HLA class II allele polymorphism in an outbreak of chikungunya fever in Middle Andaman, India.

A sudden upsurge of fever cases with joint pain was observed in the outpatient department, Community Health Centre, Rangat during July-August 2010 in Rangat Middle Andaman, India. The aetiological agent responsible for the outbreak was identified as chikungunya virus (CHIKV), by using RT-PCR and IgM ELISA. The study investigated the association of polymorphisms in the human leucocyte antigen class II genes with susceptibility or protection against CHIKV. One hundred and one patients with clinical features suggestive of CHIKV infection and 104 healthy subjects were included in the study. DNA was extracted and typed for HLA-DRB1 and DQB1 alleles. Based on the amino acid sequences of HLA-DQB1 retrieved from the IMGT/HLA database, critical amino acid differences in the specific peptide-binding pockets of HLA-DQB1 molecules were investigated. The frequencies of HLA-DRB1 alleles were not significantly different, whereas lower frequency of HLA-DQB1*03:03 was observed in CHIKV patients compared with the control population [P = 0·001, corrected P = 0·024; odds ratio (OR)  = 0, 95% confidence interval (95% CI) 0·0-0·331; Peto's OR = 0·1317, 95% CI 0·0428-0·405). Significantly lower frequency of glutamic acid at position 86 of peptide-binding pocket 1 coding HLA-DQB1 genotypes was observed in CHIKV patients compared with healthy controls (P = 0·004, OR = 0·307, 95% CI 0·125-0·707). Computational binding predictions of CD4 epitopes of CHIKV by NetMHCII revealed that HLA-DQ molecules are known to bind more CHIKV peptides than HLA-DRB1 molecules. The results suggest that HLA-DQB1 alleles and critical amino acid differences in the peptide-binding pockets of HLA-DQB1 alleles might have role in influencing infection and pathogenesis of CHIKV.

Medicinal Plants Used by the Nicobarese Inhabiting Little Nicobar Island of the Andaman and Nicobar Archipelago, India.

BACKGROUND: This study is an attempt to document the medicinal plants used by the tribal community of Little Nicobar Island. Despite modern healthcare facilities, tribals often consume medicinal herbs, with traditional knowledge practitioners (TKPs) serving as local medical experts. OBJECTIVES: The aim is to conduct an ethnomedicinal survey among the Nicobarese, whose medicinal practices are yet to be documented. METHODS: Field research was conducted in all five villages of Little Nicobar Island, situated in the southernmost part of the Andaman and Nicobar Archipelago, during 2012-2013. Seven TKPs were interviewed using a questionnaire-guided ethnomedicinal survey protocol. The data obtained were analyzed using the informant consensus factor (ICF) and use value. Voucher specimens of all the cited plant species were deposited at the Regional Medical Research Centre (Indian Council of Medical Research), Port Blair. RESULTS: Uses of 34 medicinal plant species, belonging to 23 families encompassing 32 genera, were recorded during the survey. These 34 species are employed to treat a total of 16 ailments. The highest ICF (1.00) was obtained for respiratory diseases. The Euphorbiaceae family exhibited the highest number of citations, and plants with the highest use values were Glochidion calocarpum Kurz, Senna occidentalis (L.) Link, Ocimum tenuiflorum L., and Passiflora suberosa L. Of the medicinal plants reported, the most common growth form was herbs. Remedies were generally prepared using water. The medicinal plant preparations were administered topically or orally. INTERPRETATION AND CONCLUSIONS: Traditional knowledge of herbal medicines is handed down orally through generations. These plants attained a significant role under the healthcare of the Nicobarese residing in Little Nicobar Island. Efforts to ensure their documentation are necessary in order to prevent its loss, either because of natural calamities or lack of interest among younger generations in carrying out their tradition.