Question

Apply the epidemiology triangle to the following communicable diseases: Tuberculosis

1. Identify the host, agent, and environment for tuberculosis
2. What is/are the route(s) of transmission?
3. What type of immunity is obtained, if any?
4. Describe CHN interventions at the primary, secondary, and tertiary level.
5. What are the barriers to controlling tuberculosis and how can a P/CHN intervene?
6. Identify and post an evidenced-based infographic on tuberculosis

Answer 1

Epidemiology literally means.."The study of what is upon the people."

It is nothing but the study of frequency, distribution,determinents of disease and any other health related issue in human population.

Epidemiological triad is a tool used to explain the spread of the disease throughout a community and has three components

• Agent
• Host
• Environment

​​​​​​Epidemiological triad is helpful in identifying the points of intervention to prevent the transmission.

TUBERCULOSIS :

Agent :

Mycobacterium tuberculosis, an acid fast aerobic rod shaped bacteria which is heat sensitive. This bacteria primarily effects the respiratory system causing PULMONARY TUBERCULOSIS...It also causes extra pulmonary tuberculosis in other sites in the body like lymphnodes, pericardium,bones,joints,kidneys,intestines,meninges etc.

Host :

Man is the host for this disease.. depending upon certain host factors this bacteria effects the susceptible humans and transmitted mainly from one person to other via the respiratory droplets

Environmental factors:

It is seen mostly in people with low socioeconomic status where many people are living in a small area so the spread of infection will be rapid

Spread of disease is also seen in other settings like public gatherings etc.

TRANSMISSION:

This disease is transmitted from person to person via the airborne droplets with vehicles being coughing, sneezing ,talking etc.!

The smaller the size of droplet,the larger time it can linger in the air after the infected person has left the area.

IMMUNITY:

Not all the persons exposed to mycobacteria are susceptible to infection..there is innate immune mechanism to fight against this bacteria

The manifestions of the bacterial infection reflect the balance between the bacteria and the host defence mechanism.

T Cell mediated immunity with CD4 + T cells play an important role in eliminating the organism from the body.

Cytokines,Interferron gamma etc are produced by CD4 T cells after the stimulation by mycobacterial antigens..and in people with the defects in these cells recurrent infections are seen.

Immunity acquired via the BCG vaccine against tuberculosis is more effective than the immunity acquired by the dessimenated infection

PREVENTION:

Primary prevention:

Primary prevention denotes the actions taken to prevent the development of disease in a person without that respective disease.

• Vaccination (BCG vaccine)
• prevent overcrowding
• Residing in highly ventilated areas
• ​​​​​​Taking other simple sanitary measures such as washing hands and wearing a mask when going to attend a tb patient etc.

​​​​​​​Secondary prevention:

This denotes identification of people who have already developed the disease but at the early stage of the disease and these people are identified by screening.

​​​​​​Detection of people with latent TB infection by performing

Tuberculin test

QuantiFERON -TB Gold

These tests are as suggested by CDC

We should perform the tests for high risk population and these people include:

• Health care workers
• Immuno compromised individuals
• People living in over crowded places like jails, joint families living in small home etc
• people who have travelled to TB endemic areas
• Homeless people etc

​​​​​​​Tertiary prevention:

Treatment to people who have already developed the infection..here,we have to identify the people with active tb disease and prevent the spread of infection

Drug combination given is..

isoniazid,rifampin,ethambutol,pyrazinamide.

This combination is given according to age and weight of the patient.

​​​​​​​BARRIERS TO CONTROL TB INFECTION:

Patient:

• Less knowledge regarding his condition
• Social guilt
• No belief in modren medicine
• Any issues with the local health nurse

​​​​​​​ Health care worker:

• Invincibility of health care workers
• personal beliefs regarding direct patient contact
• Less number of provider to patient units
• No proper isolation wards for patients with TB
• No proper PPE provided to the nurse.

​​​​​​​The nurse should try to educate the patient and if the nurse has any saftey issues to deal with the patient then just go to the higher officials and clear their doubts regarding the disease, patient etc.

Hope this answer helps:):)

​​​​​​​I tried to be as informative as possible and tried to present it a bit neat so that it will be easy to understand :):)