Dataset Information

Prevalence of Theileria and Babesia species in Tunisian sheep.

ABSTRACT: In this study, the prevalence of Theileria and Babesia species in sheep was assessed with Giemsastained blood smear examination and polymerase chain reaction to identify the different piroplasms in 270 sheep from three Tunisian bioclimatic zones (north, centre, and south). The overall infection prevalence by Babesia spp. and Theileria spp. in Giemsa-stained blood smears was 2.9% (8/270) and 4.8% (13/270) respectively. The molecular results showed that sheep were more often infected by Theileria ovis than Babesia ovis with an overall prevalence of 16.3% (44/270) and 7.8% (21/270) respectively (p = 0.01). The molecular prevalence by Babesia ovis was significantly higher in females than in males (p < 0.05). According to localities B. ovis was found exclusively in sheep from the centre of Tunisia (Kairouan) whereas Theileria ovis was found in all regions. Infections with T. ovis and B. ovis were confirmed by sequencing. The sequence of T. ovis in this study (accession numbers KM924442) falls into the same clade as T. ovis deposited in GenBank. The T. ovis amplicons (KM924442) showed 99%-100% identities with GenBank sequences. Moreover, comparison of the partial sequences of 18S rRNA gene of B. ovis described in this study (KP670199) revealed 99.4% similarity with B. ovis recently reported in northern Tunisia from sheep and goats. Three nucleotides were different at positions 73 (A/T), 417 (A/T), and 420 (G/T). It also had 99% identity with B. ovis from Spain, Turkey and Iraq. The results suggest a high T. ovis prevalence in Tunisia with a decreasing north-south gradient. This could be correlated to the vector tick distribution.

SUBMITTER: Rjeibi MR

PROVIDER: S-EPMC6238706 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

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Prevalence of Theileria and Babesia species in Tunisian sheep.

Rjeibi Mohamed R MR Darghouth Mohamed A MA Gharbi Mohamed M

The Onderstepoort journal of veterinary research 20160524 1

In this study, the prevalence of Theileria and Babesia species in sheep was assessed with Giemsastained blood smear examination and polymerase chain reaction to identify the different piroplasms in 270 sheep from three Tunisian bioclimatic zones (north, centre, and south). The overall infection prevalence by Babesia spp. and Theileria spp. in Giemsa-stained blood smears was 2.9% (8/270) and 4.8% (13/270) respectively. The molecular results showed that sheep were more often infected by Theileria ...[more]

PMID: 27247070

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Project description:BackgroundTheileria annae is a tick-transmitted small piroplasmid that infects dogs and foxes in North America and Europe. Due to disagreement on its placement in the Theileria or Babesia genera, several synonyms have been used for this parasite, including Babesia Spanish dog isolate, Babesia microti-like, Babesia (Theileria) annae, and Babesia cf. microti. Infections by this parasite cause anemia, thrombocytopenia, and azotemia in dogs but are mostly subclinical in red foxes (Vulpes vulpes). Furthermore, high infection rates have been detected among red fox populations in distant regions strongly suggesting that these canines act as the parasite's natural host. This study aims to reassess and harmonize the phylogenetic placement and binomen of T. annae within the order Piroplasmida.MethodsFour molecular phylogenetic trees were constructed using a maximum likelihood algorithm based on DNA alignments of: (i) near-complete 18S rRNA gene sequences (n = 76 and n = 93), (ii) near-complete and incomplete 18S rRNA gene sequences (n = 92), and (iii) tubulin-beta gene sequences (n = 32) from B. microti and B. microti-related parasites including those detected in dogs and foxes.ResultsAll phylogenetic trees demonstrate that T. annae and its synonyms are not Theileria parasites but are most closely related with B. microti. The phylogenetic tree based on the 18S rRNA gene forms two separate branches with high bootstrap value, of which one branch corresponds to Babesia species infecting rodents, humans, and macaques, while the other corresponds to species exclusively infecting carnivores. Within the carnivore group, T. annae and its synonyms from distant regions segregate into a single clade with a highly significant bootstrap value corroborating their separate species identity.ConclusionPhylogenetic analysis clearly shows that T. annae and its synonyms do not pertain to Theileria and can be clearly defined as a separate species. Based on the facts that T. annae and its synonyms have not been shown to have a leukocyte stage, as expected in Theileria, do not infect humans and rodents as B. microti, and cluster phylogenetically as a separate species, this study proposes to name this parasite Babesia vulpes sp. nov., after its natural host, the red fox V. vulpes.

Dataset Information

Prevalence of Theileria and Babesia species in Tunisian sheep.

Publications

Prevalence of Theileria and Babesia species in Tunisian sheep.

Similar Datasets

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