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PATIENT DEMOGRAPHICS
Similar to previous years, a majority of TB cases were
male (55.6%), and the largest proportion of TB cases
occurred among adults age 65 years and older (34.7%)
(Table 1). During 2017, one child younger than age five
was diagnosed with TB (Table 1).
OVERVIEW
During 2017, 124 tuberculosis (TB) cases were reported
to Alameda County (excluding the City of Berkeley).
The 2017 TB case rate in Alameda County was 8.1 cases
per 100,000 residents, a 11% decrease from the 2016
rate. The 2017 rate ranks fourth among all jurisdictions
in California and is 55.6% higher than the California
state rate of 5.2 cases per 100,000 residents. Compared
to other Bay Area jurisdictions, the Alameda County
rate ranks lower than San Francisco (12.2 per 100,000)
and Santa Clara (9.6 per 100,000), and higher than San
Mateo (7.1 per 100,000), Solano (5.9 per 100,000), and
Contra Costa (5.4 per 100,000) counties.
Figure 2: Incident TB Cases (2017)
by Place of Birth, Alameda County
Figure 1. Tuberculosis Cases and Rate per 100,000
in Alameda County, 2008-2017
The majority of 2017 TB cases (96.0%) occurred among non-White residents (Table 1). From 2015 to 2017, White resi-
dents in Alameda County had the lowest average annual case rate of 1.6 per 100,000; rates were 14 times higher among
Asian/Pacific Islander (API) (22.3 per 100,000), four times higher among Black/African American (6.8 per 100,000),
and nearly three times higher among Hispanic/Latino (4.4 per 100,000) residents.
During 2017, 85.5% of TB cases were born outside of the U.S. (Figure 2). The most frequent birthplaces remain Philip-
pines, China, India, Vietnam, Mexico, and the U.S. The 2015-2017 average annual case rate for cases born outside of
the U.S. was 22.5 per 100,000, 14 times the rate for cases born in the U.S. (1.6 per 100,000). For 2017 cases born out-
side of the U.S., 62.3% had resided in the U.S for 10 years or more before being diagnosed with TB. A majority of 2017
cases occurred among API residents, regardless of birthplace (44.4% among cases born in the U.S. and 81.1% among
cases born outside of the U.S.).
The largest proportion of 2017 TB cases occurred among residents of Oakland (28.2%), Fremont (21.8%) and Hayward
(12.9%). Five-year average rates continue to be highest in Downtown, Uptown and East Oakland, and South Fremont
(over twice the five-year county average of 8.5 per 100,000) (Figure 3).
Number of
Cases
(N=124)Percent
Average Case
Rate per
100,000
Sex Males 69 55.6%10.2
Females 55 44.4%7.5
Age Group 0-4 yrs 1 0.8%*
5-14 yrs 1 0.8%*
15-24 yrs 11 8.9%10.2
25-44 yrs 30 24.2%7.4
45-64 yrs 38 30.6%18.6
65+ yrs 43 34.7%23.6
Black / African American 10 8.1%6.8
Asian / Pacific Islander 96 77.4%22.3
Amer Ind / Native AK 0 0.0%*
Hispanic / Latino 13 10.5%4.4
White 5 4.0%1.6
Birthplace United States 18 14.5%1.6
Outside of United States 106 85.5%22.5
* 2015-2017 rates for categories with <10 cases are unstable and not presented
Race /
Ethnicity
Table 1. Incident TB Cases (2017) and Annual Average Case
Rates per 100,000 (2015-2017), Alameda County
Tuberculosis Fact Sheet
Alameda County 2017
Philippines
23.1%
China
14.5%
India
13.9%
Vietnam
10.2%
Mexico
7.8%
United
States
6.7%
Other
23.8%
134
156
177
132 136
114 108
139 135 124
9.4
10.9
12.3
9.4 9.5
7.9 7.4
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8.1
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40
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200
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20
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# Cases Alameda County California U.S.
