The Philippines is stocking up on blood supplies, and Thailand is urging people to sleep under mosquito nets. An unusually severe outbreak of dengue fever has caused alarm across Asia and baffled Singapore with a record 10,000 cases this year.
The U.S. Centers for Diseases Control and Prevention considers dengue the "most important mosquito-borne viral disease affecting humans" this year - ahead of malaria and encephalitis - with an estimated 2.5 billion people at risk worldwide.
Across Asia, governments are scrambling to curtail the spread, mainly by educating the public about the potentially fatal illness and controlling mosquito-breeding areas such as stagnant pools.
Dengue is sometimes called bone-breaker's disease because it causes severe joint pain. Other symptoms include high fever, nausea, and a rash. In the worst cases it causes internal bleeding. There is no known cure or vaccine.
While outbreaks are common in Asia, the latest has been unusually severe for reasons that remain unclear.
Dr. Kevin Palmer, a mosquito-borne diseases expert of the World Health Organization who is based in Manila, said Vietnam, Malaysia, Thailand and the Philippines all had a large number of dengue cases this year.
But Palmer is most perplexed by the spike in Singapore.
Hospitals have suspended non-emergency surgery to cope with the large number of dengue patients and health inspectors are searching public housing for mosquito-breeding areas. Soldiers are dousing their uniforms in a chemical mixture to ward off mosquitos.
Dengue afflicts an estimated 50 million worldwide annually, according to the World Health Organization. Most cases are reported in Africa, Asia and South America.
Thailand is advising people to eliminate sources of stagnant water around the home, to sleep under mosquito nets and to wear repellent.
Thailand's dengue fever cases have increased slightly this year, compared with last year, to 32,193 suspected cases, based on clinical diagnoses. The actual number of confirmed dengue cases is probably slightly lower, at around 30,000.
The Philippine government has asked local authorities to intensify educational campaigns about dengue fever, organize mosquito-control systems, ensure sufficient blood supplies for transfusions and increase surveillance of cases.
The disease has sickened at least 18,802 people in the Philippines - a 26 percent rise over last year. At least 259 have died.
In Sri Lanka, a campaign asking residents to keep their premises clean and to empty pots of stagnant water has seen infections there drop to just over 3,000 so far this year from 15,365 for all of 2004.
Indonesia has recorded 38,285 cases of dengue this year, of which 538 have been fatal, the AP reports.