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Salmonellosis in the Horse
Br. uet.]. ( 1970),
126, 100
SALMONELLOSIS IN THE HORSE By
J.
R.
BAK ER
Department of Veterinary Pathology, University of Liverpool
SUMMARY
This paper describes salmonellosis in horses as seen by the author and gives details of a bacteriological and serological survey. INTRODUCTION
The horse has its own host-specific salmonella, Salmonella abortus equi, but it is also susceptible to a variety of other salmonellae which occur in domestic· and wild species. Reports of infection in the horse are scattered through the literature but it is not proposed to give a resume of these papers. The reader is referred to Buxton (1957) for a general summary. A heavy burden of migrating strongyle larvae has been described as a predisposing cause by Dimmock, Edwards & Bruner (1940) and Sedden (1953). Stress due to transport has been described as a predisposing cause by Graham, Reynolds & Hill (1920) and Cordy & Davis (1946), and Graham et al. also readily reproduced infection with Salmonella enterditis by feeding fasted animals. The wide variety of clinical states which occur with salmonella infections in other species also occur in the horse, ranging from the asymptomatic carrier state or slight scour to dysentery and death. In these latter cases typhlitis appears to be a constant post-mortem feature. Arthritis in the neonatal animal and fistulous withers in the adult have also been associated with salmonella infec tions. From the accounts in the literature the disease appears to be principally one of the foal, although the carrier dam is not an infrequent source of infection for her offspring (Bryans, Fallon & Shepherd, 1961 ). Bacteriological surveys of horses appear to have been published only once in Britain (Smith & Buxton, 1951), although there are several in the foreign literature. These are given in Table I, the results of which were obtained from horses without enteric symptoms, but do not include surveys for S. abortus equi. A bacteriological survey of horses admitted to the University of Liverpool Veterinary Field Station was commenced after the death of a horse due to Salmonella septicaemia. The purpose of the survey was twofold, firstly to find the incidence of salmonellae in horses in the area served by the University of Liverpool Veterinary Field Station and secondly to detect infected horses before surgery so that treatment could be instigated before operation, and to prevent spread of infec tion in the hospital. However, surgery often had to be undertaken before the results of the examinations were known. In the horses the serum agglutination test has been used to assist in the diag-
SALMONELLOSIS IN THE HORSE
101
TABLE I SU MMARY OF LIT E RATURE RELATING TO BACTERIOLOGICAL SURV EY S OF HORSES FO R SALMONELLAE OTHER THAN S. abortus equi WITH NO RECORD OF ENTERIC SYMPTOMS
Author
Site examined
No. with salmonellae
Faeces 2 Spleen and mesenteric lymph nodes 0 Large bowel 23'4 per cent Conti & Sarti ( 1940) Mesenteric lymph node 2 Deblasi & Biggi ( 1954) Faeces and mesenteric lymph nodes II Gotze ( IS68) H ajdu & Korzensky ( 1938) 3 "Foals" I Hansen ( 1947) Horses at slaughter 0 Faeces 0 " Healthy horses" 0 Kuhlmann ( 1964) " Diseased horses" 20 Mann, Cavrini & Liver 2 Pieracci ( 1964) Mesenteric lymph nodes 3 Bile 0 Mantovani i 1950a) Mesenteric lymph nodes 2 Mantovani 1950b ) Mondolfo (1936) Horses in slaughterhouses II Schreiter (1960) Horses in slaughterhouses I Smith & Buxton ( 195 1) Diseased horses 2 Becker ( 1968) Benazzi ( 1949)
No. examined
100 200 136 157 1000 440 769 31 17 2 7 ::83 2 25 0 25 0 50 200 100 67 21 500 500
nos is of S. abortus equi by Hirato (1936), H enning & MacIntosh (1946), R olle (1947), and Verge (1948, 1949). All these authors mention that uninfected animals can be expected to have antibody titres, indeed the " 0" agglutinins may reach a titre of 1/300. It was suggested by Perdrix (1949) that "H" agglutinins may be more reliable for diagnostic purposes than "0" agglutinins. The use of the agglutination test in the present survey was to find the "normal" titre in uninfected animals and to assist in the diagnosis of S. typhimurium which was expec ted to occur more frequently than other species. MATERIALS AND METHODS
Faeces. Samples examined were less than I day old and many were fresh . Faeces were obtained if possible on the day of admission, on the 2 days thereafter and on the day following surgery. With the majority of samples sufficient material was available to inoculate 3 g. into 30 m!. of Selenite broth. This was incubated overnight at 37 °C and on the following day approximately 0'1 m!. was plated onto desoxycholate citrate agar, which was again incubated overnight. Suspect colonies were provisionally identified by the slide agglutination test and their identity confirmed by the Central Salmonella Reference Laboratory, to whose staff I am indebted. Agglutination tests. The agglutination titres of the sera were measured using S. typhimurium "0" and "H" antigens standardized to Browns tube 2 opacity. The dilutions used were 2, 10, 20, 40 and doubling dilutions thereafter to the end point of the titre. The tubes were incubated overnight at 37 °C and the result read the following morning.
