Microbiology M Fisk

19 April 2007

1. Genetic change in pathogen

a. viruses: frequent mutation

b. bacteria

i. acquire virulence via genetic exchange

ii. virulence encoded in pathogenicity islands and on plasmids

iii. organisms that have acquired virulence via horizontal transfer probably include:

Vibrio cholerae, Salmonella, Shigella, Yersinia, and many others

2. Change in host-pathogen ecology

a. host exposure (example - lyme disease)

i. demographics

ii. land use and habitat change of reserviors

iii. climate and pathogen range

b. host interactions and transmission host-host

i. population density

ii. movement/travel (example, globalization)

iii. personal behavior (example, sexual interactions, drug use)

3. Historic role of changes in host-pathogen ecology

a. domestication of animals caused big increase in species jumps

b. military and commercial contact among early Eurasian cultures (~3000 years ago)

c. expansionism over past 500 years

4. What are common traits of emergent pathogens?

a. RNA virus

b. zoonotic

c. vector-borne

d. transmissible between humans

e. found in areas that are experiencing ecological, demographic, social change