Mycobacterium tuberculosis and Tuberculosis (page 4)
(This chapter has 4 pages)
© Kenneth Todar, PhD
of Tuberculosis in the United States (From CDC Division
of Tuberculosis Elimination)
In the United States TB is on the decline. There was a resurgence of TB
from 1986 to 1992, but since 1993, the numbers
of cases have been going down and are now at the lowest they have
ever been. In 2007, a total of
13,293 cases were reported.
Case rates in the U.S. are highest in Hawaii, Alaska, California,
Arizona, Texas, Louisiana, the Southeastern states, New York and New
In 2006, the TB rate declined to 4.4
cases per 100,000 population, the lowest recorded rate since national
reporting began in 1953. Despite this overall improvement, progress has
slowed in recent years; the average annual percentage decline in the TB
rate slowed from 7.3% per year during 1993--2000 to 3.8% during
2000--2007. The proportion of TB cases contributed by
foreign-born persons has increased each year since 1996. In 2007, the
TB rate in foreign-born persons in the United States was 9.7 times
higher than in U.S.-born persons.
Between 1993 and 2006, the number of cases of TB in foreign-born
persons remained virtually level, with approximately 7,000�8,000 cases
each year, whereas the number in U.S.-born persons decreased from more
than 17,000 in 1993 to less than 6,000 in 2006. The percentage of all
cases occurring in foreign-born persons during this period increased
from 29% in 1993 to 57% in 2006.
In many states, especially in the
upper Midwest, and the Northeast, most new cases of TB now occur in
individuals who are foreign born.
Since 1993, there has been a gradual decline in the number
of TB patients with coinfection with HIV.
Primary drug resistance (to at least isoniazid) for the past 13 years,
has remained between 7.0% and 8.4%. However, resistance to at least
isoniazid and rifampin, known as multidrug-resistant TB (MDR TB),
decreased from 2.4% in 1993 to 1.1% in 1997, and remained at
approximately 1%, up to and including 2006.
The number of cases of multiple drug-resistant TB (MDR TB) decreased
from 2.4% in 1993 to 1.1% in 1997, and remained at approximately 1%
END OF CHAPTER
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