102
BRITISH VETERINARY JOURNAL,
126, 2
RESULTS
Clinical cases The first case was a 5-year-old gelding in the University of Liverpool Veterinary Field Station. This animal was operated on for roaring under a general anaesthetic on 2 July 1967. Over a period of several days following surgery it developed nervous symptoms, consisting of holding the head up and to the right, fever, diarrhoea and jaundice. T en days after the operation it developed acute colic and was destroyed. At post-mortem examination severe colitis, typhlitis, evidence of septicaemia and an enlarged pale liver were found. All the organs cultured revealed S. typhimurium phage type 32. No further clinical cases occurred at this time. The second case seen in September 1967 which did not occur at the Field Station, involved a Welsh Pony mare. The animal had been given a dose of piperazine as it was suspected of being infested with worms, but no worm egg count was undertaken. Following medication diarrhoea developed which was profuse, green and watery. A course of sulphaguanidine resulted in only slight improvement. Fourteen days after the anthelmintic treatment a sample of faeces was submitted to us and S. typhimurium was recovered and a course of chloramphenicol was instituted. Nineteen days later a further sample of faeces which remained thin and watery was examined, and the organism was still present. At no stage was the animal clinically ill and it continued working. Unfortunately no further examinations were possible. A summary of an outbreak involving a number of horses at the Field Station has been given by Baker (1969) and further d etails of the cases are given here. The organism was introduced into the Field Station on 23 September 1967 by a cow infected with S. typhimurium phage type U162. On 2 October 1967 a pony brought into the hospital 2 days previously for castration was found to be excreting the organism but it was discharged before the bacteriological examination was completed and it was not followed up. At no time whilst in the hospital was it clinically affected. The following day (3 October) a pony gelding operated on for roaring a few days previously was found to be excreting the same salmonella, this animal was also without clinical symptoms. The organism was not isolated on the next 2 days and on the third day treatment with chloramphenicol was instituted for 5 days. The animal was discharged 20 days after the organism was originally isolated. On 6 October 1967 a 2-year-old filly which had been in the hospital for some time for the removal of a tumour and which had not been infected when admitted, d eveloped diarrhoea and depression. The same phage type, U 162, of S. typhimurium was isolated from its faeces . The following day the horse was clinically normal although still excreting the organism. Sensitivity tests suggested that ampicillin was the drug of choice but treatm ent with it had no effect on excretion of the organism and a 5 day course of chloramphenicol was started. Faeces were bacteriologically n egative after this treatment and the animal was discharged 14 days later. A faeces sample received after the animal had been at home for a fortnight was also free of the
SALMONELLOSIS IN THE HORSE
organism. These three horses had occupied boxes which had previously been occupied by the cow.
Survey The faeces survey was conducted on a total of 20 1 horses and in addition to the cases d etailed above three further infected animals were discovered. A foal, shot on the day of admission as it had a broken leg, was examined post mortem and although no enteric lesions were found S. rostock was isolated from 20
V>
.!! a.
E o V>
o Z
Reciprocal of titre
o Z
Fig.
I.
Histogram showing the number of unaffected horses with the end point( of their "0" titres .
20
a. E o
'" o
Z
o
Reciprocal of titre
Z
Fig.
2.
Histogram showing the number of unaffected horses with the end points of their "H" titres.
