Health experts warn the public of potential Nipah epidemic a year after the deadly virus wreaked havoc across Kerala. The warning was told at the Nipah Virus International Conference 2019 where scientists say they have yet to develop a drug or vaccine to fight against it—20 years after Nipah was first discovered.
The conference was the first one that commemorated the 20th anniversary of the discovery of the virus. Experts and global health stakeholders discussed innovative and effective solutions to address the threat of Nipah, which they believe is a danger to global health security.
First outbreaks and mortality
The first recognition of the Nipah virus was in 1999 during an outbreak among pig farmers in Malaysia. It caused severe brain inflammation in 265 people at the time and caused the death of 105, according to National Geographic. Infections were first reported in pigs and other domestic animals before the virus was transmitted to humans from direct contact with the animals.
No new outbreaks were reported in Malaysia since then, but the virus spread across Southeast Asia and caused recurrent epidemics. For instance, Bangladesh has had annual breakouts of diseases due to Nipah since it was first recognized in 2001 and was periodically observed in India.
In those said countries, the infection most likely came from the consumption of fruits or fruit products that were contaminated with urine or saliva from infected fruit bats—the natural host of the virus. The WHO adds that human-to-human transmissions of Nipah have been reported through close contact with secretions and excretions of infected patients, specifically in Bangladesh and India.
"In Siliguri, India in 2001, the transmission of the virus was also reported within a health-care setting, where 75% of cases occurred among hospital staff or visitors," the UN health agency says. "From 2001 to 2008, around half of reported cases in Bangladesh were due to human-to-human transmission [by] providing care to infected patients."
For the past 20 years, the Nipa outbreaks recorded mortality rates of between 40% and 90% in Malaysia, Bangladesh, and India—with the most recent breakout in Kerala, India claiming 17 lives in 2018. Human Nipah infections range from asymptomatic infection to acute respiratory infection (mild, severe), and fatal encephalitis that could progress into a coma within 24 to 48 hours of infection.
No means to fight back
Most of the patients who survive severe cases of the infection make a full recovery. However, the WHO says 20% of these survivors have reported long-term neurologic conditions such as seizure disorder or changes in personality. It adds that a small number of people who recover either relapse or develop delayed onset encephalitis.
These outcomes show how crucial it is to prevent catching an infection but the absence of a drug or vaccine that could fight back against the virus makes prevention difficult. This, even though the WHO has identified Nipah as a priority disease.
"Twenty years have passed since its discovery, but the world is still not adequately equipped to tackle the global health threat posed by Nipah virus," Richard Hatchett, chief executive of the CEPI Coalition for Epidemic Preparedness Innovations, said during the conference.
Reuters reports that the coalition, upon its establishment in 2017, is attempting to speed up the progress of vaccines against emerging and unknown diseases—with Nipah being among its first targets.
Wang Linfa, co-chairman of the conference's organizing committee, said in a press release the CEPI assembly aims to stir discussion between experts and global stakeholders "to bring about innovative and effective solutions to boost efforts in fighting the Nipah virus."
For now, it's important to strengthen preparedness for outbreaks and quick response to infectious diseases as ever-prevalent global traveling makes transmissions spread rapidly across borders.
Reducing risks of infection
As the world waits for a vaccine against the Nipah virus, there are things that can be done to reduce the risk of infection based on outbreaks in 1999. The WHO says these past experiences show thorough and routine cleaning and disinfection of pig farms could greatly prevent animal-to-human infections
It adds that raising awareness of the risk factors and educating people about measures they can take can reduce their exposure, and by extension, prevent Nipah infection. These measures include:
• Keeping bats away from fresh food products and sap collection sires to prevent bat-to-human transmission. Boiling freshly collected date palm juice and thoroughly washing and peeling fruits should also be practiced.
• Wearing protective garments like gloves and face masks should be done when handling sick animals or tissues as well as during slaughtering and culling procedures. People should also avoid getting in contact with infected pigs and avoid setting up new farms close to bat-infested areas.
• To avoid human-to-human transmission, the WHO advises avoiding close physical contact with people infected with the Nipah virus. Regular hand washing should also be practiced after caring or visiting sick people.