Transcript Virginia 1992-1999

The Epidemiology of
Tuberculosis
Lex Gibson, Virginia TB Program
TB Infection VS TB Disease
Infection
TB Bacilli in Body
Yes
PPD
Usually Pos.
CXR
Usually Normal
Sputum Smears/Cult
Neg.
Symptoms
None
Infected
Yes
Infectious
No
A “Case” of TB
No
Disease
Yes
Usually Pos.
Usually Abn.
Usually Pos.
Cough, Fever, Wt. Loss
Yes
Often, before treatment
Yes
What is a PPD?
• Intradermal test of .1ml(5TU) of purified
protein derivative.
• Measures TB infection
• False positives(cross reactions, non-specific
in low risk populations)
• False negatives(technique, storage)
• Read in MM of induration
Reading the Mantoux Test
•
•
•
•
Read in 48-72 hours
Measure only raised area, not redness
Measure across the widest area
The diameter of the raised area should be
measured
• Measure and report results in millimeters
Interpreting the results
5mm is positive for those:
– known to have or suspected of having
HIV infection
– close contacts of a person with infectious
TB
– with a chest x-ray suggestive of previous
TB
– who inject drugs(if HIV status unknown)
10 mm is positive for those:
– with certain medical conditions, excluding HIV
infection
– who inject drugs(if HIV negative)
– foreign born persons from areas where TB is
common
– medically underserved, low income populations, including high-risk racial and ethnic
groups
– Residents of long term care facilities
– Children younger than 4 years of age
– Locally identified high risk groups
Determining Infectiousness
• Smear Results
• CXR Findings
• Symptoms
Increased Risk of Transmission
• Infectiousness of Source
• Duration of Exposure
• Environment
• Susceptibility of Contact
Contact Investigation
• Screening individuals who have shared
the same air as an infectious case of
TB
• Investigations are done systematically
• Significant reactors receive a cxr and
are evaluated for Treatment of disease
or preventive therapy
Concentric Circle
Community
Casual/Work
close
Scenario 1
• Twenty-eight year old school teacher has a
positive PPD during a routine screening.
No risk factors for TB. What do you do?
• CXR shows pleural effusions. What's next?
• Obtain sputum, pleural specimen, and
possibly start on multiple anti-TB drugs.
Sputum's are negative but pleural specimen
is sm. Pos.
• Now what do you do?
• Contact investigation- All family members
have negative PPD’s and are asymptomatic,
is further testing necessary?
• Normally not……unfortunately, word
spread through the community that an
elementary school teacher has TB. The
media, parents and school system are
demanding that PPD’s be done on everyone.
What do you do?
• Educate media, parents and school system
• Your initial compromise is to skin test just
one classroom rather than the entire school,
but your health department receives 45% of
its funding from the locality. The city
council/board of supervisors wants to know
why you are refusing to protect their school
children from getting TB. What do you do?
• If political pressure prevails and the entire
school is tested, what might be some of the
consequences?
• This is a low risk population group, greater
than 50% of the positive PPD’s identified
will be false positives. Preventive treatment
with INH exposes the individual to possible
liver damage from the INH
Scenario 2
A sputum smear, culture positive Mtb case is diagnosed in
a large open factory that manufactures circuit boards. Air
is recirculated within the facility. Three other cases have
been diagnosed in the facility during the past three years.
Over 90% of the employees are from the Philippines and
previous contact investigations have demonstrated a 7080% reactor rate. Less than 7% of past positives have
completed an adequate course of treatment for latent TB
infection. All close family contacts are previous positive
reactors. How do you proceed with the investigation?
• Who would you screen and what tools
would you use?
• PPD past negatives in the immediate
vicinity of the case, factory wide symptom
assessment of past positives, and collect
sputums on those with signs and symptoms
TB Advances Over Time
400 B.C.
Syndrome Described
1882
Bacteria Identified
1895
1934
1950
1990
X-Ray Invented
PPD Available
Effective Therapy
DOT
FUTURE ??
Funding Trends
$2,100,000
$2,000,000
$1,900,000
$1,800,000
$1,700,000
1996
1997
Not adjusted for inflation nor salary increases
1998
1999
2000
Global Tuberculosis
• 8-10 Million new cases/year
• 2-3 million deaths/year
• Tuberculosis is the 2nd leading
cause of deaths by infectious
diseases
Tuberculosis in the U.S.
