India is experiencing a rapid spread of human immunodeficiency virus type 1 (HIV-1), primarily through heterosexual transmission of subtype C viruses. To delineate the molecular features of HIV-1 circulating in India, we sequenced the V3-V4 region of viral env from 21 individuals attending an HIV clinic in Calcutta, the most populous city in the eastern part of the country, and analyzed these and the other Indian sequences in the HIV database. Twenty individuals were infected with viruses having a subtype C env, and one had viruses with a subtype A env. Analyses of 192 subtype C sequences that included one sequence for each subject from this study and from the HIV database revealed that almost all sequences from India, along with a small number from other countries, form a phylogenetically distinct lineage within subtype C, which we designate C IN . Overall, C IN lineage sequences were more closely related to each other (level of diversity, 10.2%) than to subtype C sequences from Botswana, Burundi, South Africa, Tanzania, and Zimbabwe (range, 15.3 to 20.7%). Of the three positions identified as signature amino acid substitution sites for C IN sequences (K340E, K350A, and G429E), 56% of the C IN sequences contained all three amino acids while 87% of the sequences contained at least two of these substitutions. Among the non-C IN sequences, all three amino acids were present in 2%, while 22% contained two or more of these amino acids. These results suggest that much of the current Indian epidemic is descended from a single introduction into the country. Identification of conserved signature amino acid positions could assist epidemiologic tracking and has implications for the development of a vaccine against subtype C HIV-1 in India.

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HIV-1 infection in India has been increasing steadily over the last decade. In the absence of potent antiviral therapy, estimates of HIV infection are needed to monitor the epidemic, institute prevention strategies in target populations and determine the suitable populations for vaccine studies. In this report we present the HIV-1 seroprevalence and annual estimates of seroincidence in a high risk population from Calcutta, the most populous city in the eastern part of India. In 1206 high risk subjects tested over two years between February of 1999 and December 2000, we have determined an overall seroprevalence of 40.1% using enzyme-linked immunosorbent assay followed by a confirmatory Western blot testing. Furthermore, using a newly described Standardized Testing Algorithm for Recent HIV-1 Seroconversion (STARHS), we have estimated an annual seroincidence rate of about 7% in this population during this two-year study. Such a high annual seroincidence rate makes this population well suited for studies of HIV-1 prevention, including vaccine trials.

This paper discusses a novel idea for transmission of voices in real time, underwater so that the system can be used by the deep sea divers for both lightning and data transfer applications simultaneously. Experiments were performed using white light, green and blue light respectively to transfer voice in real time in a water tank and the graphs were obtained. Based on the comparison study, we make recommendations for the selection of the right colour of light for communication efficiency in specified underwater environments.