Molecular prevalence and phylogenetic analysis of Theileria annulata and Trypanosoma evansi in cattle in Northern Tunisia

Abstract

The present study aimed to estimate the molecular prevalence of Theileria annulata and Trypanosoma evansi infection in cattle in Northern Tunisia. A total number of 96 cattle from five farms were evaluated. T. annulata and T. evansi prevalences were 61% [56/66] and 10% [7/13], respectively, at a confidence interval (CI) of 95%, while co‐infection was present in 6% [4/8] of the tested animals at a CI of 95%. There was a significant correlation between age and the prevalence of T. annulata infection, whereas, there was no significant association shown with the age of cattle and T. evansi infection. Sequence and phylogenetic analyses showed that the T. annulata Tams1 gene and T. evansi ITS1 rDNA gene were highly conserved with 97.1–100% and 98.3–100% sequence identity, respectively.

Epidemiological situation of bovine tropical theileriosis in an arid region in central Tunisia with a phylogenetic analysis of Theileria annulata

“…Theileria annulata infection was observed in all age groups, with no statistically significant difference between these groups. This finding surprisingly contrast results of previous studies on TT, which find a positive association between age and Theileria infection, where infection is higher in old animals due to repetitive exposure (Salih et al., 2007; Sallemi et al., 2017). However, infection was absent in animals of less than 1 year old.…”

“…In Tunisia, TT clinical cases are reported mainly in the north, where H. scupense is abundant (Bouattour et al., 1996; Darghouth, 2000; Gharbi et al, 2014). For example, the recorded T. annulata infection prevalence in cattle was higher in Bizerte district (15.5%) using Giemsa (Boussaadoun et al., 2015) and in Ariana district (Hessiene region) using PCR (61%) (Sallemi et al., 2017). TT was also found in Gabes Oasis in the south‐east of Tunisia, with an infection prevalence of 26.5 and 31.2% by Giemsa and PCR, respectively (Gosrani, 1999).…”

“…More recently, using PCR, Sallemi et al. (2017) estimated T. annulata infection in cattle in the same area at 61% (59/96). Interestingly, co‐infection with Trypanosoma evansi was reported in six samples.…”

“…Additionally, in Ariana district, especially in Hessiene region, which is an endemic area of TT, several studies have been conducted over the years, and prevalence using IFAT was reported to vary between 63.9 and 92.8% (Darghouth et al, 2004;Gharbi, 2006). More recently, using PCR, Sallemi et al (2017) estimated T. annulata infection in cattle in the same area at 61% (59/96). Interestingly, co-infection with Trypanosoma evansi was reported in six samples.…”

Prevalence and risk factors associated with tropical theileriosis in Egyptian dairy cattle

“…The present study revealed that the prevalence of theileriosis was higher in older (>4 years old) and middle-aged (2-4 years old) cattle compared with younger animals (<2 years old). These results agree with the previous findings in Egypt, where younger animals showed a lower prevalence of infection than adults [ 34 , 38 ]. Because of the long-term nature of infection with T. annulata , the higher prevalence in older animals may reflect increased exposure to infection or management-associated factors.…”