Massachusetts Department of Public Health Bureau of Communicable Disease Control

February 16, 2001

During the summer and fall of 2000, the Massachusetts Department of Public Health (MDPH) received reports of fifteen confirmed cases of tularemia among permanent or part-time residents of Martha’s Vineyard. MDPH has been conducting an ongoing investigation of these cases in cooperation with the federal Centers for Disease Control and Prevention (CDC), Martha’s Vineyard Hospital and the local Boards of Health on Martha’s Vineyard.

Tularemia is a rare bacterial disease that can be spread to people in a number of ways, including through a tick bite, direct contact with an infected animal, ingestion of water or meat that has been contaminated by an infected animal, or by inhalation of contaminated particles. Many animals can be sources of infection, particularly rabbits and rodents. Tularemia is not spread from person to person.

Symptoms of tularemia will vary depending on how a person was exposed to the bacteria. During this most recent outbreak on the Vineyard, eleven of the fifteen confirmed cases had pneumonia and were most likely exposed through inhalation.

Results from the joint investigation wit h the CDC showed that individuals with tularemia pneumonia were more likely to have recently used brush cutting or mowing equipment than individuals without tularemia.

Exposure to the bacteria most likely occurred by inhaling aerosols of contaminated dust, soil, or grasses during these or similar landscaping activities.

You may reduce your risk of tularemia by doing the following things:

A) Prior to operating any lawn mowing or brush cutting equipment, check the area you will mow or cut to make sure it is clear of any visible animal carcasses. When removing a carcass, never handle it with your bare hands.

Use gloves or a shovel to gently clean up the carcass and either bury it or double bag it in plastic and dispose of it in the trash.

B) Keep all outdoor gardening equipment (i.e., lawnmowers, brush cutters, weed whackers) well maintained and use them according to the manufacturer’s instructions. When operating such equipment, take care to minimize the generation of aerosols of dust, soil or grass.

C) After taking the steps described in A) and B) an individual may feel there is still a substantial risk of inhaling potentially contaminated aerosols when operating lawn mowing or brush cutting equipment.

Respirators are available for an added measure of protection. A well fitting N-95, N-99 or N-100 respirator can be effective in protecting individuals from certain respiratory hazards. The effectiveness of wearing such respirators to protect against airborne tularemia is unknown at this time. These respirators come in a variety of styles and designs, are relatively inexpensive, and are usually available at local hardware or safety supply stores. The respirator selected should be NIOSH (National Institute for Occupational Safety and Health) certified and used according to the manufacturer’s instructions.

D) Avoid any direct contact with wild animals (especially rabbits and rodents), their droppings or carcasses. If you notice a sick or injured wild animal, call your local animal control officer.

E) Do not allow your pets to roam outdoors unsupervised. If your pets do go outside unsupervised, they should be in a secured yard or kennel to avoid contact with wild animals.

F) Minimize rodent and rabbit populations near your home by keeping woodpiles off the ground and in sunny areas, by fencing off any garden areas, by never leaving pet food outside after your pet has eaten, and by securing all garbage in rodent-proof containers.

G) Use gloves, an appropriate respirator (See above), and protective eye covers when skinning or dressing wild animals. Any wild game should be cooked thoroughly before eating it and, as with other raw meats, steps should be taken to avoid cross-contamination. (I.e., Hands, utensils and surfaces should all be thoroughly washed after handling any raw meats or meat products, and the juices from raw meats should not come into contact with any cooked or ready-to-eat foods.)

H) In addition to a variety of wild animals, domestic cats are susceptible to tularemia infection and are able to transmit this infection to people. If your cat shows any signs of illness, such as fever, loss of appetite, or listlessness, you should have it checked by your veterinarian.

I) Avoid drinking water that may have been contaminated by wild animals, especially rabbits or rodents. If you receive your drinking water from a well, be sure it is protected from potential contamination by wild animals.

J) Avoid areas where ticks are likely to be found. The type of tick most likely to carry the tularemia bacteria is the common dog tick. Ticks cling to vegetation and are most numerous in brushy, wooded or grassy habitat. They are not found on open sandy beaches, but may be found in grassy dune areas. In areas where contact with ticks cannot be avoided, individuals should take the following precautions:

For further information on tularemia, call your local Board of Health or the Massachusetts Department of Public Health, Division of Epidemiology and Immunization at 617-983-6800.