Multilocus Characterization Reveals Two Geographically Structured Babesia Lineages in Sheep from Southern and...

In Kazakhstan, despite the diversity of ixodid ticks and extensive livestock movement throughout Central Asia, ovine Babesia infections are poorly characterized. The objective of this study was to determine the occurrence, genetic diversity and geographic distribution of Babesia spp. in sheep from southern and southeastern Kazakhstan. A total of 1458 blood samples from 51 settlements across five regions were screened by nested PCR targeting mitochondrial cytb. Positive samples were characterized by Sanger sequencing, with additional multilocus analysis based on 18S rRNA and mitochondrial cox1 sequences. Babesia DNA was detected in 75/1458 samples (5.1%), with variation in PCR positivity among regions. Positive samples occurred in Turkestan (3.6%), Jambyl (7.2%), and Almaty (21.2%), but not in Kyzylorda or Jetisu. Phylogenetic analyses identified two geographically structured lineages. Nine Turkestan samples formed a lineage related to the Babesia sp. Xinjiang/Dunhuang group and were provisionally designated Babesia sp. TRK. The remaining 66 samples formed a B. motasi lineage comprising five cytb genotypes and showing closer affinity to the Lintan/Tianzhu group than to the Hebei/Ningxian group. Despite high 18S rRNA identity with B. motasi, mitochondrial markers revealed substantial divergence. The findings of the current study expand understanding of ovine Babesia diversity in Central Asia and emphasize the need for genomic characterization to resolve the taxonomic status of the detected lineages.