ABSTRACT
Mechanization in agriculture, especially of harvesting practices, reduces direct exposure of the human host to animals, their excreta, and their ectoparasites which may serve as vectors of hemorrhagic fever viruses. Vaccines against Rift Valley fever and Omsk hemorrhagic fever exist, but these, especially the latter, are less widely available. Irrespective of their natural cycles, most viral hemorrhagic fevers are distinguished by the fact that hospital- and/or laboratory-acquired infections are common and carry a significant mortality. The natural maintenance and transmission mechanisms to be considered in preventive and control programs are largely those concerned with animal reservoirs and arthropod vectors/reservoirs. Mosquitoes and hard ticks are the principal vectors of arboviral hemorrhagic fevers. Control programs against mosquitoes, like those against rodents, must be adapted to locally prevailing species and their habits. They are unlikely to eliminate virus transmission but, especially in urban areas, a significant reduction can be achieved.
