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Clinical Insights May 11, 2020

Communicable Diseases Series - Tuberculosis Update: Then and Now

According to the National Institutes of Health (NIH) communicable disease is defined as an illness that is caused by bacteria or viruses which is spread from animal to animal, animal to people, people to people (Edemekong & Huang, 2020). Although, not all communicable diseases are reportable; there are many reportable illnesses. To see which diseases are reportable in your state, refer to the statutes and health department regulations of the state in which you reside.

Tuberculosis Update: Then and Now

Tuberculosis (TB) is caused by a bacteria (Mycobacterium tuberculosis) which causes an acute or latent pulmonary illness. TB is curable and preventable (Centers for Disease Control and Prevention (CDC), 2021).


  • Mycobacterium tuberculosis was first isolated in 1882 but is hypothesized to have been around for more than 150,000 years.
  • TB is an infectious/contagious disease among humans.
  • Worldwide, TB is a healthcare burden, one of the top 10 causes of death from a single infectious source
    • Currently infecting 2 billion people worldwide
    • 10.4 million new cases annually, 1.4 million deaths
  • 30 countries account for 87% of the disease
    • India leads followed by Indonesia, China, Philippines, Pakistan, Nigeria, Bangladesh, and South Africa (accounting for 2/3 of the total cases)

(World Health Organization (WHO), 2019 & Barberis, Bragazzi, Galluzzo, & Martini, 2017)

What We Know:

There are two types of TB

Latent TB Infection

  • Positive skin or blood test
  • Normal chest Xray
  • Negative sputum test
  • The bacterium is alive but inactive
  • Not infectious
  • No symptoms
  • If not treated may turn into a disease in a lifetime

TB disease

  • Positive skin or blood test
  • Abnormal chest Xray
  • Positive sputum test
  • Bacteria have overcome immune system defenses and are active
  • Infectious
  • Symptomatic
  • Requires long-term treatment

(CDC), 2012; CDC, 2020; & CDC, 2021)

Risk Factors:

  • Persons with weakened immune systems
  • Persons with recent infection with TB bacteria
    • Close contact with an infected person
    • Children under the age of 5 with positive TB test
    • Groups with high transmission rates (homeless, drug users, HIV)
    • Work within hospitals, homeless shelters, correctional facilities)
    • Immigration from areas with a high rate of TB

(CDC, 2020 & 2021)


  • A bad cough that lasts 3 weeks or longer
  • Pain in the chest
  • Coughing up blood or sputum
  • Weakness or fatigue
  • Weight loss
  • No appetite
  • Chills
  • Fever
  • Sweating at night

(CDC, 2020)


Latent TB

CDC and the National Tuberculosis Controllers Association (NTCA) preferentially recommend short-course, rifamycin-based, 3- or 4-month latent TB infection treatment regimens over 6- or 9-month isoniazid monotherapy. Short course regimens include:

  • Three months of once-weekly isoniazid plus rifapentine (3HP)
  • Four months of once-weekly rifampin (4R)
  • Three months of daily isoniazid plus rifampin (3HR)

(CDC, 2016)

TB Disease

TB disease can be treated by taking several drugs for 6 to 9 months. There are 10 drugs currently approved by the U.S. Food and Drug Administration (FDA) for treating TB. Of the approved drugs, the first-line anti-TB agents that form the core of treatment regimens are:

  • isoniazid (INH)
  • rifampin (RIF)
  • ethambutol (EMB)
  • pyrazinamide (PZA)

(CDC, 2016)


  • Raising awareness of the risk factors

It is important to note: There is are two drug-resistant variants of TB.

  • Multidrug-resistant: Resistant to isoniazid and rifampin
  • Extensively drug-resistant: Rare, resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin) (CDC, 2016)

While the United States (US) continues to have one of the lowest TB rates globally and the US rates in 2019 are the lowest ever recorded, too many people have TB disease. TB prevention and treatment are such that TB will not be eliminated in this century. Ending TB will require a dual approach of maintaining and strengthening current TB control priorities while increasing efforts to identify and treat latent TB infection in populations at risk for TB disease (CDC, 2016).

Healthcare workers are an essential part of eliminating this disease and preventing multi-drug resistant variants. Education about receiving and completing a course of treatment after a TB skin test turns positive is essential to eliminating this disease. Additionally, symptomatic patients will require support as they complete the treatment plan for TB disease. Do your part, support, and educate your patients, friends, and family.

Learn more about TB directly from the Centers for Disease Control and Prevention: Tuberculosis.

Barberis, I., Bragazzi, NL., Galluzzo, L., & Martini, M. (2017). The history of tuberculosis: from the first historical records to the isolation of Koch’s bacillus.
Centers for Disease Control (CDC). (2012). TB elimination: Tuberculosis information for employers in non-healthcare settings.
CDC. (2016). Tuberculosis.
CDC. (2020). Latent TB infection and TB disease. 
World Health Organization (WHO). (2021). Tuberculosis.