Georgia epidemiology report, Vol. 20, no. 5 (May 2004)

May 2004

volume 20 number 5

Division of Public Health http://health.state.ga.us
Kathleen E. Toomey, M.D., M.P.H. Director
State Health Officer
Epidemiology Branch http://health.state.ga.us/epi
Paul A. Blake, M.D., M.P.H. Director
State Epidemiologist
Mel Ralston Public Health Advisor
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. - Graphic Designer
Georgia Department of Human Resources
Division of Public Health Epidemiology Branch
Two Peachtree St., N.W. Atlanta, GA 30303-3186 Phone: (404) 657-2588
Fax: (404) 657-7517
Please send comments to: Gaepinfo@dhr.state.ga.us
The Georgia Epidemiology Report is a publication of the Epidemiology Branch,
Division of Public Health, Georgia Department of Human Resources

Common Tickborne Diseases in Georgia: Rocky
Mountain Spotted Fever and Human Monocytic
Ehrlichiosis
According to surveillance data collected by the Georgia Division of Public Health (GDPH), the most commonly reported tickborne diseases in Georgia are Rocky Mountain spotted fever (RMSF) and human monocytic ehrlichiosis (HME).
Introduction
Rocky Mountain spotted fever (RMSF) has been a reportable disease in Georgia since 1933, and is the most commonly reported tickborne disease in the state. RMSF is caused by the bacterium Rickettsia rickettsii and vectored by Dermacentor variabilis, the American dog tick.
Human monocytic ehrlichiosis (HME) was first recognized in 1986, and became reportable in Georgia in 1999. HME is caused by the obligatory intracellular bacterium Ehrlichia chaffeensis and is vectored by the most common human-biting tick in Georgia, Amblyomma americanum, the lone star tick. Diagnoses of RMSF and HME are thought to be underreported in Georgia due to asymptomatic and mildly symptomatic cases, misdiagnoses, and limitations of confirmatory testing.
Clinical presentation
The diagnosis of either RMSF or HME is difficult because it is often made solely on clinical and epidemiologic findings before laboratory confirmation is available. Patients initially present with a non-specific flu-like illness of 3 or 4 days duration, when classical diagnostic signs and symptoms are usually not present.
Rocky Mountain Spotted Fever Rocky Mountain spotted fever is characterized by fever (usually over 102F), headache (sometimes severe), and a maculopapular or petechial rash that begins at the extremities (characteristically involving the palms and soles) and spreads to the trunk. Malaise, myalgias, nausea, vomiting, abdominal pain, and conjunctivitis are also common. However, the classic diagnostic triad of fever, rash, and history of tick exposure is present in only 3% of patients during the first three days of illness, when patients are likely to first seek medical care (1). Additionally, only 88% of patients eventually develop a rash, so absence of rash should not rule out the diagnosis of RMSF (1). Severe complications include disseminated intravascular coagulation, adult respiratory distress syndrome, skin necrosis, renal impairment, hypotension, altered mental status, myocarditis, seizures, coma, and even death. Differential diagnoses include gastroenteritis, measles, scarlet fever, ehrlichiosis, Lyme disease, leptospirosis, meningococcemia, Epstein-Barr virus, cytomegalovirus infection, toxic shock syndrome, and bacterial sepsis. Without proper treatment, the mortality rate exceeds 20% and death can occur within 8 to 15 days after onset (2).
Human Monocytic Ehrlichiosis The spectrum of illness associated with HME can range from asymptomatic to lifethreatening. After an incubation period of 1 to 2 weeks, patients develop fever, headache, myalgias, arthralgias, malaise, and nausea. Other less commonly reported symptoms include cough, pharyngitis, lymphadenopathy, diarrhea, vomiting, abdomi-
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nal pain, and changes in mental status. Symptoms are similar to those of RMSF, but only about one-third of patients develop a rash. Rash is more common in children, and can be maculopapular or petechial, but unlike RMSF rarely involves the palms and soles (3). Laboratory findings include mild to moderate leukopenia, thrombocytopenia, and elevated hepatic transaminase levels. In severe cases, acute renal failure, metabolic acidosis, respiratory failure, hypotension, disseminated intravascular coagulopathy, hepatic failure, adrenal insufficiency, neurological signs, and myocardial dysfunction can result, leading to death in 3% of cases. Advanced age, immunosuppression including HIV infection, and delay in treatment are associated with more severe disease and death (3). The differential diagnosis is broad and includes RMSF, Lyme disease, toxic shock syndrome, upper respiratory infection, pneumonia, meningoencephalitis, sepsis, and gastroenteritis.
Laboratory Testing
The most widely available confirmatory test in the diagnosis of RMSF and HME is the immunofluorescence antibody (IFA) test in acute- and convalescent-phase serum specimens (Figures 1 and 2). Caution should be used when interpreting acute-phase tests before receiving convalescent-phase results, as false positive and false negative results are common. The Georgia Public Health Laboratory provides IFA testing on acute and convalescent serum samples through the immunology laboratory.
Treatment
Doxycycline is the treatment of choice for all patients with RMSF or HME, including young children. Chloramphenicol is appropriate for treatment of RMSF (but not HME) when tetracyclines are contraindicated (as in pregnancy), but studies have shown that patients treated with chloramphenicol are more likely to die from RMSF than those treated with a tetracycline (4). Treatment should continue for 7 to 10 days, or at least 3 days after fever subsides. Empiric therapy is indicated for any patient suspected of having RMSF or HME, but prophylactic treatment after a tick bite before symptoms develop is not recommended (5). Treatment should never be delayed while awaiting development of a rash or laboratory results; delay in treatment has been associated with severe and fatal cases (5).

