Ovine Neosporosis: The Current Global Situation

Abstract

In the past 20 years, Neospora caninum infection in sheep has been reported in at least 31 countries worldwide from all sheep-rearing continents (Europe, Asia, the Americas, Africa, and Oceania), and its role as an abortifacient agent is becoming more evident. Most studies of ovine neosporosis have focused on its epidemiology, based primarily on serological analysis, with only a few studies investigating the actual presence of the parasite by PCR and/or IHC. Individual seroprevalence rates were highly variable between countries, and even between regions within the same country, ranging from 0.0% to 67.4% positive. Furthermore, most of the studies were not directly comparable due to differences in experimental designs, sample sizes, husbandry systems, ecological factors, and serological tests (e.g., IFAT, ELISA, MAT, Western blot). The latter, along with the scarcity of studies on the relevance of N. caninum as an abortifacient agent, may bias the perception of the importance of this disease. This review summarizes the situation of N. caninum infection in sheep using all available published studies describing natural ovine neosporosis. The epidemiology shows that ovine neosporosis is found worldwide, and it poses a relevant risk to the sustainability of sheep flocks.

Global prevalence of Neospora caninum in rodents: A systematic review and meta‐analysis

“…In addition, they act as reservoirs, carriers and hosts for several parasitic pathogens (Mohammadi et al, 2022). Various studies have suggested that rodents may play a role in the maintenance of the N. caninum life cycle and the dissemination of N. caninum in the environment (Benavides et al, 2022;Ferroglio et al, 2003Ferroglio et al, , 2005Hamidinejat et al, 2011). Although a high prevalence of N. caninum has been reported in a number of herbivores and carnivores (Anvari et al, 2020;Ying et al, 2022), limited data are available on the exposure of rodent to N. caninum.…”

“…Neosporosis has been considered a cause of abortion in dairy and beef cattle worldwide. This disease can also cause abortion or neonatal mortality in sheep and goats, leading to high financial burdens and enormous economic losses (Benavides et al., 2022 ).…”

Recombinant Dense Granule Protein (NcGRA4) Is a Novel Serological Marker for Neospora caninum Infection in Goats

“…Both domestic and wild canines are considered definitive hosts for the protozoan, whereas many different types of animals, especially cattle goats and sheep, serve as intermediate hosts [1,2]. While its importance in cattle is widely recognized, this parasite may also potentially pose a significant threat as an abortifacient for small ruminants, and it is possibly the primary cause of reproductive failure for some flocks [2][3][4][5].…”