# Repeated Cross-Sectional Survey of Ectoparasites in Sheep from Central Tunisia: Does Low Prevalence Indicate Good Hygiene or Resistance to Ectoparasites?

## TL;DR

This study examines ectoparasite infestations in Tunisian sheep and finds low prevalence, possibly due to good hygiene or genetic resistance.

## Contribution

The study identifies specific ectoparasite species in Tunisian sheep and explores factors behind their low prevalence.

## Key findings

- Only 5.95% of 1243 sheep were infested by ectoparasites.
- Barbarine sheep had significantly higher infestation rates than Queue Fine de l’Ouest sheep.
- Rhipicephalus sanguineus was the most common tick species found.

## Abstract

Sheep ectoparasites such as chewing lice, fleas and ticks are serious impediments to sheep productivity. They cause enormous losses of wool and leather due to the skin lesions they cause, which reduces the market value of sheep. Some of these ectoparasites are also vectors of several pathogens. In the present study, we aim to investigate the ectoparasite population infesting 1243 autochthonous sheep in Tunisia from two breeds, Barbarine and Queue Fine de l’Ouest. A total of 74 sheep (5.95%) were infested by 3 groups of ectoparasites. The low prevalence of ectoparasite infestation in sheep reported here may be due to possible genetic resistance or simply to successful hygiene and management measures implemented by farmers.

Sheep ectoparasites such as chewing lice, fleas and ticks are serious constraints to sheep productivity and are the cause of skin lesions in animals that decrease their market value. This study aims at investigating the ectoparasite fauna infesting small ruminants in the district of Sidi Bouzid (central Tunisia). A total of 1243 Barbarine and Queue Fine de l’Ouest (QFO) sheep were examined every two months for one year. Of the total animals examined, 74 were infested by at least 1 parasite group (5.95%). Three ectoparasite groups were identified as Psoroptes ovis (0.48%; 6/1243), ticks (5.3%; n = 66/1243) and one specimen of Ctenocephalides canis (0.08%; n = 1/1243). The most abundant tick among the 358 specimens was Rhipicephalus sanguineus sensu lato (n = 337; 94.1%), followed by Hyalomma impeltatum (n = 7/358; 1.9%), H. dromedarii (n = 7/358; 1.9%), H. excavatum (n = 5/358; 1.4%) and only two specimens of H. scupense (n = 2/358; 0.55%). The sheep herds showed low infestation prevalence by ectoparasite over the year, with a significant difference according to the seasons (p < 0.05). A higher infestation prevalence was recorded in March (14.36%). Barbarine sheep breed showed significantly higher infestation prevalence (16.8%) compared to QFO (0.8%) (p < 0.01). There were no differences in infestation prevalence according to sex of the animal or age groups. Knowledge of the ectoparasite population harboured by sheep, its activity dynamics and risk factors is required to develop effective ectoparasite control options. The low prevalence of ectoparasite infestation in sheep reported here may be due to possible genetic resistance or simply to successful hygiene measures implemented by farmers.