Mosquitoes are vectors for diseases caused by parasites, bacteria, and viruses. There are many different diseases caused by mosquitoes, but here are the most common diseases mosquitoes transmit:

Diseases Mosquitoes Transmit

Malaria

A disease that has been proven deadly, especially in third-world countries, is caused by parasites of the Plasmodium genus. The Anopheles mosquito transmits malaria.

Malaria symptoms mimic the flu, encompassing fever, chills, headaches, muscle aches, abdominal pain, fatigue, and nausea. If you suspect exposure to malaria, it’s crucial to inform your healthcare provider promptly for testing.

Mosquitoes contract malaria by biting an infected individual, subsequently transmitting the parasite to another person’s bloodstream upon biting them.

Dengue Fever

Dengue outbreaks have been reported in the United States, particularly in areas where Aedes mosquitoes, the carriers of the virus, are prevalent. Dengue symptoms may include fever, severe headache, bleeding, joint and muscle pain, and rash.

Annually, approximately 390 million individuals contract dengue fever. Outbreaks have been documented across various regions, including Southeast Asia, the Western Pacific, the Eastern Mediterranean, the Americas, the Caribbean, and Africa. Forty percent of the global population resides in regions vulnerable to dengue transmission.

Zika Virus

Also transmitted by the Aedes mosquito, the Zika virus can cause birth defects, including microcephaly. The virus has recently surfaced in North America among travelers returning from regions where the virus is prevalent.

The primary transmission mode is through the bite of infected female Aedes mosquitoes. Additionally, documented modes of transmission include blood transfusion, sexual contact, and, albeit rare, transmission from mother to child.

The majority of individuals infected with Zika experience very mild or no symptoms at all, often leading to unawareness of the infection.

West Nile Virus

Infected mosquitoes of the Culex species, primarily mosquitoes, transmit this virus. Most infected with West Nile Virus experience no symptoms. Still, some develop a fever, headache, body aches, vomiting, diarrhea, or rash.

The first documented cases of West Nile infections, originating from the West Nile virus (WNV), were identified in New York City in 1999. Since then, West Nile infections have become the most commonly reported mosquito-borne disease to the CDC in the United States, with nearly 3,000 cases reported in 2005. While many individuals infected may exhibit no or very mild symptoms, about 20% may experience flu-like symptoms.

However, severe illness and even death can occur in humans, with a fatality rate ranging from 3% to 15% among diagnosed cases with clinical disease.

Chikungunya

Among many of the diseases mosquitoes transmit, Chikungunya is a viral disease transmitted by the Aedes mosquitoes. Symptoms include fever, joint pain, muscle pain, headache, nausea, fatigue, and rash.

Yellow Fever

A viral disease transmitted by infected Aedes or Haemagogus mosquitoes. Symptoms include fever, chills, headache, backache, muscle aches, loss of appetite, and nausea or vomiting. In severe cases, it can lead to jaundice, bleeding, and organ failure.

Japanese Encephalitis

Also among many of the diseases mosquitoes transmit, Japanese Encephalitis is a viral infection transmitted by Culex mosquitoes, primarily in rural agricultural areas of Asia. It can cause brain inflammation (encephalitis) with symptoms like headache, fever, confusion, and seizures.

Saint Louis Encephalitis

The discovery of the cause of St. Louis Encephalitis (SLE) dates back to 1933. Between 1964 and 1998, the United States documented 4,478 cases of SLE. Similar to West Nile Virus (WNV), SLE is transmitted by Culex mosquitoes.

While the majority of SLE infections are asymptomatic and go undetected, the virus can lead to severe illness and even death in humans, particularly affecting the elderly, with a fatality rate ranging from 3% to 30%. Children are typically less prone to severe illness, though cases of encephalitis are relatively high among those affected. Unlike WNV, SLE does not threaten horses, as it does not cause disease in equines.

Preventing Diseases Spread by Mosquitoes

Taking preventive actions in order to prevent diseases mosquitoes transmit include using insect repellent, covering exposed skin with long sleeves and pants, and removing stagnant water where mosquitoes breed can reduce the chances of contracting mosquito-borne illnesses.

For more information:

Mosquito-Bourne Diseases – Baylor College of Medicine, Department of Molecular Virology and Microbiology, lists several diseases mosquitoes transmit.
Mosquito-borne disease prevention – Learn simple steps to protect yourself and your family from mosquito bites and the illnesses they cause – Mass.gov.
Is that mosquito bite cause for concern? – Ohio State University.
Diseases – Mosquitoes – Purdue University, lists several diseases mosquitoes transmit.
Dengue – CDC

Related: Do Mosquitoes Spread HIV?

Mosquitoes are among the most annoying pests in the world. However, in the United States, they are more of a nuisance than a health risk, as they may be in other parts of the world.

