ABSTRACT
Disease emergence Public health entomologists must always be prepared to deal with vectorborne disease outbreaks. These may be old or new threats. New or at least newly described diseases, the so-called emerging diseases, continue to be described. Many of these emerging or reemerging infectious diseases are vector-borne, meaning they are transmitted by insects or other arthropods. Vector-borne diseases are an especially significant human health burden in tropical areas (Figure 6.1). Malaria-the number-one vectorborne disease worldwide-continues to be a huge public health crisis in many areas (Figure 6.2). There are an estimated 250 million cases of malaria worldwide each year, with about a million deaths.1 Several factors are responsible for the continuing scourge of malaria: (1) massive environmental changes affecting Anopheles mosquito populations in endemic areas, (2) insecticide resistance in the vector mosquitoes, (3) drug resistance in the malaria parasite, (4) deforestation, (5) human population migrations, and (6) increased travel by nonimmune expatriates.2,3 Since 1975, the mosquito-carried disease, dengue fever, has surfaced in huge outbreaks in more than 100 countries. Some experts estimate that there may be as many as 100 million cases of dengue each year,4 and the disease is spreading, even here. Approximately 25 locally acquired cases of dengue occurred in the Florida Keys in 2009, and about 60 in 2010.5,6 Dengue is called break-bone fever because the classic form is characterized by sudden onset of fever, frontal headache, retro-orbital pain, and severe myalgias. The more dangerous form of the disease, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), with internal bleeding and shock, has been emerging over the last few decades, mainly affecting children under age 15 (Figure 6.3). DHF/ DSS can be a dramatic disease with the patient’s condition deteriorating very rapidly.