(04
BRITISH VETERINARY JOURNAL,
126, 2
the rectal contents. The second case was a gelding, in hospital for removal of a cirrhous cord, the first two faeces samples from it after admission did not yield any organi.sms of significance, but S. typhimurium was obtained from the third sample. It is probable that the animal brought the organism in with it as there were no other known infections in the hospital at the time. The last case was an aged grey gelding in for attention to the teeth. Salmonella virchow was isolated from its faeces on the day of admission but not from samples taken on the following days. The serological survey was conducted on fifty animals and the results are given in Figs. 1 and 2. This survey was started some time after the faecal survey and no animal with S. typhimurium infection was examined. The foal with S. rostock had no serum "0" agglutination but it had an "H" titre of 1 /40. The remaining animals examined were free of salmonella infection at the time of examination but showed titres of up to 1/ 160. There was no correlation between "0" and "H" titres. DISCUSSION
The symptoms of salmonellosis described in this paper agree with descriptions of the disease in adult horses as described by other authors, with the exception of fistulous withers and arthritis, but horses with these latter lesions at the Field Station have not been specifically examined for salmonellae. Predisposing factors were present in two horses. One case was apparently associated with anthelmintic treatment, and one case with general anaesthesia and surgery. When this la tter case was detected the survey had not commenced and it is not known if other horsl.':s were infected although it is possible. One of the horses in the outbreak of infection was passing the organism within a few hours of contact with an infected environment but the organisms did not become established in the intestine. The horse infected with Salmonella virchow was detected shortly after the occurrence of an epidemi c of infection with this organism in humans and other animals, principally chickens. The origin of the infection in the horse could not be traced. The results of the faecal survey show that approximately 1·5 per cent of horses in this area may be clinically normal carriers. It had been anticipated that infection with Salmonella dublin might be discovered as this organism had recently been common in cattle and other species in this area. However, no cases occurred either of clinical illness or of carri ers, even after two infecte d calves with Salmonella dublin were admitted, prior to diagnosis, to the Veterinary Field Station. The presence of agglutinins to S. ~yphimurium in normal horse sera was expected following the finding of titres of S. abortus equi in normal horses by H enning & MacIntosh (1946) and others, and this is due to salmonellae having antigeni c features in common with other enterobacteraceae (Lovell, 1932, 1934). Whi.Ist no horses with Salmonella typhimurium were examined serologically the results of the survey are of interest as they indi cate that a ti.tre of at least 1/240 and probably higher would be r equired in order to indicate tha t the a nimal had been exposed to this organism.
SALMOr ELLOSIS IN THE HORSE
ACKNOWLEDGMENTS
I wish to thank Professor D . L. Hughes for help in the preparation of this paper, :Miss J. Hanson for technical assistance and Mr K. Bell for the preparation of the antigens. REFEREN CES
