Tracking an emerging,cross-border virus

Tracking an emerging,cross-border virus

Little known about killer Nipah virus,NIV team seeks to map it on Bangla border.

In 2001,Dr Mandeep Chadda and her five-member team spent two weeks at a hospital in Siliguri,treating patients for a new kind of infection that led to 22 deaths. They were initially not certain what it was.

“Infected patients had high-grade fever and headache that soon affected the brain. They often went into a state of delirium and let out cries,” she says. “What was also startling was the extent of human-to-human transmission. For instance,we recorded how one patient admitted to Medinova Hospital in February 2001 had infected 23 hospital staff and eight visitors in a short span. The outbreak occurred among hospitalised patients and medical staff of four hospitals then.”

The team went on to identify the outbreak as one caused by the Nipah virus. Today Chadda,deputy deputy with National Institute of Virology,is once again working against the emerging virus,at the forefront of a project that aims to map it in areas bordering Bangladesh.

Bangladesh has reported a series of Nipah virus outbreaks between 2001 and 2008. India has seen two in that period. Following 2001 in Siliguri,the next one was in 2007 in Nadia,both on the border in West Bengal,and which between them saw 66 people infected and 45 deaths.


According to the World Health Organisation,the emerging disease has infected 477 persons and killed 252 since 1998 in the Southeast Asian region. Indian Council of Medical Research has set up a taskforce on infections across the border.

“Our borders are extremely porous and there is increasing concern about transmission of new emerging infections,” says Dr D T Mourya,NIV director,tells The Indian Express.

Chadda stresses the case of Siliguri and the outbreaks in Bangladesh over the last decade. “In 2001,a team of our physicians and epidemiologists visited North Bengal Medical College Hospital,took medical records of the patients,met family members and even visited houses of patients who had died,” recalls Chadda. “We searched for clues to understand which disease had caused the symptoms.”

NIV scientists feel it is crucial to undertake a syndromic surveillance of the population in pockets of the region under survey.

“What we have now proposed is a sero surveillance that means detecting the presence of antibodies against Nipah virus in normal healthy people in the affected pockets ,” Mourya says.

So far Nipah virus outbreaks have been reported from Malaysia,Singapore,Bangladesh and India and cases in humans have been attributed to a zoonotic transmission from bats and pigs. Mourya says the virus causes severe illness leading to inflammation of the brain and in Bangladesh,half the cases between 2001 and 2008 were due to human-to-human transmission.

Chadda says that the virus may have caused few outbreaks but it infects a wide range of animals,besides humans,and causes death.

The disease

1999 First recognition of Nipah virus during an outbreak among pig farmers in Malaysia

12 more outbreaks,all in WHO’s Southeast Asian region. Bangladesh has had several of these

2 outbreaks in India,both on West Bengal’s border with Bangaldesh. Silguri (2001) and Nadia (2007) saw 45 deaths.

How it affects: High-grade fever,headache that soon affects the brain. Patients go into delirium,often scream. High rate of human-to-human transmission.

Sources: During the initial outbreaks in Malaysia and Singapore,most human infections resulted from direct contact with sick pigs or their contaminated tissues. In the Bangladesh and India outbreaks,consumption of fruits or fruit products (e.g. raw date palm juice) contaminated with urine or saliva from infected fruit bats was the most likely source of infection.

An indigenous vaccine against JE

Pune: An indigenous vaccine against Japanese encephalitis will be launched in the first week of this month,says Dr V M Katoch,director general of Indian Council of Medical Research. An effort of NIV in collaboration with Bharat Biotech International Ltd,the tissue culture-derived inactivated vaccine has used an Indian strain.

The virus was purified using patented technology of BBIL,says Dr Devendra Mourya,NIV director. Various strains of the virus were compared,says NIV’s Dr M M Gore,principal scientist in the team that developed the vaccine.


JE,which affects the central nervous system,is transmitted to humans via mosquito bites. Over the last three years it has claimed more than 3,000 lives: Assam,West Bengal,Bihar and Uttar Pradesh are the worst affected states. JE mostly affects children below 15 . ENS