First dominant co-circulation and simultaneous co-infection of chikungunya and dengue viruses in Dhaka, Bangladesh during 2017

Independent outbreaks of dengue virus (DENV) infection and sporadic cases of chikungunya virus (CHIKV) have been reported in Bangladesh on several occasions in the past. However, a massive febrile outbreak was observed in Dhaka city in summer 2017 and many cases turned negative for DENV. As there was high clinical suspicion of chikungunya, routine screening of serum from 1688 febrile patients were done for simultaneous detection and differentiation of chikungunya and dengue viruses by real time reverse transcriptase PCR. Interestingly, we found 627 (37.14%) cases of chikungunya and 277 (16.4%) cases of dengue and 11 (0.65%) cases of co-infection with both the viruses. This is the first report of dominant co-circulation of dengue and chikungunya and co-infections with dengue and chikungunya virus in Dhaka in a season and warrants widespread surveillance of both the viral infections in the country.