BAKER,]. R. (1969) . Vet. R ec., 85, 8. BECKER, C. R . (1968). Mich. st. Univ. Vet., Spring, p. 123. BENAZZI, A. (1949). Atti. Soc. ital. Sci. vet., 3, 505. BRYANS, ] . T., FALLON, E. H. & SHEPHERD, B. P. (1961 ). Cornell Vet., 51, 467 . BUXTON, A. (1957). Salmonellosis in Animals. Farnham Royal: C.A.B. CONTI, M. & SARTI, G. (1940). Boll. Inst. Sieroter, Milano, 19,338. CORDY, D. R. & DAVIS, R. W. (1946). J. Am. vet. med. Ass., 108,20. DEBLASI, R . & BIGGI, D. (1954) . Clin. Vet., 77, 39. DIMMOCK, W. W., EDWARDS, D. R. & BRUNER, D. W. (1940). Cornell Vet., 30, 319. GRAHAM, R. F., REYNOLDS, H. K. & HILL, ]. F. (1920). J. Am. vet. med. Ass., 56, 378. GOTZE, U . ( 1968). Zentbl. Vet. Med., B 15,878. HAJDU, C. & KORZENSKY,]. (1938). Allotov Lapok., 61, 188. HANSEN, A. C. (1947). Macinedsskr Dyrlaeg., 58, 367. HENNING, M . W. & MAcINTOSH, B. M . (1946). J.S. Afr. vet. med. Ass., 17, 88. HIRATO, K. (1936). J. Jap . Soc. vet. Sci., 15,31 9. KUHLMANN, W. (1964). Mh . VetMed., 18,790. LOVELL, R . (1932). J. Camp . Path., 45, 27. LOVELL, R. (1934) . J. Camp . Path., 47, 107. MANN, P. H., CAVRlNI, C. & PIERACCI, F. (1964) . Cornell Vet., 54, 495. MANTOVANI, A. ( 1950a) . Clin. Vet., 73, 330. MANTOVANI, A. (1950b). Atti. Soc. ital. Sci. vet., 4, 620. MONDOLFO, U. (1936). Rif Med., 52, 961. PERDRIX,]. (1949). Rev. Immunol., 13, 287. ROLLE, M. ( 1947). B erl. Munch . tieriir;;tl. Wschr., 0.4,37. SCHREITER, M. (1960). Mh . VetMed., 15, 888. SEDDEN, H. R . (1953). Commonwealth of Australia, Department of H ealth, ser. pub. No. Sydney. SMITH, H . W. & BUXTON, A. (1951 ). Br. med. J ., I , 1478. VERGE,]. (1948). Rev. camp. Path. , 49, 643. VERGE, ]. (1949). Rep. XIVth Int. Vet. Congr., L ondon, 2, 28 1.
10.
(A ccepted for publication 8 Ju f:y 1969) La Sabnonellose chez Ie cheval (Baker) R esUUle. Cet article decrit les observations de l'auteur sur la salmonellose chez les chevaux, avec d es d etails sur une etude bacteriologique et serologique. Sabnonellose des Pferdes (Baker) Zusanunenfassung. In dieser Abhandlung wird die Salmonellose d es Pferdes aus der Sicht des Authors beschrieben und Einzelheiten einer bakteriologischen und seologischen Reihenuntersuchung werden angeftihrt. Sabnonellosis en el caballo (Baker) Res UUlen. Este papel describe la salmonellosis en los caballos conforme la ve el autor, y da detalles de un estudio bacteriol6gico y serol6gico.
126, 100
SALMONELLOSIS IN THE HORSE By
J.
R.
BAK ER
Department of Veterinary Pathology, University of Liverpool
SUMMARY
This paper describes salmonellosis in horses as seen by the author and gives details of a bacteriological and serological survey. INTRODUCTION
The horse has its own host-specific salmonella, Salmonella abortus equi, but it is also susceptible to a variety of other salmonellae which occur in domestic· and wild species. Reports of infection in the horse are scattered through the literature but it is not proposed to give a resume of these papers. The reader is referred to Buxton (1957) for a general summary. A heavy burden of migrating strongyle larvae has been described as a predisposing cause by Dimmock, Edwards & Bruner (1940) and Sedden (1953). Stress due to transport has been described as a predisposing cause by Graham, Reynolds & Hill (1920) and Cordy & Davis (1946), and Graham et al. also readily reproduced infection with Salmonella enterditis by feeding fasted animals. The wide variety of clinical states which occur with salmonella infections in other species also occur in the horse, ranging from the asymptomatic carrier state or slight scour to dysentery and death. In these latter cases typhlitis appears to be a constant post-mortem feature. Arthritis in the neonatal animal and fistulous withers in the adult have also been associated with salmonella infec tions. From the accounts in the literature the disease appears to be principally one of the foal, although the