Routes by which a pathogen moves and is transmitted between host.
Chain of infection
Living or non-living object that provide pathogens with conditions for survival, reproduction, and opportunities for transmission. (Human, animal, or non-living)
Reservoirs of infection
Other humans, Mnay people harbor and transmit pathogens to each other.
The main reservoir of disease is?
A person harboring a pathogen and spreading it but with no apparent sign of illness.
Carriers
Diseases that are transmitted from other animal species to humans.
Zoonoses
exposure through direct contact, consumption, animal waste, or contaminated animal products.
Animal reservoir
Includes contaminated soil, water, or other inanimate objects.
Non-living reservoir
Contact, vehicle, and vector transmission
What are the three modes of transmission?
Direct, indirect, and droplet
What are the three contact of transmissions?
Disease agent transferred directly from one individual to another through physical direct contact between source and subject.
Direct contact
Intermediate object
In direct contact there is no?
Person-to-person or animal-to-person
Direct contact is done through?
Kissing, touching, sexual intercourse, coughing, and sneezing
Examples of direct contact
Transmission of disease from reservoir to host via contact with an inanimate, non-living object.
Indirect contact
Fomites
What is indirect contact also known as?
Pathogens transmitted through droplet nuclei in the air over short distances.
Droplet transmission
Coughing, sneezing, talking, and laughing.
Droplet transmission is done by?
Airborne.
Disease that only travel short distances are not considered?
Disease agents transferred through some type of contaminated medium.
Vehicle transmission
Usually contaminated through sewage
Vehicle transmission: Water
Contaminated food products and food poisoning
Vehicle transmission: Food
Contaminated airborne if travels distances more than 1 meter in/on droplets and dust.
Vehicle transmission: Air
Animals that carry pathogens from one host to another host.
Vector
Are not subject to it
Vectors carry the disease but?
Arthropods (insects)
What are the most common vector?
Passive transport via feet or other body parts of vector
Machanical transmission
More active transport and an important part of pathogen life cycle is in the vector. this disease is spread through bites.
Biological transmission
Lyme disease, malaria, leismaniasis, chagas disease
Vector example
An infection/disease that is acqired during a hospital stay.
Nosocomial infections
5-15
What is the % of someone getting an nosocomial infection within a hospital?
Host organism whose restistance to infection has been impaired. Can result in: Other disease, surgery, or burns.
Compromised host
Compromised host, chain of transmission, and microorgnaism in hospital environment.
Why are nosocomial infectiona so prevalent?
Due to antibiotic restistance and aseptic technique.
Why have rate of nosocomial infections increased?
Incubation, prodormal, Illness, decline, and convalesence.
What are the stages of diseases?
Interval between infection and first symptoms.
Incubation period
Short period characterized by mild early symptoms
Prodormal period
Time during which diseas symptoms are most severe and pathogens are at highest concentration.
Illness period
Signs and symptoms slowly decline as immune system clears pathogen and tissues are repaired.
Declined period
return to pre-diseased state and recovery
Covalescence
During the illness and decline stages.
Has the most vulnerability to secondary infections?
All stages but most in illnesss and decline stages.
Periods in which disease can be transmitted
