An initial survey of 150 horses from Thailand for anti-Pythium insidiosum antibodies.

This study investigated the prevalence of antibodies against an infection-causing organism, Pythium insidiosum, in horses in Thailand, and found it is higher in horses than humans in the region.

Study Overview

• The study aimed to determine the occurrence of anti-Pythium insidiosum antibodies, which indicate exposure to the organism, in the Thai equine population. The organism is responsible for a severe infection known as pythiosis, affecting both humans and a wide range of animals.
• The interest in this organism stems from an increase in reported cases of human pythiosis in Thailand since 1985, with estimates suggesting that as many as 32,000 Thai people have been exposed to Pythium insidiosum.
• Previous studies indicated potentially high exposure rates in certain animal populations, with the first animal pythiosis case in Thailand being diagnosed in a horse in 2018. This initiated the study to understand the prevalence in the equine population of Thailand.

Methodology

• A total of 150 horses from across Thailand were sampled for the presence of anti-Pythium insidiosum antibodies in their blood serum.
• Three established serological tests were used to detect the presence of these antibodies: l) Enzyme-Linked Immunosorbent Assay (ELISA), ll) Immunochromatographic Test (ICT), and lll) Western Blot analysis.

Results

• ELISA test identified anti-Pythium insidiosum antibodies in three horses.
• The ICT and Western Blot tests confirmed the presence of the antibodies in one horse.
• Based on the total count of tested horses, the study estimated the incidence rate is 0.7% in the Thai equine population.
• When compared to other populations, this incidence is higher than in the Thai human population (0.07%) but significantly less than that found in the Brazilian equine population (11.1%).

Conclusions and Implications

• The results suggest that horses in Thailand might have a higher risk of exposure to Pythium insidiosum compared to humans.
• The study could help inform the understanding of the epidemiology and host susceptibility of pythiosis in Thailand, providing essential insights for public health policy development and animal health management practices.
• Overall, the research underscores the significant role of serological surveillance in understanding disease spatial and temporal trends among different host species.