carrier dam is not an infrequent source of infection for her offspring (Bryans, Fallon & Shepherd, 1961 ). Bacteriological surveys of horses appear to have been published only once in Britain (Smith & Buxton, 1951), although there are several in the foreign literature. These are given in Table I, the results of which were obtained from horses without enteric symptoms, but do not include surveys for S. abortus equi. A bacteriological survey of horses admitted to the University of Liverpool Veterinary Field Station was commenced after the death of a horse due to Salmonella septicaemia. The purpose of the survey was twofold, firstly to find the incidence of salmonellae in horses in the area served by the University of Liverpool Veterinary Field Station and secondly to detect infected horses before surgery so that treatment could be instigated before operation, and to prevent spread of infec tion in the hospital. However, surgery often had to be undertaken before the results of the examinations were known. In the horses the serum agglutination test has been used to assist in the diag-
SALMONELLOSIS IN THE HORSE
101
TABLE I SU MMARY OF LIT E RATURE RELATING TO BACTERIOLOGICAL SURV EY S OF HORSES FO R SALMONELLAE OTHER THAN S. abortus equi WITH NO RECORD OF ENTERIC SYMPTOMS
Author
Site examined
No. with salmonellae
Faeces 2 Spleen and mesenteric lymph nodes 0 Large bowel 23'4 per cent Conti & Sarti ( 1940) Mesenteric lymph node 2 Deblasi & Biggi ( 1954) Faeces and mesenteric lymph nodes II Gotze ( IS68) H ajdu & Korzensky ( 1938) 3 "Foals" I Hansen ( 1947) Horses at slaughter 0 Faeces 0 " Healthy horses" 0 Kuhlmann ( 1964) " Diseased horses" 20 Mann, Cavrini & Liver 2 Pieracci ( 1964) Mesenteric lymph nodes 3 Bile 0 Mantovani i 1950a) Mesenteric lymph nodes 2 Mantovani 1950b ) Mondolfo (1936) Horses in slaughterhouses II Schreiter (1960) Horses in slaughterhouses I Smith & Buxton ( 195 1) Diseased horses 2 Becker ( 1968) Benazzi ( 1949)
No. examined
100 200 136 157 1000 440 769 31 17 2 7 ::83 2 25 0 25 0 50 200 100 67 21 500 500
nos is of S. abortus equi by Hirato (1936), H enning & MacIntosh (1946), R olle (1947), and Verge (1948, 1949). All these authors mention that uninfected animals can be expected to have antibody titres, indeed the " 0" agglutinins may reach a titre of 1/300. It was suggested by Perdrix (1949) that "H" agglutinins may be more reliable for diagnostic purposes than "0" agglutinins. The use of the agglutination test in the present survey was to find the "normal" titre in uninfected animals and to assist in the diagnosis of S. typhimurium which was expec ted to occur more frequently than other species. MATERIALS AND METHODS
Faeces. Samples examined were less than I day old and many were fresh . Faeces were obtained if possible on the day of admission, on the 2 days thereafter and on the day following surgery. With the majority of samples sufficient material was available to inoculate 3 g. into 30 m!. of Selenite broth. This was incubated overnight at 37 °C and on the following day approximately 0'1 m!. was plated onto desoxycholate citrate agar, which was again incubated overnight. Suspect colonies were provisionally identified by the slide agglutination test and their identity confirmed by the Central Salmonella Reference Laboratory, to whose staff I am indebted. Agglutination tests. The agglutination titres of the sera were measured using S. typhimurium "0" and "H" antigens standardized to Browns tube 2 opacity. The dilutions used were 2, 10, 20, 40 and doubling dilutions thereafter to the end point of the titre. The tubes were incubated overnight at 37 °C and the result read the following morning.
