116 0038-2809 Tydskr.S.Afr.vet.Ver. (2007) 78(3): 116–120 Article — Artikel Seroprevalence of toxoplasmosis in sheep in South Africa N Abu Samra a , C M E McCrindle a* , B L Penzhorn b and B Cenci-Goga c INTRODUCTION Toxoplasma gondii is an intracellular protozoan with a large number of inter- mediate hosts, including all warm- blooded animals (mammals and birds) and humans, and felids are its definitive hosts 5 . Serological surveys have been done in various parts of the world and show that more than a third of the human population have antibodies against T. gondii. This high seroprevalence in humans demonstrates its importance as a zoonotic disease. This has even more relevance now than when most sero- prevalence studies were originally carried out, because of the current high risk of toxoplasmosis for HIV positive people 5 . Ingestion of undercooked mut- ton is regarded as an important source of infection for toxoplasmosis in humans 16 . In South Africa a human seroprevalence of 20 % was detected in 1978 by Jacobs and Manson 8 . Despite the fact that there is some litera- ture on the seroprevalence of toxo- plasmosis in wild felids, chinchillas, ferrets, free-ranging wild felids, cheetah and a dog 1,3,4,12,20,21 , there were no data on the seroprevalence in sheep in South Africa, although these data are available for many other countries 2,6,7,11,14,16,18,22 . Data on seroprevalence in sheep are consid- ered important because consumption of mutton is universally considered to be a source of zoonotic transfer to humans 16 . The estimated worldwide seroprevalence of toxoplasmosis in livestock is; cattle 9 %, sheep 30 % and goats 15 % 5 . Although the infection in animals is often asymptom- atic, abortion storms in sheep have also been decribed worldwide 6 . Sheep farming, for both wool and mut- ton, occupies approximately 590 000 km 2 of South Africa, which represents 53 % of all agricultural land 10 . The prevalence of T. gondii in humans in South Africa is likely to be related to the prevalence of seroposi- tive cases in sheep as it is elsewhere in the world 16 . The actual distribution of toxoplasmosis in sheep in South Africa was not known, but it was important to study the situation, because of the high consumption of mutton in this country 10 . The aim of this study was to investigate the seroprevalence of T. gondii in sheep in South Africa. MATERIALS AND METHODS Five of the 8 provinces of South Africa were chosen randomly to undertake this study 17 . The provinces were KwaZulu- Natal, Eastern Cape, Western Cape, Gauteng and Free State. A list of sheep abattoirs was obtained from the Red Meat Abattoir Association. In every province 2 abattoirs were randomly selected for sam- pling. The sheep sampled at abattoirs rep- resented the formal or commercial sector. One state veterinary district was selected per province from a list obtained from the National Department of Agriculture, so as to sample animals belonging to small-scale sheep farmers (representing the informal marketing sector). At the end of the study, a total of 600 serum samples was collected. Extra animals were sam- pled to compensate for problems encoun- tered while transporting or handling the sera. The origins of the sampled sheep were traced using records supplied by the abattoir managers. Traceability com- prised both backward tracing to the location of the farm of origin as well as forward tracing to the location of the butchers that bought the carcasses for retail distribution and sale to consum- ers. It was presumed that most of the sheep from the informal sector would be a Department of Paraclinical Sciences, Faculty of Veteri- nary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa. b Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa. c Departmento d’ Ispezione degli Alimenti di origine Veteri- naria, University of Perrugia, 01600 Perugia, Italy. *Author for correspondence. E-mail: cheryl.mccrindle@up.ac.za Received: March 2007. Accepted: July 2007. ABSTRACT Serum samples from 600 sheep were collected from 5 different provinces randomly chosen in South Africa. Two sheep abattoirs (representing formal slaughter of sheep) and 1 rural location (representing informal slaughter of sheep) per province were also selected randomly. The serum samples were tested for anti-Toxoplasma gondii IgG antibodies using 2 different serological tests: an indirect fluorescent antibody (IFA) test and an enzyme-linked immunosorbent assay (ELISA) test available as a commercial kit. This study provides the first published data on seroprevalence of toxoplasmosis in sheep in South Africa, although positive titres have been found previously in wild felids, ferrets, chinchillas and a dog. Data on seroprevalence in sheep is considered important because consumption of mutton is universally considered to be a source of zoonotic transfer to humans. Seroprevalence in humans in South Africa was previously found to be 20 % and it is postulated that this may be linked to the informal slaughter and consumption of mutton. During this study, the overall national seroprevalence per province in sheep was found to be 5.6 % (IFA) and 4.3 % (ELISA), respectively. This is lower than in other countries, possibly because South Africa has an arid climate. Differences in seroprevalence in different areas studied suggested an association with the climate and a significant correlation (P > 0.05) was detected between the prevalence of T. gondii and the minimum average temperature. The seroprevalence was found to be significantly higher (P < 0.01) in sheep originating from commercial farms (7.9 %) than in rural sheep in the informal sector (3.4 %). Also, sheep managed extensively had a seroprevalence of 1.8 %, which was significantly lower (P < 0.05) than the seroprevalence in sheep under semi-intensive or intensive management systems (5.3 %). An incidental finding of interest was the considerable movement of sheep to abattoirs and mutton after slaughter. The highest consumption of mutton was in the Western Cape Province (29.9 %) while the highest concentration of sheep is found in the Eastern Cape Province (30.1 %). Key words: seroprevalence, sheep, toxoplasmosis, veterinary public health. Abu Samra N, McCrindle C M E, Penzhorn B L, Cenci-Goga B Seroprevalence of toxoplasmosis in sheep in South Africa. Journal of the South African Veterinary Association (2007) 78(3): 116–120 (En.). Department of Paraclinical Sciences, Faculty of Veterinary Sci- ence, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa.