Molecular characterization of South Indian field isolates of bovine Babesia spp. and Anaplasma spp.

Abstract

Ticks and tick-borne diseases (TTBDs) are considered major causes of economic loss in the livestock sector which incur an annual control cost estimated at US$ 498.7 million in India. Among these diseases, babesiosis, theileriosis and anaplasmosis are listed among the top ten livestock diseases in India and cause significant mortality and morbidity among cattle. However, molecular characterization of bovine Babesia and Anaplasma species are scant; thus, the aim of this study is to perform molecular characterization of field isolates of Babesia spp. and Anaplasma spp. infecting bovines in Kerala, South India. Blood smears and whole blood samples were collected from a total of 199 apparently healthy adult female cattle in Kerala. Based on microscopy, Babesia spp., Theileria orientalis and Anaplasma spp. organisms were detected in 9 (4.5%), 40 (20%) and 6 (3%) samples, respectively. Genus-specific polymerase chain reactions for amplification of 18S rRNA of Babesia spp. and 16S rRNA of Anaplasma spp. revealed positive results with 18 (9%) and 14 (7%) samples. The phylogenetic analysis of 18S rRNA gene sequences of Babesia spp. confirmed the existence of two different populations of Babesia spp. circulating in the blood of infected cattle viz., Babesia bigemina and a Babesia sp. genetically related to Babesia ovata. Further phylogenetic analysis using rap-1a sequences of isolates of B. bigemina revealed higher levels of genetic heterogeneity. However, the field isolates of B. bigemina displayed only slight heterogeneity when the rap-1c gene was examined. Polymerase chain reaction followed by sequencing and phylogenetic analysis of 16S rRNA gene of Anaplasma spp. revealed the existence of Anaplasma marginale, Anaplasma bovis and Anaplasma platys in bovines in South India. Based on msp4 gene sequences, all the field isolates of A. marginale from Kerala were clustered in a single clade with others isolated from around the world. To our knowledge, this study forms the first report on occurrence of B. ovata-like parasites and A. platys in cattle from India.

Epidemiology, Haematology and Molecular Characterization of Haemoprotozoon and Rickettsial Organisms Causing Infection in Cattle of Jammu Region, North India

“…The genetic polymorphism of Babesia spp. has been reported earlier using sequence information of 18S rRNA gene [1,33,34]. In the phylogenetic tree, the isolates of the present study formed a separate sub clade but clustered with an isolate from Iraq.…”

“…However, these distinguished itself from South African and American isolates, simulating reports from Kerala [1], wherein the isolates appeared in two different clades. In another study from India [34], close genetic relatedness was observed between B. bigemina isolates from North Eastern India with Argentina and Kenya rather than with China.…”

“…Sequence information of A. marginale isolates from the present study revealed a marked divergence from A. capra, A. central and A. ovis, although, small length of nucleotide sequence couldn't reveal any marked genetic heterogeneity from isolates of A. marginale across the world. In a study from south India, minimal heterogeneity was revealed within 16S rRNA and msp4 genes among the eld isolates from Kerala [1].…”

“…Among the various tick transmitted diseases babesiosis, theileriosis, anaplasmosis and ehrlichiosis are the signi cant ones that drive attention. Babesiosis is considered as economically important tick-borne haemoprotozoan disease in tropical and subtropical countries, the most prevalent species being Babesia bovis and Babesia bigemina [1]. B. bigemina, transmitted by brevirostrate tick, Rhipicephalus (Boophilus microplus) is usually associated with high parasitemias.…”

A Multiplex PCR Detection Assay for the Identification of Clinically Relevant Anaplasma Species in Field Blood Samples

“…However, using this method, it was difficult to clearly distinguish between A. capra, A. bovis, A. ovis, and A. phagocytophilum, as they are highly similar in terms of their morphological characteristics (Liu et al, 2012;Li et al, 2015;Wei et al, 2017;Lee et al, 2018). It was also difficult to distinguish these agents from other blood pathogenic agents, such as members of the Theileria and Babesia genera (Al-Hosary et al, 2018;Pradeep et al, 2019). Especially when the pathogen load is low, it is difficult to distinguish between these pathogens by microscopic examination.…”