The Epidemiology Of Tuberculosis Health And Social Care Essay

The purpose of this paper is to inform and educate the reader of the mechanisms that make up the respiratory disease called tuberculosis. This paper addresses the history, the study of the disease, and how it affects the health of the human population and its environmental welfare. This study’s intent is to examine and consider the epidemiology triad, symptoms, diagnostic test, isolation, treatment, Koch’s Postulates, investigation, surveillance, and eradication associated with this respiratory infectious disease.

The Epidemiology of Tuberculosis

Tuberculosis (TB) is a highly contagious disease that if not treated, can be fatal. This infection is known for initiating in the lungs, however it has the potential to affect any and all of the body. The tubercle bacillus or Mycobacterium tuberculosis is the bacterial microorganism the causes TB (Schiffman, 2010). Scientist have traced tuberculosis as far as 2400 BC in spinal fragments of Egyptian mummies and 750 BC in bones found in South American (Medical News, 2010). Throughout the years of discovery of this disease, there have been many names associated with TB: white plague, consumption, dread disease, and the king’s evil. The 19th century, the genesis of the industrial revolution conflicted with a deadly outbreak of tuberculosis that killed one out of every seven individuals infected with the bacterial infection in Europe. Eventually this contagious illness spread to the United States as the large cities became overpopulated (Endreszi, 2009).

Present day, worldwide, there is more than 2 billion infected with TB. In 2007, there was “1.77 million” TB related deaths (World Health Organization [WHO], 2009). Our society has so many potential areas of increased risk for the development of tuberculosis. The Center for Disease Control (CDC) reports that in 2009 there were “11,540 tuberculosis (TB) cases reported in the United States” which is a decrease of 4.2% in 2008 (Center for Disease Control, 2010). Risk of continuation of TB involve HIV illnesses, immigration of persons from areas with high incidence of TB, and the transmission of TB in high risk environments, such as homeless shelters, hospitals, and correctional facilities. These same environments are now reporting multi-drug resistant TB (MDR TB) and extensively drug resistant TB (XDR-TB) with an increase in death rates. MDR TB accounts for “5%” of the reported TB cases,”27 countries” make up “85% of all MDR TB cases,”(WHO, 2009) and 58 countries have been confirmed to have XDR-TB (WHO, 2010). The intention of this study is to examine the epidemiology of TB, Koch’s postulates, surveillance, control, and eradication measures related to tuberculosis.

Epidemiology Triad

The “epidemiological triad” is a tool that consists of an agent, host, and an environment used to explain the spread of disease throughout a community, to identify points of intervention to prevent transmission, and to guide epidemiologic investigations (McMurray, 2007). The agent in this study is Mycobacterium tuberculosis; an acid fast aerobic rod that reproduces slowly and is hypersensative to heat and ultraviolet light. TB primarily effects the respiratory system, however, it can also effect the pericardium, lymph nodes, menges, kidneys, intestines, bones, joints, and reproductive organs (The Merk Manual, 2010). Tuberculosis, a leading worldwide infectious disease killer, killed 1.7 million in 2009. However, “the TB death rate has fallen by 35% since 1990″(WHO, 2010).

The transmission of the Mycobacterium tuberculosis is spread from person to person by airborne droplets with vehicles being coughing, sneezing, and talking. The smaller the droplet, the longer it can linger in the air after the infected person has left the area, allowing incease probablity of inhalation by another person. Passing TB from a family member or co-worker is more likely than a stranger in a store or on the street (Reichler, Reves, and Bur, 2002). Mycobacterium tuberculosis (infectious disease agent) is readily spreaded to susceptible humans (host) through respiratory exposure in communal settings or public gatherings (environment). Individuals with impaired immunities, such as with diabetes mellitus, cancer, corticosteroid therapy, and HIV/AIDs are at greatest risk for acquiring the bacterium infection. In 2008, some Harvard Epimiology students conducted an analysis of 13 separate studies in regards to diabetic patients and the potential elevated risk for TB. Their analysis found that it is prevelant to focus on diabetics as high risk with potential decrease in TB if diabetes can be controlled(Jeon and Murray, 2008). Although, peoples with healthy immune systems are susceptible if exposed for a long period of time, for example healthcare workers. Healthcare staff are continuously exposed to illness in hospital and extended living facilities, which places these professionals at risk for TB. Early detection and treatment of the active infected person is the key to prevention of transmission of tuberculosis in the healthcare setting (Smeltzer, Bare, & Hinkle, 2007). External factors such as the environment can influence the affects of the organism. There are many environments factors that induce the susceptibility of the body for TB, such as: ethnic/racial minority, impoverished, homeless, overcrowded housing, prison systems, and immigrants. The denisity of the bacterium in the air also dictates the potential risk for aqcuiring tuberculosis (Smeltzer, Bare, & Hinkle, 2007).


