Impact of Climate Change on Insect-borne Diseases

The existence of global warming has been extensively discussed and hotly debated for decades across oceans and continents. Most of the discussions have been focusing on climate change, increased incident of natural disasters, negative impact on farming and fishery, wildlife survival and the resultant human suffering because of all these negativities.

With the sudden outbreak of mosquitoes-borne Zika virus in Central and South America countries, it appears global warming likely to bring forth another serious threat to the public- the spread of pandemic diseases in areas that are previously spared from. According to an American biologist, Daniel Brooks – “whenever the planet has faced a major climate change event, man-made or not, species have moved around and their pathogens have come into contact with species with no resistance.” The alarming rate of birth defects attributed to Zika virus is a good example of dire consequences of the chance encounter between usually benign pathogens with non-immune species. Zika virus named after the Zika Forest of Uganda was identified in 1947. Prior to 2015, Zika fever is under the radar of most world health authorities as it causes minor discomfort at most. It is now reached pandemic levels in several Central and South America countries with suspected link to unusually high numbers of babies born with microcephaly (congenital condition of severely undeveloped brain) and a neurologic conditions in adults, Guillain–Barré syndrome.

With escalating temperature, changed rainfall systems, increased human mobility and globalization, the World Health Organization has found it is necessary to remap the landscape of water-borne and vector diseases. According to WHO, a worldwide temperature rise of 2-3 C likely translate to additional 3-5% (several million) of people risking contracting malaria, another disease that is spread by mosquitoes. Female Aedes aegypti, the daytime-active mosquito that carries Yellow Fever, Zika, and other diseases, thrive in warmer conditions with plenty of stagnant water. Many other insects, including fleas and certain species of ticks, also spread faster during warmer climate. A prolong spell of temperature could see cat-scratch disease and tick-borne diseases spiking around your neighborhood.

According to Dr Diarmid Campbell-Lendrum, a WHO climate change expert scientist – “Infectious agents in water will proliferate with more flooding. It’s clear that we need to strengthen our surveillance and response to a range of diseases. Globalization, the movement of people, is an important factor too. In a world where we are disrupting the climate system, we’ll have to pay the price for that.”