A government report on dengue fever has added more evidence that this viral infection may be changing from a rainy-season disease to a year-round affliction now threatening people in remote as well as urban areas.
The 2002 report on dengue fever—prepared by the National Malaria Center and released at its annual conference last week in Phnom Penh—indicates that Phnom Penh and the provinces of Kandal, Kompong Cham, Takeo and Siem Reap have become high-risk dengue areas.
For reasons ranging from people traveling across the Thai border to sanitation problems and inadequate water supply, dengue also has spread to areas along the Thai border and to some remote parts of the country, the report said. But even with more cases than in 2001—10,265 compared to 12,441 in 2002—the number of reported fatalities dropped from 195 in 2001 to 153 last year.
“The mortality rate has sharply decreased since 1998,” said Ngan Chantha, national dengue program manager at the National Malaria Center.
The percentage of deaths per cases dropped from 2.92 percent in 1998, to 1.9 percent in 2001 and 1.23 percent last year, he said.
“Our objective is to maintain the fatality rate well below 1.5 percent in 2003,” Ngan Chantha said.
In addition to spreading outside of urban centers, one event last year confirmed what specialists fear about dengue—also called “bone-breaking fever” for the pain it causes.
Last December’s dengue outbreak in Kandal province and Phnom Penh “is very worrisome,” said Chang Moh Seng, an official with the World Health Organization.
Up to now, there had been a pattern to dengue epidemics, which would flare up every three to four years, said Chang Moh Seng, a scientist with the World Health Organization.
To control the disease, for which there is neither a vaccine nor specific medication, health authorities have gone after mosquitoes that spread it from person to person, and distributed the larvicide Abate to kill mosquito larvae in people’s water containers. The mosquitoes that transfer dengue are at their most active when people are out of bed in early morning and late afternoon, which eliminates mosquito nets as a weapon against the disease.
While mosquito-control campaigns have reduced the number of dengue cases, they might have prevented many people from building a dengue immunity, Chang Moh Seng said. This, added to the fact that many Cambodians travel throughout the country—thus raising the chances of spreading the disease—may have changed dengue’s patterns and made it an all-year disease, he said.
Still, health authorities plan an Abate campaign in 15 provinces at the start of the rainy season, when the number of cases usually start climbing, and in July and August, dengue’s peak time.
“Dengue fever can be prevented if people would put Abate in their water jars and keep them coveredand would fill water puddles [where mosquitoes breed] around their homes,” Ngan Chantha said.