Mosquitoes carry more than West Nile
Malaria, other mosquito-borne diseases infect millions
By Tal Mekel
CNN
(CNN) -- News about West Nile virus often grabs the headlines, but comparing the disease to other mosquito-borne illnesses is like comparing the insect to an elephant.
"Outside the United States there are hundreds of millions of cases of mosquito-borne diseases," says Dawn Wesson, associate professor at the Tulane School of Public Health in Louisiana. "It's just huge in terms of the magnitude."
Last year, the U.S. Centers for Disease Control and Prevention recorded 2,470 cases of West Nile virus and 88 deaths in the United States.
Those numbers are dwarfed by the statistics associated with other mosquito-borne disease such as malaria, which infects an estimated 300 million to 500 million people each year. In Africa, malaria kills one child every 30 seconds, according to the CDC.
Dengue fever afflicts tens of millions globally, while the more violent form, Dengue hemorrhagic fever, affects hundreds of thousands. And Japanese encephalitis, felt mainly in Asia, causes 30,000 to 50,000 cases a year, while yellow fever claims an estimated 30,000 lives annually in South America and Africa.
Malaria was eradicated in the United States in the 1950s. Still, about 1,300 malaria cases are reported each year, the majority of the patients being travelers and immigrants, according to the CDC.
But experts say West Nile virus is the biggest mosquito-borne threat facing Americans, just six years after being detected in the United States.
Other mosquito-transmitted diseases on the U.S. radar include eastern equine encephalitis and St. Louis encephalitis.
Eastern equine encephalitis has a much higher fatality rate than West Nile virus, but on average infects only four people a year. St. Louis encephalitis, while not as dangerous, is diagnosed in an average of 128 Americans a year.
Paying attention?
While the devastating impact of malaria and other disease is clearly felt in many developing countries, some experts say Americans aren't aware of how dire the situation is.
"We tend to just think about ourselves and [malaria as] a disease that for the most part doesn't affect us or anybody we know, so we don't have an interest in it," says Nancy Day, author of "Malaria, West Nile, and Other Mosquito-Borne Diseases."
West Nile virus, on the other hand, is a lot more personal, Day says.
"Suddenly there was a disease that seemed like a disease somebody might get in Africa, and here I am in my safe little comfortable neighborhood home and yet I could catch it."
U.S. health officials say that while malaria remains an important priority, the amount of attention directed at it is appropriate.
"When you look at the United States, West Nile is our premier mosquito-borne disease," says Dr. Rima Khabbaz, deputy director of the CDC's national center for infectious diseases. "Part of the attention is to get people to do what they ought to do to protect themselves and their neighbors."
Tulane's Wesson agrees. "West Nile is here and is currently a potential threat ... There's no ongoing malaria transmission in the U.S. that we know of."
Worldwide partnership
The global fight against malaria, which kills more than a million people a year, is led by the Roll Back Malaria Partnership, a coalition formed in 1998 by the WHO and other health organizations. The partnership coordinates control and prevention efforts and raises awareness of the disease.
 The Roll Back Malaria partnership held a concert in Dakar, Senegal, in March 2005 as part of its awareness campaign. |  |
Its efforts to halve the number of malaria-related deaths by 2010 have so far yielded mixed results.
"Today we can say that things are moving but we have a long way to go," says RBM Executive Secretary Awa Marie Coll-Seck. "We have some success stories but it is not enough."
The war on malaria faces many obstacles.
Despite contributions from donor countries, private foundations and the Global Fund -- which was created to fight AIDS, tuberculosis and malaria -- resources are not enough to meet the challenge, says Coll-Seck.
She contends that the fight against malaria requires $3 billion a year, but only $600 million is available for disbursement. The funding is crucial in light of the poverty that exists in many of the areas at risk.
Challenges have also surfaced on the scientific front. While the disease is curable if treated promptly, the parasite that causes it is developing resistance to traditional drugs, and next-generation medicine is much more expensive. Also, mosquitoes are becoming immune to common insecticides.
While scientists continue working on a vaccine, they are also researching genetically mutated mosquitoes that would be incapable of transmitting malaria and other diseases. But researchers say such tools could be many years away from becoming a reality.
With no vaccine available for West Nile virus, malaria and some other illnesses spread by mosquitoes, what's the approach? Wesson says control, prevention and mortality reduction are key.
"Eradication is probably not something we talk about in regard to mosquito-borne diseases right now," says Wesson. "If anything disappears it will probably be on its own accord and not because we've directly been trying to eradicate it."
