Infection

any organism that cannot be seen by naked eye 

Microorganism that causes disease

The presense of microorganisms causing damage to body tissue 

4 stages:

1. incubation period 

2. prodromal stage 

3. invasion period

4. convalescence 

Interval between: Exposure to infcetious agent - Apperance of first symptom 

Microorganism has entered individual and undergone colonization & begun multiplying 

Not enough microorganisms to cause symptoms, can last several hours, days, years 

FLU- 1-2 days

COVID19- 2-14 days 

CHICKENPOX- 1-10 years

Interval between: Exposure to infcetious agent - Apperance of first symptom 

Microorganism has entered individual and undergone colonization & begun multiplying 

Not enough microorganisms to cause symptoms, can last several hours, days, years 

FLU- 1-2 days

COVID19- 2-14 days 

CHICKENPOX- 1-10 years

Apperance of initial symptoms- Often mild ie feeling of discomfort and tiredness

Pathogen continues to multiply, host begins to experience general signs and symptoms of illness 

result from acivation of immune system 

       - Fever 

       - Pain

       - Soreness

       - Swelling 

       - Inflammation 

pathogen is multiplying rapidlym, invading further, affecting tissue at site of initial colonizatin & other areas

immune & inflammatory responses triggered 

specidic symptoms tp pathogen (most obvious and severe) and inflammatory response symptoms 

Individuals immune & inflammatory systems remove infectious agent 

symptoms decline 

(disease may be fatal and enter a latency phase)

resolution of symtoms until reactivation at another time 

can be contagious during all periods of disease 

depends on:

-the disease

-the pathogen 

-the mechanisms by which the disease develops and progresses