Georgia epidemiology report, Vol. 16, no. 3 (Mar. 2000)

March 2000

volume 16 number 3

Division of Public Health
http://health.state.ga.us

The Georgia Epidemiology Report is a publication of the Epidemiology Section of the Epidemiology and Health Information Branch, Division of Public Health, Georgia Department of Human Resources

Tick-borne diseases in Georgia

The medical and economic importance of ticks has long been recognized due to their ability to transmit disease to humans and animals. Ticks are vectors of a variety of pathogenic agents, including species of bacteria (Borrelia burgdorferi, Rickettsia rickettsii, Ehrlichia ssp.), viruses (tick-borne encephalitis virus - family Flaviviridae), and parasites (Babesia microti, Anaplasma marginale). Five tick-borne diseases are known to occur among humans in the southeastern United States: Rocky Mountain spotted fever (RMSF), human monocytic ehrlichiosis (HME), tularemia, Southern tick associated rash illness (STARI), and Lyme disease. While RMSF and tularemia have long been recognized as causes of human disease in this region, STARI and several forms of human ehrlichiosis have only recently emerged. Alterations in vector-host ecology are at least partly responsible for the emergence of tick-borne diseases. The public health importance of these illnesses will become more significant as human behaviors continue to alter the habitats of tick and reservoir species, resulting in increased transmission of known tick-borne diseases and the emergence of previously unrecognized zoonotic infections in humans.

Diagnosis and treatment:

The prompt diagnosis and early treatment of tick-borne infections is often associated with a reduced risk of severe complications or fatalities. Unfortunately, clinical recognition of most tick-borne diseases is difficult because many cases do not initially present with a rash or other distinguishing clinical feature, and few patients recollect a tick bite (Table 1). Moreover, laboratory tests that are currently available offer little assistance to clinicians in making a prompt and accurate diagnosis because serologic tests are usually negative during the acute stage of disease (Table 2). Collection of convalescent-phase blood samples from patients with a suspected tick-borne disease is usually required in order to confirm a diagnosis. While empiric therapy for suspect cases of tick-borne diseases is appropriate because of the potential for chronic disease (as with Lyme disease), or severe or fatal illness (as with RMSF or HME), the routine administration of prophylactic treatment after a tick bite is not currently recommended.

Director Kathleen E. Toomey, M.D., M.P.H.
Epidemiology and Health Information Branch
Acting Director Kathleen E. Toomey, M.D., M.P.H.
Acting State Epidemiologist Paul A. Blake, M.D., M.P.H.
Epidemiology Section Chief
Paul A. Blake, M.D., M.P.H.
Public Health Advisor Mel Ralston

Prevention: The best way to prevent tick-borne disease is to reduce or eliminate exposure to ticks and to promptly remove attached ticks. Studies have shown that transmission of RMSF, HME, or Lyme disease requires at least 10 hours of tick attachment, so the prompt removal of ticks should be emphasized to patients in order to minimize the risk of infection. Patients should also be made aware of the risk factors for tick exposure and should be educated about how to prevent tick bites. An educational brochure for patients is available through the Georgia Division of Public Health (GDPH). Important teaching points to be made include:
Avoid overhanging grasses, weeds or brush while hiking, camping, hunting, or doing other activities outdoors.
Wear light colored long sleeved shirts and pants that are tight at the wrists and ankles (or tuck shirts into pants and pants into socks).
Use chemical acaricides containing DEET (applied to exposed skin) or permethrin (applied to clothing) to deter tick attachment.
Inspect yourself and children for attached ticks immediately after spending time outdoors. Ticks are attracted to warm, moist areas, such as the under arms, groin, behind the knees, and scalp.
Remove attached ticks immediately by grasping them with a tweezers placed as close to the skin as possible and slowly pulling back in a direction perpendicular to the skin surface. Crushing the tick should be avoided. After tick removal, the area of tick attachment and hands should be washed with soap and water.

