Characterization of the zoonotic potential of Toxoplasma gondii in horses from Rio de Janeiro State.

This research article deals with the investigation of antibodies against Toxoplasma gondii, a zoonotic parasite, prevalent in horses of various regions in Rio de Janeiro State, Brazil, hinting at its potentially wide distribution and risk to both public and animal health.

Study Design and Sample Collection

• The research was conducted over the course of two years, from 2012 to 2013.
• A total of 624 blood samples were collected from horses across eight regions: Baixadas Litorâneas, Serrana, Norte Fluminense, Noroeste Fluminense, Centro-Sul, Metropolitana, Médio Paraíba, and Costa Verde of Rio de Janeiro State, Brazil.

Method of Testing for Toxoplasma gondii

• All samples were subjected to the modified agglutination test, which identifies the presence of anti-Toxoplasma gondii antibodies. The test threshold was set at 1:25, meaning that a positive result indicates that the sample’s antibodies could effectively agglutinate with the antigens at dilutions above this ratio.

Results of the Antibody Tests

• 22.8% (142 out of 624) of the horse samples tested positive for anti-Toxoplasma gondii antibodies, indicating that these horses had been exposed to the parasite.
• Positive results were discovered in all sampled regions, suggesting a widespread occurrence of the parasite across the state.
• Statistically significant variations were observed in seropositivity rates across regions.
• The highest rate of positive cases were detected in the Médio Paraíba region, with over half of the horse samples (54.76%, or 23 out of 42) testing positive.
• The second highest prevalence was observed in the Norte Fluminense region, with a seropositivity rate of 39.58% (38 out of 96).

Implications for Public and Animal Health

• The broad distribution of Toxoplasma gondii in horses across Rio de Janeiro State highlights a public and animal health concern, given that the parasite is zoonotic and may therefore be transmitted to humans.
• The results emphasize the necessity for heightened control and preventive measures against this parasitic disease in horses.