Dengue fever rising in South-East Asia

Jul 10, 2007, 11:19 GMT

Bangkok - Dengue fever, a mosquito-borne virus that thrives in the man-made conditions of urbanization, human migration and global warming, is heading for a record-breaking year in 2007 in South-East Asia, judging by mid-year figures, experts said Tuesday.

The worrisome thing is, last year was also a bad year for dengue.

'Now there are dengue outbreaks every year,' warned Chusak Prasittisuk, head of the World Health Organization (WHO) Regional Office for South-East Asia. 'It just varies from place to place.'

Indonesia, for instance, has already recorded 96,445 dengue cases in the country between January 1 to July 9, with 1,028 deaths.

'Last year was a bad year for Indonesia and this year it's likely to be worse,' said Chusak.

The WHO has been warning South-East Asian countries for months to mobilize their forces to battle the Aedes aegypti mosquito - the day-time biter that transmits the dengue virus to humans - because all evidence pointed to a perfect dengue year.

First there was an early monsoon, that provided the stagnant water Aedes aegypti mosquitos need to lay their eggs. Then came an unusually early break in the monsoon, speeding up the hatching process.

Furthermore, according to WHO records, the number of dengue cases had never dropped off significantly in late 2006, allowing the virus to survive in its human hosts.

Cambodia's six-month dengue death toll for this year has already hit 182, topping the entire 2006 total, Health Ministry dengue fever programme director Ngan Chantha said. From January to June some 14,986 dengue patients had been recorded, compared with 158 deaths and 16,489 cases reported in 2006, he said.

So far this year, 29,000 people have contracted dengue in Vietnam and 29 people have died, up 45 per cent from last year's death toll by July, according to Nguyen Huy Nga, director of Vietnam's national preventive medicine department under the Ministry of Health.

Dengue deaths for all 2006 totalled 55 in Vietnam, but Nga said the early surge in cases is worrisome since the peak dengue season does not usually hit until September.

Heavy rains in the Mekong Delta followed by long periods of sunshine have proved a perfect breeding ground for the mosquitoes that spread the disease, Nga said.

In Thailand, dengue cases have shot up 36 per cent during the first six months of 2007, leaving 17 dead.

Malaysia is also experiencing a dengue surge with a total of 24,808 suspected cases reported between January to June in 2007, and a 52 deaths nationwide.

In 2006, there were a total of 38,556 cases, with 83 deaths.

Myanmar, where the ruling military regime is wont to keep mum about health crises that reflect poorly on its management, has reported 30 deaths among 3,000 cases by mid-year, which independent experts deem to be an underestimate.

Even spick-and-span Singapore is suffering. Cases in the city-state hit 432 last week, a record for the year and the third epidemic in the last four weeks. The National Environment Agency defines an epidemic as more than 378 cases a week.

With the latest spike, the number of people afflicted by the infection stands at 4,029 this year. Three people have died from the virus, whose symptoms include headaches, swollen joints and fever.

Dengue hemorrhagic fever causes a rapid decrease in blood platelets and can result in uncontrollable bleeding from the eyes and even through the skin. The virus has the highest fatality rate amongst the very young and the elderly.

There is no cure and a vaccine is at least five years away.

Ultimately, dengue remains a symptom of humanity, or too many people in too many cities in the fast-developing warm climes of South East Asia.

'Unplanned urbanization is the major factor, and thereafter the uncontrolled movement of people,' said Chusak. 'It is very clear that more than 90 per cent of the breeding places are created by humans, such as trash, uncovered containers and even discarded coconut shells.'

And then there is the added factor of global warming, another man-made trend that is expected to favour the Aedes mosquito, if it hasn't already.

'Theoretically with the increase in temperatures you will also increase the vector population and shorten the incubation period, but we have not seen any scientific evidence to back this up yet,' said Chusak.