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Education Materials > Publications > Self-Study Modules on TB > Module 2 > Study Questions

Self-Study Modules on Tuberculosis

This is an archived document. The links are no longer being updated.

Module 2: Epidemiology of Tuberculosis

Answers To Study Questions

2.1. What happened to the number of TB cases in the United States between 1953 and 1984?

From 1953 through 1984, the number of TB cases reported in the United States decreased by an average of 6% each year.

2.2. What happened to the number of TB cases in the United States between 1985 and 1993?

From 1985 to 1993, the number of new cases increased by 14%.

2.3. Name four factors that have contributed to the recent increase in the number of TB cases.

  • The HIV epidemic
  • Immigration from countries where TB is common
  • The spread of TB in certain settings (for example, correctional facilities and homeless shelters)
  • Inadequate funding for TB control and other public health efforts

2.4. Name eight groups of people who are more likely to be exposed to or infected with M. tuberculosis.

  • Close contacts of people with infectious TB
  • People born in areas of the world where TB is common (for example, Asia, Africa, or Latin America)
  • Elderly people
  • Low-income groups with poor access to health care, including homeless people
  • People who inject illicit drugs
  • People who live or work in residential facilities (for example, nursing homes or correctional facilities)
  • Other people who may be exposed to TB on the job (for example, some health care workers)
  • People in other groups as identified by local public health officials

2.5. Why is the risk of being exposed to TB higher in certain settings, such as nursing homes or correctional facilities?

The risk of being exposed to TB is higher in certain settings because many people in these facilities are at risk for TB. The risk of exposure to TB is even higher if the facility is crowded.

2.6. What are some reasons why rates of TB disease are higher in correctional facilities?

First, many inmates already have TB infection and therefore are at higher risk of developing TB disease. Second, an increasing number of inmates are infected with HIV, which means that they are more likely to develop TB disease if they become infected with M. tuberculosis. Finally, some correctional facilities are crowded, which promotes the spread of TB.

2.7. Name five groups of people who are more likely to develop TB disease once infected.

  • People with HIV infection
  • People with other medical conditions that appear to increase the risk for TB
  • People recently infected with M. tuberculosis (within the past 2 years)
  • People with chest x-ray findings suggestive of previous TB disease
  • People who inject illicit drugs

2.8. What evidence shows that the HIV epidemic has played a part in the recent increase in the number of TB cases? Name four pieces of evidence.

  • The areas that have been the most affected by the HIV epidemic have also reported the largest increases in TB cases.
  • The largest increase in TB cases has occurred among people aged 25 to 44, the age group most affected by AIDS.
  • TB is common among AIDS patients.
  • HIV infection is common among TB patients.

2.9. If a person is infected with both M. tuberculosis and HIV, what are his or her chances of developing TB disease? How does this compare to the risk for people who are infected only with M. tuberculosis?

The risk of developing TB disease is about 7% to 10% each year for people who are infected with both M. tuberculosis and HIV. In contrast, the risk of developing TB disease is 10% over a lifetime for people infected only with M. tuberculosis.

2.10. What is the strongest known risk factor for the development of TB disease?

HIV infection is the strongest known risk factor for the development of TB disease in people with TB infection. HIV infection weakens the body's immune system, making it more likely that a person who has TB infection will develop TB disease.

2.11. Which racial and ethnic groups are disproportionately affected by TB?

Asians and Pacific Islanders, non-Hispanic blacks, Hispanics, and American Indians and Alaskan Natives are disproportionately affected by TB.

2.12. When a child has TB infection or disease, what may be true about the spread of TB in the child's home or community? Name three things.

When a child has TB infection or disease, we learn that
  • TB was transmitted relatively recently
  • The person who transmitted TB to the child may still be infectious
  • Other adults and children in the household or community have probably been exposed to TB; if they are infected, they may develop TB disease in the future

 


Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination - http://www.cdc.gov/tb

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