Latent tuberculosis refers to an individual that has been exposed to the bacterium and can carry the organism in the lungs without any symptoms of tuberculosis. This person can have a positive skin test, a normal chest x-ray, and a negative sputum smear. This individual will not feel sick. A person with active TB can have any, all, or none of the following symptoms: feeling tired all the time, weight loss, loss of appetite, chronic cough, fever, hemoptysis, and or night sweats. This person will have amphoric breath sounds, the chest may exhibit dullness on percussion, and increased tactile fremitus with crackles can be aucultated after coughing. These individuals often feel ill and can easily spread TB to others. The skin test on this person will be positive, and they may have an abnormal chest x-ray and or a positive sputum smear (Center for Disease Control [CDC], 2010).

Diagnostic Test

Several diagnostic studies are available to be performed to determine if Mycobacterium tuberculosis is present. First, the Mantoux skin is performed by injecting 0.1ml of PPD agent subdermally making a wheal to ensure an accurate reading. Errythema and palpable wheal. 5mm is considered a positive reading. Of course, a positive skin test does not always mean the person has active TB and the person could have been exposed in the past. Once a person tests positive with the Mantoux test, he or she should obtain other methods to determine possible exposure. A new test, Quantiferon TB gold blood test is now being used in many hospitals. This test is reportedly for valid than the skin test. A sputum sample is collected after a positive skin test to perform an acid-fast bacilli (AFB) for culture. This culture will determine if Mycoacterium is present in the donor of the sample. The third study requires a chest x-ray to be completed. The x-ray will be viewed for fibrous masses and possible lesions or inflammation related to infection the the upper lobes. A medical evaluation for TB must include a complete history, chest x-ray, and physical examination (Steadman’s Medical Dictionary, 2006). Patients that are probable extended care facility residents much have these tests performed prior to placement. Anytime a patient has an active case, that patient must be contained and specific treatment initiated to prevent an outbreak of the disease.


A confirmed tuberculosis or a susptected confirmation of the disease warrents isolation of the individual to prevent further transmission to others. The following are several control methods to decrease the risk of contamination. The first is an inititiation of AFB precautions immediately for all patients with confirmed or suspected of active TB and who may be infectious. AFB rooms are a single private room with special ventilation systems. Ultraviolet lamps or other methods may be used to supplement ventilation. The second measure is to set up a personal protective equipment (PPE) station outside the room. This station provides N95 disposable particular respirators that each person needing to enter room is required to don prior to entrance into room. These mask require a FIT test to ensure correct size is used for each person. The third measure, is isolation precautions should be continued until there is a decrease in the organisms on a sputum smear or clinical evidence of decreased infection. Fourth measure, if any evidence of medication resistance keep AFB precautions ongoing until there is a negative sputum smear. Special precautions should also be initiated when inducing a cough for smear sample (Smeltzer, Bare, & Hinkle, 2007).


Initiating treatment without delay is the only way TB can be cured. Specialized treatment is based on whether TB is an active disease or only an infections. Someone who has been infected but does not have the disease may require preventive therapy only. This preventive therapy is designed to kill the germs that have the potential to cause harm. Preventive therapy is usually a prescription for a daily dose of isoniazid, which is an inexpensive tuberculosis medication. This preventive therapy last for nine months, with periodic checkups to ensure the medication is being taken correctly. Active TB cases require treatment with effective drugs, such as: isoniazid, rifampin, pyrazinamide, and ethambutol (WHO, 2009). The treatment regiman entales an initial two month treatment phase followed by a continuation phase. The continuation phase is suggested to last four months for the majority of patients but can be extended to seven for a total of nine months. All TB medications should be taken together instead of divided doses (Center for Disease Control, 2003). Taking the medications correctly is very important due to if taken incorrectly patient can become sick and the TB will be more difficult to cure as it becomes drug resistant. Multi-drug resistant TB (MDR TB) is extremely dangerous as the bacteria becomes resistant to the medication used to treat the TB, which makes the treatment ineffective. MDR TB is generally due to the organism becoming restistant to the isoniazid or rifampin, which are the two most important anti-TB medications. Directly oserved therapy (DOT) is utilized to ensure that the patients adhere to the therapy set up for them. DOT is active when a designated person watches the patient swallow each dose of medication. This is a recommend practice for all patients due to unable to determine who will be compliant and who will not (WHO, 2008).

Koch’s Postulates

“In 1890, the German physician and bacteriologist , Robert Koch, released his celebrated criteria for judging” if a specific bacteria is the actual cause for a specific disease (Medicine Net, 2010). Dr. Koch, over one hundred years ago, developed the definitive association of Mycobacterium tuberculosis and the actual tuberculosis disease. The knowledge of the extensive make up of the bacterias, their actions to the body, their life cycles, and their transmission from person to person has been studied and observed by scientist over the last century. The tubercolusis bacteria was used by Koch in formulating “Koch’s postulates,” the systematic series of steps proved a specific organism was indeed the cause of the specific disease (Guyer, nd).

