Background: Dengue viruses of the family flaviviridae are the most common cause of arboviral disease in the world. During September–October 2012, there was a sudden spurt in the number of dengue fever cases in a training facility of security forces located in Ranga Reddy district of Andhra Pradesh, India.
Objective: To describe the distribution and determinants of the sudden surge of dengue fever cases and undertake measures to prevent further spread.
Materials and Methods: The clinical features; distribution of dengue fever cases in terms of time, place, and person; prevailing ecological conditions; entomological survey findings; and results of the biological specimens collected from the cases were studied.
Result: There were a total of 46 dengue fever cases, all male subjects, undergoing training, except one person who was a permanent staff. All of them provided history of fever of acute onset and associated with a varying combination of headache, retro-orbital pain, myalgia, arthralgia, rash, and hemorrhagic manifestations. Serological investigation revealed 26 (56.52%) and 11 (23.91%) cases positive for NS1 antigen and IgM, respectively, while nine (19.57%) cases were positive for both NS1 antigen and IgM. Leukopenia was observed among 39 (84.78%) cases. No fatality was reported. Intermittent rains coupled with favorable ambient temperature and humidity conditions and availability of breeding places helped in maintaining vector population.
Conclusion: Favorable climatological conditions, availability of hidden breeding sites of Aedes mosquitoes, and congregation of susceptible persons in large numbers at one place over a number of days led to the sudden surge in the number of dengue fever cases.
Key words: Dengue fever, NS1 antigen, IgM, Aedes mosquito
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