Prevalence of arthropod borne viral infections in a tertiary care hospital, with special reference to the 2012 dengue fever outbreak in Thanjavur and Thiruvarur districts

Aim To study the prevalence of Japanese encephalitis, Chikungunya and dengue fever ,to appreciate the seasonal changes, age and sex distribution of the diseases ,to find out the serotype and reasons for rapid increase in number of dengue cases in 2012.MATERIALS AND METHODS The study was conducted at a tertiary care hospital in suspected patients of dengue, Chikungunya, Japanese encephalitis from January to November 2012.Number of samples received for Japanese Encephalitis ,Chikungunya ,dengue were209,234,12,519respectively.The patients samples were tested using IgM capture ELISA kits ,for dengue, Japanese Encephalitis, Chikungunya diseases. For early detection of dengue, NS1Ag MICROLISA and for Rapid test, Dengue IgGIgM WB kit, Dengue Day 1Test kits were used. Serotyping was done for ten NS1 antigen positive samples by RT-PCR.RESULTS There is almost absence of Japanese Encephalitis and Chikungunya infections .Dengue fever out of 12,519, samples 2774 samples were positive. Maximum number of positive samples (96) was received between September, October, and November. Males are affected more than females. The most affected age group is below 20years (50). The use of NSI ELISA has helped to detect 60 of the cases in early stage. Dengue serotype 3 was the predominant serotype. The water stored in open containers in areas of water scarcity in Nagapattinam favored Aedes mosquito growth and spread of dengue fever. Conclusion Physicians should consider arboviral infections in fever, encephalitis patients. Vaccination should be done in Japanese Encephalitis endemic area. Effective vector control measures should be taken prior to the monsoon season. Creating awareness regarding usage of mosquito nets, repellants should be done. The study emphasizes the need for continuous seroepidemiological surveillance for the timely implementation of effective Japanese Encephalitis, Chikungunya, Dengue control programmes