Middle East DVEP - Armed Forces Pest Management Board

All dengue serotypes are now endemic in Africa. In recent years, outbreaks of denguefever have occurred on the east coast of Africa from Mozambique to Ethiopia and onsuch offshore islands as the Seychelles and Comoros. These endemic areas could be asource of reintroduction of the virus into the Middle East.Transmission Cycle(s). Dengue virus is exclusively associated with Aedes mosquitoesin the subgenus Stegomyia. The virus is maintained in a human-Ae. aegypti cycle intropical urban areas. A monkey-mosquito cycle serves to maintain the virus in sylvaticsituations in Southeast Asia and West Africa. Mosquitoes are able to transmit denguevirus 8 to 10 days after an infective blood meal and can transmit the virus for life.Vector Ecology Profiles. Aedes aegypti, the primary vector, is widely distributedthroughout the region and has been reported from every country in the Middle East. It ismore common in cities or villages than in rural areas. Aedes aegypti deposits its eggssingly or in small groups of 2 to 20 above the water line of its habitat. Larvae emergeafter submergence for 4 or more hours. Larvae are able to live in artificial watercontainers, including flowerpots, cisterns, water jugs and tires; they prefer relativelyclean, clear water. They develop quickly in warm water, maturing to the pupal stage inabout 9 days. The pupal stage remains active in the water container until adultemergence, 1 to 5 days after pupation. Aedes aegypti rarely disperses more than 50 mfrom its breeding site, but over several days, it could disperse as far as 500 to 600 m. Itdoes not fly in winds of more than a five km per hour.Aedes aegypti prefers human hosts and feeds primarily around human habitations. It is adiurnal feeder and readily enters homes. This species is not attracted to light; rather, itresponds to contrasting light and dark areas presented by human dwellings. Whenfeeding outdoors, it prefers shaded areas. It feeds on the lower legs and ankles,increasing its biting activity when temperatures and humidity are high. It is a skittishfeeder and, because it feeds during the day, is often interrupted by the movements of itshost. This behavior results in multiple bloodmeals, often taken within the same dwelling,which increases transmission of virus.Aedes caspius, a potential vector, has been reported in Iran, Iraq, Israel, Kuwait, Yemen,Saudi Arabia, and Turkey. It is more prevalent in areas with sunlit, saline, stagnantground pools and moderate rainfall. It may be found in isolated stream pools, groundpools, date palm plots, and overflow water from irrigation projects. It often occurs incoastal areas and is frequently associated with larvae of Culex pipiens pipiens and Culexunivittatus. Aedes caspius is an opportunistic feeder that attacks birds and largemammals, including cattle, sheep and humans. It can develop up to two egg batchesautogenously.Aedes albopictus was reported in Jeddah, Saudi Arabia, during a recent outbreak ofdengue. Aedes albopictus has been spreading rapidly in Italy since its accidentalintroduction in 1990. It is likely that this important vector may spread to areas of theMiddle East, including Cyprus, southwestern Saudi Arabia, Turkey and Yemen. It ismore common in rural than urban areas. Aedes albopictus has larval and feeding habits77