Destroy mosquitoes to eradicate eight deadly diseases

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Until now, Iceland, with its harsh, unique climate and geographical isolation, was the only country in the world completely free of mosquitoes. In October 2025, three mosquitoes were found in the Kjos Valley. Scientists blame rising temperatures due to climate change and increased travel for these arrivals. Mosquitoes are vectors for deadly diseases such as malaria, dengue fever, chikungunya fever, Japanese encephalitis, Zika, yellow fever, West Nile virus fever and filariasis. In 2023, there were an estimated 263 million malaria cases and 597,000 deaths worldwide. World Malaria Day on April 25 and National Dengue Day on May 16 in India highlight the need for public education, continued investment and sustained political commitment to prevention and control measures, especially ahead of the monsoon season. “Chikungunya” means “to twist” (due to severe joint pain) in the Kimakonde language of Tanzania and Mozambique.

Mosquito-borne diseases:

• Malaria is a potentially fatal parasitic disease transmitted by Anopheles mosquitoes. It manifests itself as fever, chills, headache, muscle and joint pain, and cyclical fatigue. Nausea, vomiting, sweating and abdominal pain may occur. If you visit or live in a tropical region where malaria is common, you should not ignore these symptoms as just another flu. Early diagnosis and treatment are essential.
• Dengue fever is a viral infection transmitted by Aedes mosquitoes that causes mild to debilitating high fever with severe headache, pain behind the eyes, rash, and muscle and joint pain. Most cases are mild, but some cases can progress to dengue hemorrhagic fever, a medical emergency that can lead to shock, internal bleeding and even death if not treated promptly. If you have a similar fever, it is important to avoid aspirin and NSAIDs until dengue is ruled out due to the risk of bleeding.
• Chikungunya is a viral infection transmitted by Aedes mosquitoes that causes severe, debilitating joint pain, as well as fever and a rash. It can affect multiple organs and systems, but primarily causes joint pain. In rare cases, complications may occur in the brain (encephalitis, meningitis), heart (myocarditis), kidneys (nephritis), eyes (uveitis, retinitis) and systemic inflammation of the skin and nerves.
• Japanese encephalitis is a viral infection transmitted by Culex mosquitoes from infected pigs and wading birds. It affects the central nervous system, causing fever, headache, confusion and, in severe cases, seizures, and can be fatal. It can be prevented with a vaccination. It is endemic to China, India, Vietnam, Nepal and parts of Australia.
• Zika is a viral infection transmitted by Aedes mosquitoes that can cause serious birth defects if a pregnant woman is infected. It manifests itself as fever, rash, joint pain, headache, muscle pain or conjunctivitis (red eyes). It is endemic to many parts of the Americas, Africa, Asia and the Pacific Islands. Because it is sexually transmitted, it is recommended to use condoms and avoid unprotected sex for a period of time after traveling from an endemic area.
• West Nile fever is a viral infection. Humans, horses and other mammals can be infected, but the virus persists in a cycle between birds and Culex mosquitoes. Fever, headache, body aches, vomiting, diarrhea or rash occur. Severe illnesses can cause impairment of the central nervous system, neck stiffness or paralysis and can lead to death. It is endemic to Africa, Europe, the Middle East, West and Central Asia, North America and Australia and occurs worldwide except Antarctica.
• Yellow fever is a serious viral infection that causes jaundice and is transmitted primarily by the Aedes mosquito. It can be prevented with a vaccination. It is endemic to the tropical regions of Africa and Central and South America. Vaccination is required for travel to these regions.
• Filariasis is a parasitic infection that causes chronic swelling of the limbs and genitals called elephantiasis. Different species of mosquitoes transmit different strains of the parasite. Filariasis affects over 120 million people in 80 countries and is a major social and economic problem. It is endemic to tropical and subtropical regions, particularly parts of Africa, Asia, South America, the Caribbean and the Pacific Islands. In India, there are endemic areas in states such as Bihar, Uttar Pradesh, Kerala, Andhra Pradesh, Tamil Nadu and West Bengal.

