ch 14 15
Card Set Information
ch 14 15
What are the three major factors that lead to opportunistic infections?
1. Failure of host's normal defenses (weak, unable to fight)
2. Microbe got into a wrong part of the body
3. Disturbance in Normal Microflora = super infection
How are diseases interact with population (refer to chart)
1. Endemic - low rate in population
2. Epidemic - higher than normal rate
3. Pandemic - disease high globally, spreading world wide.
Blood stream - terminology
*bacteremia - bacteria in blood
* toxemia - toxic in blood
*viremia - Virus in blood.
*Septicemia - bacteria reproducing in the blood, AKA (blood poisoning, systemic infection)
five steps of how microbe cause disease
1.Has to gain access to a host
2.Has to adhere to the host
3.Has to penetrate into a host
4.Has to evade the host immune response *with coaggulase*
5.Has to cause damage to the host
a. Direct damage b. Accumulation of toxic waste products
What are the 3 portals of entry? which is most common?
Respiratory Route, Gastrointestinal Route, and Genitourinary Route --- Respiratory tract is the easiest
Reservior of Infection
Humans, other verterbrates, and non living items
disease spread from person to person
Virulence and how it's measured
The degree of pathogenecity, ID --- dose to get 50% of population sick. LD --- toxins, dose required to kill 50% of population...
*higher dose = less virulence!
4 enzymes that penetrate the immune system
1. Hyaluranidase - separate the tissue. spread of infection
2. Coagulase - forms blood clots, shield themselves from immune cells (HELPS EVADE FROM HOSTS IMMUNE SYS.)
3. Kinase - breaks down blood cloth; allow them to continue to invade
4. Collagenase - breaks down collagen, breaks conntective tissue to invade
3 types of exotoxins
1. A-B toxins (A= active, B = binding).
2. Membrane - disruption toxins. (kill WBC, RBC)
3. superantigens - type 1 toxin = intense immune response