West Nile and EEE: What's the difference between the mosquito-borne viruses?

What you need to know about West Nile virus

Dr. Anthony Fauci, former director of the National Institute of Allergy and Infectious Diseases and former chief medical advisor to the president, was diagnosed with West Nile virus earlier this month, according to a spokesperson for Fauci. Fox News correspondent, Steve Harrigan, joins LiveNOW from FOX to share the latest, as Fauci is expected to make a full recovery

From Dr. Anthony Fauci to a small Massachusetts town, dangerous infections of mosquito-borne viruses have been in the headlines this summer.

Fauci, the former top U.S. infectious disease expert, was recently infected with West Nile virus, and a cluster of towns in Massachusetts last month took extra precautions against eastern equine encephalitis (EEE) after two people were infected.

Getting infected with either of those mosquito-borne viruses is rare, but serious.

Here are the common infections spread by the buzzing insect, and the differences between them:

West Nile Virus

West Nile is the leading cause of mosquito-borne disease in the continental United States, according to the U.S. Centers for Disease Control and Prevention.

West Nile virus was first reported in the U.S. in 1999 in New York. It gradually spread across the country. In 2003, there were nearly 10,000 cases.

West Nile Virus symptoms

Dr. Anthony Fauci hospitalized for West Nile virus

Dr. Anthony Fauci, the public face of the U.S. coronavirus pandemic response, was hospitalized earlier this month with the West Nile virus (WNV), a spokesperson for Fauci tells Fox News. The nation’s former top infectious-disease official is expected to make a full recovery from the virus, which is most commonly spread through the bite of an infected mosquito, according to the Centers for Disease Control and Prevention (CDC). Fauci was in hospital for six days.

Fortunately, most people infected with West Nile virus do not feel sick. About 2 in 10 people infected with West Nile virus develop symptoms.

Symptoms of West Nile Virus include fever, headache, body aches, vomiting, diarrhea, or rash.

How deadly is West Nile Virus?

About 1 out of 150 people infected with West Nile develop a serious, sometimes fatal, illness.

Does West Nile Virus have a vaccine?

There are no vaccines to prevent or medicines to treat West Nile in people.

You can reduce your risk by taking steps to prevent mosquito bites.

Eastern equine encephalitis (EEE)

Eastern equine encephalitis (EEE) is caused by a virus and is not very common around the world - but an infection is quite serious.

Only a few cases are reported in the United States each year. Most cases occur in eastern or Gulf Coast states. The virus typically spreads in certain swamps, including red maple and white cedar swamps.

EEE virus symptoms

Most people infected with eastern equine encephalitis don’t develop symptoms, but some can come down with fever or swelling of the brain.

Other common symptoms can include headache, vomiting, diarrhea, seizures, behavioral changes and drowsiness.

How deadly is EEE?

About one third of people infected with EEE die, and many survivors have ongoing neurologic problems, according to the CDC.

Does EEE have a vaccine?

There are no vaccines to prevent or medicines to treat eastern equine encephalitis.

Malaria

Malaria does not regularly occur or spread in the U.S. In a typical year, the U.S. reports about 2,000 cases of malaria, and most of these cases are in people who have traveled.

But around the world, malaria continues to be a leading cause of preventable death. Malaria infected nearly 250 million people globally in 2022 and killed more than 600,000, mostly children.

Malaria symptoms

Early symptoms, according to the CDC, can include fever, chills, headache, muscle aches, nausea, vomiting and diarrhea.

Malaria can be a deadly disease if not diagnosed and treated quickly.

Severe symptoms can include kidney failure, seizures, mental confusion and coma.

How deadly is malaria?

How deadly malaria is depends on how quickly the illness is diagnosed.

Untreated malaria is nearly always fatal, but with timely and effective treatment, the death rate due to malaria in the U.S. is less than 2%, according to an article in JAMA, the journal of the American Medical Association.

Does malaria have a vaccine?

Yes, several versions of a malaria vaccine are available and have been in development since the 1960s.

Current malaria vaccines reduce uncomplicated malaria by ~40%, severe malaria by ~30%, and all-cause mortality by 13%, according to the CDC.

Zika

Zika is not common in the U.S. and there are no current local transmissions of Zika virus in the continental U.S., according to the CDC.

Zika virus typically occurs in tropical and subtropical areas of Africa, the Americas, Southern Asia, and Western Pacific.

Zika virus is a unique mosquito-borne virus in that it can also spread through sex or to a fetus during pregnancy.

Zika virus symptoms

Many people infected with Zika will not have symptoms or will only have mild symptoms. The most common symptoms are fever, rash, headache, joint and muscle pain, and red eyes

How deadly is Zika virus?

Hospitalization and death from Zika are uncommon, according to the CDC.

But Zika infection during pregnancy can cause serious birth defects and is associated with other pregnancy problems, including fetal loss, stillbirth and preterm birth.

Does Zika have a vaccine?

There is no vaccine to prevent or medicine to treat Zika.

Dengue

Dengue is common in the U.S. territories of American Samoa, Puerto Rico, and the U.S. Virgin Islands.

Most U.S. cases are in people who have traveled to other countries, though the CDC says there have been about 2,600 locally acquired cases so far in 2024.

Dengue symptoms

Dengue is also known as "break-bone fever" because it can be so painful.

Not everyone gets symptoms, which can include fever, severe headaches and pain in the muscles and joints.

How deadly is dengue?

If treated properly, dengue’s mortality rate is very low.

Does dengue have a vaccine?

Yes, a vaccine can help prevent dengue and is recommended in children who have been previously infected or who live in areas where dengue is endemic.

However, there are no dengue vaccines currently approved for use in U.S. travelers who are visiting but not living in dengue-endemic areas.