title: Genetic polymorphism of Babesia bovis merozoite surface antigens-2 (MSA-2) isolates from bovine blood and Rhipicephalus annulatus ticks in Israel.
abstract: This study demonstrated the genetic diversity among MSA-2c, MSA-2a1 and MSA-2b proteins of Babesia bovis isolates obtained from bovine blood and Rhipicephalus annulatus tick samples. The least identities that were observed among the deduced amino acid sequences of MSA-2c, MSA-2a1 and MSA-2b were 55, 63, and 71%, respectively. During the study four B. bovis calves, aged about 1 month, were found to be infected with virulent field strains and developed babesiosis. Probably, the calves had received insufficient antibodies, or the antibodies raised against the vaccine strain did not cross-protect against virulent field isolates. The complete msa-2 locus from the Israeli B. bovis vaccine strain and two field isolates were characterized. Similarly to the Australian strains and isolates, the msa-2 loci of the examined Israeli strain and isolates had only two msa-2 genes - msa-2c and msa-2a/b - located between msa-2c and orfB. Several of the examined samples, contained different MSA-2 genotypes concurrently. No obvious geographical relationships among isolates from various regions of Israel were established. Moreover, in the phylogenetic analyses, the Israeli deduced MSA-2 amino acid sequences of the three examined genes were clustered together with sequences derived from other countries, proving that the msa-2 gene sequences of B. bovis shared the same genetic characters worldwide. The present study clearly showed that the MSA-2 proteins of B. bovis isolates from Israel were genetically distinct from the vaccine strains. Thus, further research will be needed in order to understand the genetic diversity mechanisms of B. bovis, and the immunological responses of the infected animals.
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel. Electronic address: moladt@int.gov.il.
authors.forename: T
authors.initials: T
authors.lastname: Molad
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel.
authors.forename: L
authors.initials: L
authors.lastname: Fleiderovitz
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel.
authors.forename: B
authors.initials: B
authors.lastname: Leibovich
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Wolkomirsky
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel.
authors.forename: O
authors.initials: O
authors.lastname: Erster
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Roth
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel.
authors.forename: M L
authors.initials: ML
authors.lastname: Mazuz
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Markovics
authors.affiliation: Division of Parasitology, Kimron Veterinary Institute, P.O. Box 12, Bet Dagan 50250, Israel.
authors.forename: V
authors.initials: V
authors.lastname: Shkap
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000235:genetics / Q000378:metabolism*; D016793:Babesia bovis / Q000235:genetics*; D001404:Babesiosis / Q000097:blood / Q000453:epidemiology / Q000469:parasitology*; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000469:parasitology*; D005786:Gene Expression Regulation; D007557:Israel / Q000453:epidemiology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D016052:Protozoan Vaccines; D048494:Rhipicephalus / Q000469:parasitology*; D014613:Vaccines, Attenuated
chemical_list: D000953:Antigens, Protozoan; C476548:MSA-2 protein, Babesia bovis; D008565:Membrane Proteins; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D014613:Vaccines, Attenuated
keywords: Babesia bovis; Cattle; Israel; MSA-2