HSC 4201 Chapter Notes - Chapter 4: Rocky Mountain Spotted Fever, Pertussis, Lyme Disease
Document Summary
Infectivity the ability of a biological agent to enter and grow in the host. Pathogenicity the capability of a communicable disease agent to cause disease in a susceptible host. Can be further classified according to the manner in which they are transmitted. Disease transmission occurs when a susceptible host and a pathogenic agent exist in an environment conducive to disease transmission. A model to conceptualize the transmission of a communicable disease from its source to a susceptible host. The pathogenic disease producing agent leaves its reservoir (infected host) via portal of exit. Pathogenic agent enters susceptible host through a portal of entry to establish infection. Many variations of the chain of infection depending on the disease agent, environmental conditions, infectivity, and host susceptibility. Reservoir for a diseases may be: case a person who is sick with a disease, carrier one who is well but infected and capable of serving as a source of infection.
