Agents Of Equine Piroplasmosis Research Articles

The first study of the prevalence and genetic diversity of Theileria equi and Babesia caballi in horses in Russia.

Equine piroplasmosis (EP) is a global worldwide infection, which can lead to the death of animals. Despite the causative agents of EP being well studied, there are no data on the distribution and genetic characteristics of EP agents in any region of Russia. In this study, blood samples from 750 horses from Novosibirsk province, Irkutsk province, and Altai region of Russian Siberia were examined for the presence of EP agents. Theileria equi and Babesia caballi were detected in all examined regions, with mean prevalence rates of 60.4% and 7.2%, respectively. The identified pathogens were genetically characterized by the 18S rRNA gene. The determined T. equi sequences were highly conserved and belonged to genotypes A and E, with genotype E being found in 88.6% of genotyped samples. In contrast to T. equi, B. caballi sequences were genetically diverse. Seven sequence variants of B. caballi were identified, and only two of them matched known sequences from the GenBank database. The determined B. caballi sequences belonged to four distinct branches within genotype A. Mixed infections with several variants of B. caballi or with T. equi and B. caballi were common. The conducted phylogenetic analysis based on all available B. caballi sequences of the 18S rRNA gene (> 900bp) from GenBank and from this study first demonstrated the presence of five monophyletic clusters within genotype A and three clusters within genotype B. Thus, the genetic study of B. caballi from Siberia has significantly expanded the data on the genetic diversity of this pathogen.

Molecular characterization and phylogenetic analysis of Babesia and Theileria spp. in ticks from domestic and wild hosts in Sardinia

Piroplasmoses are tick-borne protozoan diseases caused by hemoprotozoan parasites with considerable economic, veterinary and medical impact worldwide. Here, the presence and diversity of piroplasmids was investigated in ticks collected from domestic and wild hosts in a typical subtropical environment of Sardinia island by standard PCR, sequencing, and phylogenetic analyses. We demonstrate the presence of strains closely related to the Theileria buffeli/sergentii/orientalis complex in Rhipicephalus sanguineus s.l., Rh. bursa, Rh. annulatus, Hyalomma marginatum, Dermacentor marginatus and Haemaphysalis punctata ticks. A strain detected in two Rh. sanguineus s.l. ticks collected from dogs grouped with T. equi, the agent of equine piroplasmosis. T. ovis, the main etiological agent of ovine theileriosis, was detected in one Rh. bursa tick from a mouflon. Babesia bigemina, the causative agent of bovine babesiosis, was detected in two Rh. sanguineus s.l. ticks from dogs. Our findings expand the knowledge on the repertoire of tick-borne pathogens present in Mediterranean ticks. Further analyses are needed to determine the role of ticks in the biological or mechanical transmission of piroplasmoses in this area.

Phylogenetic analysis of Theileria equi and Babesia caballi sequences from thoroughbred mares and foals in Trinidad.

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.

Prevalence of the causative agents of equine piroplasmosis in the South West of The Netherlands and the identification of two autochthonous clinical Theileria equi infections

Equine piroplasmosis (EP) has not been considered indigenous in The Netherlands. However, following the detection of an apparently indigenous subclinical Babesia caballi infection in a horse on Schouwen-Duiveland (an island in the Zeeland Province), a survey was undertaken between May and September 2010 to assess the prevalence of the causative agents of EP in the South-West of The Netherlands. Blood samples from 300 randomly selected horses were tested for specific antibodies against Theileria equi and B. caballi using an indirect fluorescence antibody test (IFAT), and for parasite DNA using a specific polymerase chain reaction combined with reverse line blotting (PCR-RLB). Twelve of the horses (4%) were seropositive for EP. Of these, nine (75%) were positive (titre⩾1:160) for B. caballi alone and three (25%) were also positive for T. equi. PCR-RLB detected T. equi DNA in five horses (1.6%), two of which were seronegative. Four (1.3%) of the positive horses (three positive for T. equi and one for both B. caballi and T. equi) were considered truly indigenous. During the study, two indigenous ponies from a farm situated outside the sampling area were diagnosed with acute clinical piroplasmosis characterized by severe anaemia and pyrexia. Blood smears showed T. equi - like inclusions in red blood cells, and T. equi infection was confirmed in both ponies by PCR-RLB. The initial subclinical B. caballi infection, the survey results and the two acute clinical EP cases confirmed the autochthonous transmission of B. caballi and T. equi infections in The Netherlands.