Genetic characterization respiratory syncytial virus in Kerala, the southern part of India.

Respiratory syncytial virus (RSV) is an important cause of acute lower respiratory tract infection (ALRI) in infants and young children globally. RSV presents two antigenic groups RSV-A and -B. Genetic variability is also very high within each group. RSV circulation varies year to year and even varies among different regions. Data on circulatory pattern of RSV are available from other parts of India except Kerala. The aim of the study was to generate data about groups and genotypes of circulating RSV in Kerala. In this study, RSV positive samples received during January, 2012 to December, 2014 were used for genetic characterization. The samples were tested by using nucleocapsid (N) gene-based conventional multiplex reverse transcriptase polymerase chain reaction (RT-PCR) to identify the RSV group. Genotyping was done by nucleotide sequencing of the C-terminal region of the glycoprotein (G) gene. Out of the 130 patient samples tested, 49 samples were positive for RSV. Among the positive samples, 32 belong to the RSV-A and 17 belong to RSV-B virus. Phylogenetic analysis revealed that all RSV-A sequences (n = 22) belonged to NA1 genotype and five of the sequences showed the novel 72 nucleotide duplication and clustered into the newly designated ON1 genotype. All RSV-B sequences (n = 17) were clustered into the BA (BA9 and 10) genotype. From this study, we concluded both RSV-A and -B were co-circulated in Kerala and RSV-A was observed predominantly in 2012 and RSV-B in 2014. As per our best of knowledge, BA10 genotype is first observed in India.

Kyasanur Forest Disease Prevalence in Western Ghats Proven and Confirmed by Recent Outbreak in Maharashtra, India, 2016.

INTRODUCTION: Kyasanur forest disease (KFD) outbreak was confirmed in Dodamarg Taluka, Sindhudurga district (Maharashtra) in India during the year 2016. The rise in suspected KFD cases was reported in January 2016, peaked during March, and then declined gradually from April 2016. The outbreak was thoroughly investigated considering different socio-clinical parameters. METHODS: Total, 488 suspected KFD cases were investigated using KFD specific real-time RT-PCR and anti-KFDV IgM enzyme-linked immunosorbent assay (ELISA). Sero-epidemiological survey was carried out in the affected area using anti-KFDV IgG ELISA. RESULTS: Among suspected KFD cases, high age-specific attack rate (105.1 per 1000 persons) was observed in adults (aged 40-59 years). Out of 488 suspected KFD cases, 130 were laboratory confirmed. Of these, 54 cases were KFDV real-time RT-PCR positive, 66 cases were anti-KFDV IgM ELISA positive and 10 cases were positive by both the assays. Case fatality ratio among laboratory-confirmed KFD cases were 2.3% (3/130). Majority of laboratory-confirmed KFD cases (93.1%) had visited Western Ghats forest in Dodamarg for activities like working in cashew nut farms (79.8%), cashew nut fruit collection (76.6%), collection of firewood (68.5%) and dry leaves/grass (40.3%), etc., before the start of symptoms. Common clinical features included fever (100%), headache (93.1%), weakness (84.6%), and myalgia (83.1%). Hemorrhagic manifestations were observed in nearly one-third of the laboratory-confirmed KFD cases (28.5%). A seroprevalence of (9.7%, 72/745) was recorded in KFD-affected area and two neighboring villages (9.1%, 15/165). Serosurvey conducted in Ker village showed clinical to subclinical ratio of 6:1 in KFD-affected areas. CONCLUSION: This study confirms the outbreak of KFD Sindhudurg district with 130 cases. Detection of anti-KFDV IgG antibodies among the healthy population in KFD-affected area during the KFD outbreak suggested the past exposure of KFD infection. This outbreak investigation has helped health authorities in adopting KFD vaccination strategy for the population at risk.