There’s no cure and no vaccine for the Nipah Virus – and so far this year, both confirmed cases have resulted in deaths.

By Mohammad Al Amin

Before the first month of 2024 was over, Bangladesh had recorded two cases and two deaths of the bat-borne Nipah virus (NiV).   

The country has been dealing with NiV outbreaks since 2001, reporting cases and deaths every year since. 2023 saw ten deaths from the virus , the highest fatality toll in the past seven years. A further four people survived the infection.

It’s an uncommonly deadly illness, killing between 40% and 100% of people infected in outbreaks that have spanned Bangladesh, India, Malaysia and Singapore, according to the World Health Organization (WHO). Patients typically start displaying symptoms between 4 and 14 days after exposure – though incubation periods as long as 45 days have been observed – and can escalate to a range of risky clinical presentations, from brain inflammation to acute respiratory infection.

Early losses

In Bangladesh, a 38-year-old male from Manikganj district of Dhaka division was the first known patient of 2024, confirmed Prof Dr Tahmina Shirin, director of the Institute of Epidemiology, Disease Control and Research (IEDCR). He developed symptoms, including a fever, on 11 January and was admitted to a local hospital on 16 January. On 28 January, the patient was shifted to a referral hospital in the capital, where he died.

On 31 December 2023, the patient had consumed raw date palm sap, which carries the risk of Nipah infection, as fruit bats infected with the virus can contaminate the sap by licking the part of the tree that produces it. Family members of the deceased man tested negative for NiV.

The second reported patient of the year was a three-year-old girl from Shariatpur district in Dhaka. She was rushed to a nearby health complex on 30 January, with a high fever and other symptoms. After being diagnosed with encephalitis and shock, the patient was shifted to the isolation ward of a hospital in the capital on the same day. She died on 31 January. Like the Manikganj patient, the little girl’s family also reported a history of consuming raw date palm sap.

Nipah risks

According to IEDCR, as many as 341 Nipah cases have been detected in Bangladesh, with 242 deaths, since the first recorded outbreak in 2001. Until now, the virus has been reported in 34 districts out of the country’s 64.

Shirin of IECDR said that last year alone, cases were detected in seven districts of the country – namely Rajshahi, Naogaon, Rajbari, Shariatpur, Pabna, Natore and Narsingdi. She confirmed that Nipah is regarded as a disease with pandemic potential.”We carry out regular surveillance of the Nipah outbreaks. As per our report, the bat is the prime carrier of the Nipah virus in Bangladesh. After drinking raw palm date sap, human usually gets infected with the virus,” the IEDCR director explained.

Though identifying information on surviving patients is kept from the public, IECDR maintains contact with them for follow-ups, Shirin said.

Holding the line

Souri Halder, senior staff nurse and in-charge for the Nipah ward at the Infectious Diseases Hospital in Mohakhali, Dhaka city, said that handling Nipah patients is challenging, as the virus is highly infectious.

“We use the PPE [personal protective equipment] to handle the NiV patient with high care. At the same time, we also ensure proper service, carefully, as maximum patients come in critical condition.”

Dr Ariful Bashar, Senior Consultant in the Medicine, Infectious Diseases and Critical Care field at the Infectious Diseases Hospital in Mohakhali, said nine suspected Nipah patients had been rushed to the hospital so far this year. Seven of them tested negative. The remaining two died.

“Most of the Nipah patients come in critical condition,” he said, echoing his colleague. “Though very few survive, they suffer from various health complications due to brain infection caused by the Nipah virus,” he added. There’s no cure for Nipah, so patient care is limited to supportive treatment that addresses symptoms, he confirmed.

Bashar said patients with suspected NiV infection are kept isolated at first, and then given treatment as per treatment guidelines. They are taken to the Intensive Care Unit (ICU) if necessary.

It’s thought that many cases of Nipah virus, and even of deaths from Nipah virus, may go undiagnosed and unreported, as patients seek treatment locally.

Human-to-human

According to WHO, Nipah cases in Bangladesh usually occur between December and April, the time of harvesting and consuming date palm sap.

“WHO assesses the overall risk at the national levels to be moderate due to the severity of the disease, the limitation of treatment, the shared natural habitat of bats and zoonotic transmission partners, and the fact that there are no licensed vaccines to prevent NiV infection,” the body reported in late February .

Though Nipah cases are often traceable to direct or indirect contact with bats, the IEDCR said that in Bangladesh since 2004, there has been strong evidence indicative of human-to-human transmission, too.

Bangladesh’s Directorate General of Health Services (DGHS) confirms that outbreak investigations have identified two routes of transmission of the virus from its natural reservoir to humans: drinking raw date palm sap contaminated with NiV; and close physical contact with Nipah-infected patients.

Containment strategy

IECDR, together with Dhaka-based health research institute ICDDR,B, began conducting Nipah surveillance at ten district-level government hospitals countrywide back in 2006. In the years since, their field of view has widened. Today, surveillance teams around the country collect samples of bodily fluids from suspected patients and send them to laboratories for testing. Depending on the test deployed, results can be returned in as few as 24 hours.

“We also hold orientation programmes from the beginning of the year to make [different stakeholders] aware across the country. At the same time, campaign also is carried out for mass awareness among people of the country to remain away from drinking the raw date juice and to eat fruits after washing with clean water,” IECDR’s Shirin said.

The DGHS has also opened Nipah Units in different public hospitals across the country, and trains government doctors on the treatment and handling of the Nipah patients.

Country health authorities, together with WHO, first drew up guidelines for the management, prevention and control of Nipah virus infection in 2011, updating that playbook in 2016.

Shrinking forests, growing health problems

Public health expert Dr Mushtaq Hossain, also an adviser to IEDCR, said, “[V]irus transmission has spread to a large area due to movement of the infected bats from one district to another district. The forest areas have been decreased in Bangladesh. Bats are not getting enough food from forests. That’s why the bats are drinking raw date juice in the locality. So, deforestation is one of the major reasons behind the spreading of the transmission area of the Nipah virus.”

“There is no alternative to stay away from drinking raw date palm sap and half-eaten fruits to prevent Nipah infection. At the same time, people have to eat fruits after washing them with fresh water,” he cautioned.

This piece has been sourced from VaccinesWork

Image: Infectious Diseases Hospital at Mohakhali in Dhaka. Credit: Mohammad Al Amin