Geographical distribution of ixodid ticks and tick-borne pathogens of domestic animals in Ethiopia: a systematic review

Abstract

Background In Ethiopia, ixodid ticks and associated tick-borne pathogens (TBPs) are of great importance from both a veterinary and public health point of view. This review aimed at compiling available published data on the distribution of ixodid tick species and TBPs in the country. Methods A standard review approach was employed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Published peer-reviewed articles and theses/dissertations reporting on ixodid ticks and TBPs in Ethiopia were searched using different keywords in many electronic databases including PubMed, Scopus, Web of Science, Google Scholar, African Journals OnLine, and institutional repositories. Articles were screened based on inclusion and exclusion criteria using the PRISMA flowchart. Data were retrieved from eligible articles and recorded in a preformed data record sheet. Descriptive statistics were employed to present data using graphs. QGIS (Quantum GIS) software version 3.4.5 was used to show the distribution of ixodid tick species and TBPs. Results Overall, 35 articles that met the inclusion criteria were included in this review. Of these, 24 articles report only on ixodid ticks of domestic animals, six articles report only on TBPs in livestock or ticks, and five articles report on both ticks and TBPs in either animals or ticks. Of these studies, 54% were in the Oromia region, while only 3% of studies were in the Benishangul-Gumuz region. The Gambela region lacked studies on ticks and TBPs. At least 19 ixodid tick species have been recorded from different domestic animals including cattle, small ruminants, donkeys, horses, camels, dogs, and cats. Morphological characterization appears to be the sole method of tick species identification in the country. The distribution and abundance of specific tick species depend on geographical locations and agroecological factors. Sixteen molecularly confirmed TBPs have been identified in animal and tick tissue using molecular methods from only four administrative regions, despite the wide distribution of ticks. Among TBPs, five Anaplasma, two Ehrlichia, two Rickettsia, five Theileria, two Babesia, and one Coxiella species are the major pathogens in both livestock and humans. Conclusions Many ixodid ticks circulate in a wide geographical zone of Ethiopia. However, the limited reports on TBPs at the country level in general, and the absence of either tick or TBP reports around the border region with neighboring countries in particular, highlights the need for further study. Graphical Abstract

Prevalence, Species Identification, and Associated Risk Factor Ixodid Tick Infestation of Cattle in Selamago District Southern Ethiopia

“…A systematic review using 35 published articles showed about 19 tick species under the genus Amblyomma , Rhipicephalus (Boophilus ), Rhipicephalus , Hyalomma , and Haemaphysalis reported in various domestic animals in Ethiopia during the period of 2001 up to October 30, 2020. 24 Recently published articles from Gondar, Eastern Hararghe, and Selamago support the current and previous studies finding in Ethiopia, where Amblyomma is the predominant genus. 19,25,26 The overall prevalence of tick populations in the Selamago district was significantly ( P < .05) higher compared to non-infected ones.…”

“…truncatum is generally found in arid parts of tropical Africa with annual rainfall ranging from 250 to 650 mm, where this ecology is more common in Selamago than in central Ethiopia. 24 The low incidence in Ethiopia’s central highlands may be due to considerable rainfall. 49…”

“…In association with zebra and ruminants, it was reported that this species did not show specific preferences for a particular altitude, rainfall zone, or season., 49 but ticks more prefer large animals like cattle and others than small animals. 24 With a prevalence of 4.3%, Hy. truncatum was found to be the least abundant tick species collected in this study.…”

“…truncatum is generally found in arid parts of tropical Africa with annual rainfall ranging from 250 to 650 mm, where this ecology is more common in Selamago than in central Ethiopia. 24 The low incidence in Ethiopia's central highlands may be due to considerable rainfall. 49 Tick infestation in different parts of the animal body shows that the perineum region, followed by udder/scrotum and dewlap had a high proportion of tick burden sequentially.…”

Tek tırnaklı hayvanlarda Kırım Kongo Hemorajik Ateşi Virusu'na spesifik antikorların tespiti

“…CCHF, is a zoonotic arboviral disease that poses a great threat to public health therefore according to the World Health Organization (WHO), CCHFV is the most predominant causative agent of viral hemorrhagic fever outbreaks worldwide (Sorvillo et al 2020). Humans and a wide range of other animal species are at risk of contracting CCHFV (Ali et al 2019, Kaba 2022. It has been reported that CCHFV can be transmitted to humans through a tick bite, contact with blood, body fluids, or tissues of a viremic animal or human (Bente et al 2013).…”