Epidemiological trends and molecular dynamics of dengue, chikungunya virus infection, coinfection, and other undifferentiated fever during 2015-2016 in Odisha, India.

Chikungunya virus (CHIKV) infection is spatiotemporally related to dengue virus (DENV) infection and mostly undiagnosed due to similar primary symptoms. In 2013, a high rate (36%) of coinfection of DENV and CHIKV was reported in Odisha. Hence, the hospital-based study was continued to synthesis current epidemiological understanding of their single distribution or coinfection. Suspected DENV patients serum samples were tested for DENV and CHIKV by serology and reverse-transcription polymerase chain reaction. The positive samples were used for analysis of mutation, selection pressure, and phylogenetic relationship. Clinical information was also analyzed. Among 648 (2015 and 2016) suspected DENV patients, 141 (21.7%) were positive for DENV (serotypes 1-3), 22 (3.4%) were positive for CHIKV (ECSA) and 4 (2.8%) were coinfected with both. Sequence analysis showed four consistent mutations (M104V, V112A, K166N, and F169L) in CprM gene of DENV 2 and two consistent mutations (M269V, D284E) in E1 gene of CHIKV. Interestingly, the CHIKV- E1 A226V mutation was absent in the studied population. It was also noticed that the peak incidence of both the infections occurs in August-September in 2015-16. Moreover, Plasmodium species, Salmonella typhi, and Rickettsial typhi infections were also observed in DENV patients. Different etiology was also detected in other undifferentiated fever patients as mixed infections (malaria, S. typhi, and R. typhi ). Hence, this investigation shows the significant reduction of DENV-CHIKV coinfection as compared with previous report, the burden of arboviruses and acute undifferentiated fever in Odisha in 2015-2016, highlighting the importance of epidemiological picture of febrile patients for appropriate patient management.

High rates of co-infection of Dengue and Chikungunya virus in Odisha and Maharashtra, India during 2013.

Dengue viral (DENV) infection is endemic in different parts of India and because of similar primary signs and symptoms, Chikungunya virus (CHIKV) is mostly undiagnosed. Hence, we investigated 204 suspected Dengue cases in a hospital based cross-sectional study in Odisha, India in 2013. It was observed that 50 samples were positive for DENV only, 28 were positive for CHIKV only and interestingly, 28 patients were co-infected with both DENV and CHIKV. Additionally, a total of 18 confirmed Dengue samples from Maharashtra, India were screened for CHIKV and out of those, 15 were co-infected. All CHIKV strains were of East Central South African (ECSA) type and serotype 2 (genotype IV) was predominant in the DENV samples. Additionally, Dengue serotype 1 and 3 were also detected during this time. Further, sequence analysis of E1 gene of CHIKV strains revealed that two substitution mutations (M269V and D284E) were observed in almost 50% strains and they were from co-infected patients. Similarly, sequence analysis of C-prM gene showed the presence of five substitution mutations, (G70S, L72F, N90S, S93N and I150L) in all serotype 1 and two consistent mutations (A101V and V112A) in serotype 2 Dengue samples. Together, it appears that a significantly high number of dengue patients (43, 44.8%) were co-infected with DENV and CHIKV during this study. This emphasizes the need of a routine diagnosis of CHIKV along with DENV for febrile patients. This will be useful in early and proper recognition of infecting pathogen to study the correlation of clinical symptoms with single or co-infection which will ultimately help to implement proper patient care in future.