Mosquito and West Nile Virus Information

• CMMCP Information

• EEE Factsheet

• West Nile Virus Information

• WNV Factsheet

• WNV FAQ's

 

CENTRAL MASSACHUSETTS MOSQUITO CONTROL PROJECT

Updated July 7, 2004

 

The Town of Tewksbury contracts with the Central Massachusetts Mosquito Control Project to handle mosquito matters. To request a special spraying of your property, please call the project directly at 508-393-3055, or visit their website at http://www.cmmcp.org electronically.

 

From their notices of spray schedule:

“The results of an investigation may warrant the use of a mosquito insecticide to defined, site-specific areas of the town. Such an application may be accomplished by using hand or truck mounted equipment, depending on the extent of the application.

 

“Per 333CMR13.04: “No intentional application of pesticides shall be made to private property which has been designated for exclusion from such application by a person living on or legally in control of said property.” Notices were sent to all City and Town Clerks in February to alert them of the pesticide exclusion process; CMMCP will continue to accept exemptions during the spray season. Residents should contact their Town or City Clerk for more information on the exclusion process, or may contact the CMMCP office during business hours or apply for an exclusion through our website.”

 

The project will be operating in Tewksbury on the evenings of July  8, 12, 15, 20, and 28.

 

 

What is Eastern Equine Encephalitis?

 

Eastern Equine Encephalitis (EEE) is a rare but serious disease caused by a virus. The virus grows in birds that live in freshwater swamps, and it is usually found only in these birds and in mosquitoes that do not bite people.  Sometimes the virus gets picked up by other kinds of mosquitoes that bite horses and people.  The risk of getting EEE is highest from late July through September.  The virus is spread by adult mosquitoes, which are killed by frost in the fall.

 

 

What are the symptoms of EEE?

 

The first symptoms of EEE are high fever (103º to106ºF), stiff neck, headache, and lack of energy.  These symptoms show up two to ten days after infection.  Swelling of the brain, called encephalitis, is the most dangerous symptom.  The disease gets worse quickly, and many patients go into a coma within a week.

 

 

What is the treatment for EEE?

 

There is no cure for EEE, and three of every ten people who get the disease die from it.  All doctors can do is lower the fever and ease the pressure on the brain and spinal cord.  Some people who survive this disease will be permanently disabled.  Very few people recover completely.

 

 

How is EEE spread?

 

EEE is spread only by mosquitoes.  People and horses that have EEE cannot spread the disease.

 

 

How common is EEE in Massachusetts?

 

EEE is so rare that fewer than 80 people in this state have had it since it was first described in 1938.  Fewer than 50 cases have occurred since 1940.  Most cases have been in Plymouth and Norfolk counties, with a few in Middlesex, Bristol, Suffolk, Barnstable, and Essex counties.

 

 

What can you do to protect yourself?

 

There is an EEE vaccine for horses, but not for people.  The best way to protect yourself is to keep mosquitoes from biting you.  Follow these steps every summer to reduce your risk of being bitten by mosquitoes.

 

·         If you must be outdoors at dusk or dawn, when mosquitoes that carry EEE are most active, wear a long-sleeved shirt and long pants.  Use a mosquito repellent that contains DEET (the chemical N-N-diethyl-meta-toluamide) and follow the directions on the label.  DEET can be poisonous if overused.  Never use DEET on infants and do not apply repellents to the face or hands of children.  Avoid using repellents with DEET concentrations above 10-15% for children and with concentrations above 30-35% for adults.  Cream, lotion or stick formulas are best for use on skin.  Avoid products with high amounts of alcohol because these may be absorbed through the skin.

 

·         Take special care to cover up the arms and legs of children playing outdoors.  When you bring a baby outdoors, cover the baby’s carriage or playpen with mosquito netting.

 

·         Repair any holes in your screens and make sure they are tightly attached to all your doors and windows.

 

·         Mosquitoes can breed in water that collects in ditches, clogged gutters, old tires, wheelbarrows, and wading pools.  Don’t let stagnant water collect around your home.

 

 

What does the state do to protect people from EEE?

 

Mosquito traps are set up all over eastern Massachusetts.  Every year from May until the first frost, MDPH field staff collect mosquitoes and bring them to the State Laboratory for testing.  If the lab finds EEE virus in mosquitoes, MDPH will warn local boards of health, hospitals, and people who live in the affected area.  Because EEE is so rare, many doctors have never seen a case.  If a doctor thinks a patient has EEE, MDPH will run a blood test to be sure.

 

 

For more information:

 

·         Massachusetts Department of Public Health

      Division of Epidemiology and Immunization (617) 983-6800 (consultation for doctors and hospitals regarding EEE symptoms and testing) or on the MDPH website at http://www.state.ma.us/dph.

 

·         Bureau of Environmental Health Assessment (617) 624-5757 (health effects of pesticides)

 

·         Massachusetts Poison Control Center (concerning adverse reactions to pesticides)

      (617) 232-2120 (Boston) or 1-800-682-9211 (other areas in Massachusetts) or 1-888-244-5313 (hearing impaired)

 

·         Massachusetts Department of Food and Agriculture

      State Reclamation and Mosquito Control Board  (617) 626-1781 (regional mosquito control programs)

 

·         Bureau of Animal Health (617) 626-1741 (horse vaccine)

 

·         Mosquito Control Districts

 

o        Cape Cod (508) 775-1510

o        East Middlesex (781) 899-5730

o        Plymouth (781) 585-5450

o        Bristol (508) 823-5253

o        Norfolk (781) 762-3681

o        Suffolk County (617) 361-0550

o        North East Management (Essex County) (978) 474-4640

o        Central Massachusetts (508) 393-3055

o        Berkshire (413) 447-9808

 

 

·         Your local board of health

      (listed in the telephone directory under “government”)

 

West Nile Virus Information

July 7, 2004

 

West Nile Virus is a Mosquito Borne virus that is now commonly found in Massachusetts. It is expected that the virus is here to stay, and humans must therefor be prepared to protect themselves against the virus.

 

Most persons who are infected by the virus never know that they are ill. Those with symptoms usually recover easily from the virus, but some people have died from the disease. Persons most likely to suffer complications are the elderly and people who are immuno-compromised.

 

Protection Against the Virus

·        Avoid outdoor activities between dusk and dawn.

·        Wear long sleeved shirts and long pants if you must be outside.

·        Use DEET – containing mosquito repellents when outdoors during periods of high mosquito activity. When using repellents, follow label instructions carefully, do not overuse, and use appropriate low concentration products on children. Repellents should not be used on infants.

·        Ensure that household screens are intact.

·        Take care to eliminate standing pools of water where mosquitoes breed, including pails, clogged gutters, untreated pools, children’s pools, and old tires.

 

Surveillance

West Nile Virus is tracked through testing dead birds and mosquito populations. Mainly Crows and Bluejays will be tested, but sometimes the state will test other types of birds. In addition, both the state and the Central Massachusetts Mosquito Control District will be setting mosquito traps in areas to sample the population.

 

Dead Birds

The virus will be tracked through the testing of dead birds when appropriate. The Massachusetts Department of Public Health (MDPH) will test mainly CROWS and BLUEJAYS, but will accept calls about any dead bird. To report a dead bird:

 

·        Call MDPH tollfree at 1-866-627-7968; be prepared to provide your address, the type of bird found, the date found, and the condition of the bird.

·        If the Massachusetts Department of Public Health wants to collect the bird for testing, you will be given a tracking number and will be advised to call the Board of Health Office at 978-640-4470.  Town staff will arrange to collect the bird from you and submit it to the state for testing. No birds found over the weekend will be tested, due to the length of time the bird would be dead before it could be tested.

·        Birds that are missing eyes, or showing any type of decay or bug infestation will not be tested, as they will have been dead too long to provide information.

 

Important Links:

·        Massachusetts Department of Public Health - http://www.state.ma.us/dph/wnv/wnv1.htm

·        Central Massachusetts Mosquito Control District - http://www.cmmcp.org/

·        Centers for Disease Control and Prevention (CDC) - http://www.cdc.gov/ncidod/dvbid/westnile/index.htm

 

 

What is West Nile Virus (WNV) Encephalitis?

 

West Nile virus (WNV) encephalitis is a rare disease caused by a virus.  WNV grows in birds, and is transmitted from bird to bird by infected mosquitoes.  If mosquitoes infected with the virus bite horses or humans, they can also become sick.  The virus that causes WNV encephalitis occurs in Europe, Africa and Asia.  It was first identified in the United States in New York during the summer of 1999.  Since then, it has spread throughout the eastern half of the U.S. and as far west as Arkansas.  It is not known how WNV got to the U.S.

 

What are the symptoms of WNV Encephalitis?

 

Most WNV infections do not cause any symptoms.  Mild WNV infections cause fever, headache and body aches, often with a skin rash and swollen lymph glands.  In a small percentage of people infected by the virus, the disease can be serious, even fatal.  More severe infections can cause headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, paralysis and, sometimes, death.  Persons older that 50 years of age have a higher risk of developing severe illness.

 

Is there treatment for WNV Encephalitis?

 

There is no treatment for WNV infection.  Doctors can treat the symptoms of WNV encephalitis.  However, approximately 10% of people who become sick enough from the infection to be hospitalized die from it.

 

How is WNV spread?

 

WNV is spread only by adult mosquitoes that are infected with the virus.  Humans and horses that have WNV infection cannot spread the disease directly to humans.  The risk of getting WNV encephalitis is highest from late July through September.  There is no evidence that a person can get WNV from handling live or dead infected birds.  Still, you should avoid bare-handed contact when handling dead animals, including birds.  If you must handle dead birds, use gloves or double plastic bags.  If you notice a dead bird in your area, call the Massachusetts Department of Public Health at (866) 627-7968.  While most dead birds will not be collected and tested for WNV, keeping track of their locations plays an important role in directing further bird, mosquito and human surveillance activities.  The information gathered from these surveillance activities may help to identify areas at increased risk for human WNV disease.

 

How common is WNV in Massachusetts?

 

During 2001, three cases of WNV infection, including one death, were identified among residents of Massachusetts.  Additionally, WNV has been found in horses, mosquitoes and many species of birds throughout the state.  The mosquitoes that carry this virus are common throughout the state, and these mosquitoes are found in the city as well as in the woods and other less populated places.  For up-to-date information on West Nile virus in Massachusetts, visit the Massachusetts Department of Public Health’s web site at www.state.ma.us/dph.

 

What can you do to protect yourself?

 

There is no vaccine for WNV.  The best way to protect yourself is to keep mosquitoes from biting you.  Follow these steps every summer if you live in or visit an area with mosquitoes:

Avoid outdoor activities between dusk and dawn, if possible, as this is the time of greatest mosquito activity.

·         If you must be outdoors when mosquitoes are active, wear a long-sleeved shirt and long pants.  Use a mosquito repellent that contains DEET (the chemical N-N-diethyl-meta-toluamide) and follow the

directions on the label.  DEET can be poisonous if overused.  Never use DEET on infants.  Avoid using repellents with DEET concentrations above 10-15% for children and with concentrations above

30-35% for adults.  Cream, lotion or stick formulas are best for use on skin.  Avoid products with high amounts of alcohol because these may be absorbed through the skin.

·         Take special care to cover up the arms and legs of children playing outdoors.  When you bring a baby outdoors, cover the baby’s carriage or playpen with mosquito netting.

·         Fix any holes in your screens and make sure they are tightly attached to all your doors and windows.

 

What can you do to reduce the number of mosquitoes around your home and neighborhood?

 

To reduce mosquito populations around your home and neighborhood, get rid of any standing water that is available for mosquito breeding. Mosquitoes will breed in any puddle or standing water that lasts for more than four days.  Here are some simple steps you can take:

·         Dispose of or regularly empty any metal cans, plastic containers, ceramic pots and other water holding containers (including trash cans) on your property.

·         Pay special attention to discarded tires that may have collected on your property. Stagnant water in tires is a common place for mosquitoes to breed.

·         Drill holes in the bottom of recycling containers that are left outdoors, so that water can drain out.

·         Clean clogged roof gutters; remove leaves and debris that may prevent drainage of rainwater.

·         Turn over plastic wading pools and wheelbarrows when not in use.

·         Do not allow water to stagnate in birdbaths; aerate ornamental ponds or stock them with fish.

·         Keep swimming pools clean and properly chlorinated; remove standing water from pool covers.

·         Use landscaping to eliminate standing water that collects on your property.

 

What is Massachusetts doing to protect people from WNV?

 

The Massachusetts Department of Public Health (MDPH) has had a long-standing program to look for another virus carried by mosquitoes, Eastern Equine Encephalitis virus.  Every year from May until the first frost, MDPH field staff collect mosquitoes and bring them to the State Laboratory for testing.  Beginning in 2000, MDPH expanded this mosquito surveillance program to also look for WNV throughout Massachusetts.  Under this expanded program, more locations are being sampled and more mosquitoes are being examined.  Also, a system is in place to test dead birds to look for the presence of WNV.  The State Laboratory can also test for WNV infection in horses and humans.  If WNV is detected in Massachusetts, MDPH will alert local boards of health, hospitals, and people who live in the affected area.  A statewide surveillance and response plan has been developed to assist local communities in preparing for and responding to the risk of WNV.

 

To report dead birds this season:  Please call MDPH toll free at 1-866–MASS-WNV (627-7968)

 

For more information:

·         Massachusetts Department of Public Health

Division of Epidemiology and Immunization  (617) 983-6800

(for questions about WNV and consultations for health care providers and hospitals on WNV)

 

·         Bureau of Environmental Health Assessment  (617) 624-5757

(for questions about health effects of pesticides)

 

·         Massachusetts Department of Food and Agriculture

State Reclamation and Mosquito Control Board  (617) 626-1781

(for questions about regional mosquito control programs)

 

·         Your local board of health  (listed in the telephone directory under “government”)

 

Frequently Asked Questions About West Nile Virus Infection

For Health Care Providers

Massachusetts Department of Public Health, 305 South Street, Jamaica Plain, MA 02130

 

1.  What is West Nile virus infection?

 

West Nile virus infection is caused by West Nile virus (WNV), a flavivirus previously found only in Africa, Eastern Europe, Australia, and West Asia. WNV is closely related to St. Louis encephalitis virus (SLEV), which is found in the United States, and to Kunjin virus (KV), which is found in Australia, some Western Pacific islands and parts of Southeast Asia.

 

2.  What are the symptoms of WNV infection?

 

Among those who become infected with WNV, about 20% exhibit symptoms.  Mild infections are common and include fever, headache, muscle weakness, and body aches, often with skin rash and swollen lymph glands. Headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, occasional convulsions, paralysis, encephalitis and possibly death mark more severe infection.  WNV encephalitis occurs in about 1 of every 150 infected persons, with a higher incidence among the elderly.

 

3.  What is the incubation period of a WNV infection?

 

The incubation period of WNV infection is unclear; however, the incubation period for WNV encephalitis is usually five to fifteen days.

 

4.  How is WNV infection diagnosed?

 

Diagnosis of WNV infection is based on isolation of virus, demonstration of antibody to WNV, or demonstration of WN viral genomic sequences in tissue, blood, CSF or other body fluids.  If you are a health care provider and suspect a case of WNV encephalitis, please call the MDPH’s Division of Epidemiology and Immunization at (617) 983-6800.

 

5.  What is the mortality rate of WNV infection?

 

Historically, the WNV infection case-fatality rate ranges from 3% to 15% of clinically apparent cases (the higher rates are among the elderly).

 

6.  How could WNV have entered the United States?

 

WNV may have entered the United States in infected mosquitoes, birds or persons.

 

7.  How many confirmed cases of human WNV infection have there been in the United States?

 

During the 1999 New York encephalitis outbreak, there were 62 human cases, including seven deaths in New York City.  During 2000, there were 21 human cases (14 in NY, 6 in NJ, 1 in CT), including 2 deaths.  More recently, in 2001, 66 human cases were identified in the United States including 9 deaths.  Human cases were identified in NY, FL, NJ, MD, CT, GA, MA, PA, AL, and LA.

 

 

 

 

8. What about human disease in Massachusetts?

 

During 2001, three cases of WNV infection, including one death, were identified among residents of Massachusetts.  The average age of the cases was 77 years.  Additionally, WNV has been found in horses, mosquitoes and many species of birds throughout the state.

 

9. Does Massachusetts have an effective mosquito surveillance and abatement program?

 

Active statewide surveillance of mosquitoes and passive surveillance of birds, horses, and humans for WNV infection is underway.  When WNV is detected, active local surveillance for birds, horses, and human cases will be implemented.  When WNV is detected in a locality, the first level of response will be to remind the public to eliminate mosquito breeding sites from their property and to avoid mosquitoes through adequate use of screens on doors and windows in their homes and proper use of repellents.  Preemptive, intensified local mosquito control measures may be needed as outlined in the Massachusetts Surveillance and Response Plan for Eastern Equine Encephalitis and West Nile Encephalitis.  For a copy of this plan please visit the MDPH website http://www.state.us/dph.

 

10. What about dead birds?

 

If you are aware of birds that recently died in your area, call the MDPH’s WNV information line at 1-866-MASS-WNV (627-7968).  While most dead birds will not be collected and tested for WNV, keeping track of their locations plays an important role in directing further bird, mosquito and human surveillance activities.  The information gathered from these surveillance activities may help to identify areas at increased risk for human WNV disease.

 

11. How is WNV infection treated?

 

There is no specific therapy for WNV encephalitis. Hospitalization and intensive supportive therapy are indicated in more severe cases.

 

12. Who is at risk for getting WNV infection?

 

All residents of areas where active viral transmission has been identified are at increased risk of getting WNV infection, but persons older than 50 years of age have a higher risk of developing severe illness such as encephalitis.

 

13. How do people get WNV infection?

 

People are infected by the bite of a mosquito that is infected with WNV.

 

14. Can you get WNV infection from another person?

 

WNV is NOT transmitted from person to person. For example, you cannot get infected by WNV from touching or kissing a person who has the disease, or from contact with a health care worker who has recently treated someone with the disease.

 

15. Can you get WNV infection directly from birds or from insects other than mosquitoes?

 

In general, only infected mosquitoes transmit WNV. Ticks, however, may transmit WNV between birds and, possibly, from infected birds to people, but this has not been documented in the U.S.

 

 

 

 

16. Is the disease seasonal in its occurrence?

 

In temperate areas of the world, such as New England, WNV infection cases occur primarily from late summer through early fall. In tropical climates infection can occur year-round.

 

17. Is there a vaccine against WNV infection?

 

There is no vaccine for humans,;however, there is a conditionally-approved vaccine for horses.

 

18. Can other animals get sick?

 

During the 1999 New York City WNV infection outbreak, testing of crows, other birds, and horses identified the presence of WNV antibodies and/or WNV ribonucleic acid (RNA). WNV was isolated from one cat with neurological illness.  In addition, dogs, many other species of wild birds, and many species of domestic birds (chickens, ducks, geese and turkeys), while not clinically ill, were tested and shown to be serologically positive for WNV antibodies, thereby demonstrating they had been infected.  During 2000 and 2001, horses and wild and domestic birds again were infected with WNV.  In Massachusetts, five hundred mammals other than horses, have been tested for WNV.  To date, all have tested negative.

 

19. What is the basic transmission cycle?

 

Initial infection of mosquitoes occurs when they take a blood meal from birds infected with WNV. These mosquitoes then transmit WNV to humans and other animals when taking a second blood meal. Vertical transmission (adult->eggs->larvae->adult) of WNV has been demonstrated in mosquitoes in a laboratory setting.

