International researchers warn that that latest warming trend is "ideal" for dengue haemorrhagic fever. Countries in South-East Asia are at risk because their health care systems might not be able to cope with his year’s outbreak. On average, nearly 400 million infections are recorded each year.

Bangkok (AsiaNews/Agencies) – The weather phenomenon known as El Niño could lead to a dengue outbreak in Southeast Asia, and affect millions of people, a recent study said.

El Niño typically occurs every five years, within a three to seven year range. Although it can vary in intensity, it usually brings flooding, droughts and other major weather events.

The current El Niño, which has already begun and is forecast to last into next year, is expected to be among the most intense in 20 years, the study’s authors said.

Cases of dengue fever have been shown to rise along with the ocean warming trend.  “Large dengue epidemics occur unexpectedly, which can overburden the health care systems,” said lead author Willem van Panhuis, assistant professor of epidemiology at University of Pittsburgh Graduate School of Public Health.

“Our analysis,” he noted, “shows that elevated temperatures can create the ideal circumstance for large-scale dengue epidemics to spread across a wide region.”

During the last particularly strong El Niño season, in 1997 and 1998, “dengue transmission was very high, matching up perfectly with high temperatures that allowed mosquitoes to reproduce faster and spread dengue virus more efficiently,” the study said.

The dengue virus is transmitted by mosquito that thrive in swamps and marshland. For this reason, the most important step in combating the disease is eliminating it at the source, typically pools of stagnant water.

According to the World Health Organisation (WHO), dengue is the most common mosquito-borne viral disease affecting humans.

According to the latest studies, about half of the world’s population is now at risk with nearly 400 million infections each year.

The dengue haemorrhagic fever is the most violent form of the virus, and is often fatal. Symptoms can include fever, severe pain, headache, nausea, and vomiting.

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