of the wireless. Throughout history, the more ad vanced the civilization, the closer the association of humans with pi geons and doves. Pigeons are classified as flying and performance, fancy, or utility pigeons. There are standards of perfection for exhibition of almost 300 breeds of fancy pigeons. All breeds are derived from the common rock dove (Columba livia). Most of the pigeons kept are Racing Homers, trained to compete in the sport of racing. Other breeds, such as Tipplers, High Flyers, Rollers, Nose Divers, and Doneks are bred for their aerial acrobatic abilities. Pigeon meat, or squab, is still considered a delicacy in many parts of the world. Some utility breeds are capable of producing 12 to 16 pounds of meat yearly. In contrast, other breeds produce four to six young per year. Major portions of this manuscript are excerpted from Harlin RW: Pigeons. Vet Clin
North Am Small Anim Pract 24:157-173, 1994.
From the Southside Dog, Cat, and Bird Hospital, Oklahoma City, Oklahoma VETERINARY CLINICS OF NORTH AMERICA: EXOTIC ANIMAL PRACTICE VOLUME 3 • NUMBER 1 • JANUARY 2000
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HARLIN
PHYSIOLOGY AND REPRODUCTION Although pigeons usually mate for life, most birds will readily take a new mate after a short period of separation. A system of polygamous breeding called the "bull system" is often used to breed numerous hens to a prepotent cock. Eggs are fostered to feeder pairs. This system can yield two babies from the favored cock every 2 to 3 weeks, whereas natural pair methods will yield two youngsters at most every 6 to 7 weeks. The breeding season is in the spring. Pigeons lay two eggs about 40 hours apart. Incubation is 17 to 19 days. The cock assists in incubation from late morning to midafternoon. Several days before the eggs hatch, "crop milk" formation is stimulated by prolactin secreted from the pituitary gland. An actual desquamation of the crop epithelium, crop milk is very rich in protein and fats and is all that squabs receive from the parents for the first week. During the second week, grains and other food are regurgitated by the parents, and the production of crop milk ceases. The cock plays a role equal to or greater than that of the hen in feeding the squabs, particularly if the hen has begun incubation of the nest clutch naturally at about 4 weeks of age. Some fanciers believe that earlier weaning makes for a more resourceful older bird. Others prefer to leave the squabs in the nest longer, believing that extra help from the parents is beneficial. A pair typically produces two to three clutches per season. Pigeons reach maturity between 5 and 12 months of age, depending on breed and birth date. Toy breeds born early mature faster than late hatch giant breeds. Mature body weight ranges from 150 to 180 g in breeds such as the African Owl, to over 1400 g in the American Giant Runt. Most Racing Homers weigh about 360 to 480 g. Pigeons have paired vestigial ceca and no gallbladder. The normal white blood cell count ranges from 8000 to 18,000 cells/mm3 and is generally 12,000 to 15,000 cells/mm3 • The normal red blood cell count is 3 to 4 million/mm3 • Total protein should be between 2 to 4 mg/dL. Body temperature is about 105°F.
HOUSING Pigeon houses are called lofts. Pigeons do not require elaborate facilities; however, the birds are more comfortable and productive if a loft is designed specifically for breeding, racing, or whatever the fancier wishes to accomplish. Lofts must be dry. Pigeons can tolerate extreme temperatures, but moisture and dampness certainly will result in illness and poor perfor mance. Lofts must be well ventilated but without direct drafts. Respira tory problems are seen in pigeons kept in tightly closed structures in which the air is stale and dust builds up. The ideal loft is built 1 to 2 feet above dry ground with wire floors.
PIGEON THERAPEUTICS
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Ceiling vents provide good ventilation. A wire floor prevents direct contact with the droppings. Sand, cedar shavings, and many other litters have been used successfully. Some fanciers use a natural litter (dropping buildup), and their birds do well. The natural litter must be absolutely dry and should be used only in a closed flock. Generally, the cleaner the loft, the healthier the birds; however, there is evidence that a completely sterile loft is not optimal, because low-level contact of healthy birds to avirulent strains of coccidia helps to maintain immunity. Pigeons love to "own" property and raise families. It is this love of mate, loft, nest, and perch space that inspires them to excel as avian athletes. They will fly hundreds of miles under any conditions to be "home." Too many birds in too small a place destroys their morale. Overcrowding is the worst enemy of pigeon health. The fancier must judge whether certain pigeons are affecting the quality of life of others. Sometimes troublemakers have to be removed from a particular pigeon society. Happy pigeons in clean, well-ventilated lofts are generally healthy pigeons that seldom require medication. NUTRITION
Proper nutrition is essential if pigeons are to maintain good form and resistance to disease. Nutritional requirements vary greatly ac cording to season, molting, growth, breeding, and the demands of per formance or racing. Simple logic and common sense suggest that increased protein is important to growing squabs and is not as important to inactive birds in winter. More carbohydrates are beneficial in wintering birds in cold climates, because caloric needs are increased. Higher fats and protein are helpful during the moult to enhance feather quality and growth. Racing demands a judicious feeding schedule. The requirements vary with distance and race conditions. For instance, more fats can help a bird to fly 500 miles in headwinds, whereas more carbohydrates and being a bit hungry can enhance the performance of a 150-mile sprinter. There are several commercial pelleted rations and blends of grains. Following the instructions and recommendations of reputable companies is usually satisfactory; however, most fanciers have their own ideas and make additions and corrections to commercial products. Austrian, ma ple, and Canadian peas are among the best protein seeds. Safflower seeds and Spanish peanuts are often used to supplement fats before races. Barley, wheat, and corn are good carbohydrate grains for winter. These grains are usually included in mixtures in varying amounts, along with milo, kaffir, millet, oat groats, and many others. Grit can be offered, although it is probably not necessary. Many minerals are available in the balanced pelleted rations. . � unsupplemented breeder diet of only grains, without calcium, vitarruns, and trace minerals, most likely will result in defective squabs.
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HARLIN
PREVENTIVE MEDICINE
Medications are rarely necessary if these guidelines are followed by the pigeon fancier: 1. Buy quality stock from a quality breeder. Do not introduce new birds into an existing healthy flock until they have been quaran tined and physically examined. The optimal length of quarantine is the time for a pair to raise two or three sets of babies. When quarantine is over, introduce one pair at a time to the existing flock. Allow each pair to establish territory before adding the next pair. This method minimizes the stress of pairs finding a place in the loft. 2. Examine all new birds for ectoparasites such as lice mites and pigeon flies. Perform fecal flotation and direct smears to check for helminths and coccidia. Examine throat aspirates for tricho monads and blood smears for Hemoproteus. If test results are negative, do not administer any medications, because evidence suggests that some drugs cause immunosuppression. 3. During quarantine, vaccinate all new acquisitions for paramyxo virus 1 (PMVl). Salmonella vaccination is optional and is of questionable efficacy. Vaccination for pigeonpox is ideally done after the other vaccines, because birds will have an active case of pox that can decrease the immune response to other vaccines if these are given concurrently. Some practitioners administer all three vaccines at the same time with no apparent ill effects, however. 4. Vaccinate all young birds at least 6 to 8 weeks before racing or show season. Do not add unvaccinated birds to the flock at this time because they could contract clinical poxvirus infection. 5. Keep the pigeons in a clean, dry, well-ventilated loft. Do not overcrowd. Feed the birds according to their needs. If problems arise, seek a diagnosis prior to administering medications. Viral Diseases
Viral disease is probably much more common than actually diag nosed in pigeons. Most infections cause only mild illness, but subclinical infections can complicate the disease processes caused by other patho gens. Because the presence of viruses usually is confirmed on necropsy, other pathogens (e.g., protozoa, gram-negative bacteria) are more likely to be implicated as the etiologic agents. Excluding PMVl and pigeonpox virus, herpesvirus and adenovirus are the most notable pathogens; however, reovirus, rotavirus, togavirus, arbovirus, and influenza virus infections have been suggested as causes of immune system compromise.
