Prevalence and pathological lesions of onchocercosis (Onchocerca fasciata) in camels (Camelus dromedarius)

Abstract

The filarial nematode Onchocerca fasciata lives as an adult worm, forming well developed fibrous tissue nodules within the fascial sheath of various parts of the camel body. This study was conducted to identify the prevalence and pathology of camel onchocercosis. A total of 298 dromedary camels of both sexes and different ages were examined carefully before and at the time of slaughtering. Twenty nine out of 298 camels (9.73%) were infected with O. fasciata. Nineteen out of 156 females (12.17%) and ten out of 142 males (7.04%) were positive. Grossly, one or multiple nodules with 1 to 2.5 centi-meters in diameter were observed. The nodules were dry and raised, tactile or hard in their texture. On cross section, tangled masses of thin filarial worms were surrounded by a thick whitish fibrous connective tissue. Maximum number of nodular lesions was found in subcutaneous tissues of the neck, abdomen, hind limbs and other parts of infected camels. The intensity of infection, varied be-tween one nodule and 18 nodules. Histopathologically, multifocal granulomatous inflammatory reac-tions were observed to be associated with the parasites in the affected areas. Transverse and longitu-dinal cross sections or fragment of the worms with different degrees of surrounding inflammatory reaction were scattered inside the granulomas.

Keywords

• camel
• histopathology
• Onchocerca