Philippines: Japanese encephalitis a looming threat during monsoon, warns govt
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Philippines: Japanese encephalitis a looming threat during monsoon, warns govt

THE PHILIPPINES’ Department of Health has pressed the alarm bell on a deadly, lesser-known mosquito-borne disease known as Japanese encephalitis (JE) following nine deaths this year as the country is still in the midst of the rainy season.

The warning issued by health authorities against JE came as the country continues to battle other deadly mosquito-borne diseases such as dengue and chikungunya that have long plagued this typhoon-prone nation home to more than 100 million people.

Health Secretary Paulyn Jean Rosell-Ubial this week urged local government units and the general public to intensify mosquito prevention and control measures at homes and in the communities as rains are expected to pour across the country until October.

SEE ALSO: Mosquito-borne infectious diseases: Crafting an Asian solution


Monsoonal rains hit the coast of Boracay, Philippines. Source: Shutterstock

The wet season this year started on May 30 as officially declared by the state weather bureau. “As the country moves further into the rainy season, there is typically a rise in mosquito-borne diseases such as dengue, chikungunya and now Japanese encephalitis,” Rosell-Ubial said in a statement.

The DOH warning on the lesser-known JE came even if the recorded cases have dropped. As of Aug 26, 2017, the DOH-Epidemiology Bureau recorded 133 cases, a 44 percent decrease of laboratory confirmed JE cases all over the country compared to the same period last year.

The heightened awareness of the public resulted in an increased health-seeking behaviour such as in Pampanga, a province north of Metro Manila where 32 confirmed JE cases were recorded, DOH said.

Of the nine deaths that have been recorded so far, health authorities reported that seven were reported in Central Luzon, including four in Pampanga province, two in Zambales province and one in Nueva Ecija province. The other two deaths were recorded in Pangasinan and Laguna provinces.

Rosell-Ubial said that many areas in the Philippines can see more cases in the coming weeks, thus it important for local government units to step-up on reporting and notification of any suspected case. The DOH said it is firming up plans to introduce JE vaccination among young children next year.

It is important that the timing of the vaccination against the disease is factored in when administering the vaccine as studies showed that there is no known benefit of the vaccine when given during peak season.

On top of this, the hallmark of JE prevention like dengue should focus on identification and destruction of mosquito breeding sites and environmental cleanliness, the department said.

SEE ALSO: The University of Queensland testing mosquitoes for Dengue fever

JE is a viral disease characterised by inflammation of the brain (encephalitis). Most people who get infected have no telltale signs and symptoms surface five to 15 days after being bitten by a mosquito.

Signs and symptoms include fever, chills, headache, fatigue, nausea, vomiting, confusion, and in severe cases, neck stiffness, seizures, paralysis, and coma which may lead to death. Severe cases require prompt hospitalisation because treatment remains supportive only.

Those who recover from severe illness may still show signs of neurologic complications such as paralysis, recurrent seizures or inability to speak.

The virus is passed on to humans through a bite of a day- and night-biting mosquito, Culex tritaeniorhynchus. These mosquitoes commonly thrive in rural and agricultural areas.

In urban areas, these mosquitoes surround houses with water storage containers. Transmission can occur year-round, often with a peak during the rainy season when mosquito populations are higher.

JE is endemic in large parts of Asia including the Philippines.

Ubial urged the public to take JE preventive measures using the 4S, which the DOH advocates also in fighting dengue and chikungunya.

The 4S stands for Search and destroy mosquito breeding places; Self-protection measures; Seek early consultation for fever lasting more than two days; and Say no to indiscriminate fogging.

“We must get rid of standing water, maintain environmental cleanliness and eliminate potential breeding places of mosquitoes – not only within our homes, but in the entire community,” Rosell-Ubial said.

“Wear protective clothing such as long-sleeves and pants or socks to avoid mosquito bites, using mosquito nets at night time or even at day time or stay in well mosquito-protected places like our screened homes and using FDA-approved insect repellents,” she added.

Rosell-Ubial said that if people get sick or children develop a fever for two days or flu-like symptoms, they should seek immediate consultation at the nearest health facilities.


JE is endemic in large parts of Asia including the Philippines. Source: Shutterstock

The secretary discouraged unnecessary and indiscriminate fogging activities, as it is costly and does not destroy the larvae.

According to the World Health Organisation (WHO), that there is no cure for the JE disease. “Treatment is focused on relieving severe clinical signs and supporting the patient to overcome the infection,” the WHO said in a fact sheet.

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In the Philippines, dengue vaccines were commercially introduced only last March. Last year, the DOH recorded 211,108 cases, down from the 213,930 cases listed in 2015.

Asia has the highest incidence of dengue in the world, with cycles of epidemics occurring every three to five years. While the dengue cases dropped in the Philippines, the fatality rate grew by more than 50 percent from 372 in 2015 to 1,019 cases last year.

For chikungunya, over 1,000 cases were reported last year in Calabarzon alone, a region south of Metro Manila.