PIGEON THERAPEUTICS
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Pigeon Herpesvirus
Many pigeons are immune carriers of the pigeon herpesvirus (PHV ) and once infected are life-long carriers, sometimes shedding without clinical signs. Young birds are most susceptible to clinical illness, but immunocompromised older birds can show symptoms. A mild to necrotizing pharyngitis and especially esophagitis are the primary symptoms. Diphtheritic membranes and general signs of illness, including neurologic symptoms, green droppings, and anorexia, can suggest PHV infection. Vomiting with no other symptoms and inclusion body hepatitis can occur. Adenovirus
Adenovirus infection has been shown to c;ause primary illness in pigeons. Young birds are most susceptible, and the symptoms are as would be expected with hepatic necrosis of any ca.use. Treatment is supportive. Antibiotics are indicated for prevention of secondary bacterial infection. Protozoa! and helminth parasites should be eliminated and adequate hydration and nutrition provided. Paramyxovirus
Although it has been a problem in Europe and many other parts of the world for a long time, PMVl has been a problem in North America since 1984 and has spread over the whole continent since 1987 or 1989. Fanciers with absolutely closed flocks are at the lowest risk; those who race their pigeons frequently, buy, sell, trade, or allow contact with feral pigeons are most likely to have infected flocks. The primary symptoms are polyuria (not diarrhea) and central nervous signs, ranging from incoordination, difficulty picking up grains, and mild head tilt, to severe ataxia and torticollis. Surprisingly, affected pigeons do not seem to feel very ill and most eventually recover if given long-term supportive care. The most severely affected birds are unable to feed well enough to maintain bodyweight, and euthanasia could be in order. Immune carriers are possible, and old and especially young birds are most susceptible to infection. Viral shedding can precede clini cal signs, and incubation has been suggested as lasting from 1 week to as long as 6 weeks. The author recommends expedient vaccination of all birds, includ . mg young birds, in the face of an outbreak. Devastation in outbreaks has been minimized by vaccination, suggesting that incubation is long (2 to 4 weeks) or that other factors cause a moderate to slow spread in a flock. Elimination of parasites, good nutrition, and loft cleanliness promote the strength of the pigeon's immune system.
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HARLIN
Vaccination 1 to 2 months before breeding season and 6 to 8 weeks before racing or showing with the oil emulsion vaccine sub Q is recom mended. The author vaccinates his young bird racing team on weaning. The Lasota oral vaccine should not be depended on for adequate protection. Pox
Pox virus is found in saliva and in nasal and lacrimal secretions. It enters the body through defects in the skin, especially on the wattle or cere. Direct contact, insect vectors, or airborne secretions can spread the disease. Scabs and proliferations of the cere, wattle, legs, feet, and commissures of the beak occur. The first symptoms are usually conjunctivitis with excess lacrima tion and swelling of the eye cere. A diphtheroid form can occur, causing lesions on the mucosal surface inside the mouth. Secondary bacterial invasion can cause proliferative lesions, obstructing respiration and mak ing eating difficult. Treatment of infected birds is strictly supportive. Preventive mea sures (including practicing strict sanitation; providing proper nutrition; and using antibiotics, antihelminthics, and coccidiostats) should be taken in the event of an outbreak. Isolation of infected individual animals and insect control using screens or insecticides can slow the spread. Birds develop an immunity 3 to 4 weeks after administration of a commercially available vaccine. Feathers are pulled, and the vaccine is applied by a dropper or a brush. The wing web is an acceptable site. An inflammatory reaction at the site suggests successful vaccination. Birds as young as 4 weeks of age can be vaccinated, and annual vaccination is recommended 4 weeks before the mosquito season. Care should be taken not to introduce new birds into an already vaccinated loft. The incidence of pox varies greatly from year to year and by geographic area. Late summer and fall, especially in years when the first freeze comes late, increases the chances of an outbreak. Circo Virus
Circa virus, a relative to psittacine beak and feather disease virus and chicken anemia agent, has been recognized since 1986 and reported in the United States since 1990. The victims are usually young birds 2 months to 1 year of age. Clinical signs are anorexia, lethargy, diarrhea, rapid weight loss, inability to fly, sneezing, respiratory distress, and death in 3 to 5 days. The incubation period is best estimated at about 2 weeks. The circa virus generally has an immunosuppressive effect, allowing several concurrent infections to cause the demise of its victim. Among them are
PIGEON THERAPEUTICS
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Pasteurella, herpes virus, chlamydia, trichomonas, adenovirus, aspergil lus, and colibacillosis. It is the author's belief that the incidence of this viral illness is more common than reported. Often the concurrent agents previously mentioned are determined to be the cause of the illness, when they might have only been opportunistic. It is suggested that the bursa be included with liver, spleen, and other tissue for histopathology in suspected viral illnesses. Virus Hepatitis Since 1992, an acute hepatic disease in pigeons has occurred in Europe. The syndrome is very much like Pacheco's disease in parrots, except that there are no inclusions in the hepatocytes and the agent has yet to be identified. Old and young birds are affected. The birds are sick for 24 to 48 hours and they either die or recover without treatment. Some birds develop yellow slimy droppings and foul-smelling vomitus. The symptoms can contin�e for a course of 3 to 4 weeks. The mortality rate is about 30%. Hepatomegaly (pale in color) and complete destruction of all liver cells is found on postmortem and histopathology. Treatment is supportive only. BACTERIAL INFECTIONS The most important bacterial disease of pigeons and doves is paraty phoid, caused by Salmonella typhimurium var. Copenhagen. The best known symptom is swollen wing and leg joints ("boils"), which should be considered almost pathognomonic by the practitioner when observed. Most pigeons with paratyphoid present with an array of other symp toms, however, including anorexia, weight loss, ruffled feathers, dropped wings, refusal to fly, diarrhea, green droppings, reproductive problems such as embryonic or early squab death, or death of older birds. Diagnosis is made by demonstration of the organism from the live bird or on necropsy. Selenite broth onto MacConkey's or brilliant green agar are suitable for recovering the organism from intestinal or crop contents. Treatment should be determined by sensitivity testing, because many strains exist with variable drug susceptibility. Enrofloxacin has demonstrated the most consistent efficacy record, although members of the penicillin, tetracycline, and aminoglycoside families sometimes can be suitable choices. Prevention is far superior to treatment. Before introducing new stock into a disease-free loft, birds should be quarantined in individual cage _ s_ until they have raised a nest of healthy young. Cleanliness, acidi fication of floor litter, and strict control of stray pigeons are also helpful measures. Vaccination with a killed bacterin may be beneficial.
