CLIMATE CHANGE AND ITS EFFECT ON VECTORS


By Ogbuefi, Emmanuel Okwudili

Dept of Parasitology and Entomology, NAU, Awka.

The rapid warming of the Earth, caused by anthropogenic greenhouse gas emissions, has profound long-term implications for the prevention and control of vector-borne diseases (VBD). Invariably, climate change is an enduring challenge for vector-borne disease prevention and control which is already affecting vector-borne disease distribution, transmission and spread, and its impacts are likely to worsen. Interestingly; the geographic and seasonal distribution of vector populations; and the diseases they transmit depend not only on climate change; but on other eco-social factors, such as land use, socioeconomic and cultural factors, pest control, and human responses to disease risk. Daily, seasonal, and/or year-to-year climate variability can sometimes result in vector and pathogen adaptation with shifts or expansions in their geographic ranges. Such shifts can alter disease incidence depending on vector-host interaction, host immunity, and pathogen evolution. Vectors such as mosquitoes, flies, ticks or other insect species that transmit the pathogen to a host are being influenced by changes in temperature and precipitation affecting the environment in which the VBDs are transmitted. These environments may become more or less favourable to the vectors and to disease transmission. The World Health Organization (WHO) identifies the major global vector-borne diseases as Malaria, Dengue, Chikungunya, Yellow fever, Zika virus disease, Lymphatic Filariasis, Schistosomiasis, Onchocerciasis, Chagas disease, Leishmaniasis and Japanese Encephalitis. Other vector-borne diseases of regional importance include African Trypanosomiasis, Lyme disease, Tick-borne Encephalitis and West Nile fever.
For Malaria disease, it is caused by a protozoan which is transmitted by infected female Anopheles species of mosquito, Lymphatic filariasis (nematode worm) transmitted by Culex, Anopheles, Aedes species of mosquito, Dengue (virus) which is transmitted by Aedes species of mosquito and Leishmaniasis (protozoan) that is transmitted by mainly Phlebotomus species of sandfly are all being affected by climate change. In the face of ongoing climate change, we must intensify efforts to prevent and control vector-borne diseases. That’s why an urgent call for rapid reductions in greenhouse gas emissions, as well as adaptation to ongoing climate change through intensification of vector-borne disease prevention and control efforts is not only important but imminent.