HomeMy WebLinkAboutenteric-disease-fact-sheet-alameda-county-2019-2023-adaEnteric Diseases in Alameda County,
2019-2023
Background
Enteric diseases are gastrointestinal illnesses caused
by micro-organisms such as bacteria, viruses, and
parasites; most often associated with ingestion of
contaminated food or water. In California, cases of
many enteric diseases are required to be reported by
providers and laboratories to public health. In 2023, the
most commonly reported enteric diseases in Alameda
County were: Campylobacteriosis, Salmonellosis and
Typhoid Fever, Shigellosis, Giardiasis, and Shiga toxin-
producing Escherichia coli (STEC).
This fact sheet summarizes 2019-2023 probable and
confirmed cases of: Campylobacteriosis, Salmonellosis
and Typhoid Fever, Shigellosis, non-Cholera Vibriosis;
and suspect, probable, and confirmed cases for STEC.
Provider Recommendations
Enteric diseases are underreported;
we encourage testing when suspected
and reporting when identified.
Educate patients on prevention
measures, such as handwashing and
no oral/anal sex when symptomatic.
For healthcare personnel, daycare
workers and food handlers, certain
infections require evidence of
clearance through the public health
department laboratory, by state
mandate.
Perform antimicrobial susceptibility
testing for Shigellosis due to
increasing prevalence of XDR Shigella.
Figure 1. Enteric Diseases Case Rates Among Alameda County Residents, 2019—2023
Table 1. Enteric Disease Case Counts Among Alameda Country Residents, 2019 - 2023
Counts of Disease 2019 2020 2021 2022 2023
Campylobacteriosis 469 245 302 377 532
Salmonella Typhi 9 6 3 11 9
Salmonellosis (Other than Typhoid Fever)268 140 163 236 263
Shiga toxin-producing Escherichia coli (STEC)164 73 102 123 117
Shigellosis 135 72 100 138 214
Vibrio Infections (Non-Cholera)5 10 5 5 9
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Enteric Diseases in Alameda County,
2019-2023
Demographic Category Cases Percent 5-Year Case Rate per 100,000*
Age Group <1 yrs 87 2.0%491.4
1-5 yrs 497 12%535.7
6-17 yrs 497 12%213.9
18-59 yrs 2375 55%271.4
60+ yrs 842 20%258
Unknown 7 ——
Race/Ethnicity African American or Black 278 6.5%183.7
Asian 734 17%145.8
Hispanic or Latino/a/x/e 946 22%266.7
Multiracial 60 1.4%92.1
Native American 6 0.1%—
Pacific Islander 20 0.5%161.8
White 1129 26%251.3
Other/Unknown 1132 26%—
Gender Female 1959 46%249.3
Male 2337 54%308.2
Other/ Unknown 9 0.2%—
Case Counts and Rates
During this 5-year period, 4,305 cases of enteric diseases
were reported to public health in Alameda County, with a
rate of 279 cases per 100,000 residents, but varied by
area (Figure 2). Cases decreased during the COVID-19
pandemic before returning to pre-pandemic rates by
2023. Campylobacteriosis was the most commonly
reported illness, followed by Salmonellosis, Shigellosis,
and STEC (Figure 1).
These counts are just the tip of the iceberg; the burden of
disease is much larger. Only about 1 in 26 to 1 in 33 cases
of Campylobacteriosis, Salmonellosis, Shigellosis, and
STEC 0157 are laboratory-confirmed, and only 1 in 13
Typhoid cases are laboratory-confirmed, meaning the vast
majority of cases go unreported.
Case Demographics
The majority of cases were in
adults, however, case rates
were highest among children
<5 years (Table 1). Children <18
years consisted of 26% of all
cases.
Case rates were highest among
Hispanic/Latino/a/x/e and
White residents, and slightly
over half of cases were among
male residents. Enteric disease
case rates were highest among
parts of Oakland, Emeryville,
and Piedmont (Figure 2).
Table 2. Demographic Characteristics of Enteric Disease Cases in Alameda
County, 2019—2023
*Rates not presented for counts under 10 2
Enteric Diseases in Alameda County,
2019-2023
Clinical Characteristics and Epidemiology
Among cases that provided food history, 75% reported eating food prepared outside of the home
before becoming ill. Of those interviewed, 28% had travelled internationally before onset. One-
third of cases with Shigellosis reported sexual activity before becoming ill. Extremely drug-
resistant (XDR) Shigellosis is emerging in Alameda County. From 2019—2023 there were 8 cases
identified, with 5 of those cases (62%) in 2023. Among STEC cases, the average yearly incidence
rate of Hemolytic Uremic Syndrome (HUS) was 0.7 per 100,000 children, slightly higher than the
US rate of 0.6 per 100,000 children.
Almost all cases ( >98%) were symptomatic, and 18% were hospitalized. Ten out of 32
asymptomatic cases were identified as contacts of a known case. Only three deaths were
reported over the 5-year period; all had bacteremia.
Individuals who work with young children or in food or healthcare settings are considered to be in
a sensitive occupation and require testing for pathogen clearance in a public health laboratory for
certain enteric infections before returning to regular work duties in order to prevent ongoing
transmission; 13% of cases fell into this group. Many of these individuals require work
modifications and/or disability pay while clearing.
Table 3. Epidemiologic and Clinical Characteristics of Enteric Cases, Alameda
County, 2019—2023
Epidemiologic and Clinical Characteristics Case Count (%**)
Travelled internationally, N = 1910 534 (28%)
Ate food from outside house, N = 1723 1269 (73.7%)
Part of known outbreak, N = 1516 82 (5.4%)
Sexual activity prior to diagnosis, N = 448 (Shigella only)156 (34.8%)
Unhoused, N = 2380 30 (1.3%)
Symptomatic, N = 2083 2051 (98.5%)
Hospitalized, N = 1972 353 (17.9%)
Patient died, N = 457 3 (0.7%)
Hemolytic Uremic Syndrome (HUS), N = 579 (STEC only)13 (2.2%)
Required clearance testing, N = 1401 187 (13.3%)
No diagnostic test, N = 2380 43 (1.8%)
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Enteric Diseases in Alameda County,
2019-2023
For questions or additional information, contact:
Alameda County Public Health Department
Acute Communicable Diseases Section
1100 San Leandro Blvd, San Leandro, CA 94577
Phone: 510-267-3250
https://health.alamedacountyca.gov/pr
ogram/acute-communicable-diseases/
Last updated April 7th 2026
Summary
Like many other infectious diseases, the number of reported enteric illnesses decreased during
the COVID-19 pandemic. Campylobacteriosis was the most commonly reported illness, followed by
Salmonellosis. Almost all cases reported symptoms and only a small number identified were not
tested, indicating that many cases of enteric disease go undetected if patients do not see a
provider for their symptoms and get tested. Case rates were highest among children <5 years old,
White and Hispanic/Latino/a/x/e residents, and persons living in Oakland, Emeryville and Piedmont.
Alameda County Public Health Department works to decrease transmission through case
investigations, and clearance testing with work modifications/restrictions of those working in
sensitive occupations.
Figure 2. Enteric Disease Case Rates by Zip Code, 2019—2023
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