Preventing Malaria Using Genetically Modified Malaria Parasites

Syllabus: GS2/ Health, GS3/ Science and Technology

Context

  • In a radical approach, scientists have shifted their focus from genetic modification of malaria-causing mosquitoes to malaria-causing parasites. 

About

  • Traditionally, efforts to control malaria have focused on mosquito vectors. 
  • Some key approaches include:
    • Radiation-Sterilised Mosquitoes: Release of sterilised male mosquitoes prevents fertilisation, reducing mosquito populations.
    • Slowing Parasite Growth in Mosquitoes: Genetic engineering slows the growth of Plasmodium parasites within mosquito guts, halting the transmission to humans.
    • Genetically Modified Mosquitoes: Mosquitoes are engineered to thrive and spread genetic resistance to Plasmodium parasites through mating, reducing transmission rates.

Life Cycle of Malaria Parasite

  • Malaria-causing parasites first enter the human liver after a mosquito bite.
  • Infection and symptoms occur only when the parasites move from the liver into the bloodstream.

How the Modification Works?

  • Immune Priming: Genetically modified parasites act like a vaccine, priming the immune system during the liver stage to shield individuals from future infections.
  • Controlled Growth Arrest: Parasite growth is arrested on day six (late-arresting parasite), allowing sufficient time for immune system activation before the parasite is killed.
  • Early vs. Late Arrest: Early arrest (day one) limits immune exposure, reducing effectiveness, whereas late arrest enhances immune priming for better protection.

Significance of the Development

  • Vaccine-Like Effect: Genetically modified parasites act as a natural immune booster, providing protection similar to a vaccine.
  • Targeted Approach: Unlike methods focusing solely on mosquitoes, modifying parasites directly disrupts the Plasmodium life cycle, reducing the risk of disease.
  • Overcoming Resistance: With rising insecticide resistance in mosquitoes and drug resistance in parasites, this approach offers a promising alternative strategy.
  • Enhanced Efficacy: Late-arresting parasites allow for stronger immune system activation, increasing the effectiveness of malaria prevention.

Challenges and Concerns

  • Biosafety Issues: The release and use of genetically modified organisms (GMOs) carry biosafety risks that must be addressed.
  • Ethical Considerations: Genetic modification of parasites raises ethical questions about altering natural biological systems.
What is Malaria?
Malaria is a life-threatening disease spread to humans by some types of mosquitoes. It is mostly found in tropical countries.
Transmission: It is caused by plasmodium protozoa.The plasmodium parasites spread through the bites of infected female Anopheles mosquitoes.Blood transfusion and contaminated needles may also transmit malaria. 
Types of parasites: There are 5 Plasmodium parasite species that cause malaria in humans and 2 of these species – P. falciparum and P. vivax – pose the greatest threat. The other malaria species which can infect humans are P. malariae, P. ovale and P. knowlesi.
1. P. falciparum is the deadliest malaria parasite and the most prevalent on the African continent. P. vivax is the dominant malaria parasite in most countries outside of sub-Saharan Africa.  
Symptoms: Fever and flu-like illness, including chills, headache, muscle ache and fatigue.

Source: TH