Neospora

Abstract

This chapter emphasizes the research performed on canine and bovine neosporosisduring almost three decades after its description. This parasitic disease causedby the protozoan Neospora caninum is associated with neuromuscular disordersin dogs and abortions in cattle. Neosporosis was first recognized in dogs inNorway, but its description of N. caninum as a new genus and species was proposed in the USA by Dubey and collaborators in 1988. After the protozoan wasisolated from dogs suffering the disease, neosporosis was recognized as the first cause of bovine abortion in dairy cattle from California, USA. Noteworthy, N. caninum is one of the most efficiently congenitally-transmitted organisms. N.caninum-infected cows deliver up to 90% of congenitally infected calves. Afterthe indirect fluorescent antibody test was described for serological diagnosis of neosporosis, many serological tests were developed for detection of antibodies in cattle and other domestic and wild species. The definitive host was unknown until 1998, when N. caninum oocysts were identified and characterized in dogs experimentally fed with infected mouse tissues. Experimental oral infection of cattle with N. caninum oocysts was achieved later on. Nowadays, additional definitive hosts have been described: the coyote (Canis latrans), the Australian dingo (Canis lupus dingo), and the wolf (Canis lupus). Treatments of neuromuscular neosporosis in dogs have been successfully described, but no vaccine or drugs are available for controlling neosporosis in cattle even though economic losses have been estimated in over 1 billion dollars in both beef and dairy industry worldwide.