Week 7 - Epidemiology and Disease Transmission PDF

EPIDEMIOLOGY and DISEASE TRANSMISSION Factors that Contribute to the Spread of Disease 1 Virulence of pathogen 2 Susceptibility of the population...

EPIDEMIOLOGY and DISEASE TRANSMISSION Factors that Contribute to the Spread of Disease 1 Virulence of pathogen 2 Susceptibility of the population 3 Lack of immunization 4 Inadequate sanitation procedures 5 Mode of transmission of the pathogen Reservoirs of Infections any site where the pathogen can multiply or merely survive until it is transferred to the host – Human reservoir – Animal reservoir – Inanimate reservoir Human Reservoir principal living reservoir of disease because many human pathogens are specie-specific. Carrier – harbors the pathogen but have no signs and symptoms  Incubatory Carrier – transmits the pathogen during the incubation period Convalescent Carrier – transmit pathogen during convalescence or recovery period Active Carriers – completely recovered from disease but continue to harbor the Carrier pathogen indefinitely Passive Carriers – carry the pathogen without ever having the disease Animal Reservoir Zoonoses- infectious diseases that humans acquire from animal sources Routes: Direct contact – with infected animal or with domestic pet waste Inhalation – from contaminated hides, fur, feathers Ingestion – contaminated food and water; consumption of infected animal products Injection of the pathogen – insect vector Inanimate (Non-Living) Reservoir e.g. air, soil, food, milk, water, and fomites Fomites – contaminated materials e.g. clothing, bedding, urinals/bedpans, eating and drinking utensils Air – contaminated by dust, smoke, and respiratory secretions of humans expelled into the air by breathing, blowing, sneezing, and coughing  Contact Transmission Vehicle Transmission Vector Transmission MODE OF TRANSMISSION Contact Transmission - spread of an agent of disease by direct, indirect or droplet transmission Direct Contact Transmission person to person transmission of an agent by physical contact (source to susceptible host) no intermediate host involved i.e. touching, kissing, sexual intercourse Contact Transmission… Indirect Contact Transmission from source to a non-living object to a susceptible host Droplet Transmission Microbe spread in droplet nuclei that travels only a short distance ( 1 meter from the reservoir to host  animals that carry pathogens from one host to another Vector Transmission  Control of Epidemic Disease Report cases of communicable diseases to proper agencies Public health education Identification and elimination of reservoirs of infection Isolated disease person Participate in immunization program Help to treat sick person