Of the 65 cases of confirmed and probable RMSF in Georgia in 2003, none were fatal. Fifty-six percent of cases were male, and the median age was 42 (range 4-89). Of 46 cases where both race and ethnicity were known, 40 (87%) were non-Hispanic whites. Eightyone percent of cases had onsets during May-September. Counties with the most confirmed cases were Henry (2) and Jasper (2). Counties with the most confirmed and probable cases were Cobb, Gwinnett, and Newton, each with 4. The North Central Health District (serving Baldwin, Bibb, Crawford, Hancock, Houston, Jasper, Jones, Monroe, Peach, Putnam, Twiggs, Washington, and Wilkinson counties) had more confirmed cases (5) then any other health district. Eighty-four percent of cases resided north of the Piedmont Fall Line (the dividing line between the Piedmont and the Coastal Plain stretching across the state roughly from Columbus to Macon to Augusta), and most (63%) cases were residents of the 28 county Atlanta Metro Statistical Area.
GDPH received 330 reports of single positive antibody tests to Rickettsia rickettsii in 2003. Reports came largely from reference laboratories, but a small percentage were reported by clinicians. Convalescent titers were obtained for 40% of probable cases. Barriers to obtaining convalescent titers included: patient unwilling to return to physician's office after feeling better, patient unwilling to pay another copay, physician unwilling to draw another serum sample, and untimely case investigation. Case confirmation requires paired acute and convalescent sera since a single titer does not exclude the possibility of a false positive or previous infection. In fact, 63% of cases with a convalescent serum sample tested proved not to be confirmed cases. This indicates that a large percentage of the population has been exposed to Rickettsia rickettsii earlier in life, but the organism is not responsible for their acute illness. Therefore, it is important to obtain a convalescent sample whenever possible.
Although there was a large increase in confirmed and probable cases in 2003 (compared to a recent 5-year average of 13 cases per year) the number of cases of RMSF in Georgia in 2003 is comparable with numbers seen in the 1970s and 1980s, which averaged about 60 cases per year. We were able to detect and confirm more cases of RMSF in 2003 than in recent years due to an increase in epidemiologic capacity at both the State and District levels.

Surveillance Highlights
Rocky Mountain Spotted Fever There were 17 confirmed and 48 probable cases of RMSF reported to GDPH in 2003. All cases met laboratory and clinical criteria, as required by the CDC case definition (Table 1).
Table 1. Surveillance Case Definitions and Laboratory Criteria--RMSF A confirmed case of Rocky Mountain spotted fever (RMSF) is defined as a clinically compatible case that is laboratory confirmed using the following criteria:
Fourfold or greater rise in antibody titer to Rickettsia rickettsii antigen by immunofluorescence antibody (IFA) test in acute- and convalescent-phase specimens ideally taken 3 weeks apart, or
Positive polymerase chain reaction assay to R. rickettsii, or Demonstration of positive immunofluorescence of skin lesion (bi-
opsy) or organ tissue (autopsy), or Isolation of R. rickettsii from clinical specimen A probable case is a clinically compatible case with a single IFA serologic titer of 64.

