This image depicts laboratory technician, Elizabeth Wilkins, as she was looking into a sealed cylindrical cardboard container that held a large number of mosquitoes scheduled to undergo testing in this laboratory environment. The container was covered by a thin netting, and the mosquitoes inside had all lighted on its interior surface, desiring to escape in order to obtain their requisite meal of blood.
Although mosquitoes may bite at any time of day, peak biting activity for vectors of some diseases (such as dengue and chikungunya) is during daylight hours. Vectors of other diseases (such as malaria) are most active in twilight periods (dawn and dusk) or in the evening after dark. Avoiding the outdoors or taking preventive actions (such as using repellent) during peak biting hours may reduce risk. Place also matters; ticks and chiggers are often found in grasses and other vegetated areas. Local health officials or guides may be able to point out areas with increased arthropod activity.
CDC/ James Gathany
None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.
Prevent Mosquito Bites
Staying at home or traveling abroad this summer? Protect yourself and your family from mosquito bites that can make you sick.
Summer is finally here! Think backyard BBQs, swimming, and mosquitoes…Mosquito bites can be more than just annoying and itchy. They can make you really sick. Whether you and your family are staying at home or heading overseas, remember to wear your insect repellent. Wearing insect repellent is the best way to prevent diseases spread by mosquitoes.
West Nile Virus (WNV)
In the United States, West Nile is the most common virus spread through mosquito bites. Mosquitoes that spread WNV bite at night from dusk to dawn. There are no medications to treat or vaccines to prevent WNV infection. Fortunately, most people infected with WNV will have no symptoms. About 1 in 5 people who are infected will develop a fever with other symptoms. Less than 1% of infected people develop a serious, sometimes fatal, neurologic illness such as encephalitis or meningitis (swelling of the brain or surrounding tissues). In 2014, 48 states and the District of Columbia reported over 2,200 cases of WNV.
The most common symptoms of chikungunya virus infection are sudden onset of a high fever and joint pain. Other symptoms may include headache, muscle pain, joint swelling, or rash. Infection with chikungunya virus is rarely fatal, but the joint pain can often be severe and debilitating. Most patients recover in about a week, although long-term joint pain occurs in some people. Infection is thought to provide lifelong immunity. Outbreaks have occurred in countries in Africa, Asia, Europe, and the Indian and Pacific Oceans.
In late 2013, chikungunya virus was found for the first time in the Americas on islands in the Caribbean. Since then, almost 1.5 million cases have been reported. There is no vaccine to prevent or medicine to treat chikungunya virus infection. Mosquitoes become infected when they bite someone already infected with the virus. Infected mosquitoes can then spread the virus to other people. In 2014-5, 2,662 cases of chikungunya were reported in the continental U.S., most imported by travelers. Puerto Rico and the U.S. Virgin Islands also had large outbreaks.
Forty percent of the world's population lives in an area at risk for dengue and an estimated 390 million people per year are infected with the viruses. Dengue is a disease caused by one of four viruses: dengue virus 1, 2, 3, and 4. Because there are four different viruses, it is possible for someone to get dengue up to four times. Dengue is a leading cause of illness and death in the tropics and subtropics.
Like WNV and chikungunya, there is no vaccine to prevent or medication to treat a dengue infection. Most infected people infected with dengue have mild or no symptoms. About 25% of people who are infected with dengue will develop some symptoms of disease. Mild symptoms of infection begin with a fever and severe headache, pain behind the eyes, joint and muscle pain, and rash. Dengue symptoms can quickly become severe and even fatal. Early recognition of severe disease, followed by close management by a healthcare provider is critical.
Planning a trip? Do your homework before traveling.
Make a check list of everything you'll need for an enjoyable vacation and use the following resources to help you prepare.
- Pack a travel health kit. Remember insect repellent and use it to prevent mosquito bites.
- Learn about destination-specific health risks and recommendations by visiting CDC Travelers' Health website.
- See a healthcare provider familiar with travel medicine, ideally four to six weeks before your trip. Go to the Find a Clinic webpage for help in finding a travel medicine clinic near you.
Visit your healthcare provider right away if you develop a fever, headache, joint pain.
- Tell your doctor about your recent international travel.
- Visit the Getting Sick after Travel webpage for more information.