Detection and distribution of haematophagous flies and lice on cattle farms and potential role in the transmission of Theileria orientalis

Biniam T Lakew; Sarbast K Kheravii; Shu-Biao Wu; Steve Eastwood; Nigel R Andrew; Adrian H Nicholas; Stephen W Walkden-Brown

doi:10.1016/j.vetpar.2021.109516

Detection and distribution of haematophagous flies and lice on cattle farms and potential role in the transmission of Theileria orientalis

Vet Parasitol. 2021 Oct:298:109516. doi: 10.1016/j.vetpar.2021.109516. Epub 2021 Jul 3.

Authors

Biniam T Lakew¹, Sarbast K Kheravii², Shu-Biao Wu², Steve Eastwood³, Nigel R Andrew⁴, Adrian H Nicholas⁵, Stephen W Walkden-Brown²

Affiliations

¹ Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia; College of Veterinary Medicine, Haramaya University, P. O. Box 138, Dire Dawa, Ethiopia. Electronic address: blakew@myune.edu.au.
² Animal Science, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia.
³ Local Land Services, Armidale, 2350 NSW, Australia.
⁴ Insect Ecology Lab, Zoology, Natural History Museum, University of New England, Armidale, NSW 2351, Australia.
⁵ Department of Regional NSW, Central Coast Primary Industries Centre, Loop Road, Ourimbah, NSW 2250, Australia.

PMID: 34271315
DOI: 10.1016/j.vetpar.2021.109516

Abstract

On the Northern Tablelands of New South Wales, Australia, endemic Theileria orientalis infection of cattle has been reported on farms where no ticks have been observed, raising the question of how Theileria is transmitted in these areas. To investigate the potential role of mechanical transmission by insects, the present study investigated the seasonal dynamics of biting fly species trapped between December 2017 and May 2019 on six cattle farms in the region where the presence of Theileria was confirmed. These flies, sucking lice collected from these farms and pools of Culicoides species affecting cattle also trapped in the region were subjected to qPCR detection of T. orientalis. Eleven species from eight genera of biting flies were collected using unbaited Nzi traps. Tabanid species were present in all farms, with Dasybasis oculata (43.6 %) and D. circumdata (27.6 %) being the most abundant and widespread species. The effect of season on the mean count per trapping event was statistically significant and highest in the summer months for Lilaea fuliginosa and D. oculata, and the autumn months for D. circumdata, with no seasonal effect on the abundance of the undescribed Dasybasis spp. No biting flies were trapped during the winter months. Sucking (Linognathus vituli and Haematopinus eurysternus) and biting (Bovicola bovis) cattle lice were also collected from all farms with the latter detected in only one farm. PCR screening for T. orientalis of trapped hematophagous insects resulted in parasite detection in the tabanid and Stomoxyini flies, biting midges and sucking lice with the highest proportion of positive samples for Haematopinus eurysternus (4/4 pools) and H. irritans exigua (6/15 individuals). The detection of the parasite in these potential vectors indicates a possible role in the mechanical transmission of T. orientalis and may partly explain the ubiquitous presence of Theileria in areas where ticks are absent.

Keywords: C. victoriae; D. circumdata; H. eurysternus; H. irrtans exigua; Theileria orientalis.

MeSH terms

Animal Distribution*
Animals
Cattle
Cattle Diseases* / transmission
Farms / statistics & numerical data
Muscidae* / physiology
Real-Time Polymerase Chain Reaction / veterinary
Seasons
Theileria* / genetics
Theileriasis* / transmission