Neospora caninum is a protozoan parasite that causes neosporosis, a serious disease in cattle and dogs. It was previously misdiagnosed as Toxoplasma gondii. Neosporosis is a major cause of abortion in cattle, with significant economic losses. The parasite has a complex life cycle involving intermediate and definitive hosts, with dogs and coyotes as definitive hosts. Oocysts, shed in the feces of definitive hosts, can infect intermediate hosts through ingestion of contaminated food or water. Transmission can occur transplacentally or postnatally. The parasite is not known to infect humans, though some studies suggest potential zoonotic risk. The life cycle of Neospora caninum includes tachyzoites, tissue cysts, and oocysts. Tachyzoites and tissue cysts are found in intermediate hosts, while oocysts are excreted in the feces of definitive hosts. Oocysts sporulate outside the host and can survive in the environment. Transmission occurs through ingestion of tissues containing bradyzoites or sporulated oocysts. Transplacental transmission can occur when tachyzoites are transmitted from an infected dam to her fetus during pregnancy. Neospora caninum has a wide host range, including cattle, dogs, sheep, and other animals. Seroprevalence studies show that many species of mammals have been exposed to the parasite. However, the parasite has not been demonstrated in human tissues, and its zoonotic potential remains uncertain. The parasite is antigenically different from Toxoplasma gondii, and serologic cross-reactivity is considered minor. Risk factors for bovine neosporosis include the presence of definitive hosts such as dogs and coyotes, the age of cattle, and environmental factors like grazing and water sources. Transmission can occur through horizontal or vertical routes, with vertical transmission being particularly significant in cattle. The risk of abortion is influenced by the stage of pregnancy, the immune status of the dam, and the presence of other infections. Control measures include biosecurity practices, testing of replacement cattle, and prevention of transmission from definitive hosts. Vaccination is a potential control strategy, though effective vaccines are still under development. Prevention of transmission involves managing the environment to reduce the risk of oocyst contamination and implementing reproductive management strategies to minimize the risk of abortion. The parasite's life cycle and transmission routes make it a significant challenge for cattle producers, requiring ongoing research and management strategies to reduce the impact of neosporosis on livestock.Neospora caninum is a protozoan parasite that causes neosporosis, a serious disease in cattle and dogs. It was previously misdiagnosed as Toxoplasma gondii. Neosporosis is a major cause of abortion in cattle, with significant economic losses. The parasite has a complex life cycle involving intermediate and definitive hosts, with dogs and coyotes as definitive hosts. Oocysts, shed in the feces of definitive hosts, can infect intermediate hosts through ingestion of contaminated food or water. Transmission can occur transplacentally or postnatally. The parasite is not known to infect humans, though some studies suggest potential zoonotic risk. The life cycle of Neospora caninum includes tachyzoites, tissue cysts, and oocysts. Tachyzoites and tissue cysts are found in intermediate hosts, while oocysts are excreted in the feces of definitive hosts. Oocysts sporulate outside the host and can survive in the environment. Transmission occurs through ingestion of tissues containing bradyzoites or sporulated oocysts. Transplacental transmission can occur when tachyzoites are transmitted from an infected dam to her fetus during pregnancy. Neospora caninum has a wide host range, including cattle, dogs, sheep, and other animals. Seroprevalence studies show that many species of mammals have been exposed to the parasite. However, the parasite has not been demonstrated in human tissues, and its zoonotic potential remains uncertain. The parasite is antigenically different from Toxoplasma gondii, and serologic cross-reactivity is considered minor. Risk factors for bovine neosporosis include the presence of definitive hosts such as dogs and coyotes, the age of cattle, and environmental factors like grazing and water sources. Transmission can occur through horizontal or vertical routes, with vertical transmission being particularly significant in cattle. The risk of abortion is influenced by the stage of pregnancy, the immune status of the dam, and the presence of other infections. Control measures include biosecurity practices, testing of replacement cattle, and prevention of transmission from definitive hosts. Vaccination is a potential control strategy, though effective vaccines are still under development. Prevention of transmission involves managing the environment to reduce the risk of oocyst contamination and implementing reproductive management strategies to minimize the risk of abortion. The parasite's life cycle and transmission routes make it a significant challenge for cattle producers, requiring ongoing research and management strategies to reduce the impact of neosporosis on livestock.