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Safe Travels: Protect Against Mosquito-Borne Diseases

If travels to Southeast Asia, Africa, or even Florida are in your immediate future, take the time to prepare yourself against mosquito-borne illnesses. Mosquitoes thrive in warm climates, and some may carry viruses that can be passed to humans through their bites. Here is a rundown of mosquito-borne diseases you should be aware of when planning your next trip.

Encephalitis

Several mosquito-borne diseases can cause a severe condition called encephalitis, which is an inflammation of the brain. An infected person may first experience flu-like symptoms, such as headache, fever, nausea, vomiting, and fatigue. In some cases, there may not be any symptoms.

If the condition worsens, it can lead to nerve damage, coma, seizures, long-term disability, and death. For most forms of encephalitis, there is no treatment. Care is given to ease symptoms.

Below are some forms of mosquito-borne encephalitis:

Condition Cases Reported in… Mosquitoes Transfer the Virus to Humans From…
Japanese encephalitis Rural areas of Asia Infected pigs and birds
St. Louis encephalitis Most cases in Eastern and Central United States, but virus found in all lower 48 states Infected birds
–Severe cases usually seen in older adults.
La Crosse encephalitis Upper Midwest, Mid-Atlantic, and Southeastern United States Infected small mammals, such as squirrels
–Severe cases usually seen in children 16 years old and younger.
Eastern equine encephalitis (EEE) Southeastern and Eastern United States Infected animals, such as horses
Western equine encephalitis Western and Central United States Infected animals such as horses
Venezuelan equine encephalitis Central and South America Infected animals such as horses

West Nile Virus

West Nile virus has been reported in Africa, Asia, the Middle East, Europe, and the United States. Mosquitoes spread the virus to humans from feeding on infected birds. Symptoms are similar to the flu.

Symptoms may progress to memory loss, difficulty walking, or muscle weakness. There is no treatment for West Nile virus. Care is given to ease symptoms.

Dengue Fever

Several viruses carried by the Aedes aegypti mosquito cause dengue fever. Dengue fever is commonly reported in tropical urban areas in Asia, South America, Central America, North America, Africa, as well as the South Pacific and Caribbean. Fever is the main symptom, along with at least 2 of the following:

A more severe form of the disease can cause:

Symptoms are treated with rest, fluids, and pain medications.

Yellow Fever

Yellow fever occurs in tropical cities, towns, and villages of Africa and South America. It spreads from an infected human to other humans by the Aedes aegypti mosquito. Symptoms include:

Symptoms can progress to:

Treatment includes rest, fluids, and pain medications.

Rift Valley Fever

Rift valley fever is a condition found in parts of eastern and southern Africa where cattle and sheep are raised. The condition has also been reported in sub-Saharan Africa and the Middle East. It most often occurs after heavy rainfall or flooding. Humans contract the virus from a mosquito that has fed on an infected animal. Symptoms include:

More severe symptoms include:

There is no standard treatment. Recovery usually takes a few days to a week.

Malaria

Unlike other mosquito-borne diseases, malaria is caused by a parasite, not a virus. Malaria has been reported in Africa, Asia, and Latin America. The disease is spread by the Anopheles mosquito. Symptoms are similar to the flu.

Severe symptoms may include:

Antimalarial drugs are used to treat malaria by killing the parasite.

Ways to Protect Yourself

Visit the Centers for Disease Control and Prevention Travelers’ Health website for updates on travelers' health concerns in various countries. Also, visit a travelers' health clinic or talk with your doctor to find out if vaccinations or other preventive measures are required before travel.

Two common methods of protection are the yellow fever vaccine and antimalarial medications. Antimalarial medications can be prescribed at a travel clinic or by your doctor and must be started up to 2 weeks before your trip. They are also taken during and after your trip. Yellow fever vaccination is usually available only at a travel clinic and has to be completed 10-14 days prior to travel to be effective. Be sure to plan ahead to get these before you travel.

When you are at your destination, take the following steps:

RESOURCES:

Centers for Disease Control and Prevention
http://www.cdc.gov

Infectious Diseases Society of America
http://www.idsociety.org

CANADIAN RESOURCES:

Association of Microbiology and Infectious Disease Canada
http://www.ammi.ca

Public Health Agency of Canada
http://www.phac-aspc.gc.ca

REFERENCES:

Avoid bug bites. Centers for Disease Control and Prevention website. Available at: http://wwwnc.cdc.gov/travel/page/avoid-bug-bites. Updated October 21, 2016. Accessed March 30, 2017.

Dengue. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T116824/Dengue. Updated March 23, 2016. Accessed March 30, 2017.

Dengue. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/dengue. Updated January 19, 2016. Accessed March 30, 2017.

Eastern equine encephalitis. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T114677/Eastern-equine-encephalitis. Updated February 4, 2016. Accessed March 30, 2017.

Japanese encephalitis. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/japaneseencephalitis.. Updated August 5, 2015. Accessed March 30, 2017.

Malaria. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T114919/Malaria. Updated March 10, 2015. Accessed March 23, 2015.

Malaria. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/malaria. Updated March 28, 2017. Accessed March 30, 2017.

Rift valley fever. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/vhf/rvf. Updated October 19, 2016. Accessed March 30, 2017.

Saint Louis encephalitis. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/sle. Updated January 29, 2010. Accessed March 30, 2017.

West Nile virus infection. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T114644/West-Nile-virus-infection. Updated December 9, 2017. Accessed March 30, 2017.

Yellow fever. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov/yellowfever. Updated July 12, 2016. Accessed March 30, 2017.

Yellow fever. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated June 20, 2016. Accessed March 30, 2017.

Zielinski-Gutierrez E, Wirtz RA, Nasci RS. Protection against mosquitoes, ticks, and other insects and arthropods. Centers for Disease Control and Prevention website. Available at: http://wwwnc.cdc.gov/travel/yellowbook/2014/chapter-2-the-pre-travel-consultation/protection-against-mosquitoes-ticks-and-other-insects-and-arthropods. Updated July 10, 2015. Accessed March 30, 2017.

Last reviewed March 2017 by Michael Woods, MD, FAAP