Hamadan University of Medical Sciences Avicenna Journal of Clinical Microbiology and Infection 2383-0298 13 2 2026 06 29 Can Neosporosis Be a Threat to Human Health? 119 126 10.34172/ajcmi.3637 EN Razieh Hosseini https://orcid.org/0000-0002-7178-7467 Ali Hajimohammadi REVIEW 10.34172/ajcmi.3637 2025 04 06 2025 08 09 Introduction: Neospora caninum is an intracellular protozoan parasite that primarily affects domestic animals, notably dogs and cattle, but its presence in wildlife is increasing. This parasite is a significant cause of abortion in cattle and can lead to severe neurological disorders in dogs. The transmission dynamics of N. caninum, particularly from dogs to humans, have been a subject of considerable investigation. The implications of N. caninum infections in wildlife are significant, as they can affect not only the health of the animals themselves but also the broader ecosystem and agricultural practices. While the primary hosts of N. caninum are dogs and cattle, the potential for zoonotic transmission to humans has been speculated due to the biological similarities between N. caninum and Toxoplasma gondii, a well-known zoonotic pathogen. Thus, this review document has been designed to comprehensively deal with the relevance of this issue. Results: Research indicates that humans may be exposed to N. caninum through environmental contamination with oocysts shed in dog feces. This is similar to the transmission pathways of T. gondii, where the ingestion of oocysts can lead to infection. Studies have reported the presence of antibodies against N. caninum in human sera, indicating some level of exposure, in countries such as in Brazil, Egypt, the United States, and Japan. The seroprevalence of N. caninum in dogs widely varies across different regions of the world, influenced by factors such as age and geographical location. Conclusion: Although N. caninum shares biological similarities with T. gondii, current evidence does not support its classification as a zoonotic pathogen. While serological studies indicate human exposure, no confirmed cases of infection have been reported, and the parasite remains primarily a veterinary concern; however, continued surveillance and research are needed to clarify its zoonotic potential, especially in immunocompromised populations.