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Mosquitoes are flying insects that feed on human and animal blood. Female mosquitoes feed on blood for egg development. The bite of a mosquito typically results in an itchy welt, but can occasionally transmit diseases such as West Nile virus and Eastern Equine Encephalitis. There are about 50 different species of mosquitoes in Suffolk County.

 How and where and when do mosquitoes breed?

Many types of mosquitoes lay their eggs in containers around the home such as flower pots,  children’s toys, discarded tires, clogged gutters, ornamental ponds without fish, non-maintained pools or puddles on pool covers. There, the eggs hatch into larvae, develop into pupae and emerge as adults. Some species of mosquito will utilize natural freshwater habitats such as wetlands, ponds, puddles or water-filled tree holes. Other species of mosquito are able to develop in salt water habitats (e.g. saltwater marshes) and may be particularly troublesome in coastal areas.

 Do mosquitoes bite during the day?

Mosquitoes bite during the day and night. Several mosquito species, including the Asian tiger mosquito, are active during the day. The Asian tiger mosquito (Aedes albopictus), native to Southeast Asia, was first collected in the United States in Houston, TX in 1985. This species is thought to have been introduced by the import of used tires containing Asian tiger mosquito eggs. The species spread throughout the southern US and has expanded its range northward.

The Asian tiger mosquito was first detected in Suffolk County, NY in 2004. Currently, they are widespread in Suffolk County, and their range is moving eastward. They are capable of transmitting West Nile virus and eastern equine encephalitis virus. In other parts of the world, they are known to transmit other viruses that cause dengue fever and chikungunya fever. 

Asian tiger mosquitoes are named for their black and white striped legs. They are container breeding mosquitoes, meaning that they lay their eggs inside water-filled, natural or artificial container habitats. There, the eggs hatch into larvae, develop into pupae and emerge as adults. Around the home, commonly used containers include tires, wheel barrows, plastic buckets, flower pots, plastic cups and aluminum beverage cans.

Centers for Disease Control Asian Tiger Mosquito Information

Centers for Disease Control Asian Tiger Mosquito Photograph

 How can I avoid being bitten by a mosquito?

If you are outdoors, it is important to take proper precautions against mosquito bites.  Such precautions include wearing long-sleeved shirts and long pants, placing mosquito netting over infant carriers, considering staying indoors when mosquitoes are actively biting, and installing or repairing window and door screens so that mosquitoes cannot get indoors. Help reduce the number of mosquitoes by emptying and scrubbing all sources of standing water that mosquitoes may use for breeding, such as containers, clogged gutters, etc. Bird baths should be scrubbed clean and refilled weekly.

You can help: Please print and share the Suffolk County brochure:

 Is it safe to use mosquito repellents?

Repellents may be used to repel mosquitoes. Always read and follow all label directions carefully. CDC recommends repellents containing DEET, oil of lemon eucalyptus, picaridin and IR3535 (Avon’s Skin So Soft Bug Guard) may be applied to the skin and clothing. Lower concentrations of DEET are preferable, especially for children. Repellents containing permethrin may be applied to clothing only.

New York State Department of Health Mosquito Information 

Rutgers University Mosquito Information

Rutgers University Mosquito Life Cycle


Agency (EPA)

This website contains information about pesticides, health and safety, environmental effects, controlling pests, regulation of pesticides, compliance and enforcement, grants and partnerships, science and policy and more. It also contains a section for kids.

Mosquito-borne Disease Information

Centers for
Disease Control
Topics Webpage
New York State
Department of
Health Information
Centers for
Disease Control
West Nile
Virus Webpage
Centers for Disease Control EEE Virus Webpage

Disease Transmission

CDC West Nile Virus


Pesticide Poisoning

If you think you have been adversely affected by a pesticide product, contact your medical provider immediately.

For information on pesticide poisoning, call the NPIC - National
Pesticide Information
1 (800) 858-7378.

Pesticide Regulatory
Programs: New York State
Department of Environmental
Conservation (DEC)

Mosquito-borne Diseases

West Nile Virus WNV

West Nile Virus is transmitted to humans through the bite of an infected mosquito. Mild cases of West Nile infection (West Nile fever) may include a slight fever and head and body aches. Severe infections (West Nile encephalitis) may also include muscle weakness and may progress to encephalitis or meningitis.

Symptoms usually occur three to 14 days after exposure. There is no specific treatment for viral infections, other than to treat the symptoms and provide supportive care.  Persons over the age of 50 are at highest risk of becoming seriously ill from West Nile infection. Healthy children and adults are at low risk for serious illness from West Nile virus.  Horses are susceptible to WNV infection and should be vaccinated.

West Nile virus is the most common mosquito-borne disease in the U.S. It can be spread by the Culex pipiens mosquito, also known as the northern house mosquito, which is common in Suffolk County.

