Context:
Djibouti, an East African nation, is taking a bold step in the fight against malaria by deploying genetically modified (GM) mosquitoes. This pilot program, launched in May 2024, represents a significant milestone in the battle against this deadly disease.
Relevance:
GS II: Health
Dimensions of the Article:
- Why Use Genetically Modified (GM) Mosquitoes for Malaria Control?
- Malaria
Why Use Genetically Modified (GM) Mosquitoes for Malaria Control?
Purpose and Engineering:
- GM mosquitoes are developed in laboratories with two specific genes: one that limits female offspring survival to adulthood and a fluorescent marker gene for identification in natural settings.
- They are designed to decrease the population of female Anopheles stephensi mosquitoes, which are primary vectors of malaria. This strategy aims to disrupt the malaria transmission cycle.
Rationale for GM Mosquitoes:
- Djibouti has seen a significant increase in malaria cases, attributed to an invasive mosquito species, Anopheles stephensi, which has adapted well to urban environments like Djibouti City.
- Traditional control measures such as insecticide-treated bed nets and indoor spraying are losing effectiveness due to growing mosquito resistance.
Mechanism of Action:
- Only male GM mosquitoes, carrying the self-limiting gene, are released. When they mate with wild female A. stephensi mosquitoes, their female offspring inherit the gene and fail to survive to adulthood.
- This method aims to reduce the female mosquito population over time, thereby decreasing malaria transmission rates.
Environmental Concerns and Challenges:
- There are concerns about unintended ecological impacts of releasing GM mosquitoes.
- Potential issues include the evolution of unforeseen survival skills or adaptability, similar to resistance observed in Bt cotton, where GM mosquitoes might develop resistance to gene-editing mechanisms.
- Mosquitoes play a role in pollination by consuming nectar, and their population decline could affect plants dependent on them.
- Reducing mosquito populations might disrupt local food webs and biodiversity.
Malaria:
- Malaria is a disease caused by the Plasmodium parasite.
Transmission through Mosquito Bites:
- The Plasmodium parasite is primarily transmitted to humans through the bites of infected female Anopheles mosquitoes.
- These Anopheles mosquitoes are often referred to as “night-biting” mosquitoes because they are more active and likely to bite between dusk and dawn.
Variety of Parasites:
While there are many types of Plasmodium parasites, only five of them cause malaria in humans:
- Plasmodium falciparum: Predominant in Africa, responsible for most malaria-related deaths worldwide.
- Plasmodium vivax: Mainly found in Asia and South America, causing milder symptoms but capable of remaining dormant in the liver, leading to relapses.
- Plasmodium ovale: Less common, usually found in West Africa, can stay in the liver for several years without causing symptoms.
- Plasmodium malariae: Rare and primarily found in Africa.
- Plasmodium knowlesi: Extremely rare, found in parts of Southeast Asia.
Transmission Process:
- When an infected mosquito bites a person, the Plasmodium parasite enters the bloodstream and eventually travels to the liver.
- The infection develops in the liver, and then the parasites re-enter the bloodstream and invade red blood cells (RBCs).
- Within RBCs, the parasites grow and multiply. Periodically, the infected RBCs burst, releasing more parasites into the bloodstream.
- If another mosquito bites a person already infected with malaria, it can become infected and subsequently spread the parasite to other individuals.
- Notably, malaria does not transmit directly from person to person. It relies on the mosquito vector for transmission between humans.
-Source: The Hindu
