A study on canine dirofilariasis in selected areas of Sri Lanka

Objectives Canine dirofilariasis is a mosquito borne zoonotic filarial parasitic disease caused by Dirofilaria species. In Sri Lanka, human dirofilariasis is endemic and well documented. Even though canine dirofilariasis is an established infection among dog populations in Sri Lanka, the prevalence and risk factors were not documented in Kanthale divisional secretariat, Eastern Province of Sri Lanka. Therefore, the main objective of this study is to determine the prevalence of dirofilariasis and to identify the exposure-related risk factors in dogs using an interviewer administered questionnaire in Kanthale divisional secretariat. Results Out of 162 blood samples collected from dogs, 47.5% (n = 77/162) were positive for the presence of microfilariae by direct smear. Of 162 samples 58.6% (n = 95/162) were molecularly identified as D. repens. Species-specific primer pair DIR3/DIR4 that amplified 5S rRNA was used. The current study observed a significant association between mongrels and canine dirofilariasis (p = 0.049), where 61.3% (n = 95) out of 155 mongrels showed PCR positivity. This study showed no significant association between the occurrence of dirofilariasis and the age, sex, rearing method, presence or absence of skin rash, and stray or domestic dogs. Dirofilaria immitis was not identified in direct smear test and PCR.

Automated summary

This study aimed to investigate the prevalence and risk factors of canine dirofilariasis in Kanthale divisional secretariat, Eastern Province of Sri Lanka. The results showed that out of 162 blood samples, 47.5% (77/162) tested positive for microfilariae using direct smear. Of the 162 samples, 58.6% (95/162) were identified as D. repens through molecular analysis. Mongrels were significantly associated with canine dirofilariasis, with 61.3% (95/155) of mongrels showing PCR positivity. However, no significant associations were found between the occurrence of dirofilariasis and age, sex, rearing method, presence of skin rash, and stray or domestic dogs. Dirofilaria immitis was not detected in direct smear and PCR tests.