Prevalence of tick-borne haemoparasites in small ruminants in Turkey and diagnostic sensitivity of single-PCR and RLB

Abstract

BackgroundTick-borne haemoparasitic diseases (TBHDs), caused by Theileria, Babesia, Anaplasma and Ehrlichia, are common in regions of the world where the distributions of host, pathogen and vector overlap. Many of these diseases threaten livestock production and some also represent a concern to human public health. The primary aim of this study was to determine the prevalence of the above-mentioned pathogens in a large number of blood samples (n = 1979) collected from sheep (n = 1727) and goats (n = 252) in Turkey. A secondary aim was to assess the diagnostic sensitivity of a number of species-specific polymerase chain reaction (PCR) tests and the reverse line blotting (RLB) assay. DNA samples were screened using species-specific PCR for the presence of Theileria ovis, Theileria sp. MK, T. lestoquardi, T. uilenbergi, T. luwenshuni, Babesia ovis, Anaplasma ovis and A. phagocytophilum while RLB was undertaken to test for the presence of all known Theileria, Babesia, Anaplasma and Ehrlichia species. The diagnostic sensitivity of these two approaches was then compared in terms of their ability to detect single species and mixed infections.ResultsOverall, 84 and 74.43% of the small ruminants sampled were identified as hosting one or more pathogen(s) by species-specific PCR and RLB respectively. The presence of Theileria sp. OT1, T. luwenshuni and T. uilenbergi in Turkey was revealed for the first time while the presence of Babesia motasi, B. crassa and T. separata in Turkish small ruminants was confirmed using molecular methods. A high prevalence of mixed infection was evident, with PCR and RLB approaches indicating that 52.24 and 35.42% of animals were co-infected with multiple species, respectively. More than 80% of the mixed infections contained T. ovis and/or A. ovis. The RLB approach was found to be capable of detecting mixed infections with species such as Theileria sp. OT1, Theileria sp. OT3, T. separata, B. crassa and Babesia spp.ConclusionThe results indicated that pathogens causing TBHDs are highly prevalent in sheep and goats in Turkey. The diagnostic sensitivity of species-specific single PCR was generally higher than that of RLB. However, the latter approach was still capable of identifying a high proportion of individuals containing mixed-species infections. The use of species-specific single PCR is recommended to accurately estimate pathogen prevalence and to identify co-infected hosts.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2151-3) contains supplementary material, which is available to authorized users.

A Retrospective Epidemiological Study: The Prevalence of Ehrlichia canis and Babesia vogeli in Dogs in the Aegean Region of Turkey

“…Results demonstrated that PCR was more sensitive than the RLB assay. This is in agreement to previous observations [29,45]. It is well established that the sensitivity and specifi city of any PCR assay is affected by so many factors, like primers and other ingredients used during the amplifi cation phase of target DNA [46].…”

“…However, the relatively high kappa agreement (κ = 0.74) between the two tests suggests that RLB assay should still be considered a reliable assay in diagnosing Babesia spp. especially in possible cases of mixed infections [21,29].…”

“…The V4 hypervariable region of the 18S and V1 hypervariable region of the 18S rRNA gene of all Theileria and Babesia species were amplifi ed by PCR prior to RLB. PCR was performed under the previously described conditions [29] using primers given in Table 1. Then, 20 μl of biotin-labeled PCR products were then screened by RLB assay as previously described [30,31].…”

Economic and Health Impact of the Ticks in Production Animals

“…Ticks generate indirect damage due to their key role in the transmission of a large number of infectious agents [44]. As mentioned in Bilgic et al [48], in recent decades, the socioeconomic impact of small ruminants has grown worldwide, and therefore more attention is now being given to the pathogens that affect sheep and goats. As in the case of bovines, the main tick-borne diseases are babesiosis, anaplasmosis, theileriosis and heartwater [3].…”

“…As in the case of bovines, the main tick-borne diseases are babesiosis, anaplasmosis, theileriosis and heartwater [3]. Losses attributed to these diseases include mortality, production losses, diagnostic, veterinary treatment and control costs of ticks [48]. In China, it is estimated that Anaplasma, Babesia and Theileria species infect about 35 million of small ruminants.…”