2. Disease Reservoirs and Transmission

mode of transmission

In disease prevention, knowing the ________ ____ _________ is generally more important than identifying the specific agent.

disease transmission

_________ __________ is a result of the interaction between the host, agent, and environment. This is referred to as the “epi triangle.”

epi triangle

Disease transmission is a result of the interaction between the host, agent, and environment. This is referred to as the “______ _________”

reservoir, mode of transmission

The chain of infection

1. pathogenic microorganism

2. __________

3. portal of exit

4. _________ ___ _________

5. portal of entry

6. host susceptibility

exit, entry

The chain of infection

1. pathogenic microorganism

2. reservoir

3. portal of ______

4. mode of transmission

5. portal of ______

6. host susceptibility

host susceptibility

The chain of infection

1. pathogenic microorganism

2. reservoir

3. portal of exit

4. mode of transmission

5. portal of entry

6. _______ ____________

latent period

Period after exposure during which the microbial agent is replicating, but has not reached sufficient numbers for the host to become infectious.

incubation period

Period after exposure during which the microbial agent is replicating, but the host is not yet symptomatic.

false

(TRUE/FALSE): The incubation period and latent period are closely correlated.

contagious

A ____________ disease is transmissible from one human/animal to another via direct or airborne routes.

Communicable

A ______________ disease is caused by an agent capable of transmission by a direct, airborne, or indirect route (vehicles/vectors) from an infected person, animal, plant, or contaminated inanimate reservoir.

True

(TRUE/FALSE) Distinguishing between contagious and communicable diseases is important for disease control.

Reservoir

Habitat in which an infectious agent normally lives, grows, and multiplies.

false

(TRUE/FALSE): A contamination of a cave with Pseudogymnoascus destructans (the agent of white nose disease) makes that cave a reservoir.

false

(TRUE/FALSE): A population of butterflies follow the