NSG/486 Week 4: Communicable and Infectious Disease Control, sample paper

Ten Weeks of Coughing on a Processing Line: A Public Health Nurse's Tuberculosis Contact Investigation

[Student Name]

University of Phoenix

NSG/486: Public Health: Health Promotion and Disease Prevention

Week 4 Assignment

[Instructor Name]

[Date]

The worker, family, plant and figures are a composite written for a model paper. No real patient is described.

A composite 46-year-old man who works on a deboning line at a poultry processing plant had coughed for ten weeks before he went to an urgent care clinic with fever and weight loss. A chest radiograph showed a cavity in the upper lobe of his right lung, and his sputum smear was positive for acid-fast bacilli. Culture later confirmed Mycobacterium tuberculosis. The county health department received the report the next day, and a public health nurse was assigned to his case and to the contact investigation that would follow. Every week he coughed before diagnosis added to the number of people the nurse would need to find, test and, for many of them, treat. This paper describes that investigation as an example of communicable disease control.

The Chain of Infection

The chain of infection explains transmission through six links: the agent, the reservoir, the portal of exit, the mode of transmission, the portal of entry and the susceptible host. For tuberculosis, the agent is Mycobacterium tuberculosis and the reservoir is people with active disease. The portal of exit is the respiratory tract; when a person with pulmonary tuberculosis coughs, speaks or sings, droplet nuclei carrying the bacteria can remain suspended in air for hours. The portal of entry is the lungs of another person, and the susceptible hosts include anyone who shares air with the patient long enough, with young children and people with weakened immune systems at highest risk of progressing to active disease.

Control measures break specific links. Treating the patient with a multidrug regimen, supported by directly observed therapy, removes the reservoir over time. Isolation at home until he is no longer infectious blocks the portal of exit. Finding and treating infected contacts prevents them from becoming the next reservoir.

Defining the Infectious Period

The national guideline for contact investigations recommends that, for a patient with respiratory symptoms, a positive smear and a cavity, the infectious period begin three months before symptom onset (National Tuberculosis Controllers Association & Centers for Disease Control and Prevention [NTCA & CDC], 2005). His cough began ten weeks before diagnosis, so the nurse sets the start of the infectious period at about five and a half months before diagnosis, ending when he begins effective treatment and meets criteria for release from isolation. That window determines which contacts are included.

Finding and Prioritizing Contacts

The nurse interviews the patient in his home, in Spanish with a trained interpreter, to list the places he spent time and the people he shared air with during the infectious period. The guideline prioritizes contacts by the infectiousness of the patient, the closeness and duration of exposure and the contact's own risk of progression (NTCA & CDC, 2005).

High-priority contacts are household members: his wife, his 15-year-old son and his 3-year-old daughter. The daughter is at special risk because young children progress to severe disease more often. Also high priority are three coworkers who shared his car for a 40-minute commute each way, five days a week. Medium-priority contacts are the 28 workers who stood near him on the deboning line and shared the break room. Lower-priority contacts include members of a small church group he attended weekly.

The investigation expands in stages. If the testing of high- and medium-priority contacts shows infection rates above what would be expected in the community, the investigation widens to lower-priority contacts; if not, it may stop. Fox et al. (2013), in a systematic review and meta-analysis of contact investigations, found that a meaningful share of contacts of people with tuberculosis had latent infection and a smaller share had active disease, which supports systematic screening of close contacts.

Testing and Window Prophylaxis

All contacts receive an evaluation for symptoms and a test for tuberculosis infection, either an interferon-gamma release assay or a tuberculin skin test. Contacts with a positive test or symptoms receive a chest radiograph to rule out active disease. Because a test may not turn positive until eight to ten weeks after the last exposure, contacts with a negative first test are retested after that window (NTCA & CDC, 2005).

The 3-year-old daughter's first test is negative, but the nurse follows the guideline for young children and arranges treatment for latent infection while the family waits for the second test, a practice called window prophylaxis. If her second test is also negative, treatment can stop.

Treating Latent Infection

For contacts with latent infection, treatment prevents progression to active disease. Current national guidelines prefer shorter rifamycin-based regimens: three months of once-weekly isoniazid and rifapentine, four months of daily rifampin or three months of daily isoniazid and rifampin, with six or nine months of daily isoniazid as alternatives (Sterling et al., 2020). Shorter regimens have higher completion rates, which matters because a treatment that is not finished does not protect the patient or the community. The nurse arranges the weekly regimen for eligible adult contacts, with doses given in person at the health department or through video directly observed therapy, which fits workers' shift schedules.

Barriers and How the Nurse Addresses Them

Many of the plant's workers are immigrants, some without legal status, and several are afraid that a tuberculosis diagnosis could cost them their jobs or bring immigration consequences. Others cannot miss a shift to come to a clinic. Without addressing these fears, the investigation would miss the people most likely to be infected. The nurse works with the plant's occupational health office and management to offer testing on site during shifts, at no cost and without loss of pay, and she explains to workers, through interpreters and a respected coworker, that the health department does not share medical information with immigration authorities and that latent infection is not contagious and does not prevent a person from working. She also reassures the patient that his coworkers will not be told his name, only that they may have been exposed.

Evaluating the Investigation

The health department judges a contact investigation by a small set of measures that follow each step: the percentage of identified contacts who are evaluated, the percentage of infected contacts who start treatment for latent infection and the percentage of those who complete it. The nurse reports these measures for the high- and medium-priority groups separately, since a high evaluation rate among coworkers means little if the household or carpool contacts were missed. For the patient himself, the key measure is completion of his full course of treatment under directly observed therapy, followed by culture conversion. If any contact later develops active disease, the nurse reviews whether that person was identified, tested and offered treatment in time, since each missed step points to a gap in the next investigation.

Conclusion

Tuberculosis control depends on breaking the chain of infection at every link it can reach: treating the patient with active disease, isolating him while he is infectious and finding the people he may have infected before they become sick. In this composite case, a long delay before diagnosis produced a large contact list, and the public health nurse used the national guideline to set the infectious period, prioritize contacts, test within the right windows, protect a young child with window prophylaxis and offer short treatment regimens. Addressing workers' fears was as essential to the investigation as any test, because contact tracing only works when people trust the nurse enough to be found.

References

Fox, G. J., Barry, S. E., Britton, W. J., & Marks, G. B. (2013). Contact investigation for tuberculosis: A systematic review and meta-analysis. European Respiratory Journal, 41(1), 140-156. https://doi.org/10.1183/09031936.00070812

National Tuberculosis Controllers Association & Centers for Disease Control and Prevention. (2005). Guidelines for the investigation of contacts of persons with infectious tuberculosis: Recommendations from the National Tuberculosis Controllers Association and CDC. MMWR Recommendations and Reports, 54(RR-15), 1-47. https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5415a1.htm

Sterling, T. R., Njie, G., Zenner, D., Cohn, D. L., Reves, R., Ahmed, A., Menzies, D., Horsburgh, C. R., Crane, C. M., Burgos, M., LoBue, P., Winston, C. A., & Belknap, R. (2020). Guidelines for the treatment of latent tuberculosis infection: Recommendations from the National Tuberculosis Controllers Association and CDC, 2020. MMWR Recommendations and Reports, 69(1), 1-11. https://doi.org/10.15585/mmwr.rr6901a1