Mosquitos are as dangerous as they are annoying. While most of us lament the itching that comes with a mosquito bite, it isn’t the worst outcome that can come from these flying pests. In this post, we will identify some of the diseases spread by mosquitoes around the world.
How Are Diseases Spread By Mosquitoes?
Mosquitoes are disease vectors (living organisms that transfer diseases between animals and humans).
The mosquito spreads various diseases through their bite, specifically through their saliva. For instance, when a female mosquito “bites” you, she secretes saliva to act as a lubricant and anti-coagulant. This allows her to easily extract the blood she needs for her eggs. Consequently, if the mosquito feeds on an infected animal or person she can pass that infection on through her saliva to her next victim when she feeds.
List of Diseases Caused By Mosquitoes
Now that you know how mosquitoes spread diseases here are the most common diseases caused by mosquitoes.
Chikungunya
While this disease does not always get a lot of media attention, it causes outbreaks all around the globe. This disease brings aches, fever, and severe joint pain. In addition, it can be lethal to some.
Carried by Aedes mosquitos, this condition is uncomfortable and dangerous. Worst of all is the fact that some people don’t show symptoms until a full week after they have contracted the disease.
In areas with high mosquito populations, this can play a large role in the spread. When mosquitos come in contact with an infected individual, they can transmit the disease to others.
Currently, Chikungunya influences a wide variety of continents but mostly occurs in Africa and Asia. Regular outbreaks have occurred when doctors were unable to raise the alarm or keep infected individuals indoors.
Eventually, when people do become infected, there is very little that doctors can do. Taking painkillers or using an IV in dangerous situations can help, but it takes time for the symptoms to pass. Obviously, this is one of many diseases spread by mosquitoes that will make you wish you used more insect repellant.
STATS
COUNTRIES IMPACTED
60
CASES PER YEAR
Varies By Outbreak
DEATHS PER YEAR
Varies But Rare
Dengue Fever
Dengue Fever is one of the more common diseases spread by mosquitoes. Transmitted through Aedes mosquitos, the Dengue virus will compromise your immune system and leave you feeling terrible. Though some people only experience mild symptoms, others find themselves vomiting, plagued by headaches, and suffering from blood pressure changes.
Like many other mosquito diseases, Dengue Fever does not have a sure-fire treatment plan. Though there is currently a vaccine, it is only recommended for those who have had the disease or are have a high risk of infection. Prevention includes avoiding mosquito-heavy areas and standing water.
Treatment for Dengue Fever is focused on pain management and hydration, with some patients requiring blood transfusions. Though you can contract this disease in many places around the world, it is most prevalent in Africa, South America and Central America as well.
STATS
COUNTRIES IMPACTED
140
CASES PER YEAR
390,000,000+
Estimated
DEATHS PER YEAR
25,000+
Eastern Equine Encephalitis
Despite its unfamiliar name, Eastern Equine Encephalitis (EEE) is one of the more dangerous mosquito-borne diseases that you can get. Officially, there are only a few of these cases documented each year. Mild cases can cause fever, chills, and malaise. But, when this condition gets to the central nervous system, the outcomes can be dire. Some victims develop headaches, vomiting, seizures, and even behavioral changes, making it an alarming condition. Finally, the worst cases can result in a coma or even death.
This disease is usually transmitted through Culiseta Melanura mosquitos and is one of diseases spread by mosquitoes that can harm large animals like horses. It is also known to infected birds and other animals along the way. The disease is usually found near bodies of water, like swamps and lakes. While it is most often seen in states like Massachusetts, Florida, and North Carolina, it’s found in other places as well.
Japanese Encephalitis
Japanese Encephalitis is one of the mosquito-borne diseases that’s prevented with a vaccine. This disease, carried by the Culex mosquitos, is a disease that travels through mosquitos to humans, birds, pigs, and more.
This unusual illness is unassuming until it causes encephalitis, a swelling of the brain. While not every patient will develop a brain infection, it is possible. Worst of all, 30% of the people who develop this form of encephalitis die from it as a result. Though there is a vaccine, there are no real treatments for the condition aside from fluid, painkillers, and bed rest.
Japanese Encephalitis has been around for some time and found all over the world. It is most common in Asia. The disease has a fair amount of reach but thankfully does not impact that many people with its full force.
