Alaska Invasive Bacterial Disease Surveillance Report Group A Streptococcus – 2015

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Background

AIP has conducted statewide surveillance of invasive group A Streptococcus (GAS) since 2000. Beginning in January 2007, invasive GAS became a reportable condition to the State of Alaska Division of Public Health (DPH).  Reports of cases of disease caused by this organism are shared between AIP and DPH.

Population

The population of the State of Alaska in 2015 was 737,625; 144,274 (19%) were Alaska Native people.  Source:  AK Dept. of Labor & Workforce Development population estimates.

Case Definition

An isolate of GAS from a normally sterile site that has been taken from a resident of Alaska. Cases are also included when GAS has been isolated from a wound culture and accompanied by necrotizing fasciitis or streptococcal toxic shock syndrome.

Methods

Participating laboratories send isolates recovered from sterile sites to the AIP laboratory in Anchorage; materials and forms for isolate shipment and data collection are provided to each laboratory by AIP. Demographic and clinical information on the cases are collected from a review of medical records. Annually, AIP asks that each laboratory review their records and provide information on any cases that may have been overlooked.

Invasive Group A Streptococcus Cases
by Race – Alaska, 2015

Race Cases n (%) Age Adjusted Rate* % Male Deaths n (%)
Alaska Native 37 (41) 28 54% 3 (8)
Non-Native† 54 (59)† 8.5 63% 7 (13)
Total 91 59% 10 (11)

*Cases per 100,000 per percent distribution of Alaska 2010 population
†Includes 5 cases for which race was unknown

Invasive Group A Streptococcus, Cases & Rates by Age Group & Race – Alaska, 2015

Alaska Native Non-Native
Age (years) No. Cases Rate* No. Cases Rate*
<2 3 53.9 3 19.2
2-4 1 10.9 0 0
5-18 2 5.2 4 3.8
19-54 16 24 12 7.7
55-64 8 58.5 13 15.3
65+ 7 67.1 11 17.1
Total 37 25.7 54 9.1

*Cases per 100,000 population

Invasive Group A Streptococcus, Clinical Presentations – Alaska, 2015

No. %*
Cellulitis 32 35
Bacteremia 18 20
Pneumonia with bacteremia 9 10
Necrotizing fasciitis 8 9
Osteomyelitis 7 8
Septic arthritis 6 7
Empyema 4 4
Strep toxic shock syndrome 3 3
Other 4 4

*Percent of cases

Invasive Group A Streptococcus emm types
– Alaska, 2015

emm type No. %*
91 23 25
11 12 13
1 8 9
4 4 4
28 4 4
89 3 3
108 3 3
6 2 2
12 2 2
49 2 2
75 2 2
87 2 2
Other† 1 2
unknown 2 4

*Percent of cases
†Includes one case each of emm types 22, 34, 53, 81, 95, 101, 111, 113