Georgia epidemiology report, Vol. 18, no. 6 (June 2002)

June 2002

volume 18 number 06

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

Georgia's West Nile Virus Surveillance During 2001 and Plans for 2002

West Nile virus (WNV) is transmitted from wild birds to humans, horses, and other animals by the bites of infected mosquitoes. The presence of WNV was first confirmed in Georgia in July 2001 when an American crow from Lowndes County tested positive for the virus. During 2001, WNV was detected in birds, horses, mosquitoes, and humans from 58 of Georgia's 159 counties (Figure 1).

Figure 1. Distribution of WNV activity in Georgia, 2001. Information is based on laboratory-confirmed cases reported to the Georgia Division of Public Health (GDPH).

Rome

Atlanta

Athens

LaGrange Columbus

Macon

Dublin

WNV Positive Animals (Birds and/or Horses) WNV Positive Humans and Animals (Birds and/or Horses)
Augusta

Albany
Tifton

Savannah Waycross Brunswick

Valdosta
Georgia was not the only state that experienced WNV for the first time during 2001. Since WNV was first detected in New York City in 1999, it has spread rapidly and by the end of 2001 the virus had been detected in 28 states and Washington DC (Figure 2). The emergence and spread of WNV in the United States demonstrates how quickly and easily an infectious disease can be introduced and established in a new geographic area.

Figure 2.

States reporting WN virus activity during 2000.

Please send comments to: Gaepinfo@dhr.state.ga.us

States reporting WN virus activity during 2001.

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

WNV/Arbovirus Surveillance Will Continue
During 2002:
In response to the introduction of WNV to the United States in 1999, arbovirus surveillance efforts were enhanced or initiated in Georgia to quickly detect and respond to WNV in the state. Dead bird, live bird, horse, mosquito, and human surveillance were conducted in Georgia during 2000 and 2001. By boosting our efforts to detect WNV, we have also improved our ability to detect and respond to other arboviruses in Georgia, including eastern equine encephalitis (EEE), St. Louis encephalitis (SLE), and LaCrosse encephalitis (LAC) viruses.

Figure 3. The number of dead birds and horses that tested positive for WNV in Georgia are shown by week. Approximate onset dates of the six human cases are indicated by arrows. Note that detection of positive birds
and horses preceded the onset of human cases.

It can now be assumed that WNV is established in our state and is present throughout the state. However, there is still much to be learned about WNV and its public health impact. We do not yet know in which habitats the virus will establish itself (urban or rural?, coast or piedmont?, swamp or forest?), what its preferred hosts or vectors will be, or the extent of virus transmission from year to year. Surveillance for WNV and other arboviruses in birds, horses, mosquitoes, and humans will be continued through 2002. Information obtained from these surveillance efforts will be used to predict risk to human and animal populations so that appropriate control measures may be implemented.

Dead bird surveillance will be conducted in Georgia throughout 2002. Crows, blue jays, and raptors that are fresh and in good condition may be submitted by county or district health departments for arbovirus testing.

Dead Bird Surveillance--
During 2001, over 1500 dead birds were submitted to the Southeastern Cooperative Wildlife Disease Study (SCWDS) at the University of Georgia in Athens for necropsy and arbovirus testing (WN, EEE, SLE, and other arboviruses). Of those birds submitted, 326 were positive for WNV and 7 were positive for EEE virus. As predicted, dead bird surveillance was the earliest indicator that WNV had made its way to Georgia.

Horse Surveillance--
Equine surveillance for WNV will continue throughout 2002 in cooperation with the Georgia Department of Agriculture and the University of Georgia Veterinary Diagnostic Laboratories. Equine arbovirus surveillance has traditionally been an important indicator of EEE virus activity in Georgia and has been used as an indicator of human risk. During 2001 we learned that equine surveillance is also an important indicator of WNV activity in Georgia.

Summary of State and National WNV Surveillance Data, 2001:
[This information is accurate as of 2/9/02, but is subject to change as more information becomes available.]

United States*

Georgia

Birds

7058 WNV-positive birds (5036 American crows, 2022 other species) from 27 states and Washington DC.

326 WNV-positive birds (140 American crows, 161 blue jays, 25 other species) from 55 counties.

Horses

640 laboratory-confirmed cases from 20 states (AL, CT, DE, FL, GA, IL, IN, KY, LA, MA, MD, MS, NH, NJ, NY, NC, PA, RI, TN, and
VA).

68 laboratory-confirmed cases from 26 counties.