Georgia Epidemiology Report Editorial Board
Carol A. Hoban, M.S., M.P.H. - Editor Kathryn E. Arnold, M.D. Paul A. Blake, M.D., M.P.H.
Susan Lance-Parker, D.V.M, Ph. D. Kathleen E. Toomey, M.D., M.P.H.
Angela Alexander - Mailing List Jimmy Clanton, Jr. - Graphics

There is currently no vaccine available in the United States to protect against RMSF, HME, or STARI. Vaccination against tularemia is recommended in the US for people with occupational exposure, such as laboratory workers. Lyme disease vaccine, which was approved for human use in 1998, is recommended only for persons who reside, work or recreate in areas of high risk. Fortunately, all of Georgia is classified as either a low or no risk area.
Georgia Department of Human Resources Division of Public Health, Epidemiology Section Epidemiology & Health Information Branch Two Peachtree St., N.W., Atlanta, GA 30303 - 3186 Phone: (404) 657-2588 Fax: (404) 657-2586

Emerging tick-borne diseases:

study enrollment, and symptomatic participants will be encouraged to seek

Since Ehrlichia chaffeensis was identified as the cause of HME in 1986, two other species of Ehrlichia, both with tropisms for granulocytes, have emerged as causes of human granulocytic ehrlichiosis

medical attention. Participants will receive the results of tick testing when they are available. Recommended reading:
1. Walker DH. Tick-transmitted infectious diseases in the United States. Annual Review of Public Health 1998;19:237-

(HGE). In 1994, an unnamed Ehrlichia species that is genetically

69.

similar or identical to veterinary pathogens E. phagocytophila and

2. Spach DH, Liles WC, Campbell GL, et al. Tick-borne disease in the United States. NEJM 1993;329:936-47. 3. Fritz CL, Glaser CA. Ehrlichiosis. Infectious Disease Clinics of North America 1998;12:123-36.

E. equi, was first identified as an agent of HGE in the Northeast and 4. Buller R, Arens M, Hmiel P, et al. Ehrlichia ewingii, a newly recognized agent of human ehrlichiosis. New England

the Upper Midwest. Ehrlichia ewingii, which causes canine

Journal of Medicine 1999;341:148-155. 5. Dumler JS, Bakken JS. Human ehrlichioses: newly recognized infections transmitted by ticks. Annual Review of

ehrlichiosis, was first reported in 1999 to be a cause of HGE in

Medicine 1998;49:201-13.

Missouri. While disease caused by these three Ehrlichia species

6. Barbour AG. Does Lyme disease occur in the South?: a survey of emerging tick-borne infections in the region. Am J Med Sci 1996;311:34-40.

cannot be distinguished clinically, they are epidemiologically

7. Warshafsky S, Nowakowski J, Nadelman R, et al. Efficacy of antibiotic prophylaxis for prevention of Lyme disease.

distinct and they can be differentiated via laboratory techniques.

J Gen Intern Med 1996;923-933. 8. CDC. Recommendations for the use of Lyme disease vaccine: recommendations of the Advisory Committee on

Information regarding testing for human ehrlichiosis can be

Immunization Practices (ACIP). MMWR 1999;48(RR-7):1-25.

obtained by contacting the GDPH.

9. Kirkland KB, Klimko TB, Meriwether RA, et al. Erythema migrans-like rash illness at a camp in North Carolina. A new tick-borne disease? Arch Intern Med 1995;157:2635-2641.

9. Kirkland KB, Klimko TB, Meriwether RA, et al. Erythema migrans-like rash illness at a camp in
Erythema migrans-like rashes that are associated with tick bites occur in the Rocky Mountain spotted fever

southeastern portion of the US; however, studies have failed to implicate Pathogen: Rickettsia rickettsii

Borrelia burgdorferi as the etiologic agent . It is believed that STARI is caused Vector:

Dermacentor variabilis (American dog tick)

by a yet uncultivable species of Borrelia called B. lonestari carried by Amblyo- Incubation: 5-7 days (range 2 to 14)

mma americanum (Lone Star tick), the most common human-biting tick in the Clinical

Classic triad of fever, rash, and history of tick bite in 60-70% at

Southeast. STARI is a very mild illness with no known chronic manifestations.

