Know Ticks, No Lyme
an article by Stephen D. Sears, MD, MPH, State Epidemologist, Maine Center for Disease Control and Prevention.
Originally printed in Maine Medicine, a publication of the Maine Medical Association.
Spring is in the air, and with spring, comes ticks and Lyme disease; the most common vector-borne disease in Maine. We had over 1,000 cases reported in 2011 – the most ever. Ticks may be active any time that the temperature is above freezing. With this year’s mild winter ticks may be more active, so it is never too early to start doing tick checks. Celebrate May as Lyme Disease Awareness Month with the Maine CDC, and remember this is a great opportunity to educate your patients about ticks and how to prevent Lyme disease.
What’s important to remember about Lyme disease?
- Lyme disease is caused by the bacteria Borrelia burgdorferi, which is spread through the bite of an infected deer tick, Ixodes scapularis. The tick must be attached for at least 24 hours to transmit Lyme disease.
- Lyme disease can manifest itself with dematologic, rheumatologic, neurologic and cardiac abnormalities. The most common symptom of early Lyme disease is erythema migrans (EM), also known as “the bull’s-eye rash” (seen about 60-80% of the time nationwide). EM lesions are often accompanied by other acute symptoms such as fatigue, fever, headache, arthralgia, myalgia, or mildly stiff neck.
- Late manifestations include arthritis characterized by brief attacks of joint swelling, Bell’s palsy or other cranial neurities, radiculoneuropathy, lymphocytic meningitis, encephalitis, and 2nd or 3rd degree atrioventricular block.
- Last but not least, Lyme disease is preventable. The easiest way to avoid Lyme disease is to avoid contact with the ticks that carry it.
Ixodes scapularis, the deer tick, is the most problematic tick for human disease in Maine. It transmits not only Lyme disease, but two other emerging tick-borne infections in Maine: Anaplasmosis and Babesiosis. Cases of all these diseases are on the rise in Maine. Other tick-borne diseases, such as Rocky Mountain Spotted Fever (RMSF), Ehrlichiosis, and Tularemia, are uncommon in Maine, but they are becoming more common nationwide. The majority of tick-borne illnesses occur during the summer months when ticks and humans are active in the same outdoor environments. If you see a patient with “summer flu,” especially if their WBC is low – think Anaplasmosis or Babesiosis and send samples for PCR testing.
What’s the best way to diagnose tick-borne illnesses?
- Lyme Disease – Two-tier antibody testing including ElISA, followed by Western Blot for both IgG and IgM.
- Anaplasma, Babesia and Ehrlichia – PCR is the preferred method.
- RMSF and Tularemia – Serologic testing – always get both acute and convalescent samples.
All tick-borne diseases are reportable in the state of Maine so that we have accurate surveillance. Please remember to also report erythema migrans (early Lyme disease) rashes to Maine CDC by fax 1-800-293-7534 or phone 1-800-821-5841, 24/7. We want to hear about all of your tick-borne diseases, so together we can work to reduce the number of cases of Lyme (and the other tick-borne diseases) in Maine.
IDSA treatment guides available at: http://cid.oxfordjournals.org/content/43/9/1089.full
Lyme disease case report form available on the web at: http://www.maine.gov/dhhs/mecdc/infectious-disease/epi/vector-borne/lyme/index.shtml under Resources for Physicians
“Tick-Borne Disease in Maine: A Physicians Reference Manual” is available online at: http://www.maine.gov/dhhs/mecdc/infectious-disease/epi/vector-borne/index.shtml under Tick Resources. Paper copies can be requested through email@example.com.