Dengue Fever, Insect-Borne Infections Emerging as Public Health Problem

Several cases of dengue fever, a potentially fatal viral disease transmitted by the bite of urban dwelling Aedes aegypti and Aedes albopictus mosquitoes, have recently been reported in the continental United States. Prevalent in Central America and the Caribbean, dengue fever's most common symptoms include fever, chills, headache, and body aches lasting several days. The disease's more threatening form, dengue hemorrhagic fever, can cause internal bleeding, loss of blood pressure, and death. Over the past five years, outbreaks of both forms of the disease have been reported in Texas and Florida.

Despite the threat of further introduction of dengue into the mainland United States, as well as the risk of introduction of additional vector-borne diseases, President Obama's 2011 fiscal budget reduces to zero the funding to support the vector-borne infectious disease program at the Centers for Disease Control and Prevention (CDC), the only national program that focuses of detection and outbreak control of vector-borne diseases including dengue, plague, viral encephalitis and Lyme disease.

"At the American Society for Tropical Medicine and Hygiene (ASTMH), we are concerned that the currently proposed 2011 budget would not provide sufficient funding for this important government function. One in 50 people in the world dies of an illness acquired from an insect bite, and tens of thousands of Americans already fall ill each year from infections transmitted by mosquitoes and ticks. Insects do not respect state borders, and neither can our national response," says Edward Ryan, MD, president of the ASTMH. "Although we recognize and applaud the need to constantly scan the Federal budget to identify outdated or unnecessary programs, eliminating the CDC's vector-borne infectious disease program is not one of these areas. The proposed cuts to this program would be shortsighted, and would harm the health of the American people."

Considering dengue as an example, beginning in the 1980s, dengue fever re-emerged as a widespread tropical infection throughout Central America and the Caribbean, pervasive in Cuba, the Dominican Republic, and Puerto Rico. Tens of thousands of cases of dengue and several thousand dengue hemorrhagic fever cases occur annually across Central America and the Caribbean. The disease's reach is not limited to these regions, however. In 2005, dengue fever emerged in Brownsville, Texas and in 2009, the disease returned to the Florida Keys after a 75-year hiatus. These recent outbreaks of dengue and dengue hemorrhagic fever suggest that the disease could spread and become a health threat in major Gulf Coast cities such as Corpus Christi, Houston, New Orleans, Biloxi, Mobile, Pensacola and Tampa, as well as in less populated areas.

The World Health Organization estimates that 2.5 billion people risk contracting dengue, and that there may be as many as 50 million cases of dengue fever every year. The disease disproportionately affects poor populations, whose low-quality living conditions and link to poor sanitation are conducive to the establishment of mosquito breeding sites, and increase this demographics' contact with Aedes mosquitoes. Currently, there is no vaccine approved to protect humans against dengue, and the most effective protective measures are those to avoid mosquito bites (wearing bug repellent, spraying pesticides, and dumping any standing water). If infected, the early recognition and prompt treatment can help lower the risk of developing severe disease complications.