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Colibacillosis is another important problem in pigeons. Disease syn dromes previously attributed to paratyphoid recently have been shown to be caused by E. coli when proper diagnostic tests were done. Exclud ing the swollen wing and leg joints, the symptoms of the two diseases are very similar. Other bacteria, such as Streptococcus, Staphylococcus, Pasteurella, He mophilus, and Pseudomonas, have been described as pathogens but are of lesser importance than Salmonella and E. coli. Treatment of all bacterial diseases should involve cultures and sensi tivity testing. Often, fanciers and veterinarians "shotgun" flocks with antibiotics, resulting in many resistant strains of bacteria and many immunosuppressed pigeons. Streptococcus Bovis
An acute or even peracute death in pigeons has been attributed to Streptococcus bovis. The primary symptom is inability to fly (or deviant flying behavior) and dropped wings. Others have green foamy drop pings and sometimes loss of appetite, polyuria, polydipsia, and swollen abdomen. The acute disease is a septicemic disorder. Old and young birds are affected, but young birds often have pericarditis, and old birds often have yellowish breast muscles. A chronic lameness has been reported from Streptococcus bovis. The disease can easily be mistaken for paramyxovirus or salmo nellosis but is usually more acute. Amoxicillin is an effective treatment if instituted early enough. The Ornithosis Compl ex
The ornithosis complex ("eye colds" or "one-eyed roup") is common in domestic pigeons. Chlamydia is the primary causal agent, but myco plasma and gram-negative bacteria are also involved. Many herpesvirus infections are also complicated with chlamydia, so viral agents probably should be included in the complex. Frequently the same eye of all affected birds is in the windward side of wind currents. Treatment is usually successful with tylosin, but tetracyclines, linco mycin, or erythromycin are also effective. Intramuscular injection is very irritating and should be avoided in racing birds. Oral administration and sinus flushing of antibiotics can be the best methods of treatment. Supportive therapy reduces stress and enhances immune response. Topi cal ophthalmic medications are also of benefit. PARASITIC DISEASES Endoparasites
Nematodes are the primary endoparasitic problem of pigeons. Asca rids, Capillaria, tetrameres, ornithostrongylus, and dispharnyx are of
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concern; geographical location determines the particular species that a clinician will encounter. Cestodes are occasionally encountered, and trematodes are rarely, if ever, found in the United States. Diagnosis is made by fecal flotation, direct smear, or intestinal or proventricular scrapings on necropsy. Cestode proglottides can be shed after food deprivation. Because cestodes and some nematodes (e.g., Tetrameres) require intermediate hosts (e.g., pill bugs), care should be taken to prevent pigeons from foraging where these organisms are found. Raised lofts are the commonest sites where pigeons are infected. Piperazine is effective only for ascarids. Fenbendazole and meben dazole are effective for ascarids, Capillaria, and probably other parasites that feed on blood or body tissue but must be used for 3 days. Levami sole is effective against ascarids and has some value against Capillaria. Ivermectin is most effective against all nematodes, but other drugs could be better for ascarids (e.g., pyrantel pamoate). Praziquantel is the drug of choice for cestodes and trematodes. Ectoparasites
Pigeon flies, lice, and mites are the most significant ectoparasites of pigeons. Pseudolynchia carariensis, the pigeon louse fly, seldom flies. It spends most of its time feeding on the bird's blood, causing anemia and transmission of Hemoproteus. Louse flies cause considerable discomfort to the bird and can be devastating to the general health of a flock. Columbicola columbae, the slender pigeon louse, is the commonest mallo phagian parasite. It does not take blood but feeds on feathers, causing tiny pinpoint holes. When lice are found by the clinician, other diseases should be considered. Heavy louse infestations usually indicate a debili tated bird that might not feel well enough to groom properly. Dermanys sus gallinae and possibly Ornithonyssus sylvarum cause skin irritation and feed on blood. They are called red mites or roost mites and are found on the bird at night. Knemidocoptes mutans, the scaly leg mite, causes considerable skin damage. Ivermectin is very effective for ectoparasites that feed on blood and body tissues and is recommended with dusting or preferably dipping with pyrethrin products. lvermectin and pyrethrin are effective against lice when used properly. Coccidia
The role of coccidia as a primary pathogen remains controversial b�cause oocyst shedding is commonly found in healthy birds. Often, pigeons afflicted with other diseases or under stress shed large numbers of oocysts, particularly young birds. The physical examination should not end when fecal flotations reveal oocysts but should be thorough in eliminating bacterial pathogens, trichomoniasis, nutritional deficiencies, husbandry errors, and helminths.
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Evidence indicates that low-level exposure to mildly virulent strains of coccidia can help to produce immunity to more pathogenic strains. Many considerations should be taken into account before instituting therapy with coccidiostatic drugs. When a disease situation involving coccidia occurs and drugs must be used, sanitation and good husbandry to prevent fecal-oral contact should be the first therapy instituted. Heavily bred or heavily raced older birds and young birds kept under less than optimal conditions are the most susceptible to disease. Clazoril, amprolium, sulfachlorpyridazine, and other sulfas (e.g., sulfadimethoxine and sulfamethazine) are effective coccidiostats. Vita min B supplementation after therapy is beneficial. Nitrofurazone can help with secondary bacterial enteric infections but is not recommended for coccidiosis in pigeons. Three to five days are required for the oocyst to sporulate and become infective, so that frequent cleaning is the best preventive measure.
Trichomoniasis Most pigeons and doves carry Trichomonas gallinae. This parasite can be a primary pathogen or cause disease secondary to other illnesses or stressful conditions. The severity of trichomoniasis depends on the virulence of the strain and the magnitude of debility from concurrent diseases. The common name "canker" refers to the cheesy, white caseous deposits in the throats of birds with advanced disease. More often the condition is confused with respiratory diseases because the oculonasal and oral discharges are clear. The organism can easily be demonstrated by suctioning the mucus from the throat and immediately observing the sample with immersion microscopy. Trichomonas g. often accompanies the ornithosis complex, viral ill nesses, parasitic diseases, and noninfectious stressful situations. Success ful therapy involves resolving the other diseases as well as treatment of the trichomonads. The immune status of the bird is important to con sider if recovery is to be expected. Exposure to strains of low virulence in an immunocompetent bird can produce resistance against patho genic strains. Although Trichomoniasis is primarily a disease of the upper alimen tary tract, local lesions, including omphalitis, can occur, as well as infection of liver, lung, and other organs. Effective treatment involves proper use of the 5-nitroimidazole de rivatives, including ronidazole, carnidazole, dimetridazole, and metroni dazole. Prevention depends on reducing stress and controlling other dis eases. Total eradication of the organism is not practical or desirable.
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Hemoproteus
Pigeon malaria is the name frequently given to hemoproteus infec tion, but Plasmodium spp. are rarely reported in pigeons. It is much commoner in performing breeds than in fancy or utility pigeons, perhaps because the stresses and exposure to insect vectors in racing situations make the disease more apparent in racing pigeons than in sedentary exhibition pigeons. The disease is transmitted by the pigeon fly. Hemo proteus infection is diagnosed by demonstration of the organism in the red blood cell's cytoplasm without nuclear displacement, as shown on stained blood smears. Control of insect vectors is the best prevention. Dusting or dipping with pyrethrin every 2 weeks can be effective in controlling pigeon flies in endemic areas. The disease has been effectively treated with quina crine. Primaquine has been successfully used as a preventative. Hexamita
Hexamitiasis occurs primarily in young pigeons. Symptoms include weight loss, diarrhea, and general unthriftiness, and demonstration of the organism on very fresh direct fecal smears is diagnostic. The nitroimidazole derivatives, carnidazole, dimetridazole, ronida zole, and metronidazole are the most effective antiprotozoal drugs. Car nidazole is the drug of choice. Preventing fecal-oral contact is helpful in controlling hexamitiasis. Address reprint requests to Roger W. Harlin, DVM Southside Dog, Cat, and Bird Hospital 7020 South Shields Oklahoma City, OK 73149
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Table 1 . ANTI BIOTICS
Medication
Dosage
Route of Administration Nasal flush
Amikacin
PO
Amoxicillin
100 mg / kg b.i.d. 2-3 g / gallon
Drinking water
Amoxicillin / clavulanic acid
125 mg / kg b.i.d.
PO
Carbenicillin
100 mg / kg b.i.d.-t.i.d.
IM
Cefadroxil
100 mg / kg b.i.d.
PO
Cefotaxime
100 mg / kg b.i.d.-t.i.d.
