Nipah Virus: Symptoms, How It Spreads, Deaths and Which Countries It Is In

Currently, there are no vaccines developed for Nipah virus infection, and its treatment is limited to palliative care, according to authorities

Pedestrians walk along a street in an electronics market in New Delhi, India
September 18, 2023 | 04:03 PM

Bloomberg Línea — After the challenges posed by COVID-19, there are now other concerns emerging worldwide regarding the possibility of a new epidemic. Currently, the spotlight is on the Nipah virus, an infectious disease that first appeared in domestic pigs in Malaysia and Singapore in 1998 and 1999. In the past few days, India scaled up surveillance to contain the spread of the virus after two people died from the disease.

This disease, which causes respiratory symptoms and occasionally neurological signs, has a high zoonotic potential, meaning it is a disease primarily found in animals that can incidentally be transmitted to humans—a situation that has already occurred, as reported by the World Health Organization (WHO) and the World Organisation for Animal Health (OIE).

“It can also be transmitted directly from one person to another through close contact with an infected person. Fruit bats or flying foxes (Pteropus species) are the natural hosts of the Nipah virus,” explains WHO.

How is the Nipah virus transmitted?

The virus can spread through various routes, including:

  • Direct Contact: Close contact with infected animals or their bodily fluids, such as saliva or urine, can transmit the virus to humans.
  • Human-to-Human Transmission: Nipah virus can also spread through direct contact with infected individuals, particularly when caring for sick patients.
  • Consumption of Infected Food: Consumption of fruits or raw sap contaminated with bat excretions can lead to infection.
  • Nosocomial Transmission: In healthcare settings, Nipah virus can spread through contaminated medical equipment and surfaces.

Research conducted in recent years indicates that the possible incubation period ranges from four to fourteen days. However, there have been reports of an incubation period of up to 45 days.

" Its primary natural reservoir is fruit bats, also known as flying foxes. It is known that Nipah causes diseases in pigs and humans,” said Ecuadorian medical researcher Esteban Ortiz through his social media.

The WHO also details that during the acute and convalescent phases of the disease, laboratory diagnosis of a patient with a clinical history of Nipah virus infection can be performed using a combination of tests. The main tests used are RT-PCR from organic fluids and antibody detection using the ELISA method.


Symptoms of Nipah virus

In reference to the situation that has occurred in India, as well as the one that occurred in Bangladesh in early 2023, the United Nations-affiliated organization explained that Nipah virus infection typically results in a range of clinical conditions, varying from subclinical infection to acute respiratory infection and lethal encephalitis.

Infected individuals initially exhibit symptoms such as fever, headaches, myalgia (muscle pain), vomiting, and sore throat. These may be followed by dizziness, drowsiness, altered consciousness, and neurological signs indicative of acute encephalitis.

Moreover, some individuals may also experience atypical pneumonia and severe respiratory problems, including acute respiratory distress. In severe cases, encephalitis and seizures may occur, progressing to coma within 24 to 48 hours.

“Most individuals who survive acute encephalitis make a full recovery, but long-term neurological conditions have been described in survivors. Approximately 20% of patients are left with residual neurological sequelae, such as seizure disorders and personality changes,” as detailed by WHO.


List of countries where the Nipah virus were present

Since its discovery in 1998 in Malaysia, Nipah virus outbreaks have occurred sporadically across several countries in South and Southeast Asia. These outbreaks have resulted in numerous fatalities, impacting both individuals and healthcare systems. Some of the countries that have reported Nipah virus outbreaks include:

  • Malaysia
  • Bangladesh
  • India
  • Singapore

What the WHO recommends for Nipah virus

Reports available to date indicate that the global case fatality rate of the Nipah virus is estimated to be between 40% and 75%, depending on local epidemiological surveillance and clinical management capabilities. “Although antiviral drugs are being developed, there are no approved vaccines or treatments for the prevention or treatment of Nipah virus infection.”

Therefore, in the absence of an authorized vaccine or treatment for Nipah virus infection, the only way to reduce or prevent infection in individuals is to educate them about the risk factors and the measures they can take to reduce exposure to the Nipah virus.


Case management should focus on providing palliative care measures to patients. “Intensive supportive care is recommended to treat severe respiratory and neurological complications,” adds the WHO.

Read Also:

Latin America’s 500 Most Influential People in 2023