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1st
appeared 17 June 1999
Study Links Decline in San Francisco's TB Rates
to Intensified Control Programs
The rates of tuberculosis cases overall in San Francisco, as well as cases due to recently
acquired tuberculosis infection, have declined significantly in recent years, due to the
effects of more intensive control measures, according to a study led by UCSF researchers.
The study, reported in the June 15 issue of Annals of Internal Medicine, is the first
analysis using methodology called molecular epidemiology -- which combines DNA
fingerprinting techniques and conventional epidemiology -- to track the disease within a
defined population and then to determine the effect of interventions designed to halt
tuberculosis. Covering 1991-97, the study examined the rate of TB cases overall within the
City and County of San Francisco as well as rates within high-risk groups, such as persons
infected with HIV.
"We found that the intensified TB control measures established in the early 1990s in
San Francisco were associated with a decrease in TB case rates and in the rate due to
recently acquired infection," said lead investigator Robert M. Jasmer, UCSF assistant
professor of medicine who treats patients in the Division of Tuberculosis Control at San
Francisco General Hospital Medical Center.
Study findings showed annual TB rates decreased from a high of 51 per 100,000 persons in
1992 to 30 per 100,000 in 1997. The rate of cases due to recently acquired TB infection --
known as clustered cases because these persons have identical strains of the TB bacteria
-- decreased per 100,000 from 10 in 1991 to 4 in 1997.
"In San Francisco we had detected a sizable amount of transmission of TB in the early
90s, so TB control measures were established that focused on halting the spread of TB and
especially reducing the number of clustered cases. The intensified TB control measures
focused on preventing transmission and on the use of effective preventive therapy,"
Jasmer said.
Links:
Full UCSF press release
Annals of Internal
Medicine
Study Warns of Drug Resistant
Strains of HIV, TB
Source: Corinna Kaarlela, News
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