IM
Ceftidime
100 mg / kg b.i.d.-t.i.d.
IM
Cephalexin
100 mg / kg b.i.d.-t.i.d.
PO
Chloramphenicol
60-100 mg / kg t.i.d. 250 mg / kg q.i.d. 1 drop t.i.d.-q.i.d.
IM PO
Chlortetracycline and oxytetracycline Doxycycline
50 mg / kg t.i.d.-q.i.d. 1000-1500 mg / gallon-In warm weather mix fresh b.i.d. 25-50 mg / kg b.i.d.
Ophthalmic drops
PO
Drinking water
PO
Uses and Comments Useful with difficult aerobes (Pseudomonas); seldom used systemically in pigeons owing to toxicity and rapid excretion Good for animal bite wounds and postsurgical wound care Nontoxic Better spectrum against Staphylococcus sp. than amoxicillin Based on culture and sensitivity; good spectrum against gram-negative bacteria Based on culture and sensitivity or when Staphylococcus sp. is suspected Excellent gram-negative spectrum, especially against E. coli Excellent drug lung levels; similar activity to cefotaxime but may be more effective against Pseudomonas sp Based on culture and sensitivity or when Staphylococcus sp. is suspected Good penetration into all body tissues, including CNS; chlamydiostatic properties and good gram negative spectrum Use with caution owing to possible irreversible anemia in humans associated with contact Best used in combination with tylosin for ornithosis complex (see text); calcium inhibits absorption therefore grit and layer pellets should be withheld during treatment Drug of choice for chlamydiosis; especially Tylosin
Enrofloxacin
12-15 mg / kg b.i.d. 7-14 days 22 mg / kg b.i.d. 45 mg / kg s.i.d. 150-600 mg / gallon 7-14 days
IM PO PO Drinking water
Erythromycin
125 mg / kg t.i.d. 2-3 g / gallon 1 drop q.i.d. See comments
PO Drinking water Ophthalmic drops Nasal flush
Piperacillin
100 mg / kg b.i.d.-t.i.d.
IM
Spectinomycin
25-35 mg/ kg b.i.d.-t.i.d. 600-1000 mg / gallon 1200 mg / gallon 7-10 days
IM Drinking water Drinking water
1250-1500 mg/ gallon on first day followed by 750-1000 mg/ gallon for 4 days 1500 mg / gallon on first day followed by 750-1000 mg/ gallon for 4 days 60 mg / kg b.i.d. 1 800-3600 mg / gallon for 7-10 days 25-50 mg / kg 3 g / gallon (2 tsp)
Drinking water
Gentamicin
Sulfachlorpyridazine Sulfadimethoxine Sulfamethazine Trimethoprim / sulfadiazine or sulfamethoxazole or sulfademethoxine / ormetoprim Tylosin
....
V,
Drinking water
Excellent in respiratory infections; drug of choice for Salmon ell a typ himurium; dru g most likely to eliminate paratyphoid carrier states; some adverse effects reported in breeding hens and squabs (not experienced by author) Injectable use is very irritating to muscle Useful for difficult aerobes (Pseudomonas); seldom used systemically in pigeons due to toxicity and rapid excretion; author mixes equal volumes with lincomycin and flushes nostrils using an open ended tomcat catheter Drug of choice for critically ill patients with bacterial intestinal disease; often used in combination with quinolones Poorly absorbed orally; good gram-negative spectrum especi ally against E. coli Broad-spectrum antibiotic, very effective against E. coli and is a good coccidiostat Broad-spectrum antibiotic and coccidiostat; supplement B vitamins for 5 days then retreat; half-life in pigeons longer than other sulfas Broad-spectrum antibioti c and coccidiostat; supplement B vitamins for 5 days then retreat
PO Drinking water
Broad-spectrum antibiotic and coccidiostat; consider H20 consumption
IM or SQ Drinking water
Mycoplasmastatic and bacteriostatic with little efficacy against gram-negative bacteria; very irritating to muscle when injected; drug of choice for ornithosis complex (see text) when used with tetracyclines; low toxicity potential
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Table 2. ANTI FUNGALS Medication
Dosage
Route of Administration
Uses and Comments
Nystatin
100,000 U / kg b.i.d.
PO
Candidiasis
Table 3. ANTI PARASITICS
Dosage
Medication
Uses and Comments
1 tsp / gallon [20% powder] 3-5 days 8 mL / gallon [9.64% solution] 3-5 days 20 mg / kg once
Drinking water
Coccidiostat good for asymptomatic birds when attempting to alleviate oocyst shedding
PO
Claxoril
5 mg / kg once 2.5 mg tablet per Racing Homer-sized bird,
PO
Antiprotozoan compound; only drug labeled for use in pigeons in the United States Coccidiostat; stops shedding of oocysts for up to 2 wk
Dimetridazole
¼-½ tsp / gallon 3-5 days
Drinking water
Fenbendazole
10-12 mg / kg s.i.d. for 3 days
PO
lvermectin
0.5-1 mg / kg once
PO or IM
Levamisole
40 mg / kg once 1000-1500 mg / gallon for 24 hours 35 mg / kg for 2 days 300 mg/ gallon for 2 days 1-2 tablets / gallon for 10-21 days before racing then 1-2 days weekly 20-25 mg / kg 1-3 tablets / gallon for 10-21 days 400 mg / gallon for 3-5 days (½-¾ tsp)
PO Drinking water PO Drinking water Drinking water
Amprolium Carnidazole
Piperazine Primaquine Pyrantel pamoate Quinacrine Ronidazole v.l v.l
Route of Administration
once
Good antiprotozoal activity; CNS symptoms if overdosed (Canadian product); consider water consumption of flock; in hot weather use lower dose and in cold weather use higher dose Capillaria, ascarids, strongyles, and tetrameres; feather abnormalities have been reported when used during molt Anthelmintic of choice except when treating tapeworms and ascarids; effective for mites and lice that feed on body tissues; feather lice when sprayed on topically Very effective against ascarids and moderately effective against other nematodes Ascarids only; seldom used due to newer, superior anthelmintics .....,. For control of Hemoproteus; will not alleviate parasite; controls pigeon flies; treatment of choice for prevention
PO Drinking water
Roundworms Hemoproteus; controls pigeon flies
Drinking water
Protozoa! diseases; not available in the United States.
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Ta ble 4. VACCI N ES Vaccine
Route of Admin istration
Paramyxovirus (PMVl )
SQ lower 113 of neck on dorsal midline SQ cranial to thigh
Salmonella
SQ lower 113 of neck on dorsal midline SQ cranial to thigh
Poxvirus
Pull feathers from wing web or leg and apply with dropper or brush Can be placed onto a scrape-created on skin over breast area
Comments 1-2 mo before breeding season and 6-8 wk before racing or showing. Author vaccinates racing team birds on weaning and boosters 1-2 mo before racing or showing. Vaccination in the face of an outbreak can reduce losses. Pigeons have an extensive venous plexus around the neck that should be avoided when vaccinating. Questionable efficacy due to Salmonella strain variety but author's experience has been favorable in confirmed cases. Pigeons have an extensive venous plexus around the neck that should be avoided when vaccinating. First vaccine given to birds as young as 4 wk old. Annual vaccines recommended 4 wk before mosquito season. Inflammatory reaction at site suggests successful vaccination. Do not add unvaccinated birds to a vaccinated loft.
