Health Advisory
LYME DISEASE: SURVEILLANCE AND REPORTING IN DELAWARE

With the summer season quickly approaching, Delaware’s Division of Public Health (DPH) provides this reminder about surveillance and reporting Lyme Disease (LD)

Background

LD is the most common vector-borne disease in the United States. According to the Centers for Disease Control and Prevention (CDC), 350,198 confirmed and probable cases were reported in 2008 yielding a national average of 9.4 cases per 100,000 persons. In the 10 states where LD is most common, the average was 56.0 cases per 100,000 persons.

In recent years, the implementation of electronic reporting, and increased awareness and testing by the medical community, have resulted in a significant increase in the number of reported cases of LD in Delaware. From 2004 – 2008 Delaware had the highest or second highest incidence rate of LD in the U.S. In 2008, New Castle County had the highest rate in Delaware (98.1 cases per 100,000 persons), followed by Kent (90.3), and Sussex Counties (58.4).

2008 Case Definition:

• Physician diagnosed erythema migrans  OR
• At least one late manifestation exhibited (musculoskeletal, cardiovascular or neurologic) with laboratory confirmation.
  • Laboratory confirmation consists of:
    • A positive culture for B. Burgdorferi  OR
    • Two-tiered testing of a positive enzyme immunoassay (EIA) or immunofluorescent assay (IFA) followed by a positive Western immunoblot (IgM OR IgG)  OR
    • Single-tier positive IgG Western immunoblot

LD reports are not considered confirmed if the medical provider specifically states it is not a case of LD, or if the only symptom listed is “tick bite” or “tick exposure.”

Surveillance/Reporting

DPH receives electronic laboratory results that may be indicative of LD. However, we do not receive electronic notification for cases of LD that are diagnosed clinically based on the presence of the characteristic bull’s-eye rash, erythema migrans. For such cases, which can be automatically confirmed in the absence of any laboratory testing, we rely on medical providers to report these cases directly to us by phone, facsimile or mailed morbidity report.

Because laboratory reports lack necessary clinical information, case reports are instrumental for determining case status as well as supplying DPH with important epidemiologic data. When DPH receives positive laboratory results or a report of possible LD from a hospital or medical provider, a LD case report form and accompanying letter are sent to the practitioner. Practitioners are requested to complete the form and return by facsimile or in the included postage paid envelope.

Treatment

Patients treated with antibiotics in the early stages of the infection usually recover rapidly and completely. A few patients, particularly those diagnosed with later stages of disease, may have persistent or recurrent symptoms. Antibiotics commonly used for oral treatment include doxycycline, amoxicillin, or cefuroxime axetil. Patients with certain neurological or cardiac forms of illness may require intravenous treatment with drugs such as ceftriaxone or penicillin.

Treatment guidelines for LD and other tick-borne diseases have been developed by the Infectious Diseases Society of America (IDSA) and can be found at: http://www.journals.uchicago.edu/doi/full/10.1086/508667

Further Information

• CDC – Lyme disease: http://www.cdc.gov/ncidod/dvbid/lyme/index.htm
• CDC – Free Online Lyme disease CME for clinicians: http://www.cdc.gov/ncidod/dvbid/lyme/ld_clinicians.htm
• DPH – Lyme disease: http://www.dhss.delaware.gov/dph/epi/lyme.html

Contact information for DPH, Bureau of Epidemiology:

• Office – 1-888-295-5156 or 302-744-1033
• Facsimile – 1-302-223-1540
• Morbidity report – http://www.dhss.delaware.gov/dph/dpc/rptdisease.html

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