Prevalence of <i>Theileria</i> and <i>Babesia</i> species in Tunisian sheep

Abstract

In this study, the prevalence of Theileria and Babesia species in sheep was assessed with Giemsa-stained 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.

Individual variability among autochthonous sheep in Northern Tunisia to infection by abomasum nematodes and Babesia/Theileria parasites

“…The higher prevalence obtained in the work of Rjeibi et al. (2016) could be attributed to the sampling location. In fact, authors identified the different piroplasms from three Tunisian bioclimatic zones (north, centre, and south) and they found that Babesia ovis was found exclusively in sheep from the centre of Tunisia whereas Theileria ovis was found in all regions.…”

“…The overall prevalence of Babesia and Theileria infection was 4.21%. This prevalence was compared to values in the study of Rjeibi, Darghouth, and Gharbi (2016) by PCR which reached 16.3 and 7.8% for Theileria ovis and Babesia ovis respectively. The higher prevalence obtained in the work of Rjeibi et al.…”

Prevalence and climatic influence on hemoparasites of cattle and sheep in Mosul, Iraq

“…infection has been documented among sheep in Kurdistan Region of Iraq of [3]. Jatau et al [22], Rjeibi et al [8], Bilgic et al [4], and Mohammed et al [23] reported a higher prevalence of hemoparasites infections among sheep in Nigeria, Tunisia, Turkey, and Sudan, respectively. Disparity in time of study, breeds of animals sampled, differences in sample size, the diagnostic tool used, and the management and nutritional status of animals sampled could have resulted in the inconsistency of prevalence recorded in this study compared to those by other researchers.…”

“…A. phagocytophilum affects both cattle and sheep [4,7]. Babesiosis is a tick-borne hemoparasitic disease caused by numerous species of protozoa from the genus Babesia [8]. These protozoans are found in the erythrocyte, and can infect a wide range of domestic and wild animals, and occasionally man [9].…”

Prevalence, First Molecular Identification and Characterization of Theileria lestoquardi in Sheep in Alhuda National Sheep Research Station, Al Gezira State, Sudan

“…were detected in 31 animals out of 45 (68.9%) by ME, which was similar to the rate reported by Gadelrb [19] in Khartoum State, Central Sudan (68%) but higher than that found by Osman et al [20], South-Darfur State, western, Sudan (4.9%). Different prevalence rates were recorded in different parts of the world; 29% in Iran [21], 4.8% in Tunisia [22] and 1.2% in Maghreb [23]. The high prevalence rate determined in the current study compared to other regions may be attributed to differences in climatic conditions and sample collection times as observed by Yaghfoori [24].…”