Which of the following phrases describes a contagious disease?


a. a disease arising from fomites
b. a disease that is easily passed from host to host in aerosols
c. a disease that arises from opportunistic members of the resident microbiome
d. both a and b

Verified step by step guidance

1. Understand the definition of a contagious disease: A contagious disease is one that can be easily transmitted from one individual to another, typically through direct contact or through the air.
2. Analyze option a: A disease arising from fomites refers to diseases transmitted via inanimate objects, which is not typically considered 'contagious' as it involves indirect transmission.
3. Analyze option b: A disease that is easily passed from host to host in aerosols fits the definition of a contagious disease, as it involves direct transmission through the air.
4. Analyze option c: A disease that arises from opportunistic members of the resident microbiome is not considered contagious, as it involves internal changes rather than transmission between hosts.
5. Evaluate option d: Since only option b describes a contagious disease, option d, which suggests both a and b, is incorrect.

Key Concepts

Contagious Disease

A contagious disease is an infectious disease that can be easily transmitted from one individual to another, typically through direct contact or through aerosols in the air. This type of disease often spreads rapidly within populations, especially in close quarters, and is characterized by its ability to infect new hosts with relative ease.

Fomites

Fomites are inanimate objects or surfaces that can carry infectious agents, allowing for indirect transmission of diseases. While they can play a role in the spread of certain infections, diseases that primarily spread through fomites are not classified as contagious in the same way as those that spread directly between hosts.

Opportunistic Infections

Opportunistic infections are caused by pathogens that take advantage of a weakened immune system or a disruption in the normal microbiome. These infections are not typically contagious, as they arise from organisms that are normally present in the body but can cause disease when the host's defenses are compromised.