description: initial presentation. Acute onset of fever (100%), malaise (95%), severe frontal headache (90%), myalgia (80%), and vomiting

(60%). Rash on wrists and ankles spreads centrally and becomes

Surveillance of tick-borne diseases in Georgia:

petechial, papular or purpuric (60-90%). Other symptoms may include: conjunctivitis, abdominal pain, nausea, cough, renal

Lyme disease, RMSF, HME, and tularemia are all physician and

dysfunction, meningismus, and mental confusion.

laboratory reportable diseases in the state of Georgia. Currently,

Case fatality: 13-25% in absence of specific therapy, otherwise 3-5%

surveillance data is incomplete and unreliable because convalescent blood Human monocytic ehrlichiosis

samples are seldom obtained to confirm diagnoses, and there has been little Pathogen:

Ehrlichia chaffeensis

follow-up with reporting physicians to encourage collection of convalescent Vector:

Amblyomma americanum (Lone star tick)

blood and to obtain clinical information. For these reasons, it has been

Incubation: 7 days (range 1 to 28)

difficult to estimate the true morbidity and mortality associated with tick- Clinical

Symptoms from hospital cohort: fever (97%), malaise (84%),

borne infections in Georgia. In an effort to enhance surveillance for tick- description: headache (81%), myalgia and arthralgias (68%), chills (61%),

borne diseases the GDPH will be initiating several projects. The objectives of

nausea (48%), cough (26%), and confusion (20%). Non-specific

these projects will be to enhance physician and patient awareness of the

rash (30%). Laboratory: thrombocytopenia (74%), leukopenia

diseases, to better understand the epidemiology of these diseases, and to

(72%), and elevated AST/ALT (80%).

detect the emergence of new tick-borne diseases in Georgia. Data will also be Case fatality: Up to 5%

used to target public health interventions to populations at greatest risk.

Tularemia

Projects include:

Pathogen: Francisella tularensis

1) An active physician-based surveillance system for Lyme disease Vector:

Amblyomma americanum (Lone star tick) and Dermacentor variabilis

and STARI.

(American dog tick)

Dermatologists and healthcare providers at clinics in three distinct regions of Incubation: 3 to 5 days (range 1 to 14)

Georgia will be asked to participate in this project. Clinic patients at

Clinical Tick-borne tularemia typically presents with ulcer at site of tick

participating facilities will be eligible for study admission if they have, 1)

description: bite, and painful regional lymphadenopathy. Rarely can present

acute onset of an annular, erythematous, expanding EM-like rash that is at

with typhoidal form: fever, chills headache, abdominal pain, and

least 5 cm in diameter and, 2) a history of a tick bite at the rash site, or

prostration.

potential exposure to ticks within 14 days prior to rash onset. All partici- Case fatality: Rare cases of fulminant septic shock

pants will have a skin biopsy of the rash, urine, whole blood, and acute- and Lyme disease

convalescent- sera obtained for testing at CDC.

Pathogen: Borrelia burgdorferi

2) Active surveillance for HME and RMSF in the coastal region of Vector:

Ixodes scapularis (Black-legged tick)

Georgia. Healthcare providers in parts of coastal Georgia will be asked to participate in this project. All patients at participating hospitals and clinics will be eligible for study admission if they have, 1) a fever (temperature > 37.5C) of unknown etiology or, 2) a skin rash plus thrombocytopenia. Patients will be excluded if laboratory tests or procedures obtained within 72 hours of hospital admission or clinic visit provide an explanation for their illness. Acute- and convalescent-phase sera (collected 4-6 weeks apart) will be sent to the CDC for testing.

Incubation: 7 to 14 days (range 3 to 30) Clinical Erythema migrans (EM) rash (an expanding, erythematous, bulls description: eye-shaped rash) 60-90% of cases. Acute onset of fever, headache,
malaise, arthralgias, and/or myalgias. If not adequately treated may become disseminated disease: multiple secondary EM lesions (2550%), arthritis (60%), CNS manifestations (including facial palsy and meningitis) (15%) and carditis (5%). Case fatality: Rarely, if ever, fatal Southern tick-associated rash illness Pathogen: Probably Borrelia lonestari (thus far uncultivated)

3) Identification of infectious agents in ticks that have been

Vector: Probably Amblyomma americanum (Lone Star tick)

attached to Georgia residents.