1094-9194/00 $8.00 + .00
PIGEON THERAPEUTICS Roger W. Harlin, DVM
The association of humans with pigeons and doves dates back to as early as 3000 to 5000 BC. Other birds were bred for meat and egg production, but pigeons are thought to have been fept to aid agriculture. Their ability to fly long distances, select the richest nutrients, and then return to the same nesting place, made their droppings an easily collect ible source of rich fertilizer for growing crops in arid climates and on infertile land. As time went on, humans found more uses for pigeons. Best known is the part they played in communication during wartime before the invention of the wireless. Throughout history, the more ad vanced the civilization, the closer the association of humans with pi geons and doves. Pigeons are classified as flying and performance, fancy, or utility pigeons. There are standards of perfection for exhibition of almost 300 breeds of fancy pigeons. All breeds are derived from the common rock dove (Columba livia). Most of the pigeons kept are Racing Homers, trained to compete in the sport of racing. Other breeds, such as Tipplers, High Flyers, Rollers, Nose Divers, and Doneks are bred for their aerial acrobatic abilities. Pigeon meat, or squab, is still considered a delicacy in many parts of the world. Some utility breeds are capable of producing 12 to 16 pounds of meat yearly. In contrast, other breeds produce four to six young per year. Major portions of this manuscript are excerpted from Harlin RW: Pigeons. Vet Clin
North Am Small Anim Pract 24:157-173, 1994.
From the Southside Dog, Cat, and Bird Hospital, Oklahoma City, Oklahoma VETERINARY CLINICS OF NORTH AMERICA: EXOTIC ANIMAL PRACTICE VOLUME 3 • NUMBER 1 • JANUARY 2000
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HARLIN
PHYSIOLOGY AND REPRODUCTION Although pigeons usually mate for life, most birds will readily take a new mate after a short period of separation. A system of polygamous breeding called the "bull system" is often used to breed numerous hens to a prepotent cock. Eggs are fostered to feeder pairs. This system can yield two babies from the favored cock every 2 to 3 weeks, whereas natural pair methods will yield two youngsters at most every 6 to 7 weeks. The breeding season is in the spring. Pigeons lay two eggs about 40 hours apart. Incubation is 17 to 19 days. The cock assists in incubation from late morning to midafternoon. Several days before the eggs hatch, "crop milk" formation is stimulated by prolactin secreted from the pituitary gland. An actual desquamation of the crop epithelium, crop milk is very rich in protein and fats and is all that squabs receive from the parents for the first week. During the second week, grains and other food are regurgitated by the parents, and the production of crop milk ceases. The cock plays a role equal to or greater than that of the hen in feeding the squabs, particularly if the hen has begun incubation of the nest clutch naturally at about 4 weeks of age. Some fanciers believe that earlier weaning makes for a more resourceful older bird. Others prefer to leave the squabs in the nest longer, believing that extra help from the parents is beneficial. A pair typically produces two to three clutches per season. Pigeons reach maturity between 5 and 12 months of age, depending on breed and birth date. Toy breeds born early mature faster than late hatch giant breeds. Mature body weight ranges from 150 to 180 g in breeds such as the African Owl, to over 1400 g in the American Giant Runt. Most Racing Homers weigh about 360 to 480 g. Pigeons have paired vestigial ceca and no gallbladder. The normal white blood cell count ranges from 8000 to 18,000 cells/mm3 and is generally 12,000 to 15,000 cells/mm3 • The normal red blood cell count is 3 to 4 million/mm3 • Total protein should be between 2 to 4 mg/dL. Body temperature is about 105°F.
HOUSING Pigeon houses are called lofts. Pigeons do not require elaborate facilities; however, the birds are more comfortable and productive if a loft is designed specifically for breeding, racing, or whatever the fancier wishes to accomplish. Lofts must be dry. Pigeons can tolerate extreme temperatures, but moisture and dampness certainly will result in illness and poor perfor mance. Lofts must be well ventilated but without direct drafts. Respira tory problems are seen in pigeons kept in tightly closed structures in which the air is stale and dust builds up. The ideal loft is built 1 to 2 feet above dry ground with wire floors.
PIGEON THERAPEUTICS
21
Ceiling vents provide good ventilation. A wire floor prevents direct contact with the droppings. Sand, cedar shavings, and many other litters have been used successfully. Some fanciers use a natural litter (dropping buildup), and their birds do well. The natural litter must be absolutely dry and should be used only in a closed flock. Generally, the cleaner the loft, the healthier the birds; however, there is evidence that a completely sterile loft is not optimal, because low-level contact of healthy birds to avirulent strains of coccidia helps to maintain immunity. Pigeons love to "own" property and raise families. It is this love of mate, loft, nest, and perch space that inspires them to excel as avian athletes. They will fly hundreds of miles under any conditions to be "home." Too many birds in too small a place destroys their morale. Overcrowding is the worst enemy of pigeon health. The fancier must judge whether certain pigeons are affecting the quality of life of others. Sometimes troublemakers have to be removed from a particular pigeon society. Happy pigeons in clean, well-ventilated lofts are generally healthy pigeons that seldom require medication. NUTRITION
Proper nutrition is essential if pigeons are to maintain good form and resistance to disease. Nutritional requirements vary greatly ac cording to season, molting, growth, breeding, and the demands of per formance or racing. Simple logic and common sense suggest that increased protein is important to growing squabs and is not as important to inactive birds in winter. More carbohydrates are beneficial in wintering birds in cold climates, because caloric needs are increased. Higher fats and protein are helpful during the moult to enhance feather quality and growth. Racing demands a judicious feeding schedule. The requirements vary with distance and race conditions. For instance, more fats can help a bird to fly 500 miles in headwinds, whereas more carbohydrates and being a bit hungry can enhance the performance of a 150-mile sprinter. There are several commercial pelleted rations and blends of grains. Following the instructions and recommendations of reputable companies is usually satisfactory; however, most fanciers have their own ideas and make additions and corrections to commercial products. Austrian, ma ple, and Canadian peas are among the best protein seeds. Safflower seeds and Spanish peanuts are often used to supplement fats before races. Barley, wheat, and corn are good carbohydrate grains for winter. These grains are usually included in mixtures in varying amounts, along with milo, kaffir, millet, oat groats, and many others. Grit can be offered, although it is probably not necessary. Many minerals are available in the balanced pelleted rations. . � unsupplemented breeder diet of only grains, without calcium, vitarruns, and trace minerals, most likely will result in defective squabs.
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HARLIN
PREVENTIVE MEDICINE
Medications are rarely necessary if these guidelines are followed by the pigeon fancier: 1. Buy quality stock from a quality breeder. Do not introduce new birds into an existing healthy flock until they have been quaran tined and physically examined. The optimal length of quarantine is the time for a pair to raise two or three sets of babies. When quarantine is over, introduce one pair at a time to the existing flock. Allow each pair to establish territory before adding the next pair. This method minimizes the stress of pairs finding a place in the loft. 2. Examine all new birds for ectoparasites such as lice mites and pigeon flies. Perform fecal flotation and direct smears to check for helminths and coccidia. Examine throat aspirates for tricho monads and blood smears for Hemoproteus. If test results are negative, do not administer any medications, because evidence suggests that some drugs cause immunosuppression. 3. During quarantine, vaccinate all new acquisitions for paramyxo virus 1 (PMVl). Salmonella vaccination is optional and is of questionable efficacy. Vaccination for pigeonpox is ideally done after the other vaccines, because birds will have an active case of pox that can decrease the immune response to other vaccines if these are given concurrently. Some practitioners administer all three vaccines at the same time with no apparent ill effects, however. 4. Vaccinate all young birds at least 6 to 8 weeks before racing or show season. Do not add unvaccinated birds to the flock at this time because they could contract clinical poxvirus infection. 5. Keep the pigeons in a clean, dry, well-ventilated loft. Do not overcrowd. Feed the birds according to their needs. If problems arise, seek a diagnosis prior to administering medications. Viral Diseases
Viral disease is probably much more common than actually diag nosed in pigeons. Most infections cause only mild illness, but subclinical infections can complicate the disease processes caused by other patho gens. Because the presence of viruses usually is confirmed on necropsy, other pathogens (e.g., protozoa, gram-negative bacteria) are more likely to be implicated as the etiologic agents. Excluding PMVl and pigeonpox virus, herpesvirus and adenovirus are the most notable pathogens; however, reovirus, rotavirus, togavirus, arbovirus, and influenza virus infections have been suggested as causes of immune system compromise.
