Nipah virus revives pandemic fears, as Kenya risk termed low

Last Tuesday, the Ministry of Health, through the office of the Director General, Dr Patrick Amoth, issued a public advisory on the Nipah virus.

Dr Amoth sought to allay fears, stating: “There is currently no Nipah virus outbreak in Kenya, and the risk to the general public remains low.”

Yet for many Kenyans, news of another deadly illness spreading among humans may have triggered a haunting sense of déjà vu. It was not long ago that the world was plunged into lockdowns in a bid to contain Covid-19.

The World Health Organisation (WHO) has confirmed a Nipah virus outbreak in India. On average, more than 100,000 people travel to Kenya from India each year, making the situation worthy of public attention.

Scientifically known as Henipavirus nipahense, the Nipah virus naturally resides in fruit bats.

“It is a zoonotic disease; it can jump from animals to humans, or vice versa,” says Dr Victor Yamo, a veterinarian and Executive Director of the Global One Health Advocacy Alliance.

Of the three confirmed positive cases reported in India, two are healthcare workers attached to a hospital. One has suffered severe neurological illness, while the other has been placed on mechanical ventilation.

According to the WHO, Nipah can be transmitted directly from person to person through close contact, mostly in healthcare settings and among caregivers of sick people, via contact with bodily fluids.

In humans, infection ranges from asymptomatic cases to acute respiratory illness and encephalitis (brain swelling). The disease has an incubation period of between three and 14 days.

“The government has heightened surveillance,” says Dr Khadija Chepkorir of the Zoonotic Disease Unit at the Ministry of Health. “But Kenyans should not panic because the chances of the virus arriving on our shores are very minimal.”

Cases of Nipah virus infection were first reported in 1998. Since then, outbreaks have been recorded in Bangladesh, India, Malaysia, the Philippines and Singapore. The virus has never been reported in Africa.

Fruit bats, also known as flying foxes (Pteropus species), found in India, South-East Asia and Oceania, are the natural hosts of the Nipah virus. Infection does not appear to cause illness in bats. However, besides humans, the virus can also infect farm animals such as pigs.

Transmission to humans or livestock can occur through direct contact with infected animals, including bats, pigs, or horses, or by consuming fruits or fruit products, such as raw date palm juice, contaminated by infected bats.

Seasonal outbreaks

In India, seasonal outbreaks between December and May have been linked to the consumption of raw date palm sap, a favourite food of fruit bats.

Studies have shown that bats host more than 4,000 distinct viruses, including the Ebola virus.

Initial symptoms of Nipah infection include fever, headaches, muscle pain, vomiting and sore throat. These may be followed by dizziness, drowsiness, altered consciousness and neurological signs indicating acute encephalitis.

So, what are the chances the world is facing another pandemic?

Dr Yamo says: “The Nipah virus is not new. There are sporadic outbreaks in India, and part of the global response involves an alert system. 

“That is why we should not be overly worried. Surveillance systems are in place, and the situation in India is being closely monitored.”

Nonetheless, the virus is highly lethal. Based on data from previous outbreaks, the case fatality rate ranges between 40 and 75 percent. In other words, for every 10 people infected, at least four may die and the number could be as high as seven.

“This virus appears more virulent,” says Dr Yamo, “but on the other hand, it does not spread as fast as other viruses.”

There are currently no licensed medicines or vaccines for Nipah virus infection. However, early diagnosis improves outcomes through timely supportive care, including organ-support therapies such as ventilation or renal dialysis.

So far, there have been no reports of cross-border transmission, and the current cases remain geographically localised within India.