Concurrent dengue and malaria in an area in Kolkata.

Objective: To establish the nature and extent of dual dengue and malaria infections in an endemic area through a longitudinal study.

Methods: A prospective study was conducted from August 2005 to December 2010 to document the nature and extent of concurrent dengue and malaria infections in an area in central Kolkata, endemic both for dengue and malaria.

Results: Of 2 971 suspected cases of dengue fever, in 605 (20.36%) persons dengue infection was detected, of whom 46 (7.60%, 46/605) patients (40 and 6 suffered from secondary and primary dengue fever respectively) were simultaneously suffering from malaria (28 and 18 were infected with Plasmodium vivax (P.vivax) and Plasmodium falciparum (P. falciparum) respectively, such dual infections of dengue and malaria were detected in all the years of the study period, except 2007, indicating intense transmission of both dengue and malaria in the study area, and the phenomenon was not an isolated one, the rate of concomitant infections ranged from 25% in 2009 to 4.9% in 2005. Out of total population surveyed, 1.54% (46/2 971) had concurrent dengue and malaria infection.

Conclusions: These findings added a new dimension in diagnosis, treatment, epidemiology and control of dengue and malaria. The possible risk of concurrent dengue and malaria infections should always be kept in mind in endemic areas for early diagnosis employing modern technology and prompt and effective treatment to avoid serious complications.