PIGEON THERAPEUTICS
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Pigeon Herpesvirus
Many pigeons are immune carriers of the pigeon herpesvirus (PHV ) and once infected are life-long carriers, sometimes shedding without clinical signs. Young birds are most susceptible to clinical illness, but immunocompromised older birds can show symptoms. A mild to necrotizing pharyngitis and especially esophagitis are the primary symptoms. Diphtheritic membranes and general signs of illness, including neurologic symptoms, green droppings, and anorexia, can suggest PHV infection. Vomiting with no other symptoms and inclusion body hepatitis can occur. Adenovirus
Adenovirus infection has been shown to c;ause primary illness in pigeons. Young birds are most susceptible, and the symptoms are as would be expected with hepatic necrosis of any ca.use. Treatment is supportive. Antibiotics are indicated for prevention of secondary bacterial infection. Protozoa! and helminth parasites should be eliminated and adequate hydration and nutrition provided. Paramyxovirus
Although it has been a problem in Europe and many other parts of the world for a long time, PMVl has been a problem in North America since 1984 and has spread over the whole continent since 1987 or 1989. Fanciers with absolutely closed flocks are at the lowest risk; those who race their pigeons frequently, buy, sell, trade, or allow contact with feral pigeons are most likely to have infected flocks. The primary symptoms are polyuria (not diarrhea) and central nervous signs, ranging from incoordination, difficulty picking up grains, and mild head tilt, to severe ataxia and torticollis. Surprisingly, affected pigeons do not seem to feel very ill and most eventually recover if given long-term supportive care. The most severely affected birds are unable to feed well enough to maintain bodyweight, and euthanasia could be in order. Immune carriers are possible, and old and especially young birds are most susceptible to infection. Viral shedding can precede clini cal signs, and incubation has been suggested as lasting from 1 week to as long as 6 weeks. The author recommends expedient vaccination of all birds, includ . mg young birds, in the face of an outbreak. Devastation in outbreaks has been minimized by vaccination, suggesting that incubation is long (2 to 4 weeks) or that other factors cause a moderate to slow spread in a flock. Elimination of parasites, good nutrition, and loft cleanliness promote the strength of the pigeon's immune system.
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HARLIN
Vaccination 1 to 2 months before breeding season and 6 to 8 weeks before racing or showing with the oil emulsion vaccine sub Q is recom mended. The author vaccinates his young bird racing team on weaning. The Lasota oral vaccine should not be depended on for adequate protection. Pox
Pox virus is found in saliva and in nasal and lacrimal secretions. It enters the body through defects in the skin, especially on the wattle or cere. Direct contact, insect vectors, or airborne secretions can spread the disease. Scabs and proliferations of the cere, wattle, legs, feet, and commissures of the beak occur. The first symptoms are usually conjunctivitis with excess lacrima tion and swelling of the eye cere. A diphtheroid form can occur, causing lesions on the mucosal surface inside the mouth. Secondary bacterial invasion can cause proliferative lesions, obstructing respiration and mak ing eating difficult. Treatment of infected birds is strictly supportive. Preventive mea sures (including practicing strict sanitation; providing proper nutrition; and using antibiotics, antihelminthics, and coccidiostats) should be taken in the event of an outbreak. Isolation of infected individual animals and insect control using screens or insecticides can slow the spread. Birds develop an immunity 3 to 4 weeks after administration of a commercially available vaccine. Feathers are pulled, and the vaccine is applied by a dropper or a brush. The wing web is an acceptable site. An inflammatory reaction at the site suggests successful vaccination. Birds as young as 4 weeks of age can be vaccinated, and annual vaccination is recommended 4 weeks before the mosquito season. Care should be taken not to introduce new birds into an already vaccinated loft. The incidence of pox varies greatly from year to year and by geographic area. Late summer and fall, especially in years when the first freeze comes late, increases the chances of an outbreak. Circo Virus
Circa virus, a relative to psittacine beak and feather disease virus and chicken anemia agent, has been recognized since 1986 and reported in the United States since 1990. The victims are usually young birds 2 months to 1 year of age. Clinical signs are anorexia, lethargy, diarrhea, rapid weight loss, inability to fly, sneezing, respiratory distress, and death in 3 to 5 days. The incubation period is best estimated at about 2 weeks. The circa virus generally has an immunosuppressive effect, allowing several concurrent infections to cause the demise of its victim. Among them are
PIGEON THERAPEUTICS
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Pasteurella, herpes virus, chlamydia, trichomonas, adenovirus, aspergil lus, and colibacillosis. It is the author's belief that the incidence of this viral illness is more common than reported. Often the concurrent agents previously mentioned are determined to be the cause of the illness, when they might have only been opportunistic. It is suggested that the bursa be included with liver, spleen, and other tissue for histopathology in suspected viral illnesses. Virus Hepatitis Since 1992, an acute hepatic disease in pigeons has occurred in Europe. The syndrome is very much like Pacheco's disease in parrots, except that there are no inclusions in the hepatocytes and the agent has yet to be identified. Old and young birds are affected. The birds are sick for 24 to 48 hours and they either die or recover without treatment. Some birds develop yellow slimy droppings and foul-smelling vomitus. The symptoms can contin�e for a course of 3 to 4 weeks. The mortality rate is about 30%. Hepatomegaly (pale in color) and complete destruction of all liver cells is found on postmortem and histopathology. Treatment is supportive only. BACTERIAL INFECTIONS The most important bacterial disease of pigeons and doves is paraty phoid, caused by Salmonella typhimurium var. Copenhagen. The best known symptom is swollen wing and leg joints ("boils"), which should be considered almost pathognomonic by the practitioner when observed. Most pigeons with paratyphoid present with an array of other symp toms, however, including anorexia, weight loss, ruffled feathers, dropped wings, refusal to fly, diarrhea, green droppings, reproductive problems such as embryonic or early squab death, or death of older birds. Diagnosis is made by demonstration of the organism from the live bird or on necropsy. Selenite broth onto MacConkey's or brilliant green agar are suitable for recovering the organism from intestinal or crop contents. Treatment should be determined by sensitivity testing, because many strains exist with variable drug susceptibility. Enrofloxacin has demonstrated the most consistent efficacy record, although members of the penicillin, tetracycline, and aminoglycoside families sometimes can be suitable choices. Prevention is far superior to treatment. Before introducing new stock into a disease-free loft, birds should be quarantined in individual cage _ s_ until they have raised a nest of healthy young. Cleanliness, acidi fication of floor litter, and strict control of stray pigeons are also helpful measures. Vaccination with a killed bacterin may be beneficial.
