Yes, mosquitoes are abundant in Virginia due to the state’s humid, temperate climate and extensive waterways. The season generally runs from early May through early November, with the most intense activity occurring during the hot and humid summer months. Mosquitoes are more than just a nuisance, as they represent a genuine public health concern.
Common Mosquito Species and Seasonal Activity
Virginia is home to approximately 40 different mosquito species, but a few are particularly problematic for residents. The Asian Tiger Mosquito (Aedes albopictus) is one of the most common and aggressive biters, known for its daytime feeding habits in urban and suburban areas. This mosquito is a container-breeder, meaning it lays its eggs in small, artificial sources of standing water like flower pot saucers and clogged gutters.
Another prevalent type is the Northern House Mosquito (Culex pipiens), which is generally active during the cooler hours of dusk and dawn. Culex species prefer to lay their eggs in stagnant water sources, such as storm drains and rain barrels. Floodwater Mosquitoes (Aedes vexans) lay eggs in soil that remains dry until heavy rainfall or flooding causes them to hatch all at once, leading to sudden population explosions.
Mosquito activity begins to increase in the spring as temperatures rise, with the season typically lasting until the first hard frost in the late fall. Peak populations usually occur during the late summer and early fall, particularly after periods of significant rainfall and sustained heat.
Disease Transmission and State Surveillance
Mosquitoes are vectors for several diseases, making them a significant public health focus in the Commonwealth. The primary locally acquired diseases monitored in Virginia are West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE). WNV is the most common mosquito-borne illness in the state, often carried by Culex species, while EEE is considered one of the most severe due to its high fatality rate in both humans and horses.
These viruses circulate in nature among wild bird populations, and mosquitoes transmit them to humans and other mammals like horses after feeding on an infected bird. While the majority of people infected with WNV do not develop symptoms, approximately one in five experience flu-like illness, and less than one percent develop severe neurological disease.
Surveillance involves setting up traps to collect adult mosquitoes, which are then tested for the presence of WNV and EEE. VDH also uses sentinel chicken flocks, where blood samples from the chickens are tested regularly to detect the presence of the viruses in the environment. This data allows local vector control divisions to target high-risk areas with interventions like larviciding and adulticiding. While less common, the VDH also tracks travel-associated diseases like Zika, Dengue, and Chikungunya, which are typically contracted by residents traveling outside the United States.
Effective Personal and Property Control Strategies
Protecting yourself from mosquito bites starts with simple, consistent personal habits when spending time outdoors during the active season. Applying an EPA-registered insect repellent containing active ingredients like DEET, picaridin, or oil of lemon eucalyptus is highly effective. For the greatest protection, wear long-sleeved shirts and long pants, particularly during the peak activity hours of dawn and dusk, when many species are most active.
Property management should focus on eliminating breeding sites. Since a mosquito needs only a small amount of water to lay eggs—sometimes as little as a bottle cap—this requires weekly vigilance. Homeowners must empty water from flower pots, bird baths, pet dishes, and children’s toys at least once a week.
It is important to clean out clogged rain gutters and ensure that tarps and pool covers are drained. For water that cannot be drained, such as ornamental ponds or rain barrels, treatment with mosquito larvicides containing Bacillus thuringiensis israelensis (BTI) can prevent larvae from developing into biting adults. Maintaining intact screens on all windows and doors keeps mosquitoes from entering the home.