The Indian state of Kerala shut down schools and colleges in the city of Kozhikode through September 24 in response to the confirmation of six cases of Nipah virus, a bat-borne pathogen whose outbreaks have resulted in death rates as high as 94 percent.
Two of the six people confirmed to have been infected with Nipah, whose origin scientists believe to be in fruit bats, have died, while the other four are “stable,” Kerala Health Minister Veena George told the Press Trust of India (PTI) on Monday. One of the patients is a nine-year-old boy who was put on a ventilator last week but had since been removed and appeared to be improving, George said.
The patients are reportedly receiving doses of Remdisivir, an anti-viral that became a household name around the world during the Wuhan coronavirus pandemic, and India is reportedly stocking up on monoclonal antibodies from Australia to prepare for the event of a large-scale outbreak.
No vaccine exists for Nipah virus – as it was only discovered in 1999 – but Western scientists are reportedly developing such a product. In July 2022, the National Institute of Allergy and Infectious Diseases (NIAID) announced that the pharmaceutical company Moderna was launching joint clinical trials of an mRNA-based “investigational vaccine” intended to prevent Nipah infections.
“Nipah virus poses a considerable pandemic threat,” former NIAID chief Anthony Fauci said at the time, “because it mutates relatively easily, causes disease in a wide range of mammals, can transmit from person-to-person, and kills a large percentage of the people it infects. The need for a preventive Nipah virus vaccine is significant.”
Authorities in Kozhikode announced this weekend that all educational facilities in the city would not open for one week to prevent the spread of Nipah. “Online classes will be ensured throughout the week,” Asian News International (ANI) reported. Some offices in the city have also reportedly shut down as a precaution. While some parts of Kozhikode have been labeled “containment zones,” officials have not imposed travel bans on the city of greater Kerala.
Public health authorities also launched a massive contact tracing effort currently identifying over 1,200 people and using the police’s surveillance powers to read the private contents of citizens’ mobile phones in an attempt to catch potential contacts who lie to the government.
“We will find the remaining contacts by tracking their mobile networks with the help of police. Because, when we find certain persons, they claim that they were never there at that place. The gaps in the contact list will be filled with the help of police,” George told reporters on Sunday.
George said during remarks on Sunday that Nipah virus’s incubation period is believed to be 21 days, so authorities will not declare the outbreak over until 42 days after the last patient is identified, as double the incubation period is standard protocol.
“This means we must continue to remain alert and our surveillance mechanisms must be active for 42 days since the last positive case was detected,” she asserted.
On Monday, George expressed optimism regarding the four patients under hospital care.
“A very positive thing is that all four patients under treatment are now stable, and the condition of the nine-year-old boy, who was on ventilator support, is improving clinically. He is now out of ventilator support and is being given minimal oxygen support,” she told PTI.
She also expressed frustration regarding contact tracing but noted that her office had identified 1,233 people and classified them as either “high-risk” or “low-risk” for infection. Over 200 people had been tested and all resulted negative for Nipah virus, she added.
The Nipah virus causes a wide variety of symptoms that can be easily confused with other diseases, such as vomiting, respiratory problems, and fever. In the most severe cases, symptoms develop encephalitis, in which a person’s brain becomes inflamed and swells, potentially causing brain damage, a coma, or death. Doctors have documented cases in which a patient went into a coma and died within two days of the infection being identified.
Scientists documented the first human infections of Nipah virus in Malaysia in 1999, tracing the virus back to fruit bats, or flying foxes. The bats typically spend much of their time around date palm trees, where they “frequently lick the date palm sap and occasionally urinate inside collection pots.” Many of the first patients identified to have been infected with the virus drank date palm sap and thus came into contact with the bodily fluids of the bats. In at least one outbreak, the patients came into contact with the virus through pigs who had initially been infected by the bats. Some human-to-human transmission cases have been documented, particularly among health workers, but scientists have yet to detail exactly to what extent Nipah is contagious among humans. The initial Nipah virus outbreak in Malaysia, which spread to Singapore, reportedly infected nearly 300 people and killed over 100, according to the U.S. Centers for Disease Control (CDC).
The death rate for the virus has varied widely in the few outbreaks documented.
“The symptoms of NiV [Nipah virus] infection range from mild to severe, with death occurring in 40%–70% of those infected in documented outbreaks between 1998 and 2018,” the CDC observed. In an article on the spread of Nipah, Gavi, an international organization dedicated to vaccine access, documented that the deadliest outbreak on record – in Kerala, India – resulted in “a fatality rate of 94.4%.”
The current outbreak in Kerala is the third in five years in the state; medical authorities have not identified the source of this particular outbreak at press time. Some local officials fear that the virus may be spreading freely in other parts of India outside of Kerala with limited testing capacity and less developed healthcare infrastructure.
“Whenever we have undiagnosed fever cases, a team involving virologists is formed and we undertake a detailed investigation which helps us diagnose Nipah virus and other new virus outbreaks early. In other States, Nipah cases might be going undetected,” Dr. Anoop Kumar, a director of critical care medicine in Kerala, told the Hindu on Sunday. Given the repeated documentation of Nipah cases in Kerala, health workers proactively test cases in which patients have unexplained symptoms associated with that disease, which other states may not be doing so rigorously.
“The route of virus transmission from bats to humans has not been clearly established in Kerala,” the Hindu noted. “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.”
COMMENTS
Please let us know if you're having issues with commenting.