Genetically modified Aedes aegypti | 19 Sep 2019

Recently, genes from genetically-modified Aedes aegypti mosquito were found to have been transferred to naturally-occurring Aedes aegypti mosquito population in Brazil where transgenic mosquitoes were released.

  • It is unclear if the presence of transgenic mosquito genes in the natural population will affect the disease transmission capacity or make mosquito control efforts more difficult.
  • A.aegypti mosquitoes are responsible for transmitting dengue, chikungunya and Zika virus.
  • The employed genetic strategy RIDL (Release of Insects Carrying Dominant Lethal Genes) was supposed to only reduce the population of the naturally occurring A. aegypti mosquitoes and not affect or alter their genetics.
  • But the study has found transgenic genes in 10-60% of naturally-occurring mosquitoes.
  • Also, the naturally occurring A. aegypti mosquitoes carrying some genes of the transgenic mosquitoes are able to reproduce in nature.

Zika Virus

  • Zika virus is a mosquito-borne flavivirus that was first identified in Uganda in 1947 in monkeys.
  • It was later identified in humans in 1952 in Uganda and the United Republic of Tanzania. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia, and the Pacific.
  • Zika virus disease is caused by a virus transmitted primarily by Aedes mosquitoes and can be passed from a pregnant woman to her foetus.
  • Sexual transmission of Zika virus is also possible.
  • There is no vaccine or medicine for Zika. Instead, the focus is on relieving symptoms and includes rest, rehydration and acetaminophen for fever and pain.

Dengue

  • Dengue is transmitted by several species of mosquito within the genus Aedes.
  • Symptoms include fever, headache, muscle, and joint pains, and a characteristic skin rash that is similar to measles.
  • Dengvaxia is the first dengue vaccine but the Indian drug controller has yet to grant approval to it.
  • India has reported 6,210 cases and six deaths from dengue until June 9, 2019.

Chikungunya

  • Chikungunya is caused by a mosquito-borne virus.
  • It is transmitted by Aedes aegypti and Aedes albopictus mosquitoes.
  • Its symptoms are characterized by abrupt fever and severe joint pain, often in hands and feet, and may include headache, muscle pain, joint swelling or rash.
  • There is no specific antiviral drug treatment for chikungunya.
  • There is no commercial chikungunya vaccine.

Source:TH