Georgia epidemiology report, Vol. 23, no. 2 (Feb. 2007)

February 2007

volume 23 number 02

Statewide Increase in Shigella Infections Georgia 2006

Introduction Shigellosis is a bacterial infection most commonly spread person-to-person, but it also has the potential to be transmitted through food and water. Symptoms include diarrhea, which can sometimes be bloody, as well as fever and abdominal cramps. The most common species are Shigella flexneri and Shigella sonnei. Shigellosis has a cyclical nature in Georgia, with large statewide increases (or epidemics) occurring every 4 to 7 years (Figure 1). Peaks are driven by Shigella sonnei infections in primarily daycare and elementary-aged children. Shigella sonnei has a very small infectious dose, leading to efficient personto-person transmission. The following article describes the current statewide increase that began in 2006.
Epidemiology Between January 1, 2006 and December 31, 2006, 1,377 cases of laboratory-confirmed Shigella infections were reported to the Georgia Division of Public Health--two times more than were reported in 2005 during the same time period. The geographic distribution of cases has shifted in the past few years (Figures 2-4). The rates in south and southeast Georgia have increased the most dramatically in the last year. In 2004, most counties in south and southeast Georgia had rates of less than 4 cases per 100, 000 (Figure 2). These rates increased slightly in 2005

and dramatically in 2006. In fact, in 2006, certain counties have experienced rates that are over 30 times higher than the previous year. The Georgia counties with the highest rates of Shigella infections in 2006 are Clinch, Pierce, and Ben Hill counties, and 44 counties had rates greater than 14 cases per 100,000 population (Figure 4). In contrast to the current geographic distribution of shigellosis cases in southern Georgia, the previous Shigella increase in 2001, occurred in the Atlanta metropolitan area, then spread to other parts of the state (1). In addition to the geographic shift, the racial distribution among Shigellosis cases has also changed. From 2005 to 2006, the percentage of African American cases increased from 41% to 47% respectively. However, both years showed a disproportionately high number of African American cases compared to the Georgia population.
In 2006, among the 1,267 Shigella isolates reported with a known species, 94% were Shigella sonnei. There are significant epidemiologic differences between Shigella sonnei and Shigella flexneri infections. In 2006, the majority of Shigella sonnei infections occurred among children attending daycare and elementary school, and in their parents and teachers. The median age of Shigella sonnei cases was 6 years and 55% were

# of c#aofsCeasses

Figure 1: Shigella cases per year, GA 1990-2006*
2000
1800
1600
1400
1200
1000
800
600
400
200
0 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006*
*Year (2006 data through 12/13/2006) Includes all species
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Figure 2: Shigella Infections, GA, 2004

Figure 3: Shigella Infections, GA, 2005

female. For Shigella flexneri, the median age of cases was 22 years and 71% were male. While Shigella sonnei cases are distributed throughout Georgia, 66% of the Shigella flexneri cases occur in the 20 county metropolitan statistical area of Atlanta. These differences between the two species may reflect the occurrence of Shigella flexneri infections among men who have sex with men (Text box 1) (2).
Treatment of Shigella Infections Antimicrobials have a limited role in the control of epidemic shigellosis and should be reserved for patients with severe disease or for high-risk contacts of infected persons (e.g. daycare center attendees, workers in day care centers, and foodhandlers). Patients should follow their healthcare providers' advice about antibiotic treatment. Although antibiotics are effective in reducing duration of illness and eradicating the organism from stool, Shigella organisms can acquire antibiotic resistance rapidly. In 2005, 466

Shigella isolates were submitted to the Georgia Public Health Laboratory (GPHL) for antimicrobial resistance testing. Over 85% of Shigella isolates were resistant to ampicillin; 25% were resistant to trimethoprim-sulfamethoxazole .
Public Health Response Epidemiology and communicable disease staff in the 18 Georgia Health Districts are responsible for investigating cases of shigellosis. All cases of shigellosis in Georgia residents are reportable, and we request that all Shigella isolates be sent to GPHL for confirmation, speciation, and pulsed field gel electrophoresis. During epidemic years like 2006, Shigella infections cluster in daycare or school settings, and then spread to the rest of the community. Interviewing young children (or their guardians) with Shigella infections is a priority, so that we can obtain specific information about school and daycare attendance, and detect such clusters early.