Mosquitoes

911 WNV-positive mosquito pools from 16 states (CT, DE, FL, GA, IL, KY, MA, MD, MI, NH, NJ, NY, OH, PA, RI, VA) and Washington DC. WN virus-positive species have primarily been Culex, but
many other species have also tested positive.

36 WNV-positive mosquito pools from 3 counties (DeKalb, Fulton, and Lowndes). Positive species in Georgia were mostly Culex species. One pool of Aedes albopicutus
from Fulton County also tested positive for WN virus.

Humans

61 cases of WN encephalitis or meningitis were reported to CDC by 10 states: AL (2), CT (6), FL (12), GA (6), LA (1), MA (3), MD (6), NJ (9), NY (13), and PA (3). The median age of cases was 70 years (range: 3690 years). Dates of onset ranged from July 13 to December 7, 2001, and
13% (8) of the patients died.

6 cases of WN encephalitis or meningitis from 5 counties: Fulton (1), Macon (1), Pierce (1), Richmond (1), and Wayne (2). The median age was 69 (range: 61-73 years). Dates of illness onset ranged from July 25 to December 7, 2001, and 1 case died.

TOTALS

27 States + Washington DC

58 Counties

*Compiled from the Morbidity and Mortality Weekly Report (MMWR) published by the Centers for Disease Control and Prevention (CDC), the United States Geological Survey (USGS), Center for Integration of Natural Disaster Information (CINDI) website, and personal communications with CDC and state health departments. Past and current issues of the MMWR can be viewed online at http://www.cdc.gov/mmwr. The USGS/CINDI website contains updated maps of WNV activity that may be viewed at http://cindi.usgs.gov/hazard/event/west_nile/west_nile.html. Laboratory-confirmed cases reported to GDPH.

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Mosquito Surveillance--
During 2001, only 4 counties had the capacity to collect and identify mosquitoes for virus testing. Three of those counties had positive mosquito pools, as shown in the table below. A single pool of Aedes albopictus (commonly known as the "Asian Tiger Mosquito") from Fulton County tested positive for WNV. Aedes albopictus is a daytime biting mosquito and it is abundant in Georgia. Precautions should be taken to prevent mosquito bites any time mosquitoes are active in an area. Aedes albopictus prefers to lay eggs in artificial containers and the most effective way to reduce populations of this mosquito is to eliminate sources of standing water (birdbaths, flowerpots, tires, etc.). SCWDS is now able perform arbovirus testing on mosquito pools that

County
Chatham DeKalb/Fulton
Fulton Lowndes

#Pools Tested
137 108
461 420

Dates of Collection
9/25/01-12/17/01 8/2001
8/28/01-10/24/01 7/2001

# Pools Positive
0 3
32 1

serum (acute and convalescent samples drawn 2-8 weeks apart). Healthcare providers may request testing for hospitalized patients who meet at least one of the following testing criteria:
1) A diagnosis of viral encephalitis (at least 2 of the following clinical signs):

Fever (greater than 38.0C or 100.4F)

Altered mental status (altered level of consciousness,
agitation, lethargy)

Abnormal CSF (pleocytosis with predominant lympho-
cytes and/or elevated protein, and negative laboratory tests for bacterial pathogens)

Species Positive for WNV
1Culex quinquesfasciatus, 1 Culex quinquesfasciatus-restuans, 1 Culex species 31 Culex species, 1 Aedes albopictus
1 Culex salinarius



Muscle weakness (especially

flaccid paralysis) confirmed by

neurologic exam or by EMG.

2) Aseptic meningitis in patients older

than age 17.

3) Guillain-BarrJ syndrome, especially

with atypical features, such as fever,

altered mental status, and/or

pleocytosis.

are collected and submitted by county or district health departments. Mosquito pools are tested for WN, EEE, SLE, and other arboviruses by virus isolation procedures and polymerase chain reaction (PCR). GDPH now has a medical entomologist on staff to assist district and county health departments with establishing mosquito surveillance programs.
Surveillance for human arboviral infections--
In Georgia, all potential cases of arboviral encephalitis should be reported immediately to the county or district health department, or to GDPH.

To request human testing, a Viral Encephalitis Case Report Form must be completed and faxed to the Notifiable Disease Epidemiology Section (NDES) at 404-657-7517. In addition, a GPHL Microbial Immunology Submission Form (GPHL form #3432) must accompany specimens to the GPHL. Completeness of all forms is essential, and testing will be delayed if the required forms are incomplete.
Test results can be expected in approximately two weeks, and CDC will confirm specimens that test positive. Test results will be sent from GPHL directly to the submitting laboratory or physician. Specific instructions, required forms, and updates may be found on the GDPH website at http://health.state.ga.us/epi/vbd.shtml.

