Epidemiological Distribution of Major Ectoparasites Species of Small Ruminant in the Case of Chemical Control Campaign in Welkait District, Tigray Region, Ethiopia

Determination of percentage elongation at break and histopathology of skin from yankasa sheep experimentally infested with Amblyomma variegatum

Bites of haematophagous ectoparasites cause mechanical injuries and histopathological changes in their hosts' hides and skins whose resultant leathers become unsuitable for certain leather products. The effects of tick bites on the wellbeing of their hosts are known, however, knowledge of their effects on the quality of leathers is scarce. This work investigated the effects of tick bites on the histopathology of skin and the percentage elongation at break (PEB) of shoe upper leathers produced from the skins of Amblyomma variegatum infested Yankasa sheep. A total of nine apparently healthy Yankasa sheep were selectively purchased from the open market and acclimatized for four weeks in the laboratory. Three animals in each of group 1 and 2 were infested with 40 nymphs and 20 adults of Am. variegatum respectively. Group three animals served as uninfested control. All animals were euthanized after the ticks were fully engorged and detached. Skin biopsies at tick attachment points and the uninfested control were taken from flayed skins and processed for histopathological examination. All skins were processed into finished leathers and their PEB determined. Histopathological studies revealed keratinization in all Am. variegatum infested sheep skins, while the un-infested control skins were normal. Mean PEB (%) of leathers were 21.41±3.33SE (nymphs), 36.73±4.44SE (adults) and 47.83±2.78SE (control). Bites of Am. variegatum cause histopathological changes in Yankasa sheep skins that significantly (p = 0.006) reduce the PEB of resultant leathers to less than the acceptable minimum standard of 40 % whose leathers are classified as rejects. In this study, skin of Yankasa sheep infested by nymphs and adults of Am. variegatum ticks resulted in low quality leathers that are unsuitable for standard leather products production and are also of low market value due to keratinization. Sustained efforts need to be undertaken to increase the awareness on the negative impact of tick bites on leather products by encouraging livestock farmers to engage in early treatment of animals infested with ticks.

Data release: targeted systematic literature search for tick and tick-borne pathogen distributions in six countries in sub-Saharan Africa from 1901 to 2020

BACKGROUND

Surveillance data documenting tick and tick-borne disease (TBD) prevalence is needed to develop risk assessments and implement control strategies. Despite extensive research in Africa, there is no standardized, comprehensive review.

METHODS

Here we tackle this knowledge gap, by producing a comprehensive review of research articles on ticks and TBD between 1901 and 2020 in Chad, Djibouti, Ethiopia, Kenya, Tanzania, and Uganda. Over 8356 English language articles were recovered. Our search strategy included 19 related MeSH terms. Articles were reviewed, and 331 met inclusion criteria. Articles containing mappable data were compiled into a standardized data schema, georeferenced, and uploaded to VectorMap.

RESULTS

Tick and pathogen matrixes were created, providing information on vector distributions and tick-pathogen associations within the six selected African countries.

CONCLUSIONS

These results provide a digital, mappable database of current and historical tick and TBD distributions across six countries in Africa, which can inform specific risk modeling, determine surveillance gaps, and guide future surveillance priorities.

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

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.