Prevalence and genetic diversity of equine piroplasms in Tov province, Mongolia.

Equine piroplasmosis represents a serious problem in horse industry. Although, researchers suggested the possible use of sub-unit vaccines to control equine piroplasmosis, the genetic diversity of vaccine candidate antigens was not properly investigated. In the present study, we screened 250 horses reared in three different districts of Tov province, Mongolia, for Babesia caballi and Theileria equi using ELISA and nested PCR (nPCR) assays. Among these animals, piroplasms were detected in 128 (51.2%) horses by nPCR assays (B. caballi, 42.4%; T. equi, 6.4%; and mixed infections, 2.4%), while 204 (81.6%) were positive by ELISA (B. caballi, 51.6%; T. equi, 19.6%; and mixed infections, 10.4%). Male and middle-aged horses showed higher positive rates than female and younger or older horses. The findings also suggested that a combination of nPCR and ELISA techniques might be useful to detect horses that were chronically or subclinically infected with piroplasms. B. caballi-BC48 and T. equi-EMA-1 gene sequences, in addition to 18S rRNA, were subjected to phylogenetic analyses, and the findings suggested the presence of genetically diverse populations of equine piroplasms in Mongolia. BC48 sequences were separated into four clades in phylogram, and all the Mongolian sequences determined in the present study were found in a single clade. However, a single BC48 sequence previously isolated from a tick in Mongolia formed a separate branch. Similarly, EMA-1 sequences formed four clades, and Mongolian sequences were observed in two different clades, one of which was formed only of Mongolian sequences and is suggested as a new clade. This is the first report that describes the genotypes of equine piroplasms in Mongolia. The findings also emphasized the need for further investigations to study the effect of genetic diversity observed among BC48 as well as EMA-1 sequences on host's immune responses.

Amino acid polymorphisms of PrP gene in Mongolian sheep.

To characterize amino acid polymorphisms in sheep prion protein (PrP), we analyzed the PrP genes from 271 sheep of 4 breeds (Khalkh, Yeroo, Orkhon and Khangai) raised in central Mongolia (Tuv, Uvurkhangai and Selenge prefectures). A total of 16 genotypes and 8 allelic variants of the PrP gene at codons 112, 136, 154 and 171 were found. At codon 171, 1.8% of the sheep had arginine/arginine (R/R) (resistant to scrapie) and 66.8% had glutamine/glutamine (Q/Q) (susceptible to scrapie). Several Yeroo and Orkhon sheep raised in Selenge prefecture had valine at codon 136 (136V) (highly susceptible to scrapie). Several Yeroo, Orkhon and Khangai sheep raised in Selenge prefecture had histidine at codon 154 (154H). Novel polymorphisms of valine (V) and serine (S) at codon 127, lysine (K) at codon 171, and leucine (L) and arginine (R) at codon 189 were also found in Khalkh, Yeroo and Orkhon sheep. It is not known whether these novel polymorphisms affect scrapie susceptibility.

Detection of equine Babesia spp. gene fragments in Dermacentor nuttalli Olenev 1929 infesting mongolian horses, and their amplification in egg and larval progenies.

Babesia equi (EMA-1) and Babesia caballi (BC48) gene fragments were amplified by polymerase chain reaction (PCR), in blood samples, and partially fed-females and egg and larval progenies of Dermacentor nuttalli, collected from horses in Altanbulag, Tuv Province, Mongolia. While Babesia parasite DNA was detected in some horse blood samples during the first PCR, all positive cases in partially fed-female ticks, eggs and larvae were confirmed by nested PCR. Present study reinforces earlier similar findings in unfed D. nuttalli ticks collected from an open space vegetation in Bayanonjuul, Tuv Province in Central Mongolia, pointing to the most likely important role of D. nuttalli in the transmission of equine babesiosis in Mongolia. The detection of parasite DNA in eggs and larval progenies is likewise suggestive of transovarial parasite transmission in this tick species.