Surveillance for human arboviral infections was greatly enhanced during 2001 with the availability of testing at the Georgia Public Health Laboratory (GPHL). Samples from 172 humans were tested for arboviruses at GPHL during 2001. A total of 8 human arboviral infections were detected in Georgia during 2001: 6 WN (1 death), and 2 EEE (2 deaths).
Onset dates for the WN cases ranged from July 12 to December 7, 2001. Human cases occurring in Georgia as late as December indicates that year-round transmission of WNV is possible in some areas. Mosquito-bite prevention measures should be taken any time mosquitoes are active in an area. The age range of cases was 61 to 73 years, and all 6 cases were hospitalized. Five WN cases were initially diagnosed with encephalitis and one case was diagnosed with meningoencephalitis. The most common symptom after altered mental status was fever; other reported symptoms included muscle weakness and seizures. No human WN cases in Georgia were reported to have coma or acute flaccid paralysis.
Onset dates for the EEE cases were July 12 and August 7, 2001. These cases were aged 70 and 72 years, and both were hospitalized with an initial diagnosis of encephalitis. Symptoms included altered mental status, fever, headache, and coma.
The GPHL will continue to offer an arboviral panel free of charge during 2002. The panel includes testing for antibodies to WN, EEE, WEE, SLE, and LaCrosse/California encephalitis (LAC/CE) viruses. Testing may be performed on cerebrospinal fluid (CSF) or paired

Testing for WNV is not provided at GPHL for persons suspected of having WNV infection on the basis of mild illness, such as fever or headache, and recent mosquito bites. It is unlikely that such persons are infected with WNV unless levels of WNV in the community are high, and, furthermore, persons with mild illness will most likely recover completely. These patients should be advised to seek medical attention if more severe symptoms develop such as confusion, severe muscle weakness, lethargy, severe headache, stiff neck, or photophobia. For testing of outpatients, specimens should be submitted to commercial or hospital laboratories that perform testing for WNV antibodies.
Summary:
Great strides were made to improve arbovirus surveillance in Georgia during 2000 and 2001. Georgia quickly detected WNV when it appeared in the Southeast during 2001; however, public health officials still struggle to address concerns about how to safely and effectively prevent and control this and other mosquito-transmitted diseases. Information obtained from arbovirus surveillance efforts should lead to responsible and informed decisions about mosquito control as well as public education about elimination of mosquito breeding habitats and prevention of mosquito bites.
Please visit the GDPH website (http://health.state.ga.us/epi/vbd.shtml) often for maps, updates, specimens submission instructions, forms, and surveillance summaries.
This article was written by Catherine Rebmann, M.P.H., Stacy Kramer, M.P.H., Mahin Park, Ph.D. and Daniel Mead, Ph.D., M.P.H.

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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

June 2002

Volume 18 Number 06

Reported Cases of Selected Notifiable Diseases in Georgia Profile* for January 2002

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 Mar 2002 2002 37 2583 1 1 55 1334 10 52 27 1 0 3 0 1 0 72 74 5 10 27 26 0 36

Previous 3 Months Total

Ending in Mar

2000

2001 2002

102

132

103

6901

8426

8457

43

32

24

4

2

6

285

231

158

4266

4505

4322

26

30

30

57

165

149

66

105

80

2

3

2

0

0

0

22

22

7

2

5

0

18

5

3

0

0

0

229

211

211

80

71

248

38

28

19

87

70

42

142

162

119

165

231

118

6

6

0

103

85

63

Previous 12 Months Total

Ending in Mar

2000

2001

2002

656

637

611

29192

30740

32710

148

179

154

45

43

49

1362

1147

890

20433

19492

18158

82

90

109

392

484

914

257

392

410

7

11

11

0

0

0

75

53

42

6

5

4

63

39

21

0

1

0

1935

1670

1721

281

330

929

149

114

84

300

273

262

589

550

613

725

773

711

17

21

18

659

667

538

* 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.

AIDS Profile Update

Report Period
Latest 12 Months: 05/01-04/02 Five Years Ago: 05/97-04/98 Cumulative: 7/81 - 04/02

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

0

133

133

3

1484

1487

210

24726 24936

Percent Female
21.8
20.6
17.4

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

48.1

3.0

2.3

11.3

0.8

34.6

41.6

20.2

4.4

18.9

1.3

13.5

47.9

17.6

5.5

13.3

1.9

13.8

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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Race Distribution (%) White Black Other

26.3 66.2

7.5

23.5 73.8

2.7

34.4 63.2

2.4