Characterization of strains of from clinical cases in bovine using major surface protein 1a in Uruguay.

The major surface protein 1a gene has been used to characterize genetic diversity. This pathogen causes significant productivity and economic losses to the cattle industry. The objective of the present study was to report the first characterization of genetic diversity in Uruguay based on MSP1a genotypes and their putative relationship with . This cross-sectional study was conducted between 2016 and 2020. The study included whole blood samples from clinical cases of bovine anaplasmosis obtained from 30 outbreaks located in six Uruguay territorial departments. Diagnosis was performed using Giemsa-stained smears and confirmed by nested Polymerase Chance Reaction (nPCR) targeting the major surface protein gene. The genetic diversity of strains was characterized by analyzing the microsatellite and tandem repeats of MSP1a. Based on the microsatellite structure, four genotypes were identified. Genotype E was the most prevalent. Analysis of MSP1a tandem repeats showed 28 different strains from the combination of 31 repeats, with τ-10-15 and α-β-β-β-Γ being the most common. Repeats Γ, β, α, and γ were associated with the absence of with statistical significance ( < 0.05). Molecular observations showed that 46.7% of the strains identified in our samples lacked the ability to bind to tick cells; therefore, they were probably transmitted by other vectors. Strain genetic diversity provides valuable information for understanding the epidemiological behavior of A. and could contribute to the development of effective vaccines for the control of this disease.