Epidemiology of campylobacteriosis in a cohort of rural population near Calcutta

Over a 2-year period, 25 families comprising of 181 individuals of all ages were longitudinally observed for the excretion of Campylobacter species. Faecal samples were taken from all persons with diarrhoea. Specimens were also taken from apparently healthy individuals and from domestic animals living within the confines of the study families at monthly intervals. The overall diarrhoea attack rate was 19 episodes per 100 person-years with peak incidence in the 1- to 4-year-old age group (76/100 person-years). Eight (11.5%) of the total episodes were campylobacter-associated and the overall rate of campylobacter positive diarrhoeal episodes were 2.2 per 100 person-years. Of the 1002 stool samples from healthy individuals 32 (3.2/100 samples) were positive for campylobacter. The organism was most frequently isolated from children under 1 year of age both during diarrhoeal episodes (11.5 per 100 person-years) and non-diarrhoeal (11.1 per 100 samples). Multiple infections in a family were rare. In 19.4% of the occasions one or more animals were campylobacter positive. However, only in 7.7% of these occasions was a human infection recorded within 1 month after the animal was found to be positive. The study showed that the epidemiology of campylobacteriosis in this community was distinct compared to that observed in developed countries.

A controlled field trial of an aluminum phosphate-adsorbed cholera vaccine in Calcutta

A controlled field trial to determine the efficacy of a single dose of an aluminium phosphate-adsorbed cholera vaccine was conducted in Calcutta during 1975-77. An aluminium phosphate-adsorbed tetanus toxoid was used as the placebo. Follow-up of the immunized volunteers for a period of two years showed that the adsorbed cholera vaccine provided 100% protection to children under five years of age for 6 months, 88.9% for 12 months, and 91.7% for 18 months (P<0.05). The overall protection for all age groups was 58.5% for 18 months. There were no serious side effects following the anti-cholera inoculations.

Effect of sulfadoxine on transmission of Vibrio cholerae infection among family contacts of cholera patients in Calcutta

Sulfadoxine, a long-acting sulfonamide, and tetracycline were compared as regards their effectiveness in reducing transmission of cholera infection among the contacts of cholera patients in Calcutta. A total of 109 healthy family contacts of confirmed hospitalized cholera patients were treated with a single oral dose of sulfadoxine graded according to age. Another similar group of 101 contacts received 6 divided doses of oral tetracycline over a period of 3 days. All these contacts were bacteriologically examined for 15 days. Results showed that tetracycline was effective in significantly reducing the load of cholera infection from the 2nd to 6th day, while sulfadoxine was effective from the 3rd to the 6th day. The advantages and disadvantages of the two drugs as chemoprophylactic agents in cholera are discussed.