Dengue fever cases have dropped slightly nationwide this year despite more outbreaks than normal in other Southeast Asian countries, health officials said this week.
Dengue infected nearly 10,000 people resulting in 29 deaths in the first nine months of the year, compared to about 10,070 infections and 31 deaths during the same period in 2009, said Ngan Chantha, director of the Health Ministry’s national dengue control program.
“The number of children who had dengue fever decreased and the number of dead dropped by two,” Mr Chantha said. “[But] even though it decreased, we still worry.”
He claimed this year’s drop in infection rates stemmed from the Health Ministry’s efforts to raise public awareness about clearing standing water where mosquitoes breed, and its provision of 200 tons of the insecticide Abate to control larvae in water storage jars.
The mosquito-borne disease peaked this year during the rainy season from June to August, with Kompong Cham province the worst-hit province, followed by Kandal, Siem Reap, Banteay Meanchey, Phnom Penh and Kompong Speu provinces, Mr Chantha added.
Hai Ra, head of the dengue program at Kompong Cham provincial health department, said authorities had contained an outbreak among children, which started in June.
“Right now the number of children infected with dengue fever has dropped from about 70 per week to about 8 per week,” Mr Ra said, noting that during the first nine months of the year there were 943 cases and three deaths, compared to between 700 and 800 infections in the same period of 2009.
Across Southeast Asia dengue cases have been higher than usual this year with significantly more infections reported in Laos and the Philippines, but Cambodia appears to have escaped the spike, said Nima Asgari, public health specialist at the World Health Organization.
“It is bucking the trend,” Mr Asgari said. “Estimates are not showing a huge increase compared to last year.”
Cambodia’s last major dengue outbreak peaked in 2007 with nearly 40,000 infections and about 400 deaths that year.
Scientist Steven Bjorge, WHO team leader for malaria and vector-borne diseases, said the outbreak built up herd immunity to the most pathogenic dengue virus called serotype 3.
Such immunity usually lasts three to five years and may explain why Cambodia is not affected by the regional surge, Mr Bjorge said, noting that he did not know the type of dengue virus currently hitting Southeast Asia.
“The first thing I’ve been asking, but nobody has answered yet, is which serotype is it?”
Last month, the WHO warned of a surge in dengue cases in Asia this year, saying 70 percent of the 2.5 billion people at risk globally live in Asia Pacific countries, with Laos, Malaysia, the Philippines and Vietnam among the most badly affected
