Things you must know about Japanese encephalitis

Dominic Menor, ABS-CBN News

Posted at Sep 22 2017 09:41 PM

After Japanese encephalitis scare, public urged to stay calm, get proper info

Publicized cases of Japanese encephalitis (JE) have triggered a surge of queries about the disease.

There are no known cures for it, but a vaccine can prevent it. A shot can cost between P2,000 and P4,000, considered pricey in the Philippines, but those seeking vaccine shots have said they’re on wait lists because supplies are short.

Meanwhile, the Philippine Pediatric Society has assured that a proper stock of vaccines exists and the reason some people aren’t getting them is they just haven’t been delivered to their places.

On September 4, the Department of Health confirmed 9 deaths related to the disease.


Dr. Susan Pineda-Mercado, a former Department of Health (DOH) undersecretary, is aware the public is anxious and she understands why.

According to the World Health Organization, symptoms of people with Japanese encephalitis include mild fever and headache. 

A patient who is severely ill with the disease will have high fever, neck stiffness and seizures.

“You have a very healthy person who without any warning becomes very sick, so that creates fear,” she said. 

“It takes a bit of time for doctors to figure out what it is. They do all kinds of tests before they actually say it’s Japanese encephalitis. 

“The reason people panic is that the symptoms are quite unusual and shocking (to them).”

Unless the person is near where pigs and ducks breed, however, Pineda-Mercado said people need not fret.


The only way the virus can be transmitted is if a particular mosquito, a Culex, bites the animal and then comes into contact with a human. 

While the mosquito that carries the dengue virus can transfer the disease from one human host to another, that’s not the case with Culex. If the mosquito moves from human A and lands on human B, the latter doesn’t acquire the virus.

The animal host needs to be alive, too, to activate the virus, and eating an infected pig or duck doesn’t transfer the virus to the human, Pineda-Mercado added.

“If you’re in Metro Manila, that’s the better thing to do right now — make sure there are no breeding sites for mosquitoes anywhere near where you live and in the schools,” she said.

Similar to dengue prevention, maintaining clean surroundings and making sure stagnant water isn’t lying around help. Using insect-repellant lotions and mosquito nets are advised, too.

When applied to stagnant water, salt, oil and vinegar can kill mosquito larvae. 

Pineda-Mercado said even her daughter asked her if she needed her son to be vaccinated.

“I think ultimately there should be a vaccine for all the kids but right now, unless you’re really exposed or in a community with JE, then you shouldn’t really worry about it,” she said.


The rising number of Japanese encephalitis cases can be attributed to two factors, Pineda-Mercado said — doctors are properly identifying the disease now, and possibly climate change that has led to warmer temperatures in the region.

Pampanga has reported more cases of Japanese encephalitis, but it’s unclear whether the number of infected actually rose or that doctors are just diagnosing them better now.

It’s possible that the prevalence of mosquito-borne diseases has provided medical experts with more samples to work on, and consequently helped doctors to sort out the diseases and detect them more accurately.

“To diagnose (the disease), you have to think about it. If you’re not thinking about it, you might think it’s something else. For example, there’s a fever, there’s a headache, he doesn’t feel well. Usually, they might think of dengue or typhoid. They don’t really think about JE,” Pineda-Mercado said.

“We’ve always had JE in the Philippines, but there are times when there’s an unusual clustering of cases.”

She said the changing climate may be playing a role in the increasing number of mosquito-borne illnesses.

“Some have made that hypotheses,” Pineda-Mercado said. “Itong mga flooding, wet weather, the mosquitoes become more active somehow and are transmitting more diseases.” 

She said the best thing people can do is to take proper measures and be informed.

“Right now, if the stock is not available, the best thing the public can do is not to panic,” she added. “Just make sure not to be bitten by mosquitoes, whether it’s dengue or JE.”