Epidemiological aspects of Dirofilaria immitis infection in dogs from Assam of Northeast India

Objective: To analyze the epidemiology of Dirofilaria immitis (D. immitis) infection in different\udcategories of dogs in Assam.\udMethods: Microscopy of blood in wet film preparation was conducted in two dog populations\udduring 2009 and 2010, and data obtained were analyzed to investigate the infection pattern\udaccording to season, living condition, breed, sex and age of dogs.\udResults: Examination of 424 clinically ill dogs (hospital population) presented at the referral\udTeaching Veterinary Clinical Complex, Guwahati, Assam revealed 5.42% cases microfilaraemic.\udClinical cases of D. immitis infection were recorded throughout the year with 9.10% as the highest\udrecord during pre-monsoon and 1.12% as the lowest in the winter. Pet dogs staying indoor showed\ud4.76% microfilaria positive compared to 7.95% record among working dogs with restricted outdoor\udactivity. Breed wise, Dalmatian dogs representing 3.53% of the study population were negative\udto microfilaria while among the positives, Doberman showed 30.76% infection rate as the highest\udand 2.94% lowest record in the Labrador. Rate of infection was slightly higher in the males (5.81%)\udthan the females (4.81%). Dogs below 2 years of age were negative to microfilaria while it was 3.70%\udin 2-4 years age group with a rising trend reaching 28.00% as the highest in 6-8 years age group.\udExamination of non-descript (street dog population) adult dogs living outdoor showed 29.54%\udmicrofilaraemic, the rate of infection being higher in males (37.50%) than the females (25.00%).\udSimilar non-descript dogs living indoor as pets however showed only 11.11% microfilaria positive.\udConclusions: The study shows endemicity of D. immitis in dogs of Assam with living condition\udand age as the host related important risk factors, which have significant role in its epidemiology