Human Monocytic Ehrlichiosis Since HME became a reportable disease in 1999 there have been only a handful of recognized cases. However, due to increased epidemiologic capacity across the state, we were able to recognize and confirm more cases during 2003, a total of 20 (6 confirmed, 14 probable). All cases met CDC's case definition (Table 2). While HME is likely still underreported in Georgia, we estimate that this is a more accurate picture of the disease burden in the state.
Surveillance for HME poses the same challenges as surveillance for RMSF in that clinical compatibility and a four-fold change between acute- and convalescent-phase sera are required for confirmation of cases. Of 68 reports of single positive antibody tests to Ehrlichia chaffeensis received by GDPH, 20 were found to be probable or confirmed cases. None were fatal. All cases occurred during MaySeptember, with 80% of cases having onset during May-July. The median age of cases was 50, with a range of 16-73. Eleven of the 20 cases (55%) were female. Of 14 cases for which both race and ethnicity were known, 12 (86%) were non-Hispanic whites. Most

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Table 2. Surveillance Case Definitions and Laboratory Criteria--HME A confirmed case of human monocytic ehrlichiosis (HME) is defined as a clinically compatible case that is laboratory confirmed using the following criteria:
Demonstration of a four-fold change in antibody titer to Ehrlichia chaffeensis antigen by indirect immunofluorescence assay (IFA) in paired serum samples, ideally taken 4 weeks apart, or
Positive polymerase chain reaction (PCR) assay and confirmation of E. chaffeensis DNA, or
Identification of morulae in leukocytes, and a positive IFA titer to E. chaffeensis antigen, or
Immunostaining of E. chaffeensis antigen in a biopsy or autopsy sample, or
Culture of E. chaffeensis from a clinical specimen. A probable case is a clinically compatible case with either a single positive IFA titer or the visualization of morulae in leukocytes.
cases were residents of LaGrange (6) or North Central (5) health districts, and 55% of cases resided in the 28 county Atlanta Metro Statistical Area.
How to Report a Case of RMSF or HME
RMSF and HME are reportable to Public Health within 7 days after diagnosis. To report a case electronically, log on to Georgia's State Electronic Notifiable Disease Surveillance System (SENDSS) at http://sendss.state.ga.us. Alternatively, complete a Notifiable Disease Report Form (form 3095) and mail to your County Health Department, District Health Office, or State Health Office. When reporting cases of RMSF or HME, be sure to include clinical signs and symptoms in addition to laboratory results, as clinical compatibility is a requirement of the surveillance case definitions.
Other Tickborne Diseases
Human granulocytic ehrlichiosis (HGE) is a disease closely related to HME, causing similar symptoms and laboratory findings. It is caused by Anaplasma phagocytophila, and vectored by Ixodes scapularis, the same tick that carries Lyme disease. HGE is most common in the Northeast and upper Midwest, and has not been reported in Georgia. Other tickborne diseases that occur less frequently in Georgia include Lyme disease, southern tick-associated rash illness (STARI), and tularemia.
Prevention
Help educate your patients about prevention of tickborne diseases. Educational brochures are available on our website at http:// www.health.state.ga.us/epi/vbd/tick.shtml and from GDPH by calling 404-657-2588.
References
1. Helmick CG, Bernard KW, D'Angelo LJ. Rocky Mountain spotted fever: clinical, laboratory, and epidemiological features of 262 cases. The Journal of Infectious Diseases 1984;150:480-488.
2. Stallings SP. Rocky Mountain spotted fever and pregnancy: a case report and review of the literature. Obstetrical and Gynecological Survey 2001;56:37-42.
3. Paddock CD, Childs JE. Ehrlichia chaffeensis: a prototypical emerging pathogen. Clinical Microbiology Reviews 2003;16:3764.
4. Holman RC, Paddock CD, Curns AT, et al. Analysis of risk factors for fatal Rocky Mountain spotted fever: evidence for

