An outbreak of dengue fever in Peri Urban slums of Chandigarh, India, with special reference to entomological and climatic factors

Backgrounds: Dengue viral infection is one of the most important public health problem in tropical countries. Aim: An outbreak of dengue fever was investigated in a periurban slum area of Chandigarh, India, during September to December, 2002.
Materials and methods: Blood samples from 218 patients and 30 apparently healthy contacts were tested for dengue-specific immunoglobulin M (IgM) and IgG antibodies including 80 acute samples collected within 5 days of illness were subjected for virus isolation in newborn mice. The average temperature, rainfall, and humidity of the epidemic year were compared with the number of dengue cases. Statistical analysis: statistical significance was found out using β2-test.
Results: A total of 76 cases were positive by either dengue IgM capture assay (n=57) or virus isolation (n=17) or both (n=2). fifteen of nineteen viral isolates subjected for typing by type-specific multiplex reverse transcription-polymerase chain reaction were found to be of dengue virus. High rainfall and humidity with the temperature range from 21°c to 33°c during the months of August and September might have favored the breeding of mosquitoes, thus leading to an increase in the number of dengue cases in October and November, 2002.
Conclusion: The present outbreak thus emphasizes the need for continuous sero epidemiological and entomological surveillance for the timely implementation of effective dengue control programme.

Keywords
Dengue, epidemic, India, Reverse transcription-polymerase chain reaction