CLINICAL CHARACTERISTICS
Of all 2017 TB cases, 77.4% had any pulmonary
involvement and 22.6% were extrapulmonary
only (Table 2). Of all pulmonary cases, a majority
(57.3%) were acid fast bacilli (AFB) smear-
negative and 70.8% did not have evidence of
cavitary disease on chest radiography. Only 2.4%
of 2017 TB cases were co-infected with HIV, the
lowest proportion in the past five years. The
most common comorbidity was diabetes (24.2%).
DRUG RESISTANCE
Fewer drug-resistant isolates were identified dur-
ing 2017 compared to 2010-2016 (4.8% vs. 6.7-
18.5%). During 2017, six TB cases were resistant
to at least one first-line TB treatment drug
(isoniazid, rifampin, ethambutol or pyra-
zinamide). Of those six, three were resistant to
isoniazid only. Alameda County had one multi-
drug resistant TB case (resistant to both isoniazid
and rifampin) in 2017 compared to none in 2016.
DIAGNOSTIC TESTING
Among 2017 TB cases with any pulmonary dis-
ease, 61.5% received nucleic acid amplification
(NAA) tests at diagnosis, a higher proportion
than among 2016 cases (54.6%). During 2017,
more cases with positive AFB smears received
NAA tests compared to patients with negative
AFB smears (97.2% and 38.2%, respectively), a
higher percentage tested compared to 2016
(89.1% among smear-positive and 29.0% among
smear-negative cases).
SUMMARY
TB remains an important public health problem
in Alameda County. In recent years, CA and na-
tional TB reports have estimated that 80%-85%
of cases occur due to latent TB infection (LTBI)
P a ge 2 T u b e r c u l o s i s F a c t S h e e t
1000 San Leandro Blvd, First Floor, San Leandro, CA 94577
Phone: (510) 667-3096 | Fax: (510) 273-3916
http://www.acphd.org/tb.aspx
Last updated March 21, 2018
For questions or additional information, contact:
Alameda County Public Health Department
Tuberculosis Control Section
reactivation. Alameda County cases may reflect this trend, as the highest rates of disease occur among residents who
have the following indicators of LTBI reactivation: aged 65 years and older; birth place outside of the U.S.; and having
resided in the U.S. for 10 years or more. Another important factor in TB control, aside from LTBI testing and treat-
ment, is ensuring that TB cases are diagnosed early and started on TB treatment. Use of NAA tests for TB diagnosis
has been shown to increase timeliness of TB treatment initiation. During 2017, more Alameda County providers used
diagnostic NAA tests for both smear-positive and smear-negative cases compared to 2016; we continue to encourage
this practice in order to facilitate earlier TB diagnosis and reduce transmission.
Figure 3: Average Annual TB Rates per 100,000 by Zip Code
(2013-2017), Alameda County
Number Percent
Pulmonary only 80 64.5%
Extrapulmonary only 28 22.6%
Both 16 12.9%
Sputum smear Positive 36 37.5%
Negative 55 57.3%
Not done 5 5.2%
Cavitary disease Present 28 29.2%
Absent 68 70.8%
Comorbidities HIV/AIDS 3 2.4%
Diabetes 30 24.2%
End-stage renal disease 2 1.6%
Other immunosuppression*6 4.8%
Any drug resistance 6 4.8%
INH resistance 5 4.0%
Resistance to INH only 3 2.2%
Multi-drug resistance 1 0.7%
Sputum smear positive (N=36)NAAT performed 35 97.2%
NAAT positive 35 100.0%
Sputum smear negative (N=55)NAAT performed 21 38.2%
NAAT positive 8 38.1%
* Due to a medical condition, such as hematologic or reticuloendothelial malignancies or
immunosuppressive therapy, such as prolonged use of high-dose adrenocorticosteroids.
Table 2: Clinical & Laboratory Characteristics of TB Cases (2017)
Alameda County
Drug
resistance
Among cases with any pulmonary disease (N=96)
Site of
disease
Among cases with any pulmonary disease and sputum smear
performed (N=91)
Nucleic Acid
Amplification
Testing
(NAAT)
practice at
diagnosis