superiority of tetracyclines for therapy. The Journal of Infectious Diseases 2001;184:1437-44. 5. O'Reilly M, Paddock C, Elchos B, et al. Physician knowledge of the diagnosis and management of Rocky Mountain spotted fever. Annals New York Academy of Sciences 2003;990:295-301.
Written by: Laurel E. Garrison, M.P.H.
1-866-PUB-HLTH Georgia's Notifiable Disease Emergency Reporting System
Information for Healthcare Providers
What is 1-866-PUB-HLTH? 1-866-PUB-HLTH, also called the Notifiable Disease Emergency Reporting System, is a statewide service that facilitates better communication among Georgia health care providers, health departments, and emergency response personnel. This telephone number is used to report public health emergencies and immediately notifiable diseases. This includes clusters of illness as well as diseases that could result from a bioterrorism event. The Notifiable Disease Emergency Reporting System is available 24 hours a day, 7 days a week through the combined efforts of the Georgia Department of Human Resources Division of Public Health (GDPH), the Georgia Emergency Management Agency (GEMA), and District Public Health Offices.
Who should use 1-866-PUB-HLTH? Clinicians, laboratory personnel, and public health professionals should use the number to report immediately notifiable diseases. Private citizens should NOT use this number.
How does it work? When you call 1-866-PUB-HLTH, a GEMA communications officer answers the phone. The communications officer fills out a report, and then contacts the District Health Office of the patient's residence either by phone or fax, depending on the disease reported. You can request that someone from the health department return your call 24 hours a day, 7 days a week. The communications officer has no clinical or formal public health training and cannot answer questions directly, but will put you in contact with someone who can.
When should I use 1-866-PUB-HLTH versus other methods of reporting? When you have a public health emergency or diagnose an immediately notifiable disease, including clusters of any illness and potential agents of bioterrorism. To report other notifiable diseases, you may: call your County or District Health Office, OR report cases electronically through the State Electronic Notifiable Disease Surveillance System (SENDSS) at http://sendss.state.ga.us , OR complete a Notifiable Disease Report Form (#3095) and mail in an envelope marked CONFIDENTIAL to your County, District, or State Health Department.
If I report a case using 1-866-PUB-HLTH, should I also report using additional (redundant) mechanisms? No. There is no need to report a case through multiple channels.

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

PRESORTED STANDARD U.S. POSTAGE
PAID ATLANTA, GA PERMIT NO. 4528

May 2004

Volume 20 Number 5

Reported Cases of Selected Notifiable Diseases in Georgia Profile* for February 2004

Selected Notifiable Diseases
Campylobacteriosis Chlamydia trachomatis 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 February 2004 36 399 22 1 51 238 9 33 40 1 0 1 0 1 1 52 49 8 17 28 31 0 14

Previous 3 Months Total

Ending in February

2002

2003

2004

106

120

103

8329

8915

3891

33

20

50

6

7

3

165

207

172

4543

4423

2001

38

18

29

142

152

114

87

134

142

3

5

1

1

3

1

9

12

11

0

0

0

3

7

7

0

0

1

260

247

271

364

448

158

33

28

26

58

100

78

207

174

108

209

207

122

6

5

1

148

122

86

Previous 12 Months Total

Ending in February

2002

2003 2004

632

671

618

33361

35138

31027

160

114

147

48

46

26

929

940

829

18481

18826

15382

116

77

87

926

519

761

412

514

685

12

22

30

2

7

8

44

37

32

7

2

3

24

31

32

0

0

1

1707

1954

2056

886

1902

1033

103

105

128

300

370

435

709

713

669

875

776

749

25

13

7

535

577

484

* 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 Georgia.

** Other syphilis includes latent (unknown duration), late latent, late with symptomatic manifestations, and neurosyphilis.

Note: Due to activities to ensure completeness and timeliness of reporting, STD data in this edition of the GER are not current. STD data will be updated and

complete in the next GER.

AIDS Profile Update

Report Period
Latest 12 Months: 05/03-04/04 Five Years Ago: 05/99-04/00 Cumulative: 07/81-04/04

Total Cases Reported* <13yrs >=13yrs Total

5

2,090 2,095

11

1,427 1,438

216

28,143 28,359

Percent Female
27.4
26.8
18.6

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

33.8

6.3

1.6

14.8

1.5

41.9

33.2

14.2

3.5

20.7

1.5

26.9

46.6

16.4

5.2

14.4

1.9

15.5

Race Distribution (%) White Black Other

21.4 74.9

3.7

19.2 77.8

3.0

32.7 64.7

2.6

MSM - Men having sex with men

IDU - Injection drug users

HS - Heterosexual

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

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