Influence of season on gastrointestinal parasites in pigs with an emphasis on Balantioides coli in a city with a tropical climate

ABSTRACT: Rio de Janeiro is a state with a hot and humid climate throughout the year. This characteristic can generate parasitic dynamics that are poorly described in the literature, particularly in pigs, which have low tolerance for high temperatures. This study reports the diagnosis of gastrointestinal parasites in pigs in Rio de Janeiro and characterizes the effects of seasons on Balantioides coli. Samples from 21 pigs on an industrial farm were analyzed across seasons. Parasites were detected by qualitative and quantitative microscopic techniques, and B. coli was molecularly characterized in the feces of two pigs. Climatic data were retrieved from the state’s meteorological station. A statistically significant difference in the number of animals positive for parasites between the seasons of the year was detected. In addition, significant differences in the quantification of B. coli and Ascaris suum between seasons were detected, with the highest counts observed in autumn. Through molecular analysis, B. coli infection was confirmed in all fecal samples collected across seasons from two pigs, with type A0 being predominant. Genetic variants of B. coli differed according to season, highlighting the heterogeneous distribution of genetic material in parasitic cells. Overall, the diagnosis of gastrointestinal parasite infection in pigs of reproductive age kept on one property located in the state of Rio de Janeiro was most common in autumn.