City Sunday

Nipah scare forces medical fraternity for vaccine

The latest outbreak of Nipah (NiV) virus which was detected in Kozhikode in north Kerala and Mallapuram has claimed 14 lives till now, including a Kerala nurse who contracted the disease while treating an infected patient, has created a panic situation in Kerala and elsewhere. The outbreak is bound to affect the state’s tourism sector and also fruit vendors as the bats which are believed to be responsible for the spread of virus feed primarily on fruits.

As per World Health Organisation (WHO), Nipah virus (NiV) which was named after Kampung Sungai Nipah, Malaysia is a newly emerging zoonosis (a virus transmitted to humans from animals).

Origin

NiV was first identified during an outbreak of a disease in Kampung Sungai Nipah, Malaysia in 1998.

Transmission

The virus normally circulates among specific types of fruit bats that act as host belongs to fruit bats of the Pteropodidae Family, Pteropus genus.

In the first outbreak, pigs were the intermediate hosts. It was suspected that initial transmission from fruit bats to pigs probably occurred. In Bangladesh in 2004, humans became infected with NiV as a result of consuming date palm sap that had been contaminated by infected fruit bats. Human-to-human transmission has also been documented, including in a hospital setting in India.

The virus claimed over 300 lives across Malaysia, Singapore, Bangladesh and India between 1998 and 2008, according to WHO.

Symptoms

NiV infection in humans has a range of clinical presentations, from asymptomatic (no symptoms) infection to the acute respiratory syndrome and fatal encephalitis.  Fever, sore throat, headaches, vomiting and muscle pain (myalgia) are some of the common signs. The symptoms further progressed to drowsiness, dizziness. In serious cases, seizures and encephalitis occur, progressing to a state of coma within 24 to 48 hours.

Treatment

There is no vaccine for either humans or animals. The primary treatment for human cases is intensive supportive care.

WHO has listed this virus in its ‘Blueprint priority’ diseases category. The diseases identified through this process are the focus of the work of R& D Blueprint. The Virus also classified as Biosafety Level 4.  A biosafety level is a set of biocontainment precautions required to isolate dangerous biological agents in an enclosed laboratory facility

The incubation period of the Virus is anywhere between 5-14 days, but it can soon affect the respiratory and nervous system and patients can go into delirium or coma.

Prevention

The most basic and important step to avoid contacting the Virus is to protect oneself while dealing with infected people by using approved hand gloves and masks.

Not to eat fruits that have fallen on the ground and have bite marks. Thoroughly wash and peel fruits before consuming.

One needs to avoid direct contact with infected people and wash hand properly after handling infected persons.

National Centre for Disease Control in an advisory to the general public said that who are exposed to areas inhabited by fruit bats, articles contaminated by secretions such as, unused wells, caves, fruit orchards, etc are likely to be at higher risk of infection.

Persons with direct contact with sick pigs or their contaminated tissues, persons in close contact with a Nipah virus affected deceased during burial or cremation rituals prone to the deadly disease.  Healthcare workers having direct contact with probable or confirmed cases without using standard precautionary measures are also vulnerable to NiV infection.

While the WHO has not issued any specific advice to countries – including the United Arab Emirates (UAE) – that have not been affected by the Nipah virus (NiV), it has asked them to enhance the level of preparedness.

The organisation said that the preparedness level should be enhanced due to the population and goods movements between the countries and India where a current outbreak has claimed 14 lives while at least 40 others have been put in quarantine.

Among the advisories given, the WHO has advised countries to enhance surveillance at healthcare facilities including at points of entry and give case definitions among healthcare workers (HCWs).

Meanwhile, in the wake of Nipah virus cases in Kerala, the Indian Council for Medical Research (ICMR) has written to the Queensland government in Australia asking it to provide an antibody developed there to test if it can “neutralise” the virus in humans.

The antibody has not been tested on humans so far.

“We have asked them to give their monoclonal antibody for conducting a test in India to find out if it can neutralise the Nipah virus in humans ICMR added.

“In Australia, it has only been tried in vitro (happening outside the body in artificial conditions, often in a test tube) and has been found to be effective. But it has not been tested on humans,” said ICMR Director General, Dr Balram Bhargava, while clarifying that it will not lead to the creation of a vaccine.

ICMR is the apex body in India for the formulation, coordination and promotion of biomedical research.

According to Dr Bhargava, Australia is ready to share as it will help generate data on the efficacy of the antibody.

“It is not yet sure how much it will be effective,” he said, adding the infection caused by Nipah virus has a high mortality rate (50-70 pc).

According to National Vector Borne Disease Control Programme, the drug ribavirin has been shown to be effective against the viruses in vitro, but human investigations to date have been inconclusive and the clinical usefulness of the drug remains uncertain.

                                                                                                         -NAVEED AHAMAD

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