Dengue fever may be costlier than malaria BOSTON, May 4 (UPI) -- The spread of dengue fever could cause more sickness and prove more costly globally than malaria, U.S. public health experts said. Study co-author Donald Shepard of Brandeis University's Schneider Institutes for Health Policy said dengue fever inflicts a $37.8 million burden on Puerto Rico each year, but every $1 invested in traditional surveillance and prevention could save $5 in costs associated with the illness. Known as "break-bone fever" for its capacity to cause excruciating joint pain, the disease -- transmitted by a bite from the Aedes aegypti mosquito -- broke out in the Florida Keys in 2010 and threatens nearly 3 billion people worldwide, Shepard said. Puerto Rico experienced its largest outbreak ever of dengue in 2010, with 22,648 cases reported for an incidence rate of 57 per 10,000 people. The availability of treatment has limited dengue-related fatalities in Puerto Rico, with deaths averaging about 16 per year, the study found. "People generally think of dengue as a disease of poor countries; The fact that we found it to be a major burden in a U.S. territory -- and because it recently has cropped up on the U.S. mainland -- is a reminder that mosquito-borne illnesses can present an equal opportunity threat," Shepard said in a statement. The study, published the American Journal of Tropical Medicine and Hygiene, found overall, households accounted for almost half of the costs of the disease, with government paying for 24 percent, insurance companies 22 percent and employers 7 percent.