Division of Public Health http://health.state.ga.us
Stuart T. Brown, M.D. Director
State Health Officer

Epidemiology Branch http://health.state.ga.us/epi
Susan Lance, D.V.M., Ph.D. Director
State Epidemiologist

Georgia Epidemiology Report Editorial Board
Carol A. Hoban, M.S., M.P.H. Editor Kathryn E. Arnold, M.D.
Cherie Drenzek, D.V.M., M.S. Susan Lance, D.V.M., Ph.D.
Stuart T. Brown, M.D. Angela Alexander - Mailing List Jimmy Clanton, Jr. - Graphic Designer
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Two Peachtree St., N.W. Atlanta, GA 30303-3186 Phone: (404) 657-2588
Fax: (404) 657-7517

Georgia Department of Human Resources
Division of Public Health

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

Figure 4: Shigella Infections, GA, 2006

References
1. Georgia Epidemiology Report. 2002; 18(4):1-3. 2. Shiferaw B et al. Trends in Population-Based Active
Surveillance for Shigellosis and Demographic Variability in FoodNet Sites, 19961999. Clinical Infectious Diseases 2004; 38(Suppl 3):S17580.

Hand washing and environmental cleaning and disinfection are the main preventive measures to stop the spread of shigellosis in institutional settings. Some circumstances require additional measures. Food handlers must be restricted from food handling if they are ill with a Shigella infection. Specific medical or public health follow-up is required before food handlers can return to their duties. Additional stool cultures to ensure that the patient is not still carrying the bacterium in the stool, are sometimes necessary. A child under the age of 5 usually should not return to day care unless two stools are negative for Shigella infection. The Georgia Division of Public Health can coordinate this stool testing at GPHL free of charge. Please notify your local health department if you have diagnosed a food handler or young child with Shigella infection, because prompt public health follow up may prevent additional cases of illness. If possible, please have the name of the daycare or school available for the Public Health representative. To request hand washing posters from the Georgia Division of Public Health, please call 404-657-2588.
Authors: Melissa Tobin-D'Angelo, M.D., M.P.H., Stepy Thomas, M.S.P.H., Carrie Shuler, D.V.M., M.P.H., and Jennifer Gillespie, M.P.H.

Text Box 1: Epidemiology of Shigella flexneri in Georgia

Epidemiology of Shigella flexneri infections in Georgia



Less commonly reported than S. sonnei



Infections are reportable to Public Health



Documented outbreaks among men who have sex

with men (MSM) worldwide



Investigation in Metropolitan Atlanta among black

MSM during 20042005 revealed:

o Among metro-Atlanta men, black men had

significantly higher rates of S. flexneri infec-

tion compared to white men

o Among black men, metro-Atlanta men had significantly higher rates of S. flexneri infection compared to men living outside Atlanta

o Case-patients were often uninsured, but still accessed medical care

o Washing hands before and after sex might help prevent infection

o Possible increase risk of infection among HIV-positive MSM



Recommendations:

o Educate clinicians to discuss sexual practices

with patients with enteric infection

o Educate MSM population on the risk of Shigella fecal-oral transmission

o Stress washing hands before and after sex

o Expand enteric surveillance activities to include questions about sexual preference and behaviors

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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

February 2007

Volume 23 Number 02

Reported Cases of Selected Notifiable Diseases in Georgia Profile* for November 2006

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 November 2006
2006 45 2873 23 2 45 1500 11 3 14 5 1 1 0 0 0 142 221 7 17 9 37 0 41

Previous 3 Months Total

Ending in November

2004

2005 2006

154

130

149

8234

8272

9154

61

57

112

7

10

14

262

212

211

4060

4126

4892

17

23

23

61

31

8

104

42

42

6

15

11

0

1

1

5

3

5

2

0

0

8

10

7

0

0

0

608

713

642

169

299

614

24

40

16

110

142

94

73

109

45

228

234

167

1

1

0

120

134

125

Previous 12 Months Total

Ending in November

2004 2005

2006

592

597

575

34344

33106

37559

189

150

282

23

32

44

911

746

684

16022

15762

18871

118

114

116

337

139

53

451

224

185

41

39

31

12

6

8

20

18

16

2

1

5

31

51

26

1

0

0

1968

1949

1861

669

668

1334

123

135

112

483

547

420

413

398

326

862

967

898

6

3

7

523

517

510

* 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

Disease

Period Classification

Latest 12 Months**: 1/06-12/06

HIV, non-AIDS AIDS

Five Years Ago: HIV, non-AIDS
1/02-12/02 AIDS

Cumulative:

HIV, non-AIDS

Total Cases Reported*

<13yrs

>=13yrs

Total

21

2860

2881

13

2,118

2,131

-

-

-

1

1,551

1,552

242

9666

9908

Percent Female
30 27 25 34

MSM 30 32 39 30

Risk Group Distribution

IDU MSM&IDU

HS

Unknown Perinatal

8

2

14

45

0.6

7

3

12

45

0.5

-

-

-

-

-

9

3

16

32

-

8

3

12

47

1.6

White 20 20 20 22

Race Distribution

Black

Hispanic

75

4

74

5

-

-

75

5

74

3

Other 1 1 <1 1

Yrs - Age at diagnosis in years

MSM - Men having sex with men

IDU - Injection drug users

HS - Heterosexual

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

** Due to a change in the surveillance system, case counts may be artificially low during this time period

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