S255 Document heading doi: 10.1016/S2222-1808(14)60450-3 襃 2014 by the Asian Pacific Journal of Tropical Disease. All rights reserved. Epidemiological aspects of Dirofilaria immitis infection in dogs from Assam of Northeast India Kanta Bhattacharjee, Prabhat Chandra Sarmah Department of Parasitology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781022, Assam, India Asian Pac J Trop Dis 2014; 4(Suppl 1): S255-S258 Asian Pacific Journal of Tropical Disease journal homepage: www.elsevier.com/locate/apjtd *Corresponding author: Dr. Kanta Bhattacharjee, Assistant Professor, Department of Parasitology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781022, Assam, India Tel: +91 9864357161 E-mail: kantabhatta@gmail.com Foundation Project: Supported by Assam Agricultural University, Khanapara, Guwahati with the annual grant for post graduate research. 1. Introduction Dirofilaria immitis (D. immitis) is a filarial nematode which resides in the pulmonary arteries and right ventricle of heart in dogs. Mosquitoes under several genera including Culex, Aedes, and Anopheles are the competent vectors of the parasite. Dogs with heavy infection suffer from cardio- respiratory disturbances, resulting in multiple organ dysfunctions. In India, the parasite has been sporadically reported in dogs and wild captive carnivores from the north and northeastern region [1-3] . A case of human dirofilariosis was also reported from Mumbai in Central India [4] . Despite the strong belief that the parasite is confined to India’s northeastern region [2,5] , the epidemiological situation here is far from clear. Reports available so far on the prevalence of D. immitis in dogs from this region are mainly based on postmortem study in non-descript street dogs [2,3] . The present study was undertaken to analyze the risk factors of PEER REVIEW ABSTRACT KEYWORDS Dirofilaria immitis, epidemiology, dog, Assam, India. Objective: To analyze the epidemiology of Dirofilaria immitis (D. immitis) infection in different categories of dogs in Assam. Methods: Microscopy of blood in wet film preparation was conducted in two dog populations during 2009 and 2010, and data obtained were analyzed to investigate the infection pattern according to season, living condition, breed, sex and age of dogs. Results: Examination of 424 clinically ill dogs (hospital population) presented at the referral Teaching Veterinary Clinical Complex, Guwahati, Assam revealed 5.42% cases microfilaraemic. Clinical cases of D. immitis infection were recorded throughout the year with 9.10% as the highest record during pre-monsoon and 1.12% as the lowest in the winter. Pet dogs staying indoor showed 4.76% microfilaria positive compared to 7.95% record among working dogs with restricted outdoor activity. Breed wise, Dalmatian dogs representing 3.53% of the study population were negative to microfilaria while among the positives, Doberman showed 30.76% infection rate as the highest and 2.94% lowest record in the Labrador. Rate of infection was slightly higher in the males (5.81%) than the females (4.81%). Dogs below 2 years of age were negative to microfilaria while it was 3.70% in 2-4 years age group with a rising trend reaching 28.00% as the highest in 6-8 years age group. Examination of non-descript (street dog population) adult dogs living outdoor showed 29.54% microfilaraemic, the rate of infection being higher in males (37.50%) than the females (25.00%). Similar non-descript dogs living indoor as pets however showed only 11.11% microfilaria positive. Conclusions: The study shows endemicity of D. immitis in dogs of Assam with living condition and age as the host related important risk factors, which have significant role in its epidemiology. Contents lists available at ScienceDirect Peer reviewer Dr. Sanjoy Kumar Barthakur, MVSc, P h D, Assistant P rofessor ( S . G. ) , Department of Parasitology, College of Veterinary S ciences & Animal Husbandry, C entral Agricultural University, Selesih, Aizawl-796014, Mizoram. Tel: +91 9436366797 E-mail: sanjoy_barthakur@rediffmail. com Comments The authors have evaluated all the possible host related risk factors and some of the environmental risk factors related to the epidemiology of D. immitis in dogs. The results are worth publishing in the interest of companion animals’ welfare as well as from zoonotic point of view. Details on Page S257 Article history: Received 26 Nov 2013 Received in revised form 30 Dec, 2nd revised form 3 Dec, 3rd revised form 9 Dec 2013 Accepted 16 Jan 2014 Available online 28 Jan 2014