Avoid mosquito bites:
Detection of a CO2 cloud from a potential host activates dormant mosquitoes and directs their first upward flight toward the victim. Taller people and pregnant women breathe out more CO2 and attract more mosquitoes. Once a mosquito is within three feet of a potential host, it relies on skin odors, heat and visual cues to locate the landing site. Human body odor is a complex mix of chemicals such as lactic acid, ammonia, uric acid and various carboxylic acids that are created when the natural bacteria on our skin metabolize compounds in our sweat. These volatile compounds contribute to the “human scent cocktail” that attracts mosquitoes. Due to differences in personal odors, some people are “mosquito magnets” while others are less targeted. To avoid mosquito bites:

• Wear protective clothing that covers most of the body.
• Sleep in mosquito nets or in a room with screened doors and windows, under a fan, or in an air-conditioned room.
• Place fans on porches or patios because the airflow makes it harder for mosquitoes to fly and helps disperse the CO2 from the air you breathe or the smells from the skin that attract mosquitoes.
• Apply insect repellents such as DEET or picaridin-based products, essential oils such as lavender, tea tree, citronella, lemon, eucalyptus, or neem to exposed skin, but avoid use on cuts, irritated skin, or face, and wash hands after application.
• Mosquito coils contain insecticides or aromatics. Essential oils in a diffuser or burning camphor are alternatives.
• Follow all prescribed precautions when using insecticides.
• Avoid fish ponds when misting shaded areas such as dense bushes near your home.
• Plant basil, citronella, rosemary or lavender around your home.
• Strategically place mosquito traps in and around your property.

Mosquito control:
Adult mosquitoes can survive without water for a few days, but require still water for egg laying and larval and pupal development. Some mosquito eggs can survive for months when dry and will hatch when exposed to water. Mosquito fogging involves using a fine insecticide spray, such as a synthetic pyrethroid, that provides relief for a few days to two weeks. This occurs in the early evening and, when done correctly by professionals, is considered safe for people and pets, but can harm beneficial insects such as pollinators.

Mechanical methods used:

• Eliminate mosquito breeding sites by draining all standing water and clearing away open trash. Regularly empty items that collect water, such as: B. Coasters, pots, buckets, tires, clogged drains and gutters. Keep trash cans covered.
• Use a pump or fountain to circulate water in birdbaths and ponds, or keep it moving to deter mosquitoes from laying eggs.
• Clean and treat swimming pools and other water features regularly to prevent them from becoming breeding grounds.

Biological control agents in use:

• Release of fish (such as guppies or koi), copepods (water fleas), or other predators of mosquito larvae into breeding sites.
• Application of Bacillus thuringiensis israelensis (Bti), Bacillus sphaericusFungal pathogens and other environmentally friendly biopesticides for larger bodies of water that cannot be drained or covered.
• Transmission of environmentally friendly biopesticides via contaminated adults to breeding sites.

Genetic and reproductive approaches in testing:

• The Sterile Insect Technique (SIT) involves the mass release of radiation or chemically sterilized males.
• Release of Aedes mosquitoes infected with gram-negative bacteria Wolbachia.
• Release genetically modified (using the CRISPR tool) mosquitoes with defective fertility or sex ratio genes.

Chemical traps and baits tested:

• Attractive Toxic Sugar Baits (ATSB) that attract and kill adult mosquitoes.
• Attractive devices that attract adult mosquitoes, contaminate them with larvicides or fungal spores, and rely on them to spread pathogens to breeding grounds.

Monitoring, sensing and supporting technologies:

• With the help of remote sensing, remaining populations are identified and specifically eliminated.
• Entomological suppression data paired with disease incidence will be used to assess public health impacts and cost-effectiveness.

Important limitations and considerations:

• Some mosquito species develop resistance to insecticides and reproduce in new environments, such as mountainous regions.
• Ecological consequences and effects on beneficial insects limit some interventions.
• Regulatory hurdles, ethical issues and transparent risk assessment to obtain community consent.
• Scaling and long-term costs of mass rearing of manipulated mosquitoes in the laboratory, quality control and sustainable programs.
• Mosquitoes bite a variety of animals, including mammals such as dogs, cats, horses and cattle, as well as birds, reptiles (like snakes – through their eyes) and amphibians (like frogs). Each species of mosquito prefers certain hosts and will bite other animals when the preferred host is scarce or competition is high. Long-term contact with certain chemical repellents poses health risks, especially for children. If the infestation is severe, you should consider seeking professional pest control services. Seek medical advice immediately if you experience symptoms of a mosquito-borne illness, such as: E.g. fever, severe headache or joint pain.

Dr. PS Venkatesh Rao is a consultant surgeon, former lecturer at CMC (Vellore), AIIMS (New Delhi) and a polymath in Bengaluru.