Equine toxoplasmosis: a survey for antibodies to Toxoplasma gondii in horses.

This study determines the prevalence of antibodies for the Toxoplasma gondii parasite, which causes toxoplasmosis, in a diverse sample of horses from across the United States.

Methodology

• The researchers selected a nationwide sample of horses to assess the occurrence of toxoplasma antibodies in this species.
• A total of 1,294 serum samples from different breeds of horses were tested using the microtitration indirect hemagglutin test.
• The breeds tested included Arabian, Paint, Quarter Horses, Thoroughbred, and Standardbred, allowing for a varied and representative sample.

Findings

• The study revealed that 20% of the horses tested showed the presence of toxoplasma antibodies, indicating previous or current infection with Toxoplasma gondii.
• The prevalence of these antibodies seemed to vary slightly among the different breeds of horses tested. Arabian horses showed a prevalence of 19%, Paint horses 22%, Quarter Horses 13%, Thoroughbred 24%, and Standardbred 17%.
• An interesting finding was the increase in antibody prevalence with age. The study found that only 2% of horses aged one year showed presence of toxoplasma antibodies, which increased to 18% in two-year-old horses, and to a staggering 38% in horses aged twelve years.
• No significant differences in prevalence were found across different broad geographic locations in the US, indicating that toxoplasma infection in horses may not be linked to specific regional climatic or environmental conditions.

Implications of the Study

• However, significant differences were observed depending on the premises where horses were kept. Some ranches showed no traces of infection, while up to 67% of the horses on others were found to be seropositive for toxoplasmosis.
• This suggested that management practices, hygiene standards, or presence of vectors (like cats) at these premises might play a significant role in the spread of toxoplasma infection in horses.

Note: Toxoplasmosis is a disease caused by the parasite Toxoplasma gondii, which can infect most animals and birds as well as humans. It is most commonly transmitted through the ingestion of raw or undercooked meat containing Toxoplasma cysts, or through contact with cat feces, which can contain the parasite’s eggs.