102
BRITISH VETERINARY JOURNAL,
126, 2
RESULTS
Clinical cases The first case was a 5-year-old gelding in the University of Liverpool Veterinary Field Station. This animal was operated on for roaring under a general anaesthetic on 2 July 1967. Over a period of several days following surgery it developed nervous symptoms, consisting of holding the head up and to the right, fever, diarrhoea and jaundice. T en days after the operation it developed acute colic and was destroyed. At post-mortem examination severe colitis, typhlitis, evidence of septicaemia and an enlarged pale liver were found. All the organs cultured revealed S. typhimurium phage type 32. No further clinical cases occurred at this time. The second case seen in September 1967 which did not occur at the Field Station, involved a Welsh Pony mare. The animal had been given a dose of piperazine as it was suspected of being infested with worms, but no worm egg count was undertaken. Following medication diarrhoea developed which was profuse, green and watery. A course of sulphaguanidine resulted in only slight improvement. Fourteen days after the anthelmintic treatment a sample of faeces was submitted to us and S. typhimurium was recovered and a course of chloramphenicol was instituted. Nineteen days later a further sample of faeces which remained thin and watery was examined, and the organism was still present. At no stage was the animal clinically ill and it continued working. Unfortunately no further examinations were possible. A summary of an outbreak involving a number of horses at the Field Station has been given by Baker (1969) and further d etails of the cases are given here. The organism was introduced into the Field Station on 23 September 1967 by a cow infected with S. typhimurium phage type U162. On 2 October 1967 a pony brought into the hospital 2 days previously for castration was found to be excreting the organism but it was discharged before the bacteriological examination was completed and it was not followed up. At no time whilst in the hospital was it clinically affected. The following day (3 October) a pony gelding operated on for roaring a few days previously was found to be excreting the same salmonella, this animal was also without clinical symptoms. The organism was not isolated on the next 2 days and on the third day treatment with chloramphenicol was instituted for 5 days. The animal was discharged 20 days after the organism was originally isolated. On 6 October 1967 a 2-year-old filly which had been in the hospital for some time for the removal of a tumour and which had not been infected when admitted, d eveloped diarrhoea and depression. The same phage type, U 162, of S. typhimurium was isolated from its faeces . The following day the horse was clinically normal although still excreting the organism. Sensitivity tests suggested that ampicillin was the drug of choice but treatm ent with it had no effect on excretion of the organism and a 5 day course of chloramphenicol was started. Faeces were bacteriologically n egative after this treatment and the animal was discharged 14 days later. A faeces sample received after the animal had been at home for a fortnight was also free of the
SALMONELLOSIS IN THE HORSE
organism. These three horses had occupied boxes which had previously been occupied by the cow.
Survey The faeces survey was conducted on a total of 20 1 horses and in addition to the cases d etailed above three further infected animals were discovered. A foal, shot on the day of admission as it had a broken leg, was examined post mortem and although no enteric lesions were found S. rostock was isolated from 20
V>
.!! a.
E o V>
o Z
Reciprocal of titre
o Z
Fig.
I.
Histogram showing the number of unaffected horses with the end point( of their "0" titres .
20
a. E o
'" o
Z
o
Reciprocal of titre
Z
Fig.
2.
Histogram showing the number of unaffected horses with the end points of their "H" titres.
(04
BRITISH VETERINARY JOURNAL,
126, 2
the rectal contents. The second case was a gelding, in hospital for removal of a cirrhous cord, the first two faeces samples from it after admission did not yield any organi.sms of significance, but S. typhimurium was obtained from the third sample. It is probable that the animal brought the organism in with it as there were no other known infections in the hospital at the time. The last case was an aged grey gelding in for attention to the teeth. Salmonella virchow was isolated from its faeces on the day of admission but not from samples taken on the following days. The serological survey was conducted on fifty animals and the results are given in Figs. 1 and 2. This survey was started some time after the faecal survey and no animal with S. typhimurium infection was examined. The foal with S. rostock had no serum "0" agglutination but it had an "H" titre of 1 /40. The remaining animals examined were free of salmonella infection at the time of examination but showed titres of up to 1/ 160. There was no correlation between "0" and "H" titres. DISCUSSION
The symptoms of salmonellosis described in this paper agree with descriptions of the disease in adult horses as described by other authors, with the exception of fistulous withers and arthritis, but horses with these latter lesions at the Field Station have not been specifically examined for salmonellae. Predisposing factors were present in two horses. One case was apparently associated with anthelmintic treatment, and one case with general anaesthesia and surgery. When this la tter case was detected the survey had not commenced and it is not known if other horsl.':s were infected although it is possible. One of the horses in the outbreak of infection was passing the organism within a few hours of contact with an infected environment but the organisms did not become established in the intestine. The horse infected with Salmonella virchow was detected shortly after the occurrence of an epidemi c of infection with this organism in humans and other animals, principally chickens. The origin of the infection in the horse could not be traced. The results of the faecal survey show that approximately 1·5 per cent of horses in this area may be clinically normal carriers. It had been anticipated that infection with Salmonella dublin might be discovered as this organism had recently been common in cattle and other species in this area. However, no cases occurred either of clinical illness or of carri ers, even after two infecte d calves with Salmonella dublin were admitted, prior to diagnosis, to the Veterinary Field Station. The presence of agglutinins to S. ~yphimurium in normal horse sera was expected following the finding of titres of S. abortus equi in normal horses by H enning & MacIntosh (1946) and others, and this is due to salmonellae having antigeni c features in common with other enterobacteraceae (Lovell, 1932, 1934). Whi.Ist no horses with Salmonella typhimurium were examined serologically the results of the survey are of interest as they indi cate that a ti.tre of at least 1/240 and probably higher would be r equired in order to indicate tha t the a nimal had been exposed to this organism.
