The Scientist (Internet / Print) 02/25/06 Virologists are working to slow the spread of the largest recorded outbreak of chikungunya, a relatively unknown mosquito-borne disease that has swept through the island of Reunion, and was recently reported in India. Some researchers are focusing their efforts on a promising, early-stage vaccine developed by the U.S. military. Stephen Higgs, a vector biologist with the Center for Biodefense & Emerging Infectious Diseases at the University of Texas Medical Branch in Galveston, told The Scientist the virus is "kind of strange" because it doesn't seem to have animal reservoirs. Instead, chikungunya circulates between people and diurnal mosquitoes, infecting the mosquitoes when they bite people carrying high levels of the virus in their blood.