• 15 million infected
• 17,000 + new cases per year
• TB cases decreased steadily until
1985, then increased and has now
begun to decrease again
TB Case Rates
US &Virginia
1987-1999
11.5
10.5
9.5
8.5
7.5
6.5
5.5
4.5
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
3.5
US
Virginia
Epidemiology of Tuberculosis
Virginia-1999
•
•
•
•
•
334 Cases of TB in 1999
4.9/100,000
5000+ people starting INH
77,000+ skin-tests given
4,000+ contacts identified
Virginia Tuberculosis Morbidity
Rate/100,000
Districts 1999
Rate/100,000
< 3 per 100,000
3.1- 5 per 100,000
5.1 - 10 per 100,000
>10 per 100,000
Virginia Tuberculosis Morbidity
# Cases
Districts 1999
Number of TB Cases
77 cases
No Cases
1-5
6 - 15
16 - 30
> 30
Rapp/Rapidan
T. Jefferson
Pitt/Dan
Southside
W. Piedmont
Miles
0
20 40
Miles
0
20
40
Virginia Tuberculosis Morbidity
# Cases
Districts 1999
Number of TB Cases
77 cases
No Cases
1-5
6 - 15
16 - 30
> 30
Rapp/Rapidan
T. Jefferson
Pitt/Dan
W. Piedmont
Miles
0
20
40
Case rates for selected groups
In Virginia(1996)
•
•
•
•
•
•
•
Homeless- 411.3 /100,000
Vietnamese- 159.5 /100,000
Guatemalan- 108.3 /100,000
Korean- 63 /100,000
Philippines-59.9 /100,000
Foreign born- 49.7 /100,000
Nursing & Adult Homes- 39.7 /100,000
Case Rates for selected groups
•
•
•
•
•
•
Chinese- 37.7 /100,000
Corrections- 8.9 /100,000
Hispanic- 26.8 /100,000
>65 years - 17.3 /100,000
U.S. born minorities- 8.1 /100,000
U.S. born whites- 2.1 /100,000
Relative Risk of TB Disease
Selected Populations
1996
U.S. Born Minorities
3.8
Foreign Born
15
Elderly(>64)
4.1
Hispanic
5.3
Asian/Pacific Isl.
13.1
Homeless
Corrections
73.4
1.7
Nursing/Adult Home
7.8
0
10
20
Populations bases on 1990 Census Data
30
40
50
60
70
80
Percent of Total TB by Race
Virginia -1992-1999
45
40
35
30
Hispanic
Asian
Black
White
25
20
15
10
5
1992
1993
1994
1995
1996
1997
1998
1999
US & Foreign-Born TB Cases
Virginia 1992-1999
75
70
65
60
55
50
45
40
35
30
25
1992
Foreign
US Born
1993 1994
1995 1996
1997 1998
1999
% of Total TB By Age Group
Virginia 1992-1999
40
35
30
25
0-14yrs
15-24yrs
25-44yrs
45-64yrs
65+yrs
20
15
10
5
0
1992
1993
1994
1995
1996
1997
1998
1999
% Foreign-Born By Age Group
Virginia 1992-1999
60
50
0-14yrs
15-24yrs
25-44yrs
45-64yrs
65+yrs
40
30
20
10
0
1992
1993
1994
1995
1996
1997
1998
1999
% US Whites By Age Group
Virginia 1992-1999
70
60
50
0-14yrs
15-24yrs
25-44yrs
45-64yrs
65+yrs
40
30
20
10
0
1992
1993
1994
1995
1996
1997
1998
1999
% US Blacks By Age Group
Virginia 1992-1999
40
35
30
25
0-14yrs
15-24yrs
25-44yrs
45-64yrs
65+yrs
20
15
10
5
0
1992
1993
1994
1995
1996
1997
1998
1999
% Foreign-Born By Race
Virginia 1992-1999
80
70
60
50
Hispanic
Asian
Black
White
40
30
20
10
0
1992
1993
1994
1995
1996
1997
1998
1999
% Foreign-born Cases
By Region*
W. Pacific
Americas
Africa
1999
1990
SE Asia
E. Med.
Europe
0
*Based on WHO regions
10
20
30
40
50
Foreign-Born TB Cases
Arrival to Onset of Disease
1995 - 1997
•
•
•
•
•
Less than 1 year
From 1 to 2 years
From 3 to 5 years
Over 5 years
Unknown
36.1%
11.1%
15.3%
31.5%
6.0%
Tuberculosis by Agegroup and Foreign-born
1999
65+
26%
0-4
3%
5-14
1%
15-24
12%
45-64
24%
25-44
34%
US-BORN
52%
FOREIGNBORN
48%
TB/HIV-1999
12
10
• 324 TB Cases Reported
Prior to Death
• 231 (72%) were offered
HIV testing
• 197(85%) were tested
• 16 (8%) were Positive
8
6
4
2
0
15-24 25-44 45-64 65+
Agegroup
% TB Cases Tested with
Drug Resistance 1993-1999
18
16
14
12
10
8
6
1993
1994
1995
1996
1997
1998
1999
% Drug Resistant
Foreign-Born & US Born
1993-1999
90
80
70
60
50
40
30
20
US Born
Foreign
10
0
1993
1994
1995
1996
1997
1998
1999
DOT




The standard of treatment
Where one observes client taking meds
216 patients on DOT in 1999
66.6 % of cases on DOT in 1999
Percent
75
60
45
30
15
0
1992 1993 1994 1995 1996 1997 1998 1999
% TB Cases with Social
Problems that Impact Treatment
1993-1999
25
20
15
10
5
0
1993
1994
Unemploy
1995
1996
Homeless
1997
Etoh/Drug
1998
1999
Quarantine/Legal Isolation
• Intervention of last Resort
• Difficult to Accomplish(weak laws, human
rights issues)
• Limited options for isolation (Corrections)
• Have other interventions been exhausted?