Assessment of equine piroplasmids in the Nhecolândia sub-region of Brazilian Pantanal wetland using serological, parasitological, molecular, and hematological approaches.

This study evaluated the prevalence and characteristics of equine piroplasmid infections in horses in the Nhecolândia sub-region of the Brazilian Pantanal wetland. The results showed high rates of exposure and infestation, indicating that equine piroplasmids are endemic in this region.

Research Aim and Methodology

• The primary objective of this research was to gather epidemiological information on equine piroplasmids in the Nhecolândia sub-region of the Pantanal wetland. To accomplish this, researchers investigated the infection patterns of T. equi and B. caballi in different groups of horses. They also identified the tick species infesting these horses, studied phylogenetic relationships among Theileria equi 18S rRNA gene sequences, and assessed horses’ hematological parameters as indicators of potential anemia.
• Blood and serum samples were collected from 170 horses in four different categories to carry out an enzyme-linked immunosorbent assay and a polymerase chain reaction (PCR) to detect piroplasmid DNA. The collected ticks were identified and inspected for the presence of piroplasmid sporokinets.
• The researchers used three nested PCRs for phylogenetic analysis. The resulting sequences were compared to previously published sequences in GenBank for T. equi.

Key Findings

• The study found that a significant proportion (61.8% and 52.9%) of the sampled horses were exposed to T. equi and B. caballi, respectively. Moreover, piroplasmid DNA was detected in 43.5% of the horses.
• Sequencing results showed a 98-100% identity with some sequences previously published in GenBank for T. equi. Some variations, termed microheterogeneity, were noted amongst these sequences.
• About half of the horses were infested with ticks Dermacentor nitens, Amblyomma sculptum, and Rhipicephalus microplus, either singly or co-infested. These ticks serve as vectors for piroplasmosis.
• The study identified infected horses as potential asymptomatic carriers for piroplasmosis, as positive and negative animals displayed similar red blood cell counts and packed cell volume, and no sporokinets were found in the blood smears, hemolymph, and eggs of the ticks.

Implications and Recommendations

• The findings illustrate high prevalence and endemic nature of equine piroplasmids in the Pantanal region, reaffirming the need for multiple detection methods to effectively manage these parasites.
• Considering that breeding mares and foals had the highest occurrences for molecular tests and tick infestations, these demographics should be a priority in monitoring efforts to mitigate the disease’s impact.