Genetic diversity of Babesia bovis studied longitudinally under natural transmission conditions in calves in the state of Rio de Janeiro, Brazil

Matos, Carlos António; Silva, Jenevaldo Barbosa da; Gonçalves, Luiz Ricardo; Mendes, Natália Serra; Obregón, Dasiel; André, Marcos Rogério; Machado, Rosangela Zacarias

doi:10.1590/s1984-29612020089

Cited by 1 publication

(1 citation statement)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A few other genetic markers were occasionally used, but displayed low genetic diversity levels, e.g., the 18S rRNA, rhoptry-associated protein 1 (RAP-1a), Spherical Body Protein-2 (sbp-2), Spherical Body Protein-4 (sbp-4) and the Thrombospondin-Related Anonymous Protein (trap) [5,[27][28][29]. Since the MSA gene is very important for RBC invasion by Babesia merozoites/sporozoites, and there have been many B. bovis isolates tested for this gene, the present study provides the first comprehensive genetic analysis for all partial nucleotide sequences of B. bovis-MSA-tested isolates published on the GenBank from 22 studies [11,18,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49]. These isolates represent various MSA gene fragments including the MSA-1 (n = 199 isolates), MSA-2a1 (n = 24), MSA-2b (n = 193) and MSA-2c (n = 148).…”

Section: Discussionmentioning

confidence: 99%

Genetic Diversity of Merozoite Surface Antigens in Global Babesia bovis Populations

El-Alfy,

Abbas,

Elseadawy

et al. 2023

Genes

View full text Add to dashboard Cite

Cattle can be severely infected with the tick-borne protozoa Babesia bovis, giving rise to serious economic losses. Invasion of the host’s RBCs by the parasite merozoite/sporozoites depends largely on the MSA (merozoite surface antigens) gene family, which comprises various fragments, e.g., MSA-1, MSA-2a1, MSA-2a2, MSA-2b and MSA-2c, highlighting the importance of these antigens as vaccine candidates. However, experimental trials documented the failure of some developed MSA-based vaccines to fully protect animals from B. bovis infection. One reason for this failure may be related to the genetic structure of the parasite. In the present study, all MSA-sequenced B. bovis isolates on the GenBank were collected and subjected to various analyses to evaluate their genetic diversity and population structure. The analyses were conducted on 199 MSA-1, 24 MSA-2a1, 193 MSA-2b and 148 MSA-2c isolates from geographically diverse regions. All these fragments displayed high nucleotide and haplotype diversities, but the MSA-1 was the most hypervariable and had the lowest inter- and intra-population gene flow values. This fragment also displayed a strong positive selection when testing its isolates for the natural selection, which suggests the potential occurrence of more genetic variations. On the contrary, the MSA-2c was the most conserved in comparison to the other fragments, and displayed the highest inter- and intra-population gene flow values, which was evidenced by a significantly negative selection and negative neutrality indices (Fu’s Fs and Tajima’s D). The majority of the MSA-2c tested isolates had two conserved amino acid repeats, and earlier reports have found these repeats to be highly immunogenic, which underlines the importance of this fragment in developing vaccines against B. bovis. Results of the MSA-2a1 analyses were also promising, but many more MSA-2a1 sequenced isolates are required to validating this assumption. The genetic analyses conducted for the MSA-2b fragment displayed borderline values when compared to the other fragments.

show abstract