Crepuscular Man-Biting Mosquitoes Of A Tropical Zoological Garden In Enugu, South-Eastern Nigeria

Abstract

Ovitraps and human baits methods were used in sampling crepuscular man-biting mosquitoes of the Zoological Garden Enugu which were studied between February and July 2005. Aedes aegypti, A. albopictus, A. luteocephalus, A. vittatus and A. africanus were among the mosquitoes identified in the Zoo. However, six of the 7 Aedes mosquitoes were members of the Stegomyia subgenus while A. comminsii belonged to the Aedimorphus subgenus. Approximately 6 and 3 out of every nine mosquitoes biting man per hour during the study period were A. albopictus and A. luteocephalus respectively. The other species had less than one mosquito bite per man per hour. Excepting Anopheles gambiae, these are mainly diurnal and outdoor biters, feeding mainly during dusk hours between 4.00 and 8.00pm local time which corresponds to the time many tourists visit the Zoo. Members of the Stegomyia subgenus identified have been implicated in various yellow fever (YF) epidemics in Nigeria. Their preponderance, as well as the presence of the monkey reservoir hosts of YF virus and other Arboviruses, may make this zoological garden uncomfortable for the tourists. Proper care must be taken to ensure that the Zoo environment is not a potential source of epidemics. All water containers should be covered to prevent mosquitoes breeding in them. Discarded vehicle tyre, broken utensils, tin cans, snail and coconut shells must be properly disposed. Intermittent fogging of the Zoo environment with Pyrethrin insecticide may reduce adult mosquito population and thereby fly-man contact.