Mosquito Borne Diseases Outbreak

Mosquito Borne Diseases Outbreak

Subject: Science

Section: Biotechnology

Context- Climate change is causing more frequent mosquito borne disease outbreaks.

Concept-

• The latest outbreaks of Zika fever in India indicate that mosquito-borne diseases are fast spreading to new populations and regions.
• Uttar Pradesh is one of three states to report Zika cases this year along with Kerala and Magharashtra.
• Earlier, India reported Zika cases twice— in 2017 (133 cases) and 2018 (290 cases).

About Zika:

• Viruses spread by Aedes aegypti (dengue, chikungunya and Zika) generally rise when India sees extended monsoon.
• ZIKA WAS first isolated from a rhesus monkey in Uganda’s Zika forest in 1947 and in humans in 1952.
• The Zika virus is spread by Aedes aegypti and Aedes albopictus mosquitoes.
• It can also be transmitted through blood transfusions, sexual contact and via exposure to urine.
• There is no vaccine.
• The spread of mosquito-borne diseases such as Zika to new geographic regions and populations is a cause of worry on several grounds.
  • First, no specific treatment is available for most such diseases, be it Zika fever, dengue or chikungunya.
  • Second, their symptoms closely resemble covid-19 and other viral infections that spread through the bite of insects.
  • Third, erratic weather patterns due to climate change have added an uncertain, surprise dimension to the battle against mosquitoes, particularly the species of Aedes that are the most common carrier of infections like Zika, dengue, chikungunya and the haemorrhagic yellow fever.
• Originally found in tropical and sub-tropical regions, Aedes mosquitoes are now present on all continents except Antarctica.
• A aegypti is native to sub-Saharan Africa, and in its native environment it lives in tree holes and small pools of water and bites non-human primates.
  • It is believed that these mosquitoes first moved to nearby human habitations during droughts when the tree holes dried up.
  • The mosquitoes then moved out of Africa during the transatlantic slave trade.
  • The first case of yellow fever was reported outside Africa in Yucatan, Central America, in 1648.
• A albopictus is native to tropical Southeast Asia, where it was originally a forest species that fed on wild animals.
  • It first spread to the islands in the Indian and Pacific Oceans and then during the 1980s extended its range across temperate regions in Europe, Africa and the Americas.
• Breeding behaviour of the mosquitoes has also changed. Traditionally, it is believed that the mosquito species breed in clean water, but now studies suggest that they can also lay eggs in polluted water. There is also evidence that Aedes mosquitoes can breed in brackish water.
• Several other factors are also responsible for the increasing menace caused by these mosquitoes. This includes environmental cues such as light pollution. While A aegypti typically bites people during the day (early morning to afternoon), artificial lights have increased their feeding period and consequently their ability to spread diseases.
• A aegypti has also developed resistance to common insecticide permethrin.
• A aegypti is likely to expand, particularly in South Asia and sub-Saharan Africa, transmission potential of A albopictus is likely to decline substantially in the tropics as the tropics eventually become too hot for it.

Solutions:

• Controlling the vector is the only option that we have.
• Other technological strategies include engineering the mosquito to be sterile or to be refractory to the viruses using Wolbachia or genetic engineering.