Incubation: Approximately 12 days (range 2 to 21)

Public health professionals throughout the state will be asked to encourage Clinical

Tick bite-associated annular, expanding, erythematous, EM-like

Georgia residents who have removed an attached tick to call the Georgia description: lesions. Symptoms other than a rash are rare and are usually very

Poison Control Center. Callers will be asked to send the tick to the CDC to

mild, but may include headache, musculoskeletal pain, fatigue, and

be identified and tested for the presence of the agents of Lyme disease, HME,

nausea. Fever is not a characteristic feature of the illness.

and RMSF. A brief questionnaire that includes questions about tick exposures and current health status will be administered two weeks after

Case fatality: No deaths have been reported -2 -

Diagnostic Criteria for Tick-borne Diseases in Georgia
Rocky Mountain spotted fever (Rickettsia rickettsii)

Probable case

A clinically compatible case with single sera antibody titer: IFA > 1: 64 OR CF > 1:16 OR LA, IHA or MA > 1:128 OR Proteus OX-19 or OX-2 test > 1:320 OR a four-fold rise in titer in paired sample
using same test Serum: 5 mL (in red-top tube) collected both at disease onset and >3 weeks later

Confirmed case

A clinically compatible case with either:
Serum: 4-fold or greater rise in antibody titer in paired samples to R. rickettsii by IFA,
CF, LA, IHA, or MA OR
Whole blood: positive PCR assay to R. rickettsii OR Skin biopsy: positive IFA to R. rickettsii OR Clinical specimen: isolation and culture of R. rickettsii

Specimen Requirements
Whole blood: 5 mL (in purple-top tube)
Skin biopsy: 2-4 mm skin lesion in transport media collected in acute phase of the illness
Clinical specimen: (skin biopsy or whole blood) see instruction above

Human Monocytic Ehrlichiosis (Ehrlichia chaffeensis)

Probable case

A clinically compatible case with either:
Serum: single antibody titer > 1: 64 by IFA OR Intracytoplasmic morulae identified in white blood cells

Confirmed case

A clinically compatible case with either:
Serum: 4-fold or greater rise in antibody titer in paired samples to Ehrlichia species by IFA OR Whole blood: positive PCR assay to Ehrlichia species OR Skin biopsy: positive IFA to Ehrlichia species OR Clinical specimen: isolation and culture Ehrlichia species OR Serum: single antibody titer > 1: 64 by IFA plus intracytoplasmic morulae identified in white
blood cells

Tularemia (Francisella tularensis)

Serum: 5 mL (red-top tube) collected both at disease onset and 4 to 6 weeks later
Whole blood: 5 mL (purple-top tube)
Skin biopsy: 2-4 mm skin lesion in transport media collected in acute phase of the illness
Clinical specimen: (skin biopsy or whole blood) see instruction above

Probable case

A clinically compatible case with either:
Serum: single elevated antibody titer >1:160 to F. tularensis in patient
without previous tularemia vaccination OR
Clinical specimen: FA positive for F. tularensis

Confirmed case

A clinically compatible case with either:
Serum: 4-fold or greater rise in antibody titer to F. tularensis OR Clinical specimen: isolation of F. tularensis

Lyme disease (Borrelia burgdorferi)

Serum: 5 mL (red-top tube) collected both at disease onset and 4 to 6 weeks later
Clinical specimen: (ulcer exudate or lymph node aspirates) collect in a sterile vial Confirmed case

Probable case A clinically compatible case with an erythema migrans rash and history of tick exposure.

