TB - Worldwide Control, Testing Flashcards
What is primary tuberculosis infection?
Infection with Mycobacterium tuberculosis
Usually through the respiratory tract
In immunocompetent individuals, usually does not manifest into disease but rather stays latent
Worldwide, TB is the number ________ infectious killer.
one or two
________ million people die each year from TB.
Two to three
In the 1800s, TB accounted for ____ percent of deaths in metropolitan areas.
20
What percent of latent TB reactivates?
5% - 15%
M. tuberculosis bacteria can survive macrophage ___________, but not apoptosis.
necrotic death
Describe the four steps of tuberculosis infection.
1) Ingestion by alveolar macrophages
2) Multiplication of M. tuberculosis and accumulation in macrophages
3) Migration of T cells to site of infection
4a) Latent tuberculosis
4b) Decline in immunity and activation of tuberculosis infection
What is considered the highest risk group for tuberculosis skin tests?
HIV-positive individuals
Recent contact with someone who has active TB
Apical fibro-nodular disease consistent with old TB infection
Organ transplant
Anti-TNF-alpha therapy
What is the medium risk group for TB skin tests?
Homeless
Immigrants from high-risk countries
Treatment of latent TB is very effective in ____________.
preventing reactivation
Cross-reactivity occurs _____ years after BCG vaccination.
15
False negativity can occur in skin tests on those with ____________.
T cell deficiencies
Most cases of tuberculosis in the U.S. are among __________.
foreign-born individuals–both in prevalence per 100,000 and in total numbers
There is evidence that vitamin D deficiency ____________.
increases risk of tuberculosis
Why did U.S. TB rates increase in the 80s and 90s?
HIV Increased immigrant population Decline in public health infrastructure Increased nosocomial infections Drug-resistant strains
