Vector control and vaccination in the transmission dynamics of yellow fever

Abstract

Urban yellow fever is a sporadic mosquito-borne flavivirus that is endemicВ in tropical areas of sub-Saharan Africa, Central and Southern America.В It is horizontally transmitted by mosquitoes belonging to the Aedes andВ Haemogogus species [3]. Vertical transmission by mosquitoes have also beenВ reported [2]. The disease symptoms are not specific, but often have clinical manifestations ranging from mild non-specific illness to severe diseaseВ including high fever, chills, headache, jaundice, bleeding, organ failure andВ shock. It has between 20% to 50% lethality [1]. Yellow fever has no specificВ treatment (anti-viral drug) but it can be prevented by an effective vaccineВ with life long immunity and 99% efficacy [3]. We construct a compartmental model for the transmission dynamics of yellow fever with verticalВ and horizontal transmissions. The impact of vaccination and vector controlВ are assessed. The model incorporates both aquatic and non-aquatic stagesВ of mosquito development. Threshold quantities are computed, bifurcation,В stability and optimal control analysis are presented.