Deadly Diarrhoea 

A new member has been added to the 

growing list of pathogens in the city, reports Biplab Das 

Last year, till the end of October, many adult patients were admitted to the Infectious Diseases Hospital, Calcutta, with complaints of acute watery stool, vomiting and moderate to severe dehydration. The symptoms, according to the ID Hospital physicians, did not match those associated with previously known cases of adult diarrhoea. 

The puzzled experts at the hospital got in touch with the city-based National Institute of Cholera and Enteric Diseases (NICED). NICED researchers reacted with alacrity. They formed a team to study the genomic profile of the diarrhoea pathogen. 

The team found that in five cases the genomic profile of the 'unknown' pathogen matched with that of Group B (one of the three strains of the viral agent known to researchers) Adult Diarrhoea Rotavirus (ADRV). 

Rotaviruses generally cause acute diarrhoea in children below two years. According to the team - that published the study in the British journal Lancet - since 1982, it was the first confirmed outbreak of Group B rotavirus; the double stranded RNA virus that causes adult diarrhoea outside China. 

"The emergence of ADRV in Calcutta since its last large outbreak in China in 1982 is a matter of great concern," says Tribeni Krishnan, a member of the NICED team. Among the patients, 53 were found rotavirus positive; of them, 17 were adults over 18 years. 

Patients with non-Group B ADRV infections were mostly hospitalized at the end of last year with 13 cases being admitted between August and October. The Lancet report mentions that Group B ADRV cases were sporadic. Of the 48 rotavirus cases, 13 were labeled non-Group A as they did not respond to antibody-based ELISA test designed for Group A rotavirus antigen. Samples from five patients with Group B rotavirus infections failed to react to in immuno assays, which detected Group A antigen. The deadly virus resides in the small intestine before wreaking havoc in the digestive system and thus it is found in large number of patients' faeces. From patients' faecal matter, the rotavirus infections, generally water-borne, spreads. Dense population coupled with poor sanitation adds to the spread of the disease in adults and children. 

Calcutta has a large population living in unhygienic slums. If the deadly virus spreads, the damage to human health would be unimaginable. 

"Stringent surveillance and molecular epidemiological research are needed to understand the dynamics of the new virus," says S. K. Bhattacharya, director of NICED. In 1982, the virus killed scores of Chinese. Given our track record in tackling health problems the five isolated cases may soon turn into five thousand.