Health Advisory
LYME DISEASE UPDATE 2004

In preparation for the summer tick season, the Delaware Division of Public Health would like to update healthcare providers about Lyme disease in Delaware, and provide information regarding testing, treatment and prevention.

Background

Lyme disease was discovered in 1977 when arthritis was observed in a cluster of children near Lyme, Connecticut. Other clinical symptoms and environmental conditions suggested that this was an infectious disease probably transmitted by an arthropod. Further investigation revealed that Lyme disease is caused by the bacterium, Borrelia burgdorferi http://www.cdc.gov/ncidod/dvbid/lyme/bburgdorferi_sm.htm. These bacteria are transmitted to humans by the bite of infected deer ticks and caused more than 23,000 infections in the United States in 2002. Of these cases, 95% were reported from the states of Connecticut, Delaware, Rhode Island, Maine, Maryland, Massachusetts, Minnesota, New Jersey, New Hampshire, New York, Pennsylvania and Wisconsin.

Delaware first began surveillance for Lyme disease in 1988 when five cases were identified in the state. In 2003, 212 cases were reported. No deaths due to Lyme disease have been reported in Delaware.

Risk

Individuals who live or work in residential areas surrounded by woods or overgrown brush are at risk of getting Lyme disease. Working or playing in the yard, participating in recreational activities such as hiking, camping, fishing and hunting, and engaging in outdoor occupations such as landscaping, brush clearing, etc., may also increase risk of getting Lyme disease. Lyme disease is most common during the late spring and summer months (May through August) when nymphal ticks are most active and human populations are most frequently outdoors.

Clinical Syndrome

• Lyme disease most often presents with a characteristic "bulls-eye" rash (erythema migrans), accompanied by nonspecific symptoms such as fever, malaise, fatigue, headache, myalgias and arthralgias.
• The incubation period from infection to onset of rash is typically 7-14 days, but may be as short as 3 days and as long as 30 days.
• Some infected individuals are asymptomatic or manifest only the nonspecific symptoms mentioned above.
• Early disseminated infection may present as disease of the nervous system, musculoskeletal system, or heart. Early neurologic manifestations include lymphocytic meningitis, cranial neuropathy (especially facial nerve palsy), and radiculoneuritis. Musculoskeletal manifestations may include migratory joint and muscle pains with or without objective joint swelling. Cardiac manifestations are rare but may include myocarditis and transient atrioventricular blocks of varying degrees.

Diagnosis

Diagnosis of Lyme disease is based on a high index of clinical suspicion and obtaining specific laboratory tests. Serologic testing for Lyme disease can be done at any reference laboratory. Methods include antibody testing and confirmatory Western immunoblot (WB) testing. PCR has not been standardized for routine diagnosis of Lyme disease.

Treatment

Antibiotic treatment with doxycycline or Amoxicillin for 3-4 weeks is generally effective in early disease. Cefuroxime or erythromycin can be used for persons allergic to penicillin or who cannot take tetracyclines. Late disease, particularly with objective neurologic manifestations, may require treatment with intravenous ceftriaxone or penicillin for 4 weeks or more, depending on disease severity. In late disease, treatment failures may occur and retreatment may be necessary.

Prevention

To avoid tick bites and reduce the risk of infection, individuals should be encouraged to:

• Avoid tick habitats: 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:
• Wear light-colored clothing (to be able to spot ticks more easily)
• Wear long sleeves and pants
• Tuck pants into boots or socks
• Apply insect repellents containing DEET to clothes and exposed skin (less than 50% DEET for adults and less than 30% for children)
• Perform frequent tick checks and remove attached ticks

Reporting

All cases of Lyme disease should be reported to the Delaware Division of Public Health, Bureau of Epidemiology. For questions, call 1-888-295-5156.

Resources

For general questions regarding Lyme disease in humans, call the Delaware Division of Public Health, Bureau of Epidemiology (1-888-295-5156) or 302-744-4541

• Centers for Disease Control and Prevention: http://www.cdc.gov/ncidod/dvbid/lyme/index.htm
• American Lyme Disease Foundation: http://www.aldf.com/