Health authorities have said that greater efforts may be required to combat incurable, mosquito-borne dengue disease as it spreads from subtropical areas into the United States through global warming.
"Widespread appearance of dengue in the continental United States is a real possibility," said National Institute of Allergy and Infectious Diseases director Anthony Fauci, in commentary published in Journal of the American Medical Association.
Dengue fever, a flu-like illness especially dangerous in children and the elderly, "is becoming a much more serious problem along the US-Mexico border and in ... Puerto Rico," said the text co-authored by Fauci's senior scientific advisor David Morens.
While dengue-related illness in the United States "is presently minimal," global warming and poor efforts to control mosquito populations responsible for its spread could accelerate the disease's propagation northward, the experts said.
"Worldwide, dengue is among the most important reemerging infectious diseases with an estimated 50 to 100 million annual cases ... (and) 22,000 deaths," the two physicians said.
"Public health officials need to take the threat seriously ... because no specific treatments or vaccines for dengue are available" to fight dengue disease, they warned.
"The formidable challenges of understanding dengue pathogenesis and of developing effective therapies and vaccines must be met," they urged.
There is no known cure or vaccine to fight dengue fever, which can cause fatal internal bleeding. It is transmitted by a bite of the white-spotted mosquito, Aedes aegypti.
The World Health Organization believes 2007 could be on a par with 1998, when nearly 1,500 people died in Asia of dengue fever.
The illness is endemic to Malaysia, which has seen cases surge 16 percent every year since 2003. Fatalities from dengue in Malaysia reached record levels in 2004, when 102 people died.