HLTB21H3 Chapter 1: Chapters 1, 2, 3
Document Summary
Parasites organism that grow, feds, and is sheltered an or in a different organism and that does not contribute to the survival of its host. Virus ultimate mirco-parasite smaller than bacteria; neither cells not organism; can only reproduce with their host. Marco-parasites composed of many cells; cycles through transmission stages (eggs and larvae) which pass into the external environment. Transmission movement of a parasite from host to host. Incubation period interval of time required for development of a disease. Latent period seemingly inactive period between exposure to an inflection and subsequent illness. Parasite virulence capacity of a parasite to cause disease. Zoonotic infections animal infections that can be transmitted to humans. R0 (reproductive ratio of disease) - how many people one person can affect; # of 2nd infections expected. Main factors that influence the occurrence of a disease: 1. host (immunity, genetics, nutrition) 2. environment (promote exposure) 3. agent (biological, physical, chemical, psychosocial, rate of growth, persistence)
