Mosquitoes are a part of New York City’s urban ecosystem during warmer months. They become active around April and remain prevalent through October, with peak activity often observed in August and September. Residents and visitors may encounter them, especially in areas with standing water. Understanding their activity and implications helps residents stay safe.
Common Mosquito Species and Health Concerns in New York City
Several mosquito species are found in New York City, some posing public health concerns. The Northern House Mosquito (Culex pipiens) is the most common, laying eggs on fresh or stagnant water in barrels, ponds, and puddles. Another significant species is the Asian Tiger Mosquito (Aedes albopictus), an aggressive daytime biter that lays eggs above the waterline in small containers like old tires, plant saucers, and clogged gutters, needing only minimal water to complete its life cycle. While the Yellow Fever Mosquito (Aedes aegypti), a potent disease vector, is not typically found, the related Aedes albopictus is present across all boroughs.
The primary mosquito-borne illness transmitted locally in New York City is West Nile Virus (WNV). Culex mosquitoes, including Culex pipiens, are the main vectors, acquiring WNV from infected birds before transmitting it to humans. Most people infected with WNV do not develop symptoms; about 20% experience a mild illness. Symptoms can include fever, headache, body aches, nausea, vomiting, diarrhea, rash, and swollen lymph glands, appearing three to fifteen days after a bite.
In rare instances, WNV can lead to severe illness affecting the brain and spinal cord, such as encephalitis or meningitis. These cases, more common in individuals over 55 or with weakened immune systems, may present with high fever, neck stiffness, confusion, muscle weakness, tremors, paralysis, or coma. While other mosquito-borne diseases like Zika, Dengue, and Chikungunya are diagnosed in New Yorkers, these are almost exclusively travel-related. The New York City Department of Health and Mental Hygiene (DOHMH) monitors these threats; local transmission has not been identified.
Individual Protection Strategies
Protecting oneself from mosquito bites is important, especially during peak mosquito season. Using EPA-approved insect repellents is effective. Repellents containing DEET, picaridin, oil of lemon eucalyptus (OLE), or IR3535 provide protection. Always follow product label instructions for safe application, particularly for children.
Wearing appropriate clothing creates a physical barrier against bites. Long-sleeved shirts and long pants, especially during dawn and dusk when Culex mosquitoes are most active, reduce exposed skin. Ensuring window and door screens are intact helps prevent mosquitoes from entering homes. Repair or replace any screens with tears or holes.
Eliminating standing water around properties reduces mosquito breeding sites. Mosquitoes lay eggs in stagnant water; even small amounts in a flowerpot saucer, bird bath, or old tire can become breeding grounds. Regularly empty and clean containers that hold water, unclog gutters, and ensure swimming pools are treated or covered when not in use. Dedicate a short time each week to inspect and remove standing water to significantly reduce mosquito populations in residential areas.
New York City’s Mosquito Control Efforts
New York City manages mosquito populations and health risks through control programs led by the Department of Health and Mental Hygiene (DOHMH). The city employs an Integrated Pest Management (IPM) approach combining surveillance, public education, and targeted treatments. Surveillance involves setting traps to collect adult mosquitoes, which are tested weekly for viruses like West Nile. This data identifies areas with high mosquito activity and disease risk.
The city implements larviciding to target mosquitoes in their immature stages. Helicopters are used for aerial larviciding over large natural areas like marshes and wetlands, applying low-risk larvicides that prevent young mosquitoes from developing into adults. Larvicides are also applied to catch basins and other standing water bodies. This method reduces mosquito populations before they can fly and bite.
When surveillance indicates a high risk to human health, DOHMH conducts targeted adulticiding, spraying pesticides from trucks in specific residential areas and parks. These spraying events occur in the evening or overnight, using low concentrations of EPA-approved pesticides. The city provides advance notification through channels like Notify NYC and public announcements. These coordinated efforts complement individual protective measures, reducing the overall mosquito population and mosquito-borne illnesses.