Arboviral diseases — also known as arthropod-borne viral diseases — are common worldwide. Roughly 17% of all infectious diseases are caused by arboviruses.
These diseases are transmitted to humans by arthropods, which are animals with jointed legs, such as insects, spiders, and centipedes. Most arboviruses are carried by insects (called vectors) like mosquitoes and ticks. Arboviral diseases are often mild but can be severe.
What Is an Arbovirus?
There are hundreds of viruses, but not all can cause arboviral disease. An arbovirus must be able to live in a vector, be transmitted by bite, and then multiply and cause disease in humans. Many arboviruses exist in mammals or birds. When an insect bites one of these mammals or birds, the insect gets infected and then transmits the disease to humans.
Not all diseases transmitted by insects are arboviral. For example, malaria, transmitted by mosquitoes, is a parasitic disease. Similarly, Lyme disease, transmitted by blacklegged ticks, is a bacterial disease.
What Causes Arboviruses?
It's important to be aware of arboviruses, especially in certain locations and when traveling inside and outside of the U.S.
West Nile virus. The most common arboviral disease in the U.S, this is caused by the bite of a Culex mosquito. About 2,000 people are affected every year. Most people with West Nile virus are asymptomatic, but about 1% will develop a more severe disease in the nervous system.
Powassan virus. This is transmitted by Ixodes scapularis ticks found in the northeast and north-central United States. Most people infected don't have symptoms, but those with severe disease may experience infection of the brain (known as encephalitis) or in the membranes around the brain and spinal cord (known as meningitis). Approximately 1 out of 10 people that develop severe disease from Powassan virus die.
Dengue. Causing 25,000 deaths a year, dengue is the most common arboviral disease. It's transmitted by Aedes mosquitoes. Infections are more common in Asia, South America, or Africa.
Yellow fever: This dangerous disease is transmitted by Aedes mosquitoes in South America and sub-Saharan Africa. It can cause jaundice, bleeding, and kidney failure. The death rate ranges from 20% to 60%.
Zika virus. Also transmitted by Aedes mosquitoes, the Zika virus generally causes mild fever, an itchy rash, joint pain, and eye inflammation (conjunctivitis). If you're infected during pregnancy, it could pass on to your baby, who may experience brain damage. Infections most commonly occur in the U.S., South America, Southeast Asia, and the Pacific Islands.
If you have arbovirus symptoms during or soon after your travels, you should seek medical attention immediately.
What Are the Symptoms of Arboviruses?
Most arboviral diseases have similar symptoms. Symptoms typically appear a few days to two weeks after being bitten by an infected mosquito or tick.
Most of these diseases begin with fever, diarrhea, vomiting, and body aches. You may also notice a rash on your skin. Dengue and yellow fever can also cause bleeding.
You may also develop symptoms like headaches, neck stiffness, excessive sleepiness, seizures, or unconsciousness. If you experience a mix of any of these symptoms, your doctor will likely want to test you for meningitis and encephalitis.
Who Is at Risk for an Arboviral Disease?
Your risk depends on your lifestyle and location. If you live in an urban area and are indoors most of the time, your risk will be lower than if you spend more time outdoors and do more traveling.
For example, if you live in the northeastern and Great Lakes regions of the U.S. your risk for getting the Powassan virus is higher. If you travel to South America, Africa, or Asia, you'll be at greater risk of getting dengue.
Seasons are also important. About 90% of arboviral infections happen between April and September in the U.S.
What Is the Treatment for Arboviruses?
See your doctor if you have arbovirus symptoms and think you’ve been exposed to insects. They will decide whether to get you tested. If you have a mild disease, expensive laboratory testing may not be worthwhile.
Arboviruses multiply in your bloodstream for a short time and generate specific antibodies. Your doctor will order a blood test to identify which infection you may have. If you have a more severe disease, they may do a brain scan.
Arboviruses have no specific treatment. Your doctor will likely prescribe medicine like acetaminophen (Tylenol) to help reduce the fever and body aches. If you have severe symptoms, you may be admitted to a hospital to receive intravenous fluids and medicines to control fever and pain.
How Do You Prevent Arboviruses?
The way to prevent arboviruses is simply avoiding the vectors that carry them. Communities can work to spray insecticides at breeding sites and reduce stagnant water pools in their area, but protecting yourself is also important.
Personal protection includes protective clothing, nets on windows and doors, avoiding insect-infested areas, and applying insect repellents like DEET (diethyltoluamide).
There's currently a vaccine available for protection against yellow fever, and it is recommended if you plan on traveling to countries where it's common, such as Argentina, Brazil, Angola, or the Democratic Republic of Congo. Vaccines against many other arboviral diseases are still in the works.
In the future, gene-edited mosquitoes and similar technologies may be able to prevent and control arboviral diseases.