The Genetic Diversity of Merozoite Surface Antigen 1 (MSA-1) among <i>Babesia bovis</i> Detected from Cattle Populations in Thailand, Brazil and Ghana

Abstract

In the present study, we screened blood DNA samples obtained from cattle bred in Brazil (n=164) and Ghana (n=80) for Babesia bovis using a diagnostic PCR assay and found prevalences of 14.6% and 46.3%, respectively. Subsequently, the genetic diversity of B. bovis in Thailand, Brazil and Ghana was analyzed, based on the DNA sequence of merozoite surface antigen-1 (MSA-1). In Thailand, MSA-1 sequences were relatively conserved and found in a single clade of the phylogram, while Brazilian MSA-1 sequences showed high genetic diversity and were dispersed across three different clades. In contrast, the sequences from Ghanaian samples were detected in two different clades, one of which contained only a single Ghanaian sequence. The identities among the MSA-1 sequences from Thailand, Brazil and Ghana were 99.0–100%, 57.5–99.4% and 60.3–100%, respectively, while the similarities among the deduced MSA-1 amino acid sequences within the respective countries were 98.4–100%, 59.4–99.7% and 58.7–100%, respectively. These observations suggested that the genetic diversity of B. bovis based on MSA-1 sequences was higher in Brazil and Ghana than in Thailand. The current data highlight the importance of conducting extensive studies on the genetic diversity of B. bovis before designing immune control strategies in each surveyed country.

Diagnostic Tools for the Identification of Babesia sp. in Persistently Infected Cattle

“…Cattle, as well as buffaloes, have been screened with highly sensitive PCR assays to detect persistently infected animals in order to genetically characterize the Merozoite Surface Antigen (MSA-1) diversity in Babesia bovis populations present in cattle premises from Mexico [20], Thailand, Brazil and Ghana [21], Vietnam [22], Thailand [23], Sri Lanka, Mongolia and Vietnam [24].…”

Genetic Diversity of Babesia bovis MSA-1, MSA-2b and MSA-2c in China

“…Antigenic polymorphism has been applied as a strategy by most protozoan parasites to escape the immune response of mammalian hosts, and it is a major obstacle preventing the development of effective vaccines against these parasites [7]. In our present study, analysis of the genetic relationships of B. bovis MSA-1, MSA-2b and MSA-2c of Chinese isolates, with respect to almost all available related sequences deposited in the GenBank database (including Mongolia, Vietnam, Philippines, Thailand, Israel, Vietnam, Sri Lanka, Mexico, Argentina, Brazil, Japan and USA) was conducted [7,12,[18][19][20][21][22][23][24]26,30,31]. Phylogenetic analysis showed that the MSA-1 amino acid sequences had a wide distribution in four clades.…”

“…Phylogenetic analyses of B. bovis MSAs have been performed in several countries, including Mongolia, Vietnam, the Philippines, Thailand, Israel, Vietnam, Sri Lanka, Mexico, Argentina and Brazil [7,12,[18][19][20][21][22][23][24][25][26]. In China, molecular epidemiological investigations of B. bovis infection have been performed in several provinces [4,5].…”

Variable and Variant Protein Multigene Families in Babesia bovis Persistence

“…Among those families mentioned above, the rap1 , msa1 , sbp2 , and 6-cys multigene families and their encoded proteins fall into the variable category. The diversity present in variable genes coupled with their relative stability make them good markers for use in epidemiologic studies at the isolate level, and advantage has been taken of rap1 and msa1 sequences repeatedly for this purpose (for example, see [21,22,23,24,25,26,27,28,29,30]). In contrast, members of the ves multigene family are highly variant in sequence and the expressed member(s) further vary rapidly during the course of infection in an individual host [14].…”