The Veterinary Record, September 6, 1997 It is well known that diagnosis by the conventional M'Fadyean smear method, which is appropriate for most livestock species, is unreliable in the case of pigs because few B anthracis are present in the terminal bacteraemia of these animals. This observation has been reinforced in this study by the finding that, in the two pigs that died, B anthracis could not be isolated from the submandibu- lar or prefemoral lymph nodes. The best method of confirming anthrax in the pig, at least for the intestinal form of the disease, is by smear or culture of a biopsy specimen of a mesenteric lymph node. Human beings, like pigs, are omnivores and are traditionally regarded as fairly resistant to anthrax, which is primarily a disease of herbivores. Thus, if 48 of the 50 pigs survived a challenge with at least 107 spores of the most virulent strain available, then the danger to people working in an abattoir from exposure to an organ carrying B anthracis at a barely detectable level should be essen- tially nil. In most cases, people have contracted anthrax from animals only after being in contact with a carcase, or parts of a carcase, which is heavily infested with B anthracis, and >95 per cent of cases are of the cutaneous form in which the organism has entered through a cut or abrasion. In addition, it is exceed- ingly unlikely that B anthracis at the levels found in the organs would find the opportunity either to multiply in an abattoir or to persist and multiply to levels likely to give rise to human infec- tions further down the food chain. B anthracis is, to all intents and purposes, an obligate pathogen and is able to multiply outside the host only in exceptional circumstances (Bowen and Turnbull 1992, Lindeque and Turnbull 1994). Acknowledgements. - The results of this study were presented at The International Workshop on Anthrax, September 19-21, 1995, and published in the Proceedings (Salisbury Medical Bulletin Special Supplement 87, p 79). This work was supported by a MAFF grant under the Open Contracting Scheme. The authors are grateful to the Biological Resource Group, CAMR, for considerable technical help. References AMANO, H., KAJIO, N., MIZOGUCHI, T., OHMURA, K., SONE, M. & TSUCHIYA, Y. (1987) Journal of the Japanese Veterinary Medical Association 40, 124 ANTHRAX ORDER (1938) Order of the Minister of Agriculture and Fisheries, number 204, March 7, 1938. London, HMSO ANTHRAX ORDER (1991) Statutory Instruments 1991, No 2814, Animals. London, HMSO BOWEN, J. E. & TURNBULL, P. C. B. (1992) Letters in Applied Microbiology 15, 224 BRENNAN, A. D. J. (1953) Veterinary Record 65, 255 BRYAN, H. S. (1952) MSC Veterinarian 13, 19 DAY, L. E. (1937) Veterinary Medicine 33, 8 EDGINTON, A. B. (1990) Veterinary Record 127, 321 FERGUSON, L. C. (1981) Diseases of Swine. 5th edn. Ed A. D. Leman. Iowa State University Press. p 396 GEYER, H. G. & GOLDSTEIN, H. E. (1954) MSC Veterinarian 15, 31 HUDSON, J. R. (1953) State Veterinary Journal 8, 28 IPATENKO, N. G. (1966) Trenauchno-kontrol Inst. Vet. Preparatov 13, 297 (in Russian: English abstract) LINDEQUE, P. M. & TURNBULL, P. C. B. (1994) Onderstepoort Journal of Veterinary Research 61, 71 LITTLE, S. F. & KNUDSON, G. B. (1986) Infection and Immunity 52, 509 M'FADYEAN, J. M. (1903) Journal of Comparative Pathology 16, 35 SCHLINGMAN, A. S., DEVLIN, H. B., WRIGHT, G. G., MAINE, R. G. & MANNING, M. C. (1956) American Journal of Veterinary Research 17, 256 SPEARS, H. N. & DAVIDSON, J. C. (1959) Veterinary Record 71, 637 STEIN, C. D. & STONER, M. G. (1952a) Veterinary Medicine 42, 247 STEIN, C. D. & STONER, M. G. (1952b) Veterinary Medicine 47, 315 STEIN, C. D. & STONER, N. G. (1953) Veterinary Medicine 48,257 TURNBULL, P. C. B. (1990) Salisbury Medical Bulletin. Proceedings of the International Workshop on Anthrax. April 11-13, 1989, Winchester. No 68, Special supplement. p 53 TURNBULL, P. C. B., BOHM, R., CHIZYUKA, H. G. B., FUJIKURA, T., HUGH- JONES, M. E. & MELLING, J. (1993) Guidelines for the Surveillance and Control of Anthrax in Humans and Animals. Geneva, WHO. Zoon. /93.170 TURNBULL, P. C. B., BROSTER, M. G., CARMAN, J. A., MANCHEE, R. J. & MELLING, J. (1986) Infection and Immunity 52, 356 TURNBULL, P. C. B., DOGANAY, M., LINDEQUE, P. M., AYGEN, B. & McLAUGHLIN, J. (1992) Epidemiology and Infection 108, 299 VAN ES, L. (1937) Journal of the American Veterinary Medical Association 90, 331 WALKER, J. S., KLEIN, F., LINCOLN, R. E. & FERNELIUS, A. L. (1967a) Journal of Bacteriology 93, 2031 WALKER, J. S., KLEIN, F., LINCOLN, R. E. & FERNELIUS, A. L. (1967b) Journal of Bacteriology 94, 552 WILLLAMS, D. R., REES, G. B. & ROGERS, M. E. (1992) Veterinary Record 131, 363 Clinical manifestations of infectious canine cyclic thrombocytopenia S. Harrus, I. Aroch, E. Lavy, H. Bark Veterinary Record (1997) 141, 247-250 This paper describes five naturally occurring clinical cases of infectious canine cyclic thrombocytopenia that were the first serologically confirmed cases of Ehrlichia platys infection in Israel. In the USA this disease is considered subclinical, but the dogs in this study developed distinct clinical abnormalities. The signs observed by the owners included anorexia, lethargy, depression, weight loss and a mucopurulent nasal discharge. The principal findings on physical examination included lymphadenomegaly, pale mucous membranes, fever and the presence of ticks. The main abnormal haematological and biochemical findings included thrombocytopenia, the presence of giant platelets, low haematocrit, monocytosis and low albu- min concentrations. All five dogs were less than two years of age, and four were purebred dogs, suggesting that these two factors may be associated with increased risk to infection and clinical disease. Two of the dogs were seropositive to E canis, a finding which is compatible with other reports, and which con- firms that combined infections of E platys and E canis are com- mon; it also suggests that E canis infections may contribute to the pathogenesis of E plalys. The distinct clinical manifestation of the disease in these five dogs suggests that there may be a different, more virulent strain of Eplatys in Israel. INFECTIOUS canine cyclic thrombocytopenia (ICCT), caused by the rickettsia Ehrlichia platys, was first reported in Florida in the USA in 1978 (Harvey and others 1978). In blood films stained with Giemsa or new methylene blue, E platys parasites appear as blue intra-platelet inclusions resembling E canis morulae (Harvey 1990); however, the two organisms do not cross-react serological- ly (French and Harvey 1983). The rickettsia is presumed to be transmitted by the brown dog- tick, Rhipicephalus sanguineus (Hibler and others 1986, Woody and Hoskins 1991), but an experimental study failed to prove the connection and the mode of transmission therefore remains uncer- tain (Simpson and others 1991). In the USA the disease is considered to be subclinical, and is manifested mainly by parasitaemia followed by episodes of throm- S. Harrus, DVM, I. Aroch, DVM, E. Lavy, DVM, H. Bark, BVSc, PhD, Department of Clinical Sciences, School of Veterinary Medicine, Hebrew University of Jerusalem, PO Box 12, Rehovot, Israel 247