Apr 16, 2010 (CIDRAP News) Dengue fever cases in some of the world's tropical regions have surged during the first 3 months of the year, fueled by an El Nino-related drought that has forced people to store water, providing a breeding site for mosquitoes that spread the disease, according to the Pan American Health Organization (PAHO).
Some Central American and Caribbean countries have declared epidemics, which is unusual for this time of year, according to PAHO. Outbreaks in South American countries are occurring at the normal time in areas where the disease is endemic.
In an Apr 8 epidemiological update, PAHO reported 251,285 cases so far, including 7,041 cases of the more serious dengue hemorrhagic fever (DHF) and 97 deaths.
The Latin American dengue outbreaks have been largely ignored by English-language news media, according to Crawford Kilian, an author and former writing professor at Capilano University in North Vancouver, British Columbia, who frequently translates and posts Latin American dengue reports on his infectious-disease news and resource blog titled H5N1.
In a Mar 31 blog post, Kilian wrote that it was unfortunate that English-language news outlets were overlooking the toll dengue outbreaks are taking in Latin America, and he worried about the impact the outbreaks are having on the local health infrastructure.
"Hundreds of millions of people in Latin America (plus hundreds of millions more in Africa and Asia) are contending with a very nasty disease. Its case fatality ratio isn't large, but the sheer numbers of cases must be making a brutal impact on countless communities," Kilian wrote. "Public-health agencies and their workers must be stretched to the limit, trying to cope."
Another dengue hot spot that Kilian has flagged is Sri Lanka, where the health ministry at the end of March reported that about 11,000 people had been infected so far this year, with 63 deaths. Indonesia, Malaysia, and the Philippines are also reporting increasing numbers of dengue cases.
Other regions, such as Singapore, are anticipating a rise in dengue infections, which have been known to spiral during El Nino years, Kilian noted in his blog posts.
Dengue fever is a flu-like illness transmitted by certain Aedes mosquito species. Symptoms include headaches, rashes, cramps, and back and muscle pain. DHF, a potentially deadly complication, is characterized by high fever, bleeding, thrombocytopenia, increased vascular permeability, and in particularly severe cases, circulatory failure. No effective treatment or vaccine is available.
Four similar but closely related viruses cause dengue infections, and infection with one provides lifelong immunity against that specific virus, but only partial or temporary protection against the others. Evidence suggests that patients who have a second dengue infection have a greater risk of DHF.
Mar 8 PAHO dengue report
Apr 8 PAHO dengue surveillance update
World Health Organization dengue fact sheet
Crawford Kilian's H5N1 blog