Genetic Analysis of Babesia Isolates from Cattle with Clinical Babesiosis in Sri Lanka

Abstract

Bovine babesiosis is a serious threat to the cattle industry. We prepared blood DNA samples from 13 cattle with clinical babesiosis from the Badulla ( = 8), Jaffna ( = 3), and Kilinochchi ( = 2) districts in Sri Lanka. These DNA samples tested positive in PCR assays specific for ( = 9), ( = 9), and ( = 1). Twelve cattle were positive for and/or One cow was negative for the tested species but was positive for on microscopic examination; the phylogenetic positions of 18S rRNA and cytochrome oxidase subunit III gene sequences suggested that the cow was infected with sp. Mymensingh, which was recently reported from a healthy cow in Bangladesh. We then developed a novel sp. Mymensingh-specific PCR assay and obtained positive results for one other sample. Analysis of gene sequences from the cow with positive -specific PCR results demonstrated that the animal was infected not with but with sp. Hue-1, which was recently reported from asymptomatic cattle in Vietnam. The virulence of sp. Hue-1 is unclear, as the cow was coinfected with and However, sp. Mymensingh probably causes severe clinical babesiosis, as it was the sole species detected in a clinical case. The present study revealed the presence of two bovine species not previously reported in Sri Lanka, plus the first case of severe bovine babesiosis caused by a species other than ,, and .

Host range and geographical distribution of Babesia sp. Mymensingh

“…In addition to these morphological differences, 18S rRNA, cytochrome oxidase subunit III (cox3) and apical membrane antigen 1 (ama-1) genes from Babesia sp. Mymensingh were phylogenetically different from those genes in B. bovis and B. bigemina (Roy et al, 2018;Sivakumar et al, 2018). These findings indicate that Babesia sp.…”

“…Moreover, the ring form of Babesia sp. Mymensingh is much smaller than that of B. bigemina (Sivakumar et al, 2018). In addition to these morphological differences, 18S rRNA, cytochrome oxidase subunit III (cox3) and apical membrane antigen 1 (ama-1) genes from Babesia sp.…”

“…Babesia sp. Mymensingh also morphologically differs from B. bigemina, because the angle between paired merozoites is obtuse in the former, but is acute in the latter (Lempereur et al, 2017;Sivakumar et al, 2018). Moreover, the ring form of Babesia sp.…”

“…In non-immune adult cattle, acute infection with Babesia induces massive intravascular haemolysis, which leads to clinical symptoms such as fever, hemoglobinuria, anaemia and jaundice (Bock, Jackson, Vos, & Jorgensen, 2004). Importantly, the affected animal may die if treatment with anti-babesial agents is delayed (Mosqueda, Olvera-Ramirez, Aguilar-Tipacamu, & Canto, 2012;Sivakumar et al, 2018;Vial & Gorenflot, 2006). Therefore, bovine babesiosis causes serious economic losses in the cattle industry (Kivaria, 2006).…”

“…Mymensingh, causing clinical babesiosis in cattle (Sivakumar et al, 2018). Based on 18S rRNA sequence comparison, this parasite was previously identified in an asymptomatic cow in Bangladesh (Roy et al, 2018).…”