Officials with the World Health Organization (WHO) warn that five billion people around the globe could soon be at risk of contracting dengue fever. According to WHO, the number of cases of dengue, globally, exceeds 100 million. In the past, the mosquito borne disease was largely confined to Southeast Asia, but now has spread to more than 100 countries on nearly every continent. In November, it reappeared in Florida for the first time in more than 50 years.
Scientists studying dengue say part of the rapid spread of the disease is a change in the rain cycle. Intermittent rain year round means that the mosquitoes carrying dengue have pools of water in which to breed over longer periods of time. The scientists also say a small increase in global temperatures will allow the virus causing dengue to multiply more quickly, coupled with the fact that as temperatures increase, so do the frequency that mosquitoes bite. Scientists in Malaysia are using more than 30 years of DNA collected from the virus which causes dengue to try and develop a vaccine.
In Costa Rica, geographers are using remote sensing technologies to determine correlations between certain types of urban infrastructure, types of vegetation and the spread of infectious disease, particularly dengue. So far, this work has found that certain properties of urban structures are correlated to higher incidences of dengue infection. This work also provides methodological tools for studying risks for dengue in urban environments elsewhere.
Read Adriana Troyo, Douglas O. Fuller, Olger Calderón-Arguedas, Mayra E. Solano and John C. Beier. 2008. Urban Structure and Dengue Incidence in Puntarenas, Costa Rica. Singapore Journal of Tropical Geography. 30(2), pps. 265-282.