Nipah Virus Outbreak in Kerala

Context:

Two people have died and four others are under treatment after contracting Nipah virus in Kerala’s Kozhikode district. While the Nipah virus does not spread as quickly as the Covid-19 virus, it is more deadly.

Relevance:

GS II: Health

Dimensions of the Article:

1. Nipah virus
2. Signs, Symptoms, Diagnosis, and Treatment of Nipah Virus Infection
3. Nipah Virus Spread and Past Outbreaks

Nipah Virus

Nipah virus is classified as a zoonotic disease, indicating that it is transmitted to humans through contact with infected animals or via the consumption of contaminated food.

Origin and Early Outbreak

• The virus was first identified during an outbreak in Malaysia and Singapore, with its primary impact observed in pigs and individuals closely associated with them.
• The name “Nipah” is derived from the Malaysian village of Sungai Nipah, where this outbreak initially occurred. Since 1999, no new outbreaks have been reported in Malaysia.

Family and Natural Hosts

• Nipah virus belongs to the Paramyxoviridae family and shares a close relationship with the Hendra virus.
• The Paramyxoviridae family comprises a group of single-stranded RNA viruses responsible for causing infections in vertebrates.
• Fruit bats are the natural hosts for the Nipah virus, interestingly, these bats do not exhibit apparent signs of the disease themselves.

Transmission to Humans

• The primary mode of transmission to humans occurs through contact with infected animals, especially fruit bats, commonly known as flying foxes.
• Fruit bats are recognized as the principal carriers of the virus and can transmit it to other animals like pigs, dogs, cats, goats, horses, and sheep.
• The transmission from animals to humans is primarily facilitated through the consumption of contaminated food.
• Importantly, human-to-human transmission is also possible, primarily through close contact with the bodily fluids of individuals who are already infected.

Signs, Symptoms, Diagnosis, and Treatment of Nipah Virus Infection

Signs and Symptoms:

• Human infections caused by the Nipah virus can manifest across a wide spectrum, ranging from asymptomatic cases to more severe conditions, including acute respiratory infections and fatal encephalitis.
• Initial symptoms typically include fever, headaches, myalgia (muscle pain), vomiting, and a sore throat.
• The incubation period, which is the time from infection to the onset of symptoms, is estimated to span 4 to 14 days.

Diagnosis:

• Early signs and symptoms of Nipah virus infection are often nonspecific, and healthcare professionals may not initially suspect this disease.
• The diagnosis of Nipah virus infection can be established by considering clinical history during both the acute and convalescent phases of the illness.
• Diagnostic tests employed include the use of real-time polymerase chain reaction (RT-PCR) on bodily fluids and the detection of antibodies through enzyme-linked immunosorbent assay (ELISA).

Treatment:

• As of now, there are no specific drugs or vaccines designed to target Nipah virus infection, although it has been recognized as a priority disease by the WHO Research and Development Blueprint.
• Management of Nipah virus infection primarily relies on intensive supportive care, particularly for individuals experiencing severe respiratory and neurologic complications.

Nipah Virus Spread and Past Outbreaks

Spread Rate:

• The Nipah virus is known for spreading at a slower pace compared to highly contagious viruses like SARS-CoV-2 (COVID-19). However, its potential to cause fatalities is a major concern.
• The World Health Organization (WHO) estimates that the global case fatality rate of Nipah virus infection ranges from 40% to 75%.
• It’s worth noting that, to date, all outbreaks of the Nipah virus have been localized and contained relatively quickly.
• One key reason for the relatively swift containment of Nipah virus outbreaks is that it is not highly infectious, and human-to-human transmission is not easily facilitated.
• Furthermore, the virus’s high mortality rates contribute to lower transmission because it often leads to severe illness and death before extensive transmission can occur.

Past Outbreaks:

Nipah virus outbreaks have been documented in various locations over the years. Notable instances include:

• Malaysia and Singapore: The virus was first identified during an outbreak in Malaysia and Singapore. The outbreak was primarily associated with pigs and individuals working closely with them.
• Bangladesh (2001): Nipah virus was recognized in Bangladesh in 2001, and it has led to nearly annual outbreaks in the country since then.
• Eastern India: Periodic cases of the disease have also been identified in eastern India.
• Other Countries: Evidence of the virus has been found in the known natural reservoir, fruit bats, as well as several other bat species in multiple countries, including Cambodia, Ghana, Indonesia, Madagascar, the Philippines, and Thailand.

-Source: Indian Express