Week 3 - Evolution of host resistance and tolerance

Question 1

What is the difference between resistance and tolerance?

Answer 1

Resistance is the ability to prevent infection or limit parasite replication and burden while tolerance is the ability to limit health effect of the parasite without preventing or controlling the infection. They are relative concepts that require data on both the host and parasite performance.

Question 2

What is the difference between a resistant host, a carrier and a tolerant host?

Answer 2

A resistant host is able to prevent infection. A carrier is a more or less healthy host that is capable of transmitting the parasite to other hosts and a tolerant host is infected but managing the burden of infection

Question 3

What are examples of resistance and tolerance?

Answer 3

An example of resistance is the protective immunity conferred by sick cell trait against Plasmodium falciparum.

An example of tolerance is living with helminth infections which can cause malnutrition but the body manages without directly acting on the parasite