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HARLIN
Colibacillosis is another important problem in pigeons. Disease syn dromes previously attributed to paratyphoid recently have been shown to be caused by E. coli when proper diagnostic tests were done. Exclud ing the swollen wing and leg joints, the symptoms of the two diseases are very similar. Other bacteria, such as Streptococcus, Staphylococcus, Pasteurella, He mophilus, and Pseudomonas, have been described as pathogens but are of lesser importance than Salmonella and E. coli. Treatment of all bacterial diseases should involve cultures and sensi tivity testing. Often, fanciers and veterinarians "shotgun" flocks with antibiotics, resulting in many resistant strains of bacteria and many immunosuppressed pigeons. Streptococcus Bovis
An acute or even peracute death in pigeons has been attributed to Streptococcus bovis. The primary symptom is inability to fly (or deviant flying behavior) and dropped wings. Others have green foamy drop pings and sometimes loss of appetite, polyuria, polydipsia, and swollen abdomen. The acute disease is a septicemic disorder. Old and young birds are affected, but young birds often have pericarditis, and old birds often have yellowish breast muscles. A chronic lameness has been reported from Streptococcus bovis. The disease can easily be mistaken for paramyxovirus or salmo nellosis but is usually more acute. Amoxicillin is an effective treatment if instituted early enough. The Ornithosis Compl ex
The ornithosis complex ("eye colds" or "one-eyed roup") is common in domestic pigeons. Chlamydia is the primary causal agent, but myco plasma and gram-negative bacteria are also involved. Many herpesvirus infections are also complicated with chlamydia, so viral agents probably should be included in the complex. Frequently the same eye of all affected birds is in the windward side of wind currents. Treatment is usually successful with tylosin, but tetracyclines, linco mycin, or erythromycin are also effective. Intramuscular injection is very irritating and should be avoided in racing birds. Oral administration and sinus flushing of antibiotics can be the best methods of treatment. Supportive therapy reduces stress and enhances immune response. Topi cal ophthalmic medications are also of benefit. PARASITIC DISEASES Endoparasites
Nematodes are the primary endoparasitic problem of pigeons. Asca rids, Capillaria, tetrameres, ornithostrongylus, and dispharnyx are of
PIGEON THERAPEUTICS
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concern; geographical location determines the particular species that a clinician will encounter. Cestodes are occasionally encountered, and trematodes are rarely, if ever, found in the United States. Diagnosis is made by fecal flotation, direct smear, or intestinal or proventricular scrapings on necropsy. Cestode proglottides can be shed after food deprivation. Because cestodes and some nematodes (e.g., Tetrameres) require intermediate hosts (e.g., pill bugs), care should be taken to prevent pigeons from foraging where these organisms are found. Raised lofts are the commonest sites where pigeons are infected. Piperazine is effective only for ascarids. Fenbendazole and meben dazole are effective for ascarids, Capillaria, and probably other parasites that feed on blood or body tissue but must be used for 3 days. Levami sole is effective against ascarids and has some value against Capillaria. Ivermectin is most effective against all nematodes, but other drugs could be better for ascarids (e.g., pyrantel pamoate). Praziquantel is the drug of choice for cestodes and trematodes. Ectoparasites
Pigeon flies, lice, and mites are the most significant ectoparasites of pigeons. Pseudolynchia carariensis, the pigeon louse fly, seldom flies. It spends most of its time feeding on the bird's blood, causing anemia and transmission of Hemoproteus. Louse flies cause considerable discomfort to the bird and can be devastating to the general health of a flock. Columbicola columbae, the slender pigeon louse, is the commonest mallo phagian parasite. It does not take blood but feeds on feathers, causing tiny pinpoint holes. When lice are found by the clinician, other diseases should be considered. Heavy louse infestations usually indicate a debili tated bird that might not feel well enough to groom properly. Dermanys sus gallinae and possibly Ornithonyssus sylvarum cause skin irritation and feed on blood. They are called red mites or roost mites and are found on the bird at night. Knemidocoptes mutans, the scaly leg mite, causes considerable skin damage. Ivermectin is very effective for ectoparasites that feed on blood and body tissues and is recommended with dusting or preferably dipping with pyrethrin products. lvermectin and pyrethrin are effective against lice when used properly. Coccidia
The role of coccidia as a primary pathogen remains controversial b�cause oocyst shedding is commonly found in healthy birds. Often, pigeons afflicted with other diseases or under stress shed large numbers of oocysts, particularly young birds. The physical examination should not end when fecal flotations reveal oocysts but should be thorough in eliminating bacterial pathogens, trichomoniasis, nutritional deficiencies, husbandry errors, and helminths.
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Evidence indicates that low-level exposure to mildly virulent strains of coccidia can help to produce immunity to more pathogenic strains. Many considerations should be taken into account before instituting therapy with coccidiostatic drugs. When a disease situation involving coccidia occurs and drugs must be used, sanitation and good husbandry to prevent fecal-oral contact should be the first therapy instituted. Heavily bred or heavily raced older birds and young birds kept under less than optimal conditions are the most susceptible to disease. Clazoril, amprolium, sulfachlorpyridazine, and other sulfas (e.g., sulfadimethoxine and sulfamethazine) are effective coccidiostats. Vita min B supplementation after therapy is beneficial. Nitrofurazone can help with secondary bacterial enteric infections but is not recommended for coccidiosis in pigeons. Three to five days are required for the oocyst to sporulate and become infective, so that frequent cleaning is the best preventive measure.
Trichomoniasis Most pigeons and doves carry Trichomonas gallinae. This parasite can be a primary pathogen or cause disease secondary to other illnesses or stressful conditions. The severity of trichomoniasis depends on the virulence of the strain and the magnitude of debility from concurrent diseases. The common name "canker" refers to the cheesy, white caseous deposits in the throats of birds with advanced disease. More often the condition is confused with respiratory diseases because the oculonasal and oral discharges are clear. The organism can easily be demonstrated by suctioning the mucus from the throat and immediately observing the sample with immersion microscopy. Trichomonas g. often accompanies the ornithosis complex, viral ill nesses, parasitic diseases, and noninfectious stressful situations. Success ful therapy involves resolving the other diseases as well as treatment of the trichomonads. The immune status of the bird is important to con sider if recovery is to be expected. Exposure to strains of low virulence in an immunocompetent bird can produce resistance against patho genic strains. Although Trichomoniasis is primarily a disease of the upper alimen tary tract, local lesions, including omphalitis, can occur, as well as infection of liver, lung, and other organs. Effective treatment involves proper use of the 5-nitroimidazole de rivatives, including ronidazole, carnidazole, dimetridazole, and metroni dazole. Prevention depends on reducing stress and controlling other dis eases. Total eradication of the organism is not practical or desirable.
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Hemoproteus
Pigeon malaria is the name frequently given to hemoproteus infec tion, but Plasmodium spp. are rarely reported in pigeons. It is much commoner in performing breeds than in fancy or utility pigeons, perhaps because the stresses and exposure to insect vectors in racing situations make the disease more apparent in racing pigeons than in sedentary exhibition pigeons. The disease is transmitted by the pigeon fly. Hemo proteus infection is diagnosed by demonstration of the organism in the red blood cell's cytoplasm without nuclear displacement, as shown on stained blood smears. Control of insect vectors is the best prevention. Dusting or dipping with pyrethrin every 2 weeks can be effective in controlling pigeon flies in endemic areas. The disease has been effectively treated with quina crine. Primaquine has been successfully used as a preventative. Hexamita
Hexamitiasis occurs primarily in young pigeons. Symptoms include weight loss, diarrhea, and general unthriftiness, and demonstration of the organism on very fresh direct fecal smears is diagnostic. The nitroimidazole derivatives, carnidazole, dimetridazole, ronida zole, and metronidazole are the most effective antiprotozoal drugs. Car nidazole is the drug of choice. Preventing fecal-oral contact is helpful in controlling hexamitiasis. Address reprint requests to Roger W. Harlin, DVM Southside Dog, Cat, and Bird Hospital 7020 South Shields Oklahoma City, OK 73149
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Table 1 . ANTI BIOTICS
Medication
Dosage
Route of Administration Nasal flush
Amikacin
PO
Amoxicillin
100 mg / kg b.i.d. 2-3 g / gallon
Drinking water
Amoxicillin / clavulanic acid
125 mg / kg b.i.d.