STATS
COUNTRIES IMPACTED
24
CASES PER YEAR
68,000
DEATHS PER YEAR
14,000-20,000
Saint Louis Encephalitis
Like many other forms of mosquito-transmitted encephalitis, Saint Louis Encephalitis is not dangerous to most people who get it. For instance, most people who come down with the condition will not show any symptoms at all. However, for those who are symptomatic, the symptoms include fever, headache, nausea, disorientation, vomiting, and tiredness. Likewise, people with severe cases may develop a neuroinvasive disease, such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord).
Treatment usually involves working to support the individual’s body while they recover from the infection, as well as applying emergency medical treatment if needed.
There are periodic outbreaks of St. Louis Encephalitis. Though cases can occur year-round, they are most common during ideal temperatures that support the habits of Culex mosquitos. It is mainly a problem in the United States alone, unlike more global mosquito diseases.
STATS
COUNTRIES IMPACTED
Mainly United States
CASES PER YEAR
5-15
DEATHS PER YEAR
0
Malaria
STATS
COUNTRIES IMPACTED
100+
CASES PER YEAR
229,000,000+
DEATHS PER YEAR
409,000
Rift Valley Fever
West Nile Virus
STATS
COUNTRIES IMPACTED
34
CASES PER YEAR
Varies By Outbreak
540 in US (2020)
DEATHS PER YEAR
33 in US (2020)
Yellow Fever
STATS
COUNTRIES IMPACTED
47
CASES PER YEAR
200,000
DEATHS PER YEAR
30,000
Zika Virus
STATS
COUNTRIES IMPACTED
84
CASES PER YEAR
Varies By Outbreak
DEATHS PER YEAR
Rare
Conclusion
In conclusion, mosquitos are unfortunately the perfect vector for many different diseases. Since these small pests deal in blood, they are a major source for contracting and spreading diseases around the globe. For this reason, it is important to recognize these risks and take necessary precautions to avoid being bit. Read our Guide to Controlling Mosquitoes to help reduce the mosquito population at home.
Be extra vigilant when travelling to other areas and be aware of the mosquitoes in those areas and the diseases they may carry.
A valuable resource to track outbreaks of diseases spread by mosquitoes in the United States is available from the CDC.
If you have experienced a mosquito bite and exhibit any of the symptoms described seek professional advice from your medical doctor as soon as possible. Mosquito-Borne diseases are a serious matter.
The information on this site is not medical advice. This information does not create any patient-physician relationship, and is not a substitute for professional diagnosis, advice and treatment.
Please read here for additional information regarding our disclaimer policy.
FAQ
Frequently Asked Questions
Can mosquitoes transmit AIDS or HIV ?
No. Studies conducted by the Centers for Disease Control and Prevention have shown no evidence of HIV transmission through mosquitoes or any other insects, even in countries with extremely high rates of HIV and high levels of mosquito infestations.
From a biological perspective it would be difficult for mosquito bites to result in blood-to-blood transmission (which is considered the route of infection for a blood-borne virus like HIV). The mosquito draws blood through a needle like tube. It uses similar but separate tubes to inject it’s saliva into the bite to aid in the drawing of the blood.
Another factor is the HIV infected people do not have constant high level of HIV in their bloodstreams and the mouthparts of a mosquito does not hold large amount of blood.
Mosquitoes also do not fly to feed on another person after a meal but rather fly off to rest and digest their blood meal.
What is the most common disease transmitted by mosquitoes ?
The most common disease transmitted by mosquitos is Dengue Fever. While less deadly than Malaria it is estimated that more than 390 million people contract Dengue Fever every year. 3.9 Billion people are at risk by living in the range of the Aedes mosquito that carries the disease.
Can mosquitoes spread diseases to pets ?
Yes. Mosquitoes can spread heartworms to both dogs and cats. You can read our article here on How to Protect Your Pets.
Horses and other equines are at risk for eastern equine encephalitis, western equine encephalitis and West Nile Virus. Vaccines are available to protect them.
What is the most dangerous mosquito ?
There are over 3,500 different species of mosquitoes in th world. However, the most dangerous are certain species of Aedes, Anopheles and Culex mosquitoes.
Aedes aegypti spreads chikungunya, dengue fever, encephalitis, yellow fever, and zika.
Anopheles spreads encephalitis, filariasis and malaria.
Culex mosquitoes carry encephalitis, filariasis and West Nile virus.
You can learn more about these mosquitoes here.
Can mosquitoes spread the Coronavirus ?
There is no evidence that the Coronavirus can be spread by mosquitoes. Both the WHO and the CDC have issued statements to this effect.
There was also a study done in July 2020 that confirmed that it was extremely unlikely that Coronavirus could be transmitted by mosquitoes.