NIPAH VIRUS

NIPAH VIRUS

CONTEXT :

• Recently, two deaths from Nipah have been reported in India, from Kerala. More than a dozen people reported infected.

WHAT IS NIPAH VIRUS ?

• Nipah is a zoonotic virus, transmitted when a person is in contact with an animal carrying the virus or consumes or handles food contaminated by it or through close contact with a human carrying the infection.
• Nipah virus (NiV) was first discovered in 1999 following an outbreak of disease in pigs and people in Malaysia and Singapore.
• NiV is a member of the family Paramyxoviridae, genus Henipavirus.
• It is a zoonotic virus, meaning that it initially spreads between animals and people.
• The animal host reservoir for NiV is the fruit bat (genus Pteropus), also known as the flying fox.

• Epidemiologists clarify, of 1,00,000 bats only four or five could be carrying the Nipah virus.
• Shedding of the virus in secretions is not uniform , so it takes a lot of things coming together for a virus to jump species.

ABOUT PAST NIPAH OUTBREAKS:

• In the first recognised outbreak in Malaysia (that also affected Singapore), the infection came from direct contact with sick pigs or contaminated tissue.
• Later infections in Bangladesh and India are said to have been from the consumption of fruits, fruit products (raw date palm juice) contaminated with the urine or saliva from infected fruit bats, according to the World Health Organization.
• Usually, people with Nipah virus infection present with encephalitic symptoms.
• But in the latest outbreak, patients presented with pure respiratory symptoms, not reported anywhere in the world before.
• In the 2019 and 2021 outbreak, there was only a single case without any human-to-human transmission.

MORTALITY AND CONTAGION  RISK IN NIPAH VIRUS :

• The Nipah virus must be contained, given its high mortality rate.

• The infection can lead to acute respiratory distress, encephalitis, and/or seizures, and can progress to coma within 24 to 48 hours.
• The case fatality rate is estimated at 40-­ 75 per cent, the WHO said.
• Although this could vary depending on local capabilities for epidemiological surveillance and clinical management.
• The Nipah virus has low infectivity (R0 of 0.2-0.3 compared with R0 of over 1.5 in the case of SARS-CoV-2 virus).
• The infectivity from first-degree to second-degree patients is low when infected with Nipah virus but high in the case of index cases.

TREATMENTS FOR THE INFECTION:

• Those infected by the Nipah virus are treated with supportive care, as there is no primary treatment or vaccine available for people or animals.
• Immunological and drug therapies are said to be under development.
• But there are simple ways to prevent and contain transmission of infection — including staying away from (and not destroying) bat habitats.
• Not consuming half-­bitten fruits and maintaining hygiene standards — including boiling freshly collected date palm juice, washing and peeling these fruits before consumption.
• Hygienic agricultural practices involving the handling of pigs and goats, for example in farms help keep the virus at bay.

WHY FREQUENT NIPAH OUTBREAKS IN KERALA ?

• As per a 2021 study, Nipah virus was found to be in circulation in fruit bats (Pteropus species) in many districts in Kerala.
• Fruit bats that can cause Nipah virus outbreaks in humans are not restricted to Kozhikode district.
• An ongoing nationwide survey in 14 States by NIV Pune has found Nipah virus antibodies in fruit bats (Pteropus medius) in nine States, including Kerala, and the Union Territory of Pondicherry.
• The four outbreaks in five years may be because the virus has either become endemic in bats in Kerala or is a reflection of Kerala’s superior healthcare system that thoroughly investigates undiagnosed fever cases for possible Nipah virus infection or both.
• However, with fruit bats positive for Nipah virus antibodies being found in other States, it is likely that Nipah virus infection and deaths may be going undetected in other States while they get picked up in Kerala, especially in Kozhikode district.

GOVERNMENT INTERVENTIONS :

• The Centre has sent teams to Kerala to take steps required to contain the virus, and samples have been sent to National Institute of Virology (Pune).
• The Kerala government has set up containment zones in Kozhikode, where the infections were first diagnosed.
• Also contact tracing has been undertaken and educational institutions have been shut, as a preventive action.

WAY FORWARD:

• The outbreaks of Nipah virus may be another indication that habitat loss as a result of human incursion forces greater contact between humans and animals increasing the risk of animal-to-human transmission.
• A key step in preventing outbreaks of Nipah and other bat-borne viruses is developing better ways of managing wildlife that lives close to communities.
• One approach that could go a long way towards heading off future outbreaks is to restore forest areas to improve bat habitats, which would provide them with more a reliable food source and reduce the risk of spillover.

SYLLABUS: MAINS, GS-3, DISEASES

SOURCE: THE HINDU