The study, conducted on children below the age of five in three age-groups — below 24 months, between 24 and 59 months and below five years — has shown young children suffer the most from cholera. Among the three cholera-endemic sites surveyed, Jakarta in Indonesia, Beira in Mozambique and Kolkata, the lowest overall rate was reported in Jakarta at 0.5 cases for 1000 people per year. The incidence was three times higher in Kolkata and eight times higher in Beira at 4.0 per 1000 people per year.

The survey was conducted by Dr Jacqueline L Deen of the IVI and Dr Dipika Sur, deputy director, NICED, in 2005 in Narkeldanga and Manicktala (ward nos. 29 and 30) in the city. Titled “The High Burden of Cholera in Children: Comparison of Incidence from Endemic Areas in Asia and Africa”, the report was published in the open source journal PLoS Neglected Tropical Diseases.

According to the authors, the cholera burden was calculated using the site population as denominator and the number of cholera cases as numerator. According to a WHO epidemological report published in August last year, 99 per cent of cholera incidence is suspected to be in Africa. The number of cholera cases reported to WHO during 2006 rose dramatically, reaching the level of the late 1990s. A total of 2,36,896 cases were notified from 52 countries, including 6,311 deaths (a case-fatality rate (CFR) of 2.66 per cent), an overall increase of 79 per cent compared with the number of cases reported in 2005.

This increase in number of cases is the result of several major outbreaks that occurred in countries where cases have not been reported for several years. Globally, the number of deaths rose from 2,272 to 6,306, a three-fold increase compared with 2005, the report adds.

At NICED, director G B Nair says 15 per cent of diarrhoea cases reported to the Infectious Diseases and Beliaghata General Hospital (attached to NICED) prove to be cholera cases. “Kolkata was included in the survey not as a place with alarmingly high incidence of cholera, but rather as a spot with presence of cholera and suitable conditions for the spread of the virus, such as adequate water bodies, unhygienic living conditions, humidity etc. In fact, it is similar to both Beira and Jakarta and can be attributed the dubious distinction of the ‘homeland of cholera’.”