Chain of Infection
By: Elizabeth S, Isabelle G, Mallory L, & Ashley M
Causative Agent - Isabelle
-Causative agent: the virus, bacteria, fungus, or protozoan that causes the disease.
-Causative agent if AIDS is the human immunodeficiency syndrome (HIV)
-Causative agent of Mononucleosis is the Epstein-Barr Virus
-Bacterium: Gastroenteritis, Salmonellosis
-Fungi: Tinea, oral thrush
-Helminth (worms): Tapeworm infestation
-Protozoan: Malaria, Toxoplasmosis
-Virus: Comon cold, Hepatitis, polio
Micro organisms
Inside persons own body: endogenous infection
Outside persons own body: exogenous infection
In 1995 TB Killed more people more people worldwide than any other disease
9 million cases
3 million deaths
Reservoir- Elizabeth
Human Reservoirs-
Examples- STDs, measles, mumps, streptococcal, infection, and respiratory pathogens
Real life example: humans were the only reservoirs for smallpox virus, so when they figured that out, they were able to isolate the disease.
Carriers:
-Asymptomatic- don't show signs of disease
- Incubatory- transmit the agent during incubation period before clinical illness begins
- Convalescent- recovered from their illness but remain capable of transmitting to others
- Chronic- continue to hold a pathogen such as hepatitis B, it's in an individual for life
Real life example- A woman named Mary Mallon was an Asymptomatic chronic carrier of Salmonella Typhi. She was a cook in NYC and New Jersey in the early 1900's. She infected dozens of people until she was put in isolation on an island, where she died 23 years later.
Animal Reservoirs-
Zoonosis- refers to an infectious disease that is transmissible under natural conditions from vertebrae animals to humans.
Examples- Brucellosis (cows and pigs), Anthrax (sheep), plaque (rodents) & rabies (dogs, raccoons, bats etc)
Real world example- bubonic plague spread by rodents in early Europe
Environmental Reservoirs-
Plants, soil, and water can spread infection
Examples- fungal agents, and gistoplasmosis
Real world example- Legionnaires are from water supplies in cooling towers and evaporative condensers
Portal of Exit- Mallory
Portal of exit (how the pathogen leaves the host)
-depends where pathogen is located
ex. influenxa virsuses would exit through the respiratory tract and schistosomes through urine, and cholera vibrios in feces
-exits include skin, mucous membranes, respiratory tract, feces, saliva, blood, urine, tears, and sexual excretions
-understanding this can help prevent transimission of the pathogens