Confirmed case

A clinically compatible case with an erythema migrans rash or a late manifestation history of tick exposure plus:
Serum: 2-step process for early disease: 1) EIA or IFA IgG and IgM 2) if positive, do
Western blot IgG and IgM. If late disease: IgG Western blot. If neuroborreliosis, EIAIgG serum and CSF. Calculate index if EIA elevated.
Skin biopsy: isolation and culture of B. burgdorferi OR CSF: isolation and culture of B. burgdorferi OR Synovial fluid: isolation and culture of B. burgdorferi OR

Serum: 5 mL serum (red-top tube) collected both at disease onset and 4 to 6 weeks later
Skin biopsy: 2-4 mm skin lesion in transport media collected in acute phase of the illness
CSF: 5-10 mL in sterile tube
Synovial fluid: 5-10 mL in sterile tube

Abbreviations: IFA indirect fluorescent antibody test, CF - compliment fixation, LA - latex agglutination, IHA indirect hemagglutination, MA microagglutination, PCR - polymerase chain reaction, EIA - enzyme-linked immunosorbent assay, WB - Western immunoblot.

-3 -

The Georgia Epidemiology Report Epidemiology and Health Information Branch Two Peachtree St., NW Atlanta, GA 30303-3186

Bulk Rate U.S. Postage
Paid Atlanta, Ga Permit No. 4528

March 2000

Volume 16 Number 3

Reported Cases of Selected Notifiable Diseases in Georgia Profile* for December 1999

Selected Notifiable Diseases
Campylobacteriosis Chlamydia genital infection Cryptosporidiosis E. coli O157:H7 Giardiasis Gonorrhea Haemophilus influenzae (invasive) Hepatitis A (acute) Hepatitis B (acute) Legionellosis Lyme Disease Meningococcal Disease (invasive) Mumps Pertussis Rubella Salmonellosis Shigellosis Syphilis - Primary Syphilis - Secondary Syphilis - Early Latent Syphilis - Other Syphilis - Congenital Tuberculosis

Total Reported for December 1999
1999 32
1792 9 5
109 1382
6 17 11 0 0 10 0 3 0 123 16 22 34 92 121 3 107

Previous 3 Months Total

Ending in December

1997

1998

1999

232

189

142

4227

7841

7763

24

47

38

7

17

14

313

337

357

5065

5426

5686

12

24

21

224

233

76

52

36

48

4

0

2

3

0

0

17

22

19

1

1

0

2

8

7

0

0

0

363

501

476

491

204

52

50

46

52

100

81

92

327

236

198

333

241

236

1

6

3

171

172

200

Previous 12 Months Total

Ending in December

1997

1998

1999

766

769

715

16164

25508

30653

74

152

167

46

84

41

916

1215

1355

18525

20832

21153

41

69

80

763

879

478

224

209

203

6

8

4

9

5

0

107

103

72

11

2

4

18

38

46

0

0

0

1380

1839

1959

1204

1138

280

259

125

141

703

230

283

1864

795

703

1156

799

733

24

29

19

694

629

657

* The cumulative numbers in the above table reflect the date the disease was first diagnosed rather than the date the report was received at the state office, and therefore are subject to change over time due to late reporting. The 3 month delay in the disease profile for a given month is designed to minimize any changes that may occur. This method of summarizing data is expected to provide a better overall measure of disease trends and patterns in Ge orgia.
** Other syphilis includes latent (unknown duration), late latent, late with symptomatic manifestations, and neurosyphilis.

AIDS Profile Update

Report Period

Total Cases Reported*

Percent Female

MSM

Risk Group Distribution (%) IDU MSM&IDU HS Blood Unknown

Latest 12 Months: 1/99 - 12/99 Five Years Ago: 1/94 - 12/94 Cumulative: 7/81 - 12/99

1693

25.8

33.4

13.1

3.2

17.6

1.4

2352

18.2

44.2

22.9

6.1

13.3

1.6

21477

16.1

49.8

18.9

5.8

13

1.9

MSM - Men having sex with men

IDU - Injection drug users

* Case totals are accumulated by date of report to the Epidemiology Section

31.4
11.8
10.7
HS

- 4-

Race Distribution (%) White Black Other

19.3 78.5

2.2

32.7 65.7

1.6

36.9 61.1

2.1

- Heterosexual