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The pandemic of COVID-19 has created an unprecedented burden on the healthcare system and medical communities resulting in new public health challenges. On the other hand, in tropical countries, another concern arises due to the similar spectrum of clinical manifestations between COVID-19 and dengue fever. Thus, the neglected tropical disease 'Dengue' writhed with more inattention. This study aims to find the effect of the COVID-19 pandemic on dengue infections in endemic areas of West Bengal, India, and their combined impact on public health. The alterations in circulating dengue serotype and their genomic diversity in different COVID-19 waves were also monitored. A total of 1782 patients were included in this study. Dengue NS1 ELISA, molecular serotyping, genotyping and their phylogenetic analysis were performed. GISaided analysis of various dengue serotypes and hotspot identification for risk maps of severe dengue in endemic zones were done. The burden of dengue fever and the sustainability of their viral strains with changing meteorological parameters in parallel to COVID-19 waves were analyzed. Co-circulation of all the four dengue serotypes with rapid change in the pattern of prevalent serotype DENV4 (Genotype-I) in the year 2020 and DENV3 (Genotype-III) in 2021 were observed, in parallel to different circulating strains of COVID-19. Spatiotemporal distribution of DENV using Geographic Information System (GIS) applications observed a serotypic shift and hotspot mapping for risk analysis detected Kolkata as a dengue hotspot, which has also reported the maximum number of COVID-19 cases. This study indicates the increased fitness of circulating dengue virus strains with optimal virulence as per changing environmental conditions and the inhabitant's immunity. The high infectivity rate of both the RNA viruses and considering.the consequences of severe dengue and COVID-19 in the population of the same geographical settings is an alarming risk. [ABSTRACT FROM AUTHOR]

Recombination in RNA virus is a rare event in the survival and evolution to evade host immune system. This is increasing within high risk group population (HRG) due to super infection that occurs by continuous sharing of common drug equipment by HCV infected or HIV-HCV co-infected recurrent drug users. Recombination causes impediment to vaccine development and therapeutic intervention as standard HCV treatment is still genotype specific. Blood samples of 194 people who inject drugs (PWID) were collected from an Opioid Substitution Therapy Centre in Kolkata, India. HCV sero-reactivity was checked by ELISA. Detection of HCV RNA by nested RT-PCR and genotyping by DNA sequencing were done. Phylogenetic analysis, Simplot, Bootscan plot, Recombination Detection Program were used for recombinant strain identification. Out of 80 HCV sero-reactive samples, 77 were RNA positive (96.25%). Out of 74 HIV mono-infected individuals, 12 HCV sero-nonreactive samples were HCV RNA positive. Out of total 89 RNA positive samples, 64 paired partial core and NS5B region (71.9%) were sequenced by Sanger's method. Two major genotypes (1 and 3), four subtypes and an inter-genotype recombinant strain (3a/1a) with a novel breakpoint in the NS4B coding region were found. [ABSTRACT FROM AUTHOR]

Highlights: [•] 91.20% of the study population were HCV viremic. [•] Eight different HCV subtypes were detected from north-eastern state of Manipur. [•] Emergence of new genotype 6 has a direct evolutionary link with the strains of Vietnam and South-China. [ABSTRACT FROM AUTHOR]