Ixodes inopinatus infesting cattle in high plateaus areas from North-Eastern Algeria: Sympatric occurrence with Ixodes ricinus, comments on its geographic distribution, and detection of Rickettsia spp.

Ixodes ricinus and Ixodes inopinatus are closely related sister taxa which show high morphological similarity resulting in challenges to proper species determination. It is unclear how these two species are geographically distributed in areas where both species could occur (i.e., North Africa) and what this could mean towards potential pathogenic microorganisms. Here we report on Ixodes ticks (n = 31) collected from cattle in high plateau areas (Guelma province) of north-eastern Algeria. Three Ixodes species (I. ricinus, n = 10; I. inopinatus, n = 19; I. ventalloi, n = 2) were identified morphological and confirmed molecularly through analysis of the trospa gene sequence. Clear morphological markers between the three species were found in line with the original descriptions, although molecular analysis did not support morphological identification for all I. ricinus and I. inopinatus ticks (n = 7). With this we found no significant association between the molecular and morphological identification of I. inopinatus (phi coefficient of rϕ = 0.088, p = 0.71). Taking molecular identification as a standard, a literature search was performed to determine the geographic extent of I. inopinatus and associate this with Köppen and Geiger climate classifications. Geographically, I. inopinatus is likely restricted to the western Mediterranean Basin of North Africa and Europe and most likely adapted to the Mediterranean climate (Csa). The three investigated tick species were tested to be positive for DNA of Rickettsia helvetica and Rickettsia monacensis. This study confirmed the sympatric presence of I. inopinatus and I. ricinus as well as reported, for the first time, the occurrence of I. ventalloi in the high plateaus from north-eastern Algeria. In addition, the present study highlights the detection of R. helvetica and R. monacensis in I. inopinatus infesting cattle, which represent valuable findings of significant epidemiological interest, opening potential questions on the influence I. inopinatus could play in relation to rickettsioses in cattle.