It's that time of year: ticks and Lyme disease
If you or your pet companion have been outside this spring, then chances are you’ve seen a tick. Tick season is in full swing. From now until early July, the risk of being bitten by the poppy seed-sized black-legged tick that transmits Lyme disease is high.
What is Lyme disease?
Lyme disease is caused by a bacterium, Borrelia burgdorferi, transmitted by tick bites. It can cause complications such as meningitis, facial palsy, arthritis and heart abnormalities if untreated. It usually occurs in the summer months. Often, but not always, individuals develop a large circular rash around or near the tick bite. Symptoms include chills, a fever, a headache, fatigue, a stiff neck, swollen glands and muscle and/or joint pain. Symptoms usually appear within a month of exposure.
A physician should be consulted if Lyme disease is suspected. Antibiotics are very effective in treating the disease, but early diagnosis improves the outcome.
New Hampshire Cases increasing
The rising incidence of Lyme disease in New Hampshire is due to a number of factors, including increased tick and deer populations, increased recognition of the disease, increased establishment of residences in wooded areas and the increased potential for contact with ticks. UNH Cooperative Extension professor and entomologist Alan Eaton expects ticks, including the black-legged tick, to be abundant this summer. Heavy snow cover ensured that survival rates over the winter would be high.
The black-legged tick
Lyme disease is transmitted by the bite of a black-legged tick (Ixodes scapularis), formerly known as a deer tick.
The ticks become infected when they have a blood meal courtesy of an infected wild rodent (its host). If the tick later bites a human, the tick may transmit the disease to a person. The tick can carry other harmful diseases such as Anaplasmosis and Babesiosis, but the incidence of infection in New Hampshire is low compared with Lyme disease. The chance of getting infected is greatest during the tick’s nymph stage, from May to July, when it is smaller than the head of a pin and hard to detect.
Adult ticks can also transmit the disease, but at 1/16 to 1/8 inch long, they are easier to see and can subsequently be removed before the bacteria can be transmitted. If a tick is attached to the skin for less than 24 hours, the chance of getting Lyme disease is extremely small.
The black-legged tick has four stages in its 2-year, three-host life cycle: egg, six-legged larva, eight-legged nymph and adult (male or female). The larvae feed to excess on the blood of the first animal host. The tick then drops to the ground and molts into a nymph. The nymphs must find and attach to another host, engorge, drop to the ground and molt to an adult.
The white-footed mouse is the principle source for infection among larvae and nymphs, but other small animals and birds may be hosts. White-tailed deer are the principle host for adult ticks, which feed on a variety of medium- to large-sized mammals. Adults usually mate on their host but not always. The blood-filled female tick drops to the ground and lays a single large mass of eggs, typically about 2,000, and dies.
Removing a tick
Use thin-tipped tweezers or forceps and grasp the tick as close to the skin surface as possible. Pull the tick straight upward with steady even pressure. Do not use petroleum jelly, heat from matches or gasoline or other chemicals to remove ticks.
∎ Disinfect the area with alcohol; a topical antibiotic may also be applied.
∎ Save the tick in a sealed container for reference or possible testing. Note the site and date of the bite.
∎ Watch for signs and symptoms of Lyme disease and be aware that localized tick bite reactions may develop rapidly and can sometimes resemble a Lyme disease rash. Consult your physician if you are in doubt.
∎ 30,000 cases of Lyme disease are reported every year
∎ 1,689 New Hampshire cases were reported in 2013
∎ 526 cases were reported in Rockingham County in 2013
∎ 147 cases were reported in Merrimack County in 2013
∎ 60 percent of black-legged ticks were found to be infected with Lyme disease in 2012
∎ Wear light-colored clothing with long pants tucked into socks to make ticks easier to detect and keep on the outside of the clothing.
∎ Use a DEET or permethrin-based repellent.
∎ Keep away from leaf litter, low-lying brush and wooded areas. Minimize contact with vegetation.
∎ Carefully inspect the entire body, including hair. Wash and dry clothing. A tick may survive a washing but it won’t survive an hour in the dryer.
∎ Practice landscape management by keeping lawns mowed, reducing leaf litter, brush and weeds at the edge of the lawn and eliminating areas where rodents will nest.
∎ For black-legged ticks use a repellent with a 30 percent concentration of DEET on skin and clothing. DEET is safe when used according to directions, but it is not recommended for use on children under 2 months old. Apply sparingly to young children. DEET is not water-soluble and will last several hours.
∎ Use permethrin-based repellents only on clothing or fabrics such as netting or tents. It works primarily by killing ticks on contact. Wash immediately with soap and water if it gets on the skin. Do not apply while clothing is being worn. Spray clothing and let dry before wearing.
∎ Botanicals and other “green” repellents have not been shown to be effective in deterring tick bites.
Protect your pets
Pet owners can keep their pets safe by avoiding tick habitat, reducing ticks on the animal and daily tick checks. There are a variety of products on the market to repel or kill ticks on your pets, available over the counter and through your veterinarian.
New Hampshire Department of Health and Human Services: for information on Lyme disease and tick identification dhhs.nh.gov. For specific concerns or questions about Lyme disease call 271-4496, ext. 4496.
The Centers for Disease Control and Prevention: cdc.gov/lyme
UNH Cooperative Extension: for information about Lyme disease in New Hampshire and identification, extension.unh.edu
Sources: New Hampshire Department of Health and Human Services, Bureau of Infectious Disease Control; University of New Hampshire Cooperative Extension; The Centers for Disease Control and Prevention; The Connecticut Agricultural Experiment Station; University of Rhode Island Tick Encounter Resource Center; photo by Scott Bauer, USDA Agricultural Research Service, Bugwood.org