SALMOr ELLOSIS IN THE HORSE
ACKNOWLEDGMENTS
I wish to thank Professor D . L. Hughes for help in the preparation of this paper, :Miss J. Hanson for technical assistance and Mr K. Bell for the preparation of the antigens. REFEREN CES
BAKER,]. R. (1969) . Vet. R ec., 85, 8. BECKER, C. R . (1968). Mich. st. Univ. Vet., Spring, p. 123. BENAZZI, A. (1949). Atti. Soc. ital. Sci. vet., 3, 505. BRYANS, ] . T., FALLON, E. H. & SHEPHERD, B. P. (1961 ). Cornell Vet., 51, 467 . BUXTON, A. (1957). Salmonellosis in Animals. Farnham Royal: C.A.B. CONTI, M. & SARTI, G. (1940). Boll. Inst. Sieroter, Milano, 19,338. CORDY, D. R. & DAVIS, R. W. (1946). J. Am. vet. med. Ass., 108,20. DEBLASI, R . & BIGGI, D. (1954) . Clin. Vet., 77, 39. DIMMOCK, W. W., EDWARDS, D. R. & BRUNER, D. W. (1940). Cornell Vet., 30, 319. GRAHAM, R. F., REYNOLDS, H. K. & HILL, ]. F. (1920). J. Am. vet. med. Ass., 56, 378. GOTZE, U . ( 1968). Zentbl. Vet. Med., B 15,878. HAJDU, C. & KORZENSKY,]. (1938). Allotov Lapok., 61, 188. HANSEN, A. C. (1947). Macinedsskr Dyrlaeg., 58, 367. HENNING, M . W. & MAcINTOSH, B. M . (1946). J.S. Afr. vet. med. Ass., 17, 88. HIRATO, K. (1936). J. Jap . Soc. vet. Sci., 15,31 9. KUHLMANN, W. (1964). Mh . VetMed., 18,790. LOVELL, R . (1932). J. Camp . Path., 45, 27. LOVELL, R. (1934) . J. Camp . Path., 47, 107. MANN, P. H., CAVRlNI, C. & PIERACCI, F. (1964) . Cornell Vet., 54, 495. MANTOVANI, A. ( 1950a) . Clin. Vet., 73, 330. MANTOVANI, A. (1950b). Atti. Soc. ital. Sci. vet., 4, 620. MONDOLFO, U. (1936). Rif Med., 52, 961. PERDRIX,]. (1949). Rev. Immunol., 13, 287. ROLLE, M. ( 1947). B erl. Munch . tieriir;;tl. Wschr., 0.4,37. SCHREITER, M. (1960). Mh . VetMed., 15, 888. SEDDEN, H. R . (1953). Commonwealth of Australia, Department of H ealth, ser. pub. No. Sydney. SMITH, H . W. & BUXTON, A. (1951 ). Br. med. J ., I , 1478. VERGE,]. (1948). Rev. camp. Path. , 49, 643. VERGE, ]. (1949). Rep. XIVth Int. Vet. Congr., L ondon, 2, 28 1.
10.
(A ccepted for publication 8 Ju f:y 1969) La Sabnonellose chez Ie cheval (Baker) R esUUle. Cet article decrit les observations de l'auteur sur la salmonellose chez les chevaux, avec d es d etails sur une etude bacteriologique et serologique. Sabnonellose des Pferdes (Baker) Zusanunenfassung. In dieser Abhandlung wird die Salmonellose d es Pferdes aus der Sicht des Authors beschrieben und Einzelheiten einer bakteriologischen und seologischen Reihenuntersuchung werden angeftihrt. Sabnonellosis en el caballo (Baker) Res UUlen. Este papel describe la salmonellosis en los caballos conforme la ve el autor, y da detalles de un estudio bacteriol6gico y serol6gico.