No abstract

Summary Cancer of the oesophagus is the most commonly diagnosed cancer in males in Assam, in north-eastern India, and ranks second for females. The chewing of betel nut, with or without tobacco and prepared in various ways, is a common practice in the region and a case-control study has been designed to study the pattern of risk associated with different ways of preparing and chewing the nuts. 358 newly diagnosed male patients and 144 female have been interviewed together with 2 control subjects for each case chosen at random from among the attendants who accompanied patients to hospital. There were significant trends in risk ratios associated with the frequency of chewing each day, with the duration of chewing in years and with the age at which the habit was started that were apparent for both males and females and which remained significant after allowance was made for other known risk factors, notably tobacco smoking and alcohol consumption. The adjusted ratios, in comparison with non-chewers, were 13.3 M and 5.7 F for chewing more than 20 times a day, 10.6 M and 7.2 F for persons who had chewed for more than 20 years and 10.3 M and 5.3 F for those who had started before the age of 20. Among the different combinations of ingredients that were chewed the adjusted odds ratios were highest for those who had been using fermented betel nut with any form of tobacco (7.1 M and 3.6 F). The risk associated with tobacco smoking and alcohol consumption, which are high in some parts of the world, were less in Assam than those associated with the chewing of betel nut.

No abstract

High percentage of unmarried people (>45%) reporting with STD, which points to potential danger of HIV transmission in the region.

To estimate the vectorial capacity of Anopheles dirus, the main vector of forest malaria in the northeastern region of India, in order to gain an understanding of entomological factors related to malaria transmission in forest-fringe areas of Assam, India, an isolated village in the tropical rain forest-fringed area in the district of Dibrugarh, Assam, under the influence of An. dirus alone was studied. Data on various entomological variables required for computation of the vectorial capacity were generated in each month from June 1999 to May 2000 in the field using standard techniques. Malaria prevalence was also studied during the same period in the study village and correlated with the estimated vectorial capacity of An. dirus. Vectorial capacity of An. dirus was highest, 0.779 for Plasmodium vivax (Pv) and 0.649 for Plasmodium falciparum (Pf), during the hot-monsoon season (June-September) and decreased to 0.08 (Pv) and 0.07(Pf) in the temperate postmonsoon season (October-November) before attaining zero values in the cool-dry season (December-February). With increasing temperature in the temperate premonsoon season (March-May), vectorial capacity recorded was 0.119 and 0.82 for Pv and Pf, respectively. Significant positive correlation was seen between the estimated vectorial capacity of An. dirus and the number of new Pf (r = 0.86, p < 0.001) and Pv (r = 0.69, p < 0.02) cases in the study village in different months. Thus, this study highlights the pattern of malaria transmission by An. dirus in a forest-fringe area of Assam that begins in March, peaks in July/August, subsides by November, and remains interrupted between December and February. Measures for controlling malaria in forest-fringe areas should be scheduled accordingly.