Koch’s postulates are as follows:

The bacteria must be present in every case of the disease.

The bacteria must be isolated from the host with the disease and grown in pure culture.

The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.

The bacteria must be recovered from the experimentally infected host.

In order to find “fulfillment” of Koch’s postulates it is still a requirement for associating an infectious agent with a disease (Medicine Net, 2010).


Every state is required to report active TB cases and suspected cases to the health department by the clinician, infection control nurses, or by the pharmacies when the TB medications are dispensed. Laboratories are also required to report all positive TB smears and cultures. Early reporting is vital to the control of tuberculosis and provides the clinicians access to the resources of the health department for assistance in case management and contact investigation. Health departments routinely conduct contact investigations for all cases of active pulmonary tuberculosis to identify secondary cases of active TB and latent TB infection. This action will eleminate a TB epidemic by initiating therapy as needed during these investigations. Investigations are categorized by the amount of exposure to TB the person obtained. Health department staff notify exposed contacts so that the contact is scheduled for a PPD. A follow up test is recommend three months from the initial test or last exposure. All positive contacts are provided a chest xray, as well as young children and immunocompromised contacts to determine whether they have active TB (Reichler, Reves, and Bur, 2002).


Public health surveillance “is the ongoing, systematic collection, analysis, interpretation, and dissemination of health data” (CDC, 2010). As for any surveillance system, it is a tool for enhancement. This type of tool is to ensure timely detection of the exposure to TB. Nurses, generally the first contact with the health care system, may find themselves tracking and alerting the proper authorities and initiating disease containment programs. The concepts of epidemiology, early detection, and surveillance should be considered (Veenema & Toke, 2006).

World Health Organization 2008 guidelines to reduce TB transmission:

Routine surveillance of reported cases and monitoring outcomes of treatments should be a first line of evaluating epidemiology and control.

All programs should be strong in the performance of the systems used for reporting TB cases so the data reflects accurately the true incidence of TB and its trends. The evaluation process should be supported by appropriate operational research studies.

The analysis of disaggregated surveillance data should be encouraged so as to draw out the maximum information of the TB epidemic and the impact of control measures.

Appropriate computer software should be developed and implemented to improve routine recording and reporting.

Implementation of these specific guidelines prevents a tuberculosis outbreak from occurring. Tracking of infected individuals requires continuous monitoring through clinics and other healthcare facilities. Factors important to monitoring include the person’s age, the area they reside, and other factors to record and report to community.


In 2006, the World Health Organization (WHO) launched the new Stop TB Strategy, a global plan to stop TB. More than twenty-two million patients have been treated under direct observation therapy-based services, since the initial launch. Over 500 groups and organizations have come together to achieve this goal. The strategy consists of plans to reduce TB prevalence by fifty percent when compared to 1990 and total eradication by 2050 (World Health Organization, 2006). In the pursuit to eradicate tuberculosis, there are six components of the stop TB strategies implemented by the World Health Organization.

These are the outlines listed below:

Pursue high quality DOTS expansion and enhancement.

Address TB/HIV MDR/XDR- TB and other challenges.

Contribute to health systems stregthening.

Engage all healthcare providers.

Empower people with T B and community.

Enable and promote research.

Currently, TB is not a candidate for eradication efforts: eradication is defined as the achievement of a status whereby no further cases of a disease occur anywhere and control measures are unnecessary. As long as the epdicemic of untreated HIV infection exist and until a concerned effort is made to control TB in all countries, tuberculosis will increase despite optimal application of currently available TB control technologies (Mississippi Department of Health, 2010).


Since 1953, when the first national report came out, tuberculosis cases have been on a decline. “In total, 13,779 TB cases were reported in the United States in 2006. This represents a 3.1% decline in the rate since 2005” (Center for Disease Control, 2007). The TB infection rate for foreign born people was 9.5 times greater than U.S. born people. Screening foreign born persons as they enter in the U.S. will allow the person to benefit from therapeutic and preventative measures and greatly reduce the risk of spreading the infection to others. These measures will include identifying and completely treating all persons who have active TB, contact investigation to evaluate all persons in contact with TB patient to determine TB infection or disease for appropriate treatment, and screening the populations at high risk for TB to locate persons infected with TB to provide complete therapy in prevention of the investion from progressing to active, infectious disease (Centers for Disease Control, 2010). The CDC indicates that providers need training so they will “think TB” in the first place and become more familiar with the advantages of collaborating with the health department. Public health staff should find more effective strategies to assure that providers are current and remain current with new guidelines for the diagnosis and treatment of TB (American Journal of Infection Control [AJIC], 2007).