Pathological lesions associated with Cordylobia anthropophaga infestations of dogs in Kitui County, Kenya

Abstract

Myiasis is the infestation of living tissues of human and animals with larvae of flies in the Order Diptera. This study determined the gross and histopathological lesions due to Cordylobia anthropophaga infestations of Dogs in Kitui County, Kenya. Four dogs identified and confirmed to have canine cutaneous myiasis (CCM) infestation were purchased for the study. All the study animals were clinically examined for skin lesions characteristic of CCM and euthanized for complete necropsy examination and histopathological sample collection. Tissue sections were collected from areas with lesions of CCM namely; skin, skeletal muscles and regional draining lymph nodes. They were preserved in 10% buffered formalin and were processed and analyzed using standard methods. Grossly, all dogs had poor body condition, patches of alopecia, emaciated and had the pathognomonic lesions for canine cutaneous myiasis (CCM) characterized by multifocal coalescent nodular lesions (harboring Cordylobia anthropophaga larvae) with 3 mm diameter central pore (furuncles) and erythematous base. Some had serous, hemorrhagic or purulent discharges from the furuncles that matted surrounding hairs. Lesions were distributed mainly on the ventral abdomen, axilla, flanks, legs, perineum and external reproductive organs. Examination of the skin revealed that the furuncular lesions extended throughout the skin thickness from epidermis to the sub-cutis and underlying pale skeletal muscles. There was regional lymphadenopathy in affected body regions. Histopathology confirmed the main lesions in all the dogs were parasitic granulomas, congested blood vessels in the surrounding tissues and eosinophilic lymphadenitis. The granulomas were located in the skin and the underlying skeletal muscles. The lesions were characterized by centrally located parasite, surrounded by connective tissue and heavy infiltration with inflammatory cells predominantly eosinophils. Draining lymph nodes had eosinophilic lymphadenitis. The reported pathological lesions resulted in unthriftiness, alopecia, lethargy and anorexia due to pain and stress resulting to emaciation and possible death. There is need to eradicate the etiological agent as it affects the wellbeing of dogs in the study area.