West Nile Virus (WNV) in Suffolk County

* Number in parentheses indicates number of deaths
Year Mosquito Samples Testing Positive Humans Cases*
2021 111 5 (0)
2020 88 5 (0)
2019 86 3 (0)
2018 142 11 (0)
2017 119 6 (2)
2016 125 5 (0)
2015 200 5 (0)
2014 186 1 (0)
2013 178 5 (0)
2012 210 14 (0)
2011 81 4 (0)
2010 295 25 (3)
2009 17 1 (0)
2008 41 9 (0)
2007 12 0
2006 57 2 (0)
2005 76 9
2004 8 0
2003 40 10 (2)
2002 34 8 (2)
2001 68 1 (0)
2000 121 0

Chikungunya, Dengue & Zika Virus

Dengue, Chikungunya and Zika viruses are spread primarily by Aedes mosquitoes. Aedes mosquitoes will bite anytime during the day or night. The vast majority of these infections are acquired while traveling to other countries.


Globally, dengue is the most common mosquito-borne disease. In the U.S., outbreaks of dengue have occurred in the south and Hawaii, with only one locally acquired infection having been reported in Suffolk County.


Chikungunya outbreaks have occurred throughout Asia, Africa and Europe, and more recently in the Caribbean. No locally acquired infections have been reported in Suffolk County.


In addition to the bite of an infected mosquito, Zika virus can also be spread through sexual contact or blood transfusions. It can also be passed from mother to fetus during pregnancy. Infection during pregnancy can cause certain birth defects. Zika virus outbreaks have occurred in parts of Africa, South and Central America, Mexico and the Caribbean. No locally acquired infections have been reported in Suffolk County.

Click here for more information about Zika virus.

Travel: Precautions should be taken when traveling to places where these viruses are circulating. Visit the CDC’s website for current information on at risk travel destinations.

More about Aedes Mosquitoes: According to the CDC, Aedes aegypti mosquitoes are more capable of spreading viruses than Aedes albopictus (also known as Asian Tiger) mosquitoes.

  • Currently, Aedes aegypti mosquitoes are not found in New York.
  • Aedes albopictus mosquitoes have been found in Suffolk County since 2004.
  • Aedes albopictus mosquitoes have not been known to cause infection in Suffolk County, but are capable of transmitting viruses and have been implicated in outbreaks in other countries.

Eastern Equine Encephalitis (EEE)

Eastern equine encephalitis virus (EEEV) is transmitted to humans through the bite of an infected mosquito. Eastern equine encephalitis (EEE) is a rare illness in humans, and only a few cases are reported in the United States each year. Eastern Equine Encephalitis virus is typically spread by a variety of mosquitoes from swampy regions.  In Suffolk County, this virus has been found sporadically in mosquitoes but there has never been a human infection.

Most persons infected with EEEV have no apparent illness. Severe cases of EEE (involving encephalitis, an inflammation of the brain) begin with the sudden onset of headache, high fever, chills and vomiting. The illness may then progress into disorientation, seizures, or coma. EEE is one of the most severe mosquito-transmitted diseases in the United States with approximately 33 percent mortality and significant brain damage in most survivors.

There is no specific treatment for EEE; care is based on symptoms. You can reduce your risk of being infected with EEEV by using insect repellent, wearing protective clothing, and staying indoors while mosquitoes are most active. If you think you or a family member may have EEE, it is important to consult your healthcare provider for proper diagnosis. Horses are susceptible to EEEV infection and should be vaccinated.

Eastern Equine Encephalitis Virus (EEEV) in Suffolk County

● Only years where EEEV has been found are shown
● EEEV has not been found in horses since 2003
● There has never been an identified EEEV human case in Suffolk County
● Equine vaccines for EEEV reduce horse cases
Year Mosquito Samples Testing Positive Humans Cases
2019 9 0
2017 4 0
2008 3 0
2003 1 0
1997 5 0
1996 26 0
1994 49 0
1993 6 0
1990 1 0
1978 1 0
1973 1 0


Public Health Videos:

A two-part look at how mosquitoes are captured and tested for mosquito-borne diseases.

The Science
of Catching and
Testing Mosquitoes
Video (Part 1)
Mosquitoes for
West Nile
Virus Testing
Video (Part 2)
How To Stop
Mosquitoes From
Breeding in
Your Back Yard
Video (Part 3)

Public Health Information Line:

Residents are encouraged to report sightings of dead birds, such as crows, blue jays and hawks that may have been infected with the virus to the Department of Health Services Public Health Hotline

from 9 AM to 4:30 PM Monday through Friday. June 1st- September 1st.

Questions about Mosquitoes and Mosquito-Borne Diseases in Suffolk County
If you have questions about mosquitoes or mosquito-borne diseases, send them to:  Mosquito.Prevention

Mosquito Control

Mosquito Control Flyer

The Suffolk County Department of Public Works, Division of Vector Control, is responsible for controlling mosquito infestations that are of public health importance. For more information about mosquito spraying, or for an online mosquito complaint form, visit Vector (Mosquito) Control or to learn more about the "No Spray" Law
and how to

Spraying Notices

Vector (Mosquito)
Control and
Wetlands Management
Long-Term Plan

Division of Vector
Control 2022
Plan of Work

Suffolk County Government

H. Lee Dennison Bldg

100 Veterans Memorial Hwy
P.O. Box 6100
Hauppauge, NY 11788

Riverhead County Center

County Road 51
Riverhead, NY 11901