| Is that boiled water'
New Delhi, Sept. 4: Some doctors may call it the “price” of drinking boiled water.
Infection patterns displayed by a virus, which traditionally caused jaundice mainly in children, have changed in India with a greater proportion of adults now falling sick, medical researchers have reported.
More adults are getting jaundice from the Hepatitis A virus (HAV) now than a few years ago, possibly because they have not acquired natural immunity against the virus, researchers said.
“We’re witnessing early signs of a shift in HAV patterns,” said Premashis Kar, a professor of medicine at the Maulana Azad Medical College in New Delhi. “What we’re seeing may be the result of better hygiene and water quality.”
People pick up HAV through contaminated water or food. In the past, most children would ingest small doses of the virus through water — doses too small to cause disease but good enough to build natural immunity.
But over the years, the proportion of people to acquire natural immunity in this manner appears to have dropped in India as the risk of picking up HAV through contaminated water in childhood has reduced.
The virus is killed by boiling at 85 degrees Celsius for one minute. Adequate treatment and chlorination of water can also kill the virus.
Several studies point to the trend of HAV infections in adults. A hospital study in New Delhi earlier this year showed that HAV infection among adult patients with hepatitis has grown from 3.4 per cent to 12 per cent over the past five years.
Virologist Vidya Arankalle and her colleagues at the National Institute of Virology in Pune have just published a research report on the first HAV outbreak among adults in India — in Kottayam (Kerala) during 2004 with 1,180 patients.
Doctors estimate that HAV accounts for about 15 per cent of viral jaundice observed in India. Another virus, Hepatitis E (HEV), makes up 40 per cent of the cases of viral jaundice, while HBV, HCV — both picked up through blood or tainted needles — and other viruses account for the rest.
HAV causes a short illness — the jaundice ranging from mild to severe — but it can keep patients in bed for weeks.
But virologists caution that HAV could lead to loss of productivity. “Among 100 children who get infected, only five will get jaundice, the rest will not show any symptoms. But a far greater proportion of infected adults fall sick,” Arankalle said.
“This trend of HAV shifting towards adults is not surprising. It has been previously observed in some developed countries,” said Kar.
Surveys by Arankalle in the 1980s and 1990s showed that people in the higher socio-economic groups — who are more likely to have access to clean water — are also more likely to lack natural immunity.
Scientists had used the results of those surveys to predict HAV epidemics among adults in high socio-economic groups.
Some doctors recommend that people should be screened for anti-HAV antibodies to find out whether they possess natural immunity. Those who are not protected might consider taking a vaccine against HAV, Kar said.
But not all doctors believe the shift in HAV patterns is imminent.
Gastroenterologist Anoop Saraya at the All India Institute of Medical Sciences said vaccination against HAV might not be required in many parts of India because most people continue to be naturally protected from the virus.
In a survey of nearly 2,000 schoolchildren four years ago, Saraya had shown that 95 per cent of the children had acquired natural immunity against HAV.