When people think of the diseases mosquitos carry, they often think of malaria. However, mosquitos can also transmit a range of viruses, such as the Zika virus.
Mosquitos are common flying insects that belong to a group of animals called arthropods, along with flies, fleas, and ticks. Many arthropods can be hosts, or vectors, of pathogens that include:
The term for viruses that mosquitos carry is arthropod-borne viruses or arboviruses. However, only female mosquitos transmit diseases since it is only the females that consume blood.
Arboviruses use arthropods to transport viruses from one vertebrate to another. For example, a mosquito will acquire the virus when feeding on the blood of a host with the infection. It will then transfer the virus to a new host during its next feed.
The following is a list of diseases that mosquitos can transmit to humans.
Malaria is not a virus — a parasite causes this mosquito-borne disease. The parasite uses the Anopheles genus of mosquito as a host when transmitting the disease between humans.
Malaria can cause a flu-like illness, with fever and chills. It can become severe and even lead to death without treatment.
Children in sub-Saharan Africa have the highest risk of malaria and account for most cases globally. In 2020, there were around 241 million cases of the disease across the world, causing 627,000 deaths.
Doctors diagnose around 2,000 cases of malaria each year in the United States. Most of these cases are people returning from high-malaria zones.
However, a groundbreaking vaccine for malaria gained regulatory approval in 2021.
As with many mosquito-borne viruses, the Zika virus uses a genus of mosquito called Aedes as a host.
The Zika virus does not usually cause symptoms, and people may not realize when they have the infection. Additionally, the virus is not usually very severe and rarely results in death. However, it can cause complications during pregnancy, as the virus can cause congenital disabilities such as microcephaly.
As well as via mosquitoes, the Zika virus is transmissible through sexual contact.
Dengue is another viral infection that mosquitoes transmit in the Aedes genus. The virus occurs most frequently in warm and tropical climates.
There are four different dengue viruses, or serotypes, that can cause infection. Symptoms can range from mild to severe, depending on the serotype that causes the infection. Common symptoms can include fever and bleeding more easily, which can occur due to a low platelet count.
While there is no treatment for a dengue virus infection, doctors can manage symptoms with supportive treatment.
Yellow fever is a high risk virus that is simple to prevent with vaccination. However, it has the potential to cause widespread transmission.
The virus can pass through mosquitos from either the Aedes or Haemagogus genus and can affect humans and monkeys, depending on the transmission cycle.
Yellow fever is difficult to diagnose during the early stages, and in some people, the condition can rapidly become critical.
West Nile virus
The West Nile virus transmits through mosquitoes of the Culex genus. It is the most common cause of mosquito-borne illness in the continental United States.
Most people do not get very sick with the West Nile virus, with only around 1 in 5 individuals developing symptoms. Around 1 in 150 people develop severe illness after contracting the virus. This can include encephalitis, which causes symptoms that include headache, fever, and confusion.
The chikungunya virus, which transmits through Aedes mosquitoes, can cause severe health issues, including:
However, chikungunya does not cause more morbidity or disability compared with the other viruses in this article. Its symptoms are similar to those of dengue, with fever, headache, and an increased chance of joint pain and red eyes.
Additionally, some signs of the chikungunya virus overlap with the Zika and dengue viruses, which can lead to misdiagnosis.
Symptoms of mosquito-borne diseases typically overlap. They may include:
Prevention is the most effective weapon against mosquito-borne diseases. A person can take measures to prevent these viruses by:
- vaccination where possible
- using insect repellant on exposed skin
- covering skin with long pants, long sleeves, and socks
- ensuring windows have screens
- removing standing water near properties where mosquitos breed
There is no specific treatment for mosquito-borne diseases, and antibiotics are ineffective against their viruses. However, doctors typically treat symptoms and provide supportive therapy, and people often recover completely.
In more severe cases, a healthcare professional may treat a person with hospitalization, intravenous fluids, and respiratory support, they can also help manage any other infections that arise.
Many people who acquire infection through a mosquito bite will not develop symptoms and may be unaware that they have a disease. If symptoms do develop, they usually become present within 3-15 days after the bite.
If a person experiences any symptoms after being in an area where mosquito-borne diseases are common, they should contact a doctor. If a pregnant person may have had exposure to Zika, they should also consult a healthcare professional, even if they do not display symptoms.
Mosquito-borne diseases can be fatal, so people should take precautions against them. However, these diseases typically do not cause severe symptoms and rarely result in death.
Many people recover completely from these diseases after managing symptoms for a short period.
Mosquitos can transport diseases by feeding off the host of an illness then carrying the infection to a new host during their next feed.
The diseases that mosquitos carry can be parasitic, such as malaria, or viral. Mosquito-borne viruses include:
- yellow fever
- West Nile fever
Mosquito-borne diseases often remain mild and recede on their own after a short time. However, it is important to take precautionary measures, such as getting relevant vaccinations before entering a high risk area. Mosquito-borne viruses can quickly cause outbreaks that overwhelm healthcare systems and cause fatalities.