Discuss how poor ventilation and inadequate air circulation increases risk of TB. Discuss what constitutes adequate ventilation.

Explain what all can be a source of TB infection and how the type of source may affect the infectiousness / risk of transmission of disease.

Overcrowding is the situation where people located within a given space are more than what is considered tolerable from a safety and health perspective. Generally in living/ dwelling areas an measure of 50 square feet is the minimum requirement for space per person; less than this is considered overcrowding.

Calculating the floor space per person: The number of persons in the household divided by the total area of the house gives the floor space per person.

Discuss overcrowding and increased population density as a risk factor for TB infection and disease. 

Explain the concept of contact with an infectious case of TB and how it increases the risk of TB.

Tuberculosis is transmitted mainly through the air via droplet nuclei generated when a TB patient coughs or sneezes. 

It is estimated that every sputum smear-positive patient spreads the infection to 10 – 15 persons annually, if untreated..

Figure: Transmission of TB bacteria through air via droplet

Resources:

Environmental conditions have a huge role in the development of TB disease and are an important component of the epidemiological triad for TB disease.

The various environmental factors influencing TB are:

Host factors in TB disease are various factors/attributes of the host(person who is developing TB disease/infection).

The various host factors are as follows:

Mycobacterium tuberculosis (M. tuberculosis) belonging to the family Mycobacteriaceae cause Tuberculosis (TB).

These are rod shaped bacilli and require oxygen to survive (aerobic bacteria).

The following characteristics of these bacilli help them to survive in human body for a long time and resist the action of drugs: