The Carlisle Mosquito Online

Friday, August 25, 2006


Board of Health Advisory on mosquito, tick bites

With the recent headlines about two confirmed cases of Eastern Equine Encephalitis in the southeastern part of the state, the Board of Health would like to remind residents of the importance of protecting against mosquito-borne illnesses such as West Nile Virus (WNV) and Eastern Equine Encephalitis (EEE) and the tick-borne Lyme Disease. In 2005 there were six cases of WNV infection in Massachusetts with one fatality and four cases of EEE with two fatalities. For both WNV and EEE the state's surveillance program involves testing mosquito pools, tracking incidences of disease and testing birds. The incidences of Lyme Disease have also been on the increase the past few years with 14 confirmed cases reported through July this year. The higher the percentage of positive birds, mosquitoes and ticks in a geographic area, the more likely the risk of transmission to humans. By learning how to limit exposure, children and adults can continue to enjoy outdoor activities while reducing health risks.

Eastern Equine Encephalitis

Last week the Massachusetts Department of Public Health (DPH) confirmed two cases of EEE in the southeastern part of the state. It has also been identified in a sample of mosquitoes on Cape Cod. EEE is a rare but serious disease that is only spread by mosquitoes. The virus infects birds that live in freshwater swamps and is spread from bird to bird by infected mosquitoes. Human-biting mosquitoes are the bridge for spreading the illness to humans. The risk of getting EEE is highest from late July through September. Symptoms are high fever, stiff neck, headache and lack of energy. Symptoms show up three to ten days after exposure. Inflammation of the brain, encephalitis, is the most serious risk. Horses are also vulnerable to EEE, but an infected horse is not considered a threat to humans because of insufficient virus in their bloodstream.

West Nile Virus

WNV causes symptoms from mild to serious. It is also spread by mosquitoes that bite both birds and humans. Mild infections can cause fever, headache, body aches, skin rash and swollen lymph glands. A small percentage of people contract more serious symptoms including high fever, coma, convulsions, and disorientation. Persons older than 50 years of age have a higher risk of developing severe illness. The risk of contracting WNV is highest from late July through September.

WNV is often fatal in certain kinds of birds such as Blue Jays, Robins and American Crows which is why the state only accepts these birds for testing. To report a dead bird, residents should call the Board of Health or the state dead bird reporting line at 1-866-627-7968. Callers will be asked the following questions: What kind of bird and where and how did it die? Are the eyes sunken in? Are there flies/maggots on the bird? Is the head intact? Is the bird mutilated in any way? If the bird is to be submitted, it will be assigned a case number and instructions will be given on how to package and transport the bird to a local repository. The Board of Health has supplies for packaging. Even if the bird is not tested, its location and species will be used for monitoring purposes. If a bird is not to be submitted, residents will be given instructions on how to dispose of it.

Lyme Disease

Lyme Disease is caused by bacteria that are spread by tiny infected deer ticks. Both people and animals can be infected. The ticks cling to plants and bushes near the ground and attach to people and animals that brush against them. A tick must be attached for approximately 24 hours to pass on the bacteria. An early symptom of Lyme Disease is a rash that appears from three days to a month after the bite. Flu like symptoms are also common. Once the early symptoms subside the person can still remain infected. About 60% of people with untreated Lyme Disease get arthritis in their large joints. Later symptoms often involve major organs including joints, heart and nervous system. Early treatment with antibiotics usually prevents later problems. Ticks can be tested by private laboratories for the disease, so it is important to save a tick after removal.

Incidences of Lyme Disease are tracked by the state. The local health department is advised of a positive laboratory result. This diagnosis is then confirmed with the treating physician. If a Lyme Disease Case Report has not been filled out by the physician, a nurse from Emerson Home Care will contact the resident to collect information on symptoms, demographics, and treatment. This information is entered into the state database to better understand the disease and its progress. In Carlisle, the number of "suspect" cases remains very high compared to surrounding towns.

No human vaccines available

There is a EEE vaccine for horses but not for people. There is no human vaccine for WNV nor is there currently a vaccine on the market for Lyme Disease. The best way to protect yourself is to keep mosquitoes and ticks from biting you by wearing appropriate clothing (long sleeves and long pants), avoiding times of peak mosquito activity around dawn and dusk, using mosquito repellents that contain DEET (Never use DEET on infants less than two months of age or in concentrations greater than 30% on children and adults), eliminating mosquito breeding grounds around your home, avoiding areas where ticks are likely to be found (brushy, wooded and grassy areas), and checking carefully for ticks after being outside. Whenever you use an insect repellent, always follow the directions carefully and wash as soon as you return inside. Ticks should be removed with fine point tweezers, being careful to remove the entire tick.

The above information was obtained from Public Health Facts Sheets and the Mass. Dept of Public Health. Additional information can be found at the MDPH website: or by calling the Board of Health at 1-978-369-0283.

2006 The Carlisle Mosquito