Southeast Asia battles dengue surge, climate fears

By Adhityani Arga and Ed Davies

JAKARTA (Reuters) - Southeast Asian nations are battling a surge in dengue cases, amid signs that climate change could make 2007 the worst year on record for a disease that often gets less attention than some higher-profile health risks.

The spread of dengue, which is transmitted by the Aedes aegypti mosquito and is endemic in much of the region, has also accelerated in recent years due to increasing urbanization and travel or migration within the region, experts say.

Efforts to develop a vaccine are proving difficult because dengue can be caused by four viruses. So the only real method to fight the disease at present is to eliminate likely breeding spots for mosquitoes from discarded tyres to plant pots.

"The threat of dengue is increasing because of global warming, mosquitoes are becoming more active year by year and their geographical reach is expanding both north and south of the Equator," said Lo Wing-lok, an expert in infectious diseases.

"Even Singapore, which is so affluent and modern, can't exercise adequate control," Hong Kong-based Lo added.

Dengue cases in Hong Kong usually involve people returning from hotter parts of Asia, but Lo warned that warmer temperatures meant the disease could ultimately become endemic in southern China.

Dengue sufferers often describe the onset of high fever, nausea and intense joint pain. There is no real treatment, apart from rest and rehydration, and in severe cases it can be fatal.

In Indonesia, where concerns over bird flu more frequently grab headlines, dengue saw a dramatic peak earlier this year after much of the Jakarta area was flooded.

"It's not so much the rise in temperature that affects dengue, rather the rising rainfall has lengthened the lifespan of the epidemic each season," said Wiku Adisasmito, a dengue expert at the University of Indonesia.

The Asian Development Bank developed a model suggesting that dengue might rise three-fold in Indonesia due to climate change.

By last month there had been 68,636 cases and 748 deaths so far this year, according to Health Ministry data.

Although cases are slowing at the end of the wet season, experts warn that 2006's record 106,425 cases could easily be overtaken. The record number of deaths was 1,298 in 2005.

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The picture looks similar in neighboring countries.

Thailand had more than 11,000 cases of dengue fever and 14 deaths by this month, up 18 percent from the same period of 2006.