Neospora caninum and Wildlife

Bovine neosporosis caused by Neospora caninum is among the main causes of abortion in cattle nowadays. At present there is no effective treatment or vaccine. Serological evidence in domestic, wild, and zoo animals indicates that many species have been exposed to this parasite. However, many aspects of the life cycle of N. caninum are unknown and the role of wildlife in the life cycle of N. caninum is still not completely elucidated. In North America, there are data consistent with a sylvatic cycle involving white tailed-deer and canids and in Australia a plausible sylvatic cycle could be occurring between wild dogs and their macropod preys. In Europe, a similar sylvatic cycle has not been established but is very likely. The present review is a comprehensive and up to date summary of the current knowledge on the sylvatic cycle of N. caninum, species affected and their geographical distribution. These findings could have important implications in both sylvatic and domestic cycles since infected wildlife may influence the prevalence of infection in cattle farms in the same areas. Wildlife will need to be taken into account in the control measures to reduce the economical losses associated with this important disease in cattle farms. 1. Introduction Neospora caninum is an obligate intracellular protozoan first described in dogs in 1984 [1] and identified since then in a wide range of warm-blooded animals, including many wildlife species [2–4]. Before 1988, when Dubey et al. [5] described a new genus and species, N. caninum, this parasite was probably misdiagnosed as Toxoplasma gondii [5]. Nowdays N. caninum is considered to be one of the main causes of abortion in cattle worldwide [4]. The control and prophylaxis measures necessary for bovine neosporosis, already complex, will be further complicated if wildlife plays a role in the domestic and sylvatic cycle of the parasite, as seems likely. The knowledge of the role of wildlife species as reservoirs of N. caninum and its implications in the cycle of this parasite is increasing, and many studies have been reported to date. The present review is a comprehensive analysis of present knowledge on the sylvatic cycle of N. caninum and summarizes the studies of presence of specific antibodies, DNA detection and isolation of N. caninum in wildlife to date, species affected, and their geographical distribution. Previous reviews [2–4] described prevalence levels from many studies, therefore, details on specific prevalence levels will only be given for the most recent studies. 2. Life Cycle and Transmission of