ABSTRACT
Background & objectives: Infection by hepatitis B virus (HBV) results in acute or chronic hepatitis. Based on sequence differences of eight per cent or more, HBV is divided into 10 genotypes (A to J) and 35 sub-genotypes. Molecular characterization of the circulating HBV genome has helped in understanding the epidemiology and its clinical importance. Spiti valley in Himachal Pradesh, which shares its border with Tibet, is one of the most HBV prevalent areas in India. Since information about the circulating genotype/s of HBV in this area is limited, this study was conducted to identify the circulating HBV genotypes. Methods: The surface and partial reverse transcriptase gene regions were sequenced using 14 hepatitis B surface antigen-positive samples. Results: Out of the 14 hepatitis B surface antigen-positive samples 11 sample gave quality sequence for further analysis. All the 11 samples belonged to subtype ayw2. The phylogenetic and recombination analysis revealed that five out of 11 samples were of genotype CD1 and the rest six were of genotype D3. Interpretation & conclusions: The CD1 recombinant sub-genotype might have immigrated during past or present transcontinental migration between the adjacent countries. Further studies using full-genome sequencing and high sample size will be helpful to understand this epidemiology and to combat the high prevalence of HBV in the area.
ABSTRACT
Background: Dengue and chikungunya present with very similar signs and symptoms in the initial stage of illness and so it is difficult to distinguish them clinically. Both are transmitted by Aedes aegypti and Aedes albopictus mosquitoes. This study was conducted with the aim to explore the co-circulation of dengue and chikungunya viruses in central India. Materials and methods: Samples from suspected dengue cases were subjected to dengue immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and dengue-negative samples were tested with chikungunya-specific IgM ELISA. The samples collected in acute phase of illness were tested by nested reverse transcription polymerase chain reaction (nRT-PCR). Chikungunya virus (CHIKV) sequences were analysed to determine their genotype. Results: Of 138 samples screened for dengue, 21 (15.2%) were positive, and of 119 samples screened for chikungunya, 13 (10.9%) were positive. Dengue viruses 1 and 4 were found co-circulating with chikungunya virus in Jabalpur, central India. The chikungunya virus detected belonged to the East Central South African genotype. Conclusion: Accurate and timely diagnosis would help in patient management and use of resources. It is advocated to simultaneously test samples for these two diseases in endemic areas. This will also aid in understanding the epidemiology of chikungunya.
ABSTRACT
Background: Vector-borne diseases (VBDs) caused by parasites and viruses are a major cause of morbidity and mortality in Madhya Pradesh (MP), central India. These diseases are malaria, lymphatic filariasis, dengue and chikungunya. Epidemiological information is lacking on different VBDs that are commonly prevalent in rural-tribal areas of MP, except on malaria. Methods: The studies were carried out at the request of Government of Madhya Pradesh, in three locations where many VBDs are endemic. Data on malaria/filaria prevalence were collected by repeatedly undertaking cross-sectional parasitological surveys in the same areas for 3 years. For dengue and chikungunya, suspected cases were referred to the research centre. Results: Monitoring of results revealed that all the diseases are commonly prevalent in the region, and show year-to-year variation. Malaria slide positivity (the number of malaria parasitaemic cases, divided by the total number of blood smears made) was 18.7% (190/1018), 16.4% (372/2266) and 20.4% (104/509) respectively in the years 2011, 2012 and 2013. There was a strong age pattern in both Plasmodium vivax and P. falciparum. The slide vivax rate was highest among infants, at 5% (odds ratio [OR] = 3.8; 95% confidence interval [CI] = 1.5 to 9.4; P<0.05) and the highest slide falciparum rate was 20% in children aged 1–4 years (OR = 2.0; 95% CI 1.5 to 2.7; P<0.0001). This age-related pattern was not seen in other VBDs. The microfilaria rate was 7.5%, 7.6% and 7.8% in the years 2010, 2012 and 2013, respectively. Overall, microfilaria rates were higher in males (8.7%) as compared to females 6.4% (OR = 1.5; 95% CI = 1.1 to 2.0; P < 0.01). The prevalence of dengue was 48% (dengue viruses 1 and 4 – DENV-1 and DENV-4), 59% (DENV-1) and 34% (DENV-3) respectively, in the years 2011, 2012 and 2013 among referred samples, while for chikungunya very few samples were found to be positive. Conclusion: Despite recent advances in potential vaccines and new therapeutic schemes, the control of VBDs remains difficult. Therefore, interruption of transmission still relies on vector-control measures. A coordinated, consistent, integrated vector-management approach is needed to control malaria, filaria, dengue and chikungunya.