Mycobacteria such as those causing tuberculosis can spread by which route?

• A. Airborne transmission via coughing, sneezing, or spit
• B. Direct blood contact
• C. Contaminated food only
• D. Animal bites

Answer: (A)

The concept being tested is how tuberculosis spreads from one person to another. Tuberculosis bacteria are transmitted through the air in tiny particles that are expelled when someone with active pulmonary TB coughs, sneezes, talks, or sings. These small droplets, called droplet nuclei, can stay suspended in crowded or poorly ventilated spaces and can be inhaled by people nearby, leading to infection. This airborne route is why airborne precautions—such as good ventilation, appropriate masking, and, for healthcare workers, respirators—are essential in preventing TB transmission.

The other routes don’t fit TB transmission. Direct blood contact is characteristic of blood-borne infections, not TB. Contaminated food is a common route for various foodborne illnesses but not the typical way TB spreads. Animal bites transmit other zoonotic infections rather than TB.