 

20. Do birds naturally infected with WNV die or become ill?

 

Since 1999, large numbers of North American crows and other birds have become seriously ill and died.  Many other species of birds become infected, develop a high viremia and then immunity, but do not become ill.

 

21. What about migrating birds?

 

Infected migrating birds have dispersed WNV infection to many parts of the United States and Canada.  Depending on the species infected, birds can be infectious for feeding mosquitoes for several days, providing ample time for wide dispersal.

 

22. What about ticks?

 

Ticks have been found infected with WNV in Europe and Asia.  Infection was transmitted vertically (adult->eggs->larvae->nymphs->adults).  Although no WNV was isolated from ticks in the U.S. during the 1999 outbreak, ticks may still prove to be vectors of WNV transmission in the U.S. in the future.  It is important to realize that infected ticks cannot be killed by aerial insecticide spraying like mosquitoes, and that infected ticks, therefore, may prove to be a vector in the possible future spread of WNV in the United States.

 

23. Does WNV successfully over-winter in mosquitoes?

 

Yes.  In March 2000, WNV was isolated from mosquitoes over-wintering in New York City and from a red-tailed hawk that died in Westchester County, New York. It is likely that infected mosquitoes, which hibernate and over-winter in sheltered areas, will emerge in the spring and further continue the spread of WNV in Massachusetts in 2002.

 

24. How can the number of mosquitoes around the home and neighborhood be reduced?

 

Populations of the primary WNV mosquito vector species Culex spp. (container breeders), and the risk of infected mosquitoes, can be decreased in an area by reducing the amount of standing water available for mosquito breeding.

·         Dispose of or regularly empty any metal cans, plastic containers, ceramic pots and other water holding containers (including trash cans) on your property.

·         Pay special attention to discarded tires that may have collected on your property. Tires are a common place for mosquitoes to breed.

·         Drill holes in the bottom of recycling containers that are left outdoors, so that water can drain out.

·         Clean clogged roof gutters; remove leaves and debris that may prevent drainage of rainwater.

·         Turn over plastic wading pools and wheelbarrows when not in use.

·         Do not allow water to stagnate in birdbaths; aerate ornamental ponds or stock them with fish.

·         Keep swimming pools clean and properly chlorinated; remove standing water from pool covers.

·         Use landscaping to eliminate standing water that collects on your property.

 

25. How can I protect myself from bites by mosquitoes?

 

There is no vaccine for WNV.  The best way to protect yourself is to keep mosquitoes from biting you.  Follow these steps every summer if you live in or visit an area with mosquitoes:

·         Avoid outdoor activities between dusk and dawn, if possible, as this is the time of greatest mosquito activity.

·         If you must be outdoors when mosquitoes are active, wear a long-sleeved shirt and long pants.  Use a mosquito repellent that contains DEET (the chemical N-N-diethyl-meta-toluamide) and follow the directions on the label.  DEET can be poisonous if overused.  Never use DEET on infants.  Avoid using repellents with DEET concentrations above 10-15% for children and with concentrations above 30-35% for adults.  Cream, lotion or stick formulas are best for use on the skin.  Avoid products with high amounts of alcohol because these may be absorbed through the skin.

·         Take special care to cover up the arms and legs of children playing outdoors.  When you bring a baby outdoors, cover the baby’s carriage or playpen with mosquito netting.

·         Fix any holes in your screens and make sure they are tightly attached to all your doors and windows.

 

26. Where can I go if I need more information about West Nile virus?

 

You may visit the Massachusetts Department of Public Health (MDPH) WebPage at www.state.ma.us/dph/wnv/wnv1.htm for more information about WNV and preventing exposure to WNV.  You will also find on the MDPH website a daily surveillance report that lists the State Laboratory’s testing results for West Nile virus in Massachusetts. Additional information can also be found on the Centers for Disease Control and Prevention (CDC) website at www.cdc.gov/.  To report a dead bird, call the MDPH’s toll free number 1-866-MASS-WNV (627-7968).