Fortunately, not all mosquitos transmit diseases. As vectors of disease-causing agents, they can be deadly. In the United States, we do not have the problem of mosquito-borne illnesses as many other countries experience. To most people, mosquitos are more of a nuisance in the United States, as they can turn a good summer activity into a painful experience.

Mosquitoes are vectors, or transmitters, of several viruses that can cause severe disease and even death in humans. In the United States, The West Nile Virus, St. Louis Encephalitis Virus, LaCrosse Encephalitis Virus, Eastern Equine Encephalitis Virus, and Western Equine Encephalitis Virus have caused illness and death.

There are about 60 different species of mosquitoes in Ohio, but only a dozen or more species are a public health concern. Aedes albopictus, the Asian tiger mosquito, and Ochlerotatus japonicus, the East Asian bush or rock pool mosquito, are two in particular.

Asian Tiger Mosquito

Where do mosquitoes breed?

Mosquitoes breed in areas of standing water. Therefore, eliminating standing water is the most critical step in reducing and potentially eliminating mosquitoes in the area.

There are several places around the home where mosquitoes breed, many of which the homeowner may not be aware of. Some areas of concern:
Any standing water – puddles, stagnate ponds and creeks, tires, buckets, other containers.
Improperly maintained gutters – keep your gutters clean and free-flowing.
Catch basins that alternate between wet and dry.
Areas where floodwaters naturally collect, such as streams and stagnate ponds.

What do mosquitoes eat?

Adult male mosquitoes feed on honeydew, plant sap, and nectar. Females are attracted to warm-blooded animals, but some female species feed on honeydew, plant sap, and nectar. Purdue University states, “Female mosquitoes detect carbon dioxide emitted from warm-blooded animals over long distances. As a female flies upwind to a host, other cues play a role, including vision, moist air currents arising from a host, and specific odors emitted by a host.”

Some mosquito species feed nearby (about a quarter mile or so), while others have been known to feed several miles downwind from their habitats (See the Cleveland Clinic article, Mosquito Bites).

How do mosquitoes “bite”?

Male mosquitoes do not bite. Female mosquitoes, the blood-feeders, “bite” and suck blood for reproduction; they require the proteins from blood to produce eggs. They have a long mouth part called a proboscis, a long “needle” extending from their head. The proboscis pierces the skin, sucking blood, while injecting saliva into the bloodstream. Therefore, when a mosquito “bites,” it is piercing and sucking. That sucks.

When secreting saliva into the bloodstream, the “body registers the saliva as an allergen. Your immune system then sends the chemical histamine to the area where the mosquito bit you to remove the allergen from your body. Histamine is what causes your mosquito bites to itch and swell. Most people have a mosquito bite allergy” (See the Cleveland Clinic article, Mosquito Bites).

How do mosquitoes spread disease?

As a blood-sucking vector (a living thing that carries diseases between animals and humans; ticks and fleas are also blood-carrying vectors), mosquitoes carry infections through the blood they acquire. It transmits the disease when it secretes its saliva into the blood.

A female mosquito will feed on a person or an infected animal and passes the disease on when it bites. The female mosquito is also known as a sip-feeder, which means she acquires blood from multiple sources, which increases the likelihood of spreading infection.

What attracts mosquitoes to bite people?

Some people get bit by mosquitoes more than others. There are several reasons this may be the case. Wearing dark-colored clothing tends to attract more mosquitos than light-colored clothing. Wearing perfume can attract more as well. Emission of CO2, Blood type, and body temperature can also play a role in attracting mosquitoes as well.

Mosquito Facts:

Only female mosquitoes bite.
Mosquitoes typically lay eggs in standing water. Eliminating any sources of standing water around your home is an excellent start to reducing the population. Bird baths, buckets, water, and creeks that have standing water are all sources of breeding sites.
Mosquitoes can detect carbon dioxide from 75 feet away. They are very sensitive to CO2, which attracts mosquitoes to humans.
Mosquitoes are responsible for the deaths of more people than any other animal on the planet. Not sharks, lions, or Big Foot. Mosquitoes.
One study showed that a full moon increases mosquito activity by nearly 500%.
Worldwide, there are over 3500 species of mosquitoes, 176 known species in the United States, and about 60 different species in Ohio.
“Mosquitoes find hosts by sight (they observe movement); by detecting infra-red radiation emitted by warm bodies; and by chemical signals (mosquitoes are attracted to carbon dioxide and lactic acid, among other chemicals) at distances of 25 to 35 meters” (www.mosquito.org/page/funfacts).
The average lifespan of a mosquito is two months.
Female mosquitoes lay up to 300 eggs, usually at night.
Mosquitoes feed not only on humans but other animals such as birds and frogs.