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Tufts OpenCourseware
Author: David R. Snydman
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1. General Introduction

The approach to ID requires some degree of detective work ala Bertrand Roche, some knowledge of epidemiology, knowledge of microbiology, and immunology as well as good diagnostic skills. Infections occur in all parts of the body so from a pathophysiologic perspective one needs to understand infection in the context of each organ system in addition to understanding microbiology, immunology and pharmacology.

2. Host Factors

Travel is a significant factor. Malaria prevention varies by geographic region – ie is chloroquine resistant strain present or absent.

Fever in someone returning from a trip to Arizona may be due to Coccidiomycosis.

Sexual behavior is a risk factor for many STD’s. Men who have sex with men will be at risk for HIV. Female sex workers have high rates of STD’s.

Occupational exposures, such as health care workers (TB, HIV, HBV) may be relevant. Underlying diseases such as diabetes may be associated with difficult response to infection. Immunocompromised hosts are subject to endogenous fungi (Candida, Aspergillus).

3. Agent Factors

Covered in microbiology.

4. Environment

Presence of vectors, temperature, and even presence of organism may make one region susceptible to an agent. For example, Eastern Equine Encephalitis is located in Taunton/Lakeville region in Massachusetts.

5. Specimens

There is ability to perform cultures, molecular studies, antibodies, drug levels on blood and body fluids.

6. Ancillary Material

6.1. Readings

6.1.1. Suggested

Schaechter Textbook, Chapter 55; pages 503-512.