Interview with Peter John Hudson, PhD and Emily Gurley, PhD
(Scroll to the bottom to learn more about Dr. Hudson and Dr. Gurley)
Recently, in learning more about different emerging infections, I've become fascinated by the Nipah virus. Wanting to learn more about how this virus is different from others and how it spreads (more particularly, how social and cultural factors play into its transmission), I reached out to two professors/researchers within the particular study of this virus for answers.
How is the Nipah virus different from zoonotic viruses we've previously seen? How is it similar? Are there any differences/similarities to COVID-19?
According to Dr. Hudson, Nipah virus is very different from the Filoviruses like Ebola and the Coronaviruses like SARS-Cov-2; it is a paramyxovirus that does not use the ACV2 receptor. It is very similar to the Hendra virus which gets transmitted from bats to horses to people. Nipah also has the ability to spread from pigs to people.
However, Nipah has special attributes that make it a greater threat to public health. According to Dr. Gurley, “It is unlike most zoonotic viruses in that it can also be transmitted between people.” Dr. Hudson adds that Nipah has a very high case fatality rate (~60% of infected people die) unlike SARS-Cov-2 where it is about 2%. In this respect, Nipah is much worse, but Dr. Hudson ensures that scientists don’t think it causes asymptomatic cases (which would make it harder to diagnose cases, and therefore easier for the virus to spread). Also, the low transmission rate makes it unlikely to really take off unless there is some mutation that increases its transmission.
In comparison to COVID-19, it is similar in that bats carry both types of viruses. However, COVID-19 is different because it’s now a human pathogen. Nipah can be transmitted between people but cannot currently propagate itself sufficiently to become a human pathogen. Dr. Hudson has an idea for why this is so: “Human to human transmission is rare and the reason I think is because we need a large dose of Nipah virus to get an infection.”
How is this disease transmitted in low-income countries specifically? Are there any social or cultural practices that affect its transmission?
Depending on the region in which the Nipah virus exists, there are different reasons as to why the disease is transmitted. This largely has to do with how, socially and culturally, people live in those regions.
Dr. Gurley explains that in the first outbreak in Malaysia, there was a large outbreak among pigs on commercial farms and humans were primarily infected through contact with sick pigs. In Bangladesh, humans are primarily infected through consumption of date palm sap, a very common substance in that particular region, which is also consumed by fruit bats.
“Of course people get infected when they drink palm juice where the bats have urinated in it; I think this gives them a higher dose of infection,” Dr. Hudson suggests. If people stop drinking palm juice or simply create some sort of covering that stops the bats feeding on the juice, then this issue could largely be solved. But, of course, this is easier said than done.
The inventor of the AstraZeneca COVID vaccine said that Nipah could cause a COVID-similar pandemic. Is this true?
“We do not know which pathogen will cause the next pandemic, only that another pandemic will come,” says Dr. Gurley. Nipah can infect humans, and can be transmitted between humans, so it does pose a risk compared to other zoonotic viruses that don’t have this capability. But, “We’re doing all we can to increase capacity to stop future pandemics. We’re even developing vaccines against Nipah and other diseases that pose this kind of risk,” Dr. Gurley adds.
In fact, one of Dr. Hudson’s colleagues has a Nipah virus vaccine developed and “ready to go.” However, he points out that “manufacturing vaccines seems to be much too slow.”