Sant Candice, Allicock Orchid M, d'Abadie Roger, Charles Roxanne Albertha, Georges Karla
School of Veterinary Medicine, Faculty of Medical Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago.
Department of Preclinical Sciences, School of Medicine, Faculty of Medical Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago.
Parasitol Res. 2019 Apr;118(4):1171-1177. doi: 10.1007/s00436-019-06240-x. Epub 2019 Feb 13.
The agents of equine piroplasmosis, Theileria equi and Babesia caballi, are endemic in Trinidad, West Indies. While transmission is mainly by ixodid ticks, transplacental transmission of T. equi has also been reported. This disease has contributed to foetal losses as well as morbidity and mortality of neonatal foals and adult horses. Previous 18S rRNA-based phylogenetic studies indicated a noticeable degree of variation within and among B. caballi and T. equi isolates from different geographical regions. The objective of this study was to evaluate the diversity of T. equi and B. caballi obtained from horses in Trinidad by amplifying a region of the 18S rRNA gene. The phylogenetic trees for T. equi sequences obtained from horses in 2006 and 2011-2013 revealed that Trinidad sequences were of genotype A. Additionally, all of the B. caballi sequences from Trinidad were grouped together with other B. caballi sequences of genotype A. However, T. equi sequences from horses in Saint Kitts and Nevis clustered with sequences of genotype C. This study also identified two genotypes of T. equi in the equine population of Brazil. All of the T. equi and B. caballi sequences obtained from horses in Trinidad belong to genotype A and were similar to T. equi and B. caballi sequences of the same genotype that were submitted to GenBank™ databases. Countries in close proximity to Trinidad have T. equi sequences belonging to genotype C; therefore, movement of horses between these countries can introduce a new genotype of T. equi into the equid population of Trinidad.
马梨形虫病的病原体，即马泰勒虫（Theileria equi）和驽巴贝斯虫（Babesia caballi），在西印度群岛的特立尼达岛呈地方流行性。虽然传播主要通过硬蜱，但也有马泰勒虫经胎盘传播的报道。这种疾病导致了胎儿死亡以及新生马驹和成年马的发病和死亡。先前基于18S rRNA的系统发育研究表明，来自不同地理区域的驽巴贝斯虫和马泰勒虫分离株在内部和之间存在显著程度的变异。本研究的目的是通过扩增18S rRNA基因的一个区域来评估从特立尼达岛的马匹中获得的马泰勒虫和驽巴贝斯虫的多样性。从2006年以及2011 - 2013年的马匹中获得的马泰勒虫序列的系统发育树显示，特立尼达岛的序列属于A基因型。此外，来自特立尼达岛的所有驽巴贝斯虫序列都与其他A基因型的驽巴贝斯虫序列归为一类。然而，来自圣基茨和尼维斯岛马匹的马泰勒虫序列与C基因型的序列聚类。本研究还在巴西的马群中鉴定出了马泰勒虫的两种基因型。从特立尼达岛的马匹中获得的所有马泰勒虫和驽巴贝斯虫序列都属于A基因型，并且与提交到GenBank™数据库的相同基因型的马泰勒虫和驽巴贝斯虫序列相似。与特立尼达岛相邻的国家有属于C基因型的马泰勒虫序列；因此，这些国家之间马匹的流动可能会将马泰勒虫的新基因型引入特立尼达岛的马属动物群体中。