PO
Carbenicillin
100 mg / kg b.i.d.-t.i.d.
IM
Cefadroxil
100 mg / kg b.i.d.
PO
Cefotaxime
100 mg / kg b.i.d.-t.i.d.
IM
Ceftidime
100 mg / kg b.i.d.-t.i.d.
IM
Cephalexin
100 mg / kg b.i.d.-t.i.d.
PO
Chloramphenicol
60-100 mg / kg t.i.d. 250 mg / kg q.i.d. 1 drop t.i.d.-q.i.d.
IM PO
Chlortetracycline and oxytetracycline Doxycycline
50 mg / kg t.i.d.-q.i.d. 1000-1500 mg / gallon-In warm weather mix fresh b.i.d. 25-50 mg / kg b.i.d.
Ophthalmic drops
PO
Drinking water
PO
Uses and Comments Useful with difficult aerobes (Pseudomonas); seldom used systemically in pigeons owing to toxicity and rapid excretion Good for animal bite wounds and postsurgical wound care Nontoxic Better spectrum against Staphylococcus sp. than amoxicillin Based on culture and sensitivity; good spectrum against gram-negative bacteria Based on culture and sensitivity or when Staphylococcus sp. is suspected Excellent gram-negative spectrum, especially against E. coli Excellent drug lung levels; similar activity to cefotaxime but may be more effective against Pseudomonas sp Based on culture and sensitivity or when Staphylococcus sp. is suspected Good penetration into all body tissues, including CNS; chlamydiostatic properties and good gram negative spectrum Use with caution owing to possible irreversible anemia in humans associated with contact Best used in combination with tylosin for ornithosis complex (see text); calcium inhibits absorption therefore grit and layer pellets should be withheld during treatment Drug of choice for chlamydiosis; especially Tylosin
Enrofloxacin
12-15 mg / kg b.i.d. 7-14 days 22 mg / kg b.i.d. 45 mg / kg s.i.d. 150-600 mg / gallon 7-14 days
IM PO PO Drinking water
Erythromycin
125 mg / kg t.i.d. 2-3 g / gallon 1 drop q.i.d. See comments
PO Drinking water Ophthalmic drops Nasal flush
Piperacillin
100 mg / kg b.i.d.-t.i.d.
IM
Spectinomycin
25-35 mg/ kg b.i.d.-t.i.d. 600-1000 mg / gallon 1200 mg / gallon 7-10 days
IM Drinking water Drinking water
1250-1500 mg/ gallon on first day followed by 750-1000 mg/ gallon for 4 days 1500 mg / gallon on first day followed by 750-1000 mg/ gallon for 4 days 60 mg / kg b.i.d. 1 800-3600 mg / gallon for 7-10 days 25-50 mg / kg 3 g / gallon (2 tsp)
Drinking water
Gentamicin
Sulfachlorpyridazine Sulfadimethoxine Sulfamethazine Trimethoprim / sulfadiazine or sulfamethoxazole or sulfademethoxine / ormetoprim Tylosin
....
V,
Drinking water
Excellent in respiratory infections; drug of choice for Salmon ell a typ himurium; dru g most likely to eliminate paratyphoid carrier states; some adverse effects reported in breeding hens and squabs (not experienced by author) Injectable use is very irritating to muscle Useful for difficult aerobes (Pseudomonas); seldom used systemically in pigeons due to toxicity and rapid excretion; author mixes equal volumes with lincomycin and flushes nostrils using an open ended tomcat catheter Drug of choice for critically ill patients with bacterial intestinal disease; often used in combination with quinolones Poorly absorbed orally; good gram-negative spectrum especi ally against E. coli Broad-spectrum antibiotic, very effective against E. coli and is a good coccidiostat Broad-spectrum antibiotic and coccidiostat; supplement B vitamins for 5 days then retreat; half-life in pigeons longer than other sulfas Broad-spectrum antibioti c and coccidiostat; supplement B vitamins for 5 days then retreat
PO Drinking water
Broad-spectrum antibiotic and coccidiostat; consider H20 consumption
IM or SQ Drinking water
Mycoplasmastatic and bacteriostatic with little efficacy against gram-negative bacteria; very irritating to muscle when injected; drug of choice for ornithosis complex (see text) when used with tetracyclines; low toxicity potential
c., N
Table 2. ANTI FUNGALS Medication
Dosage
Route of Administration
Uses and Comments
Nystatin
100,000 U / kg b.i.d.
PO
Candidiasis
Table 3. ANTI PARASITICS
Dosage
Medication
Uses and Comments
1 tsp / gallon [20% powder] 3-5 days 8 mL / gallon [9.64% solution] 3-5 days 20 mg / kg once
Drinking water
Coccidiostat good for asymptomatic birds when attempting to alleviate oocyst shedding
PO
Claxoril
5 mg / kg once 2.5 mg tablet per Racing Homer-sized bird,
PO
Antiprotozoan compound; only drug labeled for use in pigeons in the United States Coccidiostat; stops shedding of oocysts for up to 2 wk
Dimetridazole
¼-½ tsp / gallon 3-5 days
Drinking water
Fenbendazole
10-12 mg / kg s.i.d. for 3 days
PO
lvermectin
0.5-1 mg / kg once
PO or IM
Levamisole
40 mg / kg once 1000-1500 mg / gallon for 24 hours 35 mg / kg for 2 days 300 mg/ gallon for 2 days 1-2 tablets / gallon for 10-21 days before racing then 1-2 days weekly 20-25 mg / kg 1-3 tablets / gallon for 10-21 days 400 mg / gallon for 3-5 days (½-¾ tsp)
PO Drinking water PO Drinking water Drinking water
Amprolium Carnidazole
Piperazine Primaquine Pyrantel pamoate Quinacrine Ronidazole v.l v.l
Route of Administration
once
Good antiprotozoal activity; CNS symptoms if overdosed (Canadian product); consider water consumption of flock; in hot weather use lower dose and in cold weather use higher dose Capillaria, ascarids, strongyles, and tetrameres; feather abnormalities have been reported when used during molt Anthelmintic of choice except when treating tapeworms and ascarids; effective for mites and lice that feed on body tissues; feather lice when sprayed on topically Very effective against ascarids and moderately effective against other nematodes Ascarids only; seldom used due to newer, superior anthelmintics .....,. For control of Hemoproteus; will not alleviate parasite; controls pigeon flies; treatment of choice for prevention
PO Drinking water
Roundworms Hemoproteus; controls pigeon flies
Drinking water
Protozoa! diseases; not available in the United States.
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Ta ble 4. VACCI N ES Vaccine
Route of Admin istration
Paramyxovirus (PMVl )
SQ lower 113 of neck on dorsal midline SQ cranial to thigh
Salmonella
SQ lower 113 of neck on dorsal midline SQ cranial to thigh
Poxvirus
Pull feathers from wing web or leg and apply with dropper or brush Can be placed onto a scrape-created on skin over breast area
Comments 1-2 mo before breeding season and 6-8 wk before racing or showing. Author vaccinates racing team birds on weaning and boosters 1-2 mo before racing or showing. Vaccination in the face of an outbreak can reduce losses. Pigeons have an extensive venous plexus around the neck that should be avoided when vaccinating. Questionable efficacy due to Salmonella strain variety but author's experience has been favorable in confirmed cases. Pigeons have an extensive venous plexus around the neck that should be avoided when vaccinating. First vaccine given to birds as young as 4 wk old. Annual vaccines recommended 4 wk before mosquito season. Inflammatory reaction at site suggests successful vaccination. Do not add unvaccinated birds to a vaccinated loft.