Although dengue fever cases have reached epidemic levels this year, 2012’s bout has been less fatal than previous years and is on the decline due to seasonal patterns and growing immunity, World Health Organization officials said at a press meeting yesterday.
“It certainly fulfils all the criteria [for an epidemic] this year, but although there have been many more cases, they’ve not been as serious, with not as many deaths,” said Dr Nima Asgari, team leader in the WHO in Cambodia’s emerging diseases surveillance and response unit.
The decrease in deaths was largely due to better education about dengue treatment and prevention, and particularly to public hospitals – which often used to rehydrate patients to the point of drowning them – becoming more aware of the need to adjust fluid dosage to individual patients’ needs, Asgari said.
“Based on historical data we do expect a decrease from now on this year,” he added.
According to Dr Steven Bjorge, WHO team leader for malaria and other vector-borne diseases, this year’s large number of reported dengue cases – the largest since 2007 – may mean a greater drop-off of cases later in the year, as individuals already exposed to one of the disease’s four strains cannot recontract that given strain.
The Health Ministry’s Cheamon Thavy, director of dengue fever health education at the Health Ministry’s National Centre for Parasitology, Entomology and Malaria Control, agreed this year’s dengue levels show an increase from other years except 2007 and added: “I think it will decrease from now on.”
As of August 14, the Ministry of Health reported the year’s dengue numbers at 24,127 cases and 106 deaths in 33 public hospitals, Thavy said.
By the same time last year there were less than 10,000 cases and in the dengue epidemic of 2007 there had been 29,000 by the eighth month.
WHO officials acknowledged that such data did not represent all dengue cases because they do not include patients who went to private clinics or did not seek medical care, and they may include chikungunya, another mosquito-borne virus with similar symptoms.
Nevertheless, Bjorge maintained that, with an approved dengue vaccine many years and dollars away, the data show that Cambodians must continue to focus on changing personal habits – for example, getting rid of uncovered still water or filling it with guppy fish, which eat mosquito larvae.
Hai Ra, head of dengue control for the provincial health department in Kampong Cham, which has seen more than 100 dengue cases and eight dengue-attributed deaths this year, said yesterday that dengue case rates have been falling despite increasingly wet weather as the torrential end of the rainy season approaches.
He said health officials have had success encouraging community participation in dengue education campaigns but stressed that these programs must continue regardless of whether the rate of dengue cases increase or decrease over the coming months.