Centers for Disease Control & Prevention
Fighting the World’s Deadliest AnimalMosquitoes are vectors for a multitude of perilous diseases including malaria, dengue fever, Zika virus, West Nile virus, chikungunya, and yellow fever, among others.
The World Health Organization estimates that every year, mosquito-borne diseases cause millions of deaths; notably, malaria alone was responsible for 409,000 deaths in 2019.
Throughout history, it is not unreasonable to hypothesize that mosquitoes have caused hundreds of millions, or even billions of deaths, given that malaria has historically been a ubiquitous threat to human populations, coupled with other deadly diseases transmitted by mosquitoes.
The precise number remains elusive as record-keeping has not been consistent throughout human history, and many cases likely went undocumented. However, it remains indisputable that mosquitoes are the deadliest animals on Earth, their minuscule size belying their immense impact on human health, leveraged through their relentless transmission of pathogens that have shaped demographic and societal patterns for millennia.
Efforts to control mosquito populations and the diseases they carry include a range of strategies, from the development of vaccines and treatments to integrated vector management strategies that aim to reduce mosquito populations and prevent disease transmission.
What is Malaria?
In 2021, 619,000 people died from malaria, and over 247 million became ill across 84 countries. Nearly 3.2 billion people of the world’s population is at risk of this preventable disease.
Since 2000, CDC and partners have saved nearly 12 million lives and prevented over 2 billion malaria infections. CDC co-implements the President’s Malaria Initiative with the U.S. Agency for International Development (USAID) in 24 African partner countries (with plans to expand to three more) and three programs in the Greater Mekong Subregion of Southeast Asia.
What is West Nile Virus?
The most common mosquito-borne disease in the continental United States is West Nile virus (WNV). On average, there are 2,400 reported cases each year. The largest WNV outbreak in the United States occurred in 2021 in Maricopa County, Arizona, sickening 1,715 people, resulting in 125 deaths.
What is Dengue?
Dengue viruses are spread to people through the bite of an infected Aedes species (Ae. aegypti or Ae. albopictus) mosquito. Almost half of the world’s population, about 4 billion people, live in areas with a risk of dengue. Dengue is often a leading cause of illness in areas with risk.
What is the Chikungunya Virus?
Chikungunya virus is spread to people by the bite of an infected mosquito. The most common symptoms of infection are fever and joint pain. Other symptoms may include headache, muscle pain, joint swelling, or rash. Outbreaks have occurred in countries in Africa, the Americas, Asia, Europe, and the Caribbean, Indian and Pacific Island nations. There is a risk the virus will be spread to unaffected areas by infected travelers. There is currently no vaccine to prevent or medicine to treat chikungunya virus infection.
What is Lymphatic filariasis (LF)?
Lymphatic filariasis is a parasitic disease transmitted through repeated mosquito bites over a period of months. Globally, the World Health Organization estimates that at least 51 million people in 44 countries are infected with LF. Neglected tropical disease (NTD), is a parasitic disease caused by microscopic, thread-like worms. The adult worms only live in the human lymph system. The lymph system maintains the body’s fluid balance and fights infections. Lymphatic filariasis is spread from person to person by mosquitoes. People with the disease can suffer from lymphedema and elephantiasis and in men, swelling of the scrotum, called hydrocele. Lymphatic filariasis is a leading cause of permanent disability worldwide. Communities frequently shun and reject women and men disfigured by the disease. Affected people frequently are unable to work because of their disability, and this harms their families and their communities.
What is the Zika Virus?
Zika primarily spreads through infected mosquito bites. You can also get Zika through sex.
Many areas in the United States have the type of mosquitoes that can spread Zika virus. These mosquitoes bite during the day and night. Zika can also be passed through sex from a person who has Zika to his or her sex partners, even if the person doesn’t have symptoms. Since 2018, no local mosquito-borne Zika virus transmission has been reported in the continental United States. If you are traveling outside of the continental United States, see Zika Travel Information to learn about your destination.
