Outbreaks of Illness:
2011 End of Year Report
Outbreaks occur when there is an increase in the number of disease cases, above what would normally be expected within
a specific place or group of people and within a certain period of time. In 2011, 148 outbreaks were investigated by
Maricopa County Department of Public Health (MCDPH). Of those 148 outbreaks, 1 was ruled out. This report describes
trends and provides summary statistics for outbreaks occurring in Maricopa County in 2011. For more information, please
contact the Office of Epidemiology at MCDPH (602) 372-2605.
Characteristics of Reported Outbreaks: Maricopa County, 2011
Year Total*

Number of Persons Ill per Outbreak†
2 =Minimum
190 =Maximum
8 =Median

147
*1 reported outbreak was later ruled-out and not
included in this summary
†For cases whom information was available

2011 Outbreaks by Etiology
Gastrointestinal
E. coli
Giardia
Norovirus
Salmonella
Gastrointestinal- Unknown Type

75 (51%)
1 (1%)
1 (1%)
39 (26%)
7 (5%)
27 (18%)

Other
Conjunctivitis
Hand, Foot, and Mouth Disease
Head Lice
Mercury Contamination

17 (11%)
5 (3%)
7 (5%)
4 (2%)
1 (1%)

Rash
Staphylococcal Skin Infection
Scabies

9 (6%)
1 (1%)
8 (5%)

Respiratory
Influenza
Influenza-like Illness
Mycoplasma Pneumonia
Respiratory Syncytial Virus (RSV)
Strep Throat (Type A, non-invasive)
Respiratory- Unknown Type

21 (14%)
3 (2%)
4 (2%)
1 (1%)
1 (1%)
6 (4%)
6 (4%)

Vaccine-Preventable
Pertussis
Varicella

25 (17%)
2 (1%)
23 (16%)

For more information, please visit our website: http://www.maricopa.gov/PublicHealth/Services/EPI/default.aspx
For data requests, please contact: (602) 372-2631

Number of Outbreaks Reported by Month 2009-2011
2009 (n=160)

2010 (n=144)

Number of Outbreaks Reported by Type and Month 2011
(n=147)

2011 (n=147)

Gastrointestinal
30

Respiratory

Vaccine-Preventable

Other

12

25

10

20

Number of Outbreaks

Number of Outbreaks

Rash

15

8

6

10

4

5

2

0

0
Jan Feb Mar Apr May Jun Jul
Month

Aug Sep Oct Nov Dec

Number of Outbreaks by Type and Facility 2011
(n=147)
Gastrointestinal

Rash

Respiratory

Vaccine-Preventable

Jan Feb Mar Apr May Jun Jul
Month

Aug Sep Oct Nov Dec

Percentage of Gastrointestinal Outbreaks by Etiology
2011
Other

30

Number of Outbreaks

25

E. coli
1% Giardia 1%

20
15

Unknown 36%

10

Norovirus 52%
Salmonella
10%

5
0

Type of Facility

For more information, please visit our website: http://www.maricopa.gov/PublicHealth/Services/EPI/default.aspx
For data requests, please contact: (602) 372-2631