Lyme Disease

Paul Mead, MD, MPH

Division of Vector-borne DiseasesCenters for Disease Control and Prevention

Lyme disease cause and discovery

Caused by a spiral bacteria, Borrelia burgdorferi

First described in 1976 as cluster of arthritis among children in Lyme, Connecticut

Soon recognized as multi-system disease in US and Europe linked to tick bite

Photo credit: Jay Carroll

Common human-biting ticks in the U.S.

Transmit Lyme

disease

Lyme disease transmission cycle

Risk of human infection

greatest in late spring and summer

Signs and symptoms of Lyme disease in humans

Erythema migrans (EM)

70-80% of cases

Rarely painful

Appears ~7-14 days after tick bite

Expands slowly over days

Distinct from allergic reaction

Other presentations of EM

From: Nadelman RB, Wormser GP. Management of tick bites and early Lyme disease, Lyme disease. 1998; Philadelphia: American College of Physicians. 49-75

Later stages of Lyme disease

Arthritis Facial palsy

Lyme disease cases reported to CDC,United States, 1992-2008

Increase in reports due to more complete surveillance, plus expansion in some areas

Reported Lyme disease cases, United States, 2008

Reported Lyme disease cases, Northeastern United States, 2008

Lyme disease incidence by age and sex,United States, 1992-2006

0123456789

10

0-4 5-9 10-14

15-19

20-24

25-29

30-34

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

80-84

>84

Age (years)

Cas

es/1

00,0

00/y

ear

Male Female

Reported Lyme disease cases by onset month, United States, 1992-2006

0

10,000

20,000

30,000

40,000

50,000

60,000

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Month of Onset

Cases

Clinical features of reported Lyme disease cases, United States, 1992-2006

0 10 20 30 40 50 60 70 80

EM

Arthritis

Bells palsy

Radiculopathy

Heart block

Percent of Cases

N = 150,829

Diagnosis

Lyme disease is diagnosed by considering:

symptoms and physical findings likelihood of exposure appropriate laboratory testing

In an endemic area, EM alone is considered diagnostic without the need for blood testing

Other forms of illness not sufficiently distinctive to confirm diagnosis without lab testing

Laboratory testing for Lyme disease

Mainstay is a blood test like those used for HIV, viral hepatitis, syphilis, toxoplasmosis, etc.

Detects antibodies the immune system makes against the organism

not positive until several weeks into the infection

remains positive for months or years after the infection is cured

2 step process recommended

Similar to HIV testing Step 1 is quantitative to

determine if antibody levels are elevated

Step 2 is qualitative to determine if antibodies are specific for Lyme disease

Skipping either step increases false positives

IgM test only meaningful during first month of illness

ELISA / EIA

negative

positive or indeterminate

IgM

Immunoblot

StopStop

IgG

How good is 2-tier testing?

Bacon et al. JID 2003; 187:1187–99

Lyme Disease Stage Patients who test positive

Acute EM 38%

Arthritis 97%

Late neurological 100%

A negative test does not exclude infection in patients who have been ill less than a few weeks

A negative test strongly suggests against infection in patients who have been ill longer than a few weeks

Alternative tests

Don’t use tests whose accuracy and clinical usefulness have not been adequately validated, including: urine antigen tests lymphocyte transformation

assays Westernblot using criteria

not validated and published in peer-review scientific literature

Treatment and outcome

Lyme disease is treated with antibiotics

Recommended regimens range from 2-4 weeks, by pill or intravenously, depending on stage of illness

Most patients treated with antibiotics recover completely

A few patients, particularly those diagnosed with later stages of disease may have persistent symptoms

objective (e.g., facial paralysis, arthritis)

subjective (e.g., fatigue, muscle aches, reduced concentration)

Symptoms after treatment for Lyme disease

Long term follow up of 96 patients with culture-confirmed EM in 1991-4Nowakowski et al. Am J Med 2003; 115:91-96

“Post Lyme disease syndrome” and “Chronic Lyme disease”

Terms used to describe patients with persistent subjective symptoms after recommended treatment

Question is not whether such patients exist

Questions are:

what is the cause of these symptoms?

are additional antibiotics the best treatment?

Placebo-controlled studies have found no sustained benefit to prolonged antibiotic treatment

prolonged antibiotic treatment not recommend

Principles of prevention

1. Personal protection 2. Environmental management

3. Community intervention

1. Personal protection

Avoid tick habitat

ticks prefer wooded and bushy areas with high grass and lots of leaf litter

walk in the center of the trail to avoid contact with brush

take extra precautions in May, June, and July when nymphal ticks most active

1. Personal protection

Use repellent

20-30% DEET on skin and clothing

permethrin on clothes only

1. Personal protection

Check for ticks daily

inspect body carefully including armpits, scalp, groin

ticks must attached for 36+ hours to transmit Lyme disease

prompt removal reduces risk of infection, even if the tick is infected

Tick Removal

Use fine-tipped tweezers to grasp tick close to skin

With a steady motion, pull tick away from skin

Clean skin with soap and warm water

Avoid crushing the tick’s body

Don’t use petroleum jelly, a hot match, nail polish, or other products to remove ticks

1. Personal protection

Avoid tick habitat Use repellent Check for ticks daily

Know the symptoms and seek care promptly

2. Environmental management

From: Kirby Stafford, Tick Control Handbook, Connecticut Agricultural Experiment Station

Ticks die quickly in sunny, dry areas

Landscape yard to create tick-safe zones

clear brush and leaf litter

wood chips or gravel between lawns and wooded

keep playground equipment away from yard edges and trees

2. Environmental management

From: Kirby Stafford, Tick Control Handbook, Connecticut Agricultural Experiment Station

Properly timed, a single application of acaracide in late May or early June can reduce tick populations by 68-100%

Fungi that kill ticks also being evaluated

3. Community prevention

Deer do not get Lyme disease but are an important source of the blood adult ticks need to reproduce

Interventions related to controlling deer movement, populations, or tick burdens best accomplished at the community level

Thank You!Thank You!

The findings and conclusions in this report have not been formally disseminated by the Centers for Disease Control and Prevention and should

not be construed to represent any agency determination or policy