Occurrence of Canine Demodicosis in Selected Veterinary Hospitals in Kalutara District, Sri Lanka

Canine demodicosis, commonly known as demodectic mange, is a dermatological condition caused by mites of the genus Demodex. Dogs are particularly susceptible to this ectoparasitic infestation, which can present as localised or generalised disease, ranging from mild alopecia to severe ulcerative lesions. Despite its global distribution, published data on demodicosis in Sri Lanka remain limited. This study aimed to determine the occurrence of Demodex infection in pet dogs presented to selected veterinary hospitals in the Kalutara District. A cross-sectional survey was conducted using convenience sampling, and 100 dogs presenting with dermatological lesions were examined. Deep skin scrapings were collected, processed with potassium hydroxide, and microscopically examined to identify mites. Thereafter, morphometric measurements were recorded to differentiate species. Results revealed Demodex mites in 7 out of 100 samples, indicating an occurrence of 7%. Morphometric data showed that the specimens (mean body length 108.9 µm; gnathosoma 11.7 µm; podosoma 31.8 µm; opisthosoma 60.6 µm) were smaller than D. canis (156–269 µm) and excluded the larger D. injai (250–300 µm), aligning most closely with D. cornei (130–170 µm). However, definitive species identification requires molecular confirmation. Statistical analysis of host and environmental factors, including age, breed, sex, coat type, hygiene practices and diet, showed no significant associations with demodicosis (p > 0.05). These findings suggest that canine demodicosis occurs at a relatively low level in the Kalutara District and that conventional morphological methods alone are insufficient for accurate species differentiation. The study highlights the need to incorporate molecular diagnostic tools, including PCR and DNA sequencing, to achieve accurate species identification. It further emphasises the importance of conducting a larger-scale investigation to clarify the epidemiology and genetic diversity of Demodex infections in Sri Lanka, which would be a critical step towards developing effective treatment and preventive strategies.