VC2B VC WASH Cluster – Emergency Training 1 Vector Control Module 2B Mosquito borne diseases

VC2B VC WASH Cluster – Emergency Training 2 Behaviour of mosquitoes GenusBreeding siteDisease and distribution Anopeline mosquito Biting period : NIGHT Non polluted water: Edges of rivers, swamps, tanks, rice fields, saltwater without wave action, Malaria : Tropical and sub-tropical Filariasis : Asia and Africa Aedes mosquito Biting period : DAY Small water containers: Cans, jars, gutters Yellow fever : Africa and Americas Dengue : Africa and Americas, Asia Filariasis : Pacific Culex mosquito Biting period : NIGHT Any dirty water: Waste water ditches, latrines, septic pits, Filariasis : Most tropical areas Encephalitis virus: worldwide

VC2B VC WASH Cluster – Emergency Training 3 Mosquito Life Cycle

VC2B VC WASH Cluster – Emergency Training 4 Transmission by mosquitoes –Anophelenes and Culicines Filarial worms, Mainly Wuchereria bancrofti, –Also Brugia malayi or B. timori Lymphatic Filariasis

VC2B VC WASH Cluster – Emergency Training 5 Lymphatic Filariasis Endemic Areas Endemic in 83 countries Guerrant et al 2006, Tropical Infectious Diseases 2 nd Ed.

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VC2B VC WASH Cluster – Emergency Training 7 Clinical Disease Hydrocoele Elephantiasis Tropical Pulmonary Eosinophilia

VC2B VC WASH Cluster – Emergency Training 8 Chichungunya 'Chikungunya' 'that which bends up' Swahili 1st documented in 1952 to 1953 in Africa Alphavirus of family Togaviridae Primary vectors : Aedes albopictus or aegypti to ,000 cases = 35.0% of the population in Reunion, Madagascar, Mauritius and Seychelles –2007 Outbreaks in India, Sri Lanka & Italy

VC2B VC WASH Cluster – Emergency Training 9 Chikungunya Global Distribution

VC2B VC WASH Cluster – Emergency Training 10 Outbreaks have increased in scale and frequency in recent years. Distribution follows dengue as it can be transmitted same vectors.

VC2B VC WASH Cluster – Emergency Training 11 Insecticide Treated Nets (ITN) Also help to reduce fleas and mites in the bed clothing and mattress

VC2B VC WASH Cluster – Emergency Training 12 Environmental Control The elimination of mosquito breeding sites.The elimination of mosquito breeding sites. In most circumstances, difficult because of lack of staff, the extent of the breeding sites and cost.In most circumstances, difficult because of lack of staff, the extent of the breeding sites and cost. Some breeding sites may also be the only available water.Some breeding sites may also be the only available water. Malaria mosquitoes can fly several km.Malaria mosquitoes can fly several km. Localised (household) grass cutting and bush cleaning not useful for malaria control.Localised (household) grass cutting and bush cleaning not useful for malaria control.

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VC2B VC WASH Cluster – Emergency Training 14 Mosquito prefer pregnant women

VC2B VC WASH Cluster – Emergency Training 15 Issue for Control #1 Different insect vectors may peak in different seasons. The malaria vector may be present during the dry season when other mosquito populations are low. It is important to use LLITN throughout the year if you want to control malaria.

VC2B VC WASH Cluster – Emergency Training 16 Longevity (daily survivorship)

VC2B VC WASH Cluster – Emergency Training 17 Issue for Control #2 Mosquitoes don’t live very long – most will die before they can transmit malaria. A mosquito will rest on the wall after it feeds. Therefore Indoor residual spraying (IRS) works It kills the mosquito sometime within the incubation period Spraying your own house, but not the others in the community will not protect your family from malaria.

VC2B VC WASH Cluster – Emergency Training 18 Issue for Control #3 At 25 º it takes 12 days before a mosquito can transmit malaria – most will die before then. Below 19 º malaria can not be transmitted. Malaria falls off in winter because of the cooler temperature, but can happen before the rains as long as there is ground water IRS works by killing the mosquito sometime within the incubation period

VC2B VC WASH Cluster – Emergency Training 19 VBD Control Myths 1.All mosquitoes are the same 2.Cutting grass and maize is useful 3.Filling in puddles around house is useful 4.Clearing garbage is useful for malaria control 5.Wearing long sleeve shirts and pants protects 6.Spraying individual houses protects the family

VC2B VC WASH Cluster – Emergency Training 20 VBD Control Facts Sleeping under an LL ITN every night provides good protection against malaria, some filariasis and Lieshmaniasis IRS also protects equally well against malaria if >85% of houses in a community are sprayed. It may also be effective against mosquito borne Rift valley fever Larval control works well for dengue fever and to a lesser extend also malaria (i.e. temporary floods etc) but all breeding sites within the flight range of the vector need to be eliminated