Recent work has highlighted and enumerated the economic annual losses due to Neospora caninum abortions worldwide, which should provide strong motivation for the control of bovine neosporosis. However, with the recent withdrawal from sale of the only commercially available vaccine, control options for N. caninum have become more restricted. While researchers continue to work on developing alternative efficacious vaccines, what are the control options presently available for the cattle industries? At the practical level, recommendations for ‘Test-and-cull’, or ‘not breeding from seropositive dams’ stand diametrically opposed to alternative options put forward that suggest a primary producer is better advised to keep those cows in the herd that are already seropositive, i.e. assumed to be chronically infected, and indeed those that have already aborted once. Treatment with a coccidiostat has been recommended as the only economically viable option, yet no such treatment has gained official, regulatory approval. Dogs are central to the life cycle of N. caninum and have repeatedly been associated with infection and abortions in cattle by epidemiological studies. Knowledge and understanding of that pivotal role should be able to be put to use in control programmes. The present review canvasses the relevant literature for evidence for control options for N. caninum (some of them proven, many not) and assesses them in the light of the authors’ knowledge and experience with control of N. caninum.
Neospora caninum: Seroprevalence and DNA detection in blood of sheep from Aguascalientes, Mexico
A. Castañeda-Hernández, C. Cruz-Vázquez, L. Medina-Esparza
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.
Neosporosis in animals—The last five years
J.P. Dubey, a,1, G. Schares, b
a Animal Parasitic Diseases Laboratory, Animal and Natural Resources Institute, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA
b Institute of Epidemiology, Friedrich-Loeffler-Institut – Federal Research Institute for Animal Health, Seestrasse 55, D-16868 Wusterhausen, Germany
Neospora caninum is a protozoan parasite of animals. Until 1988, it was misdiagnosed as Toxoplasma gondii. Since its first recognition in 1984 in dogs and the description of a new genus and species Neospora caninum in 1988, neosporosis has emerged as a serious disease of cattle and dogs worldwide. Abortions and neonatal mortality are a major problem in livestock operations and neosporosis is a major cause of abortion in cattle. This review is focused on current status of neosporosis in animals based on papers published in the last five years. Worldwide seroprevalences are tabulated. Strategies for control and prevention are discussed.
Gray wolf(Canis lupus) is a natural definitive host for Neospora caninum
J.P. Dubey?, M.C.Jenkins, C.Rajendran, K.Miska, L.R.Ferreira, J.Martins, O.C.H. Kwok, S.Choudhary
United States Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, Building 1001, Beltsville, MD 20705-2350, USA
The graywolf(Canis lupus) was found to be a new natural definitive host for Neospora caninum. Neospora-like oocysts were found microscopically in the feces of three of 73 wolves from Minnesota examined at necropsy. N. caninum-specific DNA was amplified from the oocysts of all three wolves. Oocysts from one wolf were infective for the gamma interferon gene knockout(KO)mice. Viable N. caninum (designated NcWolfUS1)was isolated in cell cultures seeded with tissue homogenate from the infected mouse.Typical thick walled tissue cysts were found in outbred mice inoculated with the parasite from the KO mouse. Tissue stages in mice stained positively with N. caninum-specific polyclonal antibodies. Our observation suggests that wolves may be an important link in the sylvatic cycle of N. caninum.