Lyme Disease is Here!
The recent announcement
that Lyme Disease is now endemic in Berrien, Van Buren and Allegan
Counties increases the level of concern that physicians and the public
must have regarding preventing tick bites, treating tick-related
rashes, and evaluating patients for Lyme Disease.
Until recently, people in Southwest Michigan could take some
reassurance regarding possible tick exposure because the only area in
Michigan which was endemic for Lyme Disease was Southern Menominee
County which is in the Upper Peninsula adjacent to Wisconsin. However,
Lyme Disease has been present in Northwestern Indiana, and
investigators from Michigan State University (MSU) have been surveying
the tick and rodent populations of Berrien, Van Buren, Allegan, Cass
and St. Joseph Counties. Preliminary results from their survey now
indicate that Lyme Disease has extended up into Berrien, Van Buren and
Allegan Counties.
Ixodes scapularis is the tick which transmits Borrelia burgdorferi,
the spirochete responsible for Lyme Disease. I. scapularis, also known
as the Black Legged Tick, or in the past known as the Deer Tick, are
new to the Southwestern Michigan area. Of roughly 52 sites checked so
far in the 5 county area, 10 have shown the presence of I. scapularis.
Several ticks tested have also shown infection with B. burgdorferi.
The local presence of Lyme Disease is also demonstrated by tests of
trapped rodents. In addition to deer, I. scapularis can live on
white-footed mice, the primary reservoir for the infection.
Researchers leave small mammal traps in areas under investigation then
return to test the trapped wild rodents for B. burgdorferi infection.
Several such rodents have tested positive.
The sites testing positive for the presence of I. scapularis ticks are
primarily along the coastline of Lake Michigan. However, two locations
which are considerably inland have tested positive, as well. The tick
can migrate into new areas on deer and they can also migrate on
certain ground nesting birds.
Ixodes scapularis, the Black Legged tick
From left to right: Adult female, adult male, nymph, and larva
on a centimeter scale.
These ticks are much smaller than common dog and cattle ticks. In their
larval and nymphal stages, they are no bigger than a pinhead.
Formal compilation and analysis of the tick and rodent data will not be
presented for many months; the researchers are still in the data
collection phase of their work. Dr. Ned Walker and Erik Foster of MSU
are heading up the local work.
Dogs can get ill from Lyme Disease. A vaccine is available for them.
However, the human vaccine for Lyme Disease was removed from the market
in February 2002. Since its removal from the market, the primary means
to prevent the chronic disease include: avoiding tick habitats, using
personal protection measures, and seeking early diagnosis and treatment.
Avoid tick habitats: Whenever possible, avoid entering areas that are
likely to be infested with ticks, particularly in spring and summer when
nymphal ticks feed. Ticks favor a moist, shaded environment, especially
areas with leaf litter and low-lying vegetation in wooded, brushy or
overgrown grassy habitat.
Use personal protection measures: If you are going to be in areas that
are tick infested, wear light-colored clothing so that ticks can be
spotted more easily and removed before becoming attached. Wearing
long-sleeved shirts and tucking pants into socks or boot tops may help
keep ticks from reaching your skin.
The risk of tick attachment can also be reduced by applying insect
repellents containing DEET to clothes and exposed skin, and applying
permethrin (which kills ticks on contact) to clothes. DEET can be used
safely on children and adults but should be applied according to
Environmental Protection Agency (EPA) guidelines to reduce the
possibility of toxicity.
Perform a tick check and remove attached ticks: The transmission of Lyme
disease from an infected tick is unlikely to occur before 36 hours of
tick attachment. For this reason, daily checks for ticks and promptly
removing any attached tick that you find will help prevent infection.
Embedded ticks should be removed using fine-tipped tweezers. DO NOT use
petroleum jelly, a hot match, nail polish, or other products. Grasp the
tick firmly and as closely to the skin as possible. With a steady
motion, pull the tick's body away from the skin. The tick's mouthparts
may remain in the skin, but do not be alarmed. The bacteria that cause
Lyme disease are contained in the tick's midgut or salivary glands.
Cleanse the area with an antiseptic.
Early diagnosis and treatment: The early diagnosis and proper antibiotic
treatment of Lyme disease are important strategies to avoid the costs
and complications of infection and late-stage illness. In many
circumstances, treating persons who only have a tick bite is not
recommended; however, persons with the rash, erythema migrans, should be
treated. Individuals who are bitten by a deer tick should remove the
tick promptly, and may wish to consult with their health care provider.
Persons should promptly seek medical attention if they develop any signs
and symptoms of early Lyme disease.
Lyme disease most often presents with a characteristic "bull's-eye"
rash, erythema migrans, accompanied by nonspecific symptoms such as
fever, malaise, fatigue, headache, muscle aches (myalgia), and joint
aches (arthralgia). The incubation period from infection to onset of
erythema migrans is typically 7 to 14 days but may be as short as 3 days
and as long as 30 days. Some infected individuals have no recognized
illness.
The signs of early disseminated infection usually occur days to weeks
after the appearance of a solitary erythema migrans lesion. In addition
to multiple (secondary) erythema migrans lesions, early disseminated
infection may be manifest as disease of the nervous system, the
musculoskeletal system, or the heart.
Lyme disease infection in the untreated or inadequately treated patient
may progress to late disseminated disease weeks to months after
infection. The most common objective manifestation of late disseminated
Lyme disease is intermittent swelling and pain of one or a few joints,
usually large, weight-bearing joints such as the knee. Some patients
develop chronic axonal polyneuropathy, or encephalopathy, the latter
usually manifested by cognitive disorders, sleep disturbance, fatigue,
and personality changes. Infrequently, Lyme disease morbidity may be
severe, chronic, and disabling. An ill-defined post-Lyme disease
syndrome occurs in some persons following treatment for Lyme disease.
Lyme disease is rarely, if ever, fatal.
Tick Identification and Testing: Expert tick identification is
available. Contact the Environmental Health Division of your Local
Health Department for instructions regarding submission. The tick will
be forwarded to the Michigan Department of Agriculture. If the tick is
still alive and of the appropriate species, it can be tested for
infection with Lyme Disease (I. scapularis) or Rocky Mountain Spotted
Fever (the dog tick, D. variabilis). The Environmental Health Division
of the Van Buren/Cass District Health Department can be reached at (269)
621-3143 x311.
Much valuable information regarding Lyme Disease is
available on the CDC and Michigan Websites. Click on the following
links to find out more:
CDC Lyme
Disease Home Page
Lyme Disease on the Michigan Department of Agriculture Website
