A panel of minisatellite markers for the molecular characterization of Babesia bovis isolates.

GIL, G.; MORETTA R; ECHAIDE I; MOSQUEDA J; SUAREZ C; FARBER M; WILKOWSKY S

Mérida, México

Congreso; 9th Biennial Conference of the Society of Tropical Veterinary Medicine; 2007

Society of Tropical Veterinary Medicine

Prevention against babesiosis is currently obtained by vaccination with attenuated strains. When vaccine failures sporadically happens, it would be convenient to differentiate whether they are due to vaccine mishandling or to infection with Babesia field strains against the vaccinial strains are not protective . Besides, in B. bovis, there is a lack of basic knowledge about field strain diversity and geographical strain distribution due to the scarce number of molecular markers available. Minisatellites are tandem arrays of short repeated units of DNA that are frequently polymorphic. Tandem repeat typing is a new generic method which has been proved to be very efficient for the genotyping of microorganisms using PCR. The purpose of this work was to identify a panel of minisatellites that could be applied to the characterization of B. bovis isolates. The Tandem Repeat Finder program was used to search for minisatellites through the available sequences from the B. bovis ESTs Sequencing Project. In addition, we checked the results against the B. bovis genome to discard intron-containing sequences. Four regions harbouring repeated sequences were chosen and the corresponding primers matching the conserved region were designed. Two of them were the previously described Bv80 and TRAP. The other two were named p200 (according to a related antigen reported in B. bigemina) and Anonymous 3. Amplification by PCR, sequencing and comparative analysis of 11 strains from Argentina, Brazil, Uruguay, Mexico and USA determined that the tandem repeats varied in number and sequence among the isolates. Genome analysis of the four markers described in this work revealed that the PCR fragments were single copy and localized in chromosomes 2 and 3. The stability along the time course of infection was corroborated for Bv80 and Anonymous 3. Although a large number of field isolates must be tested to assess the feasibility of these methods, the markers proposed in this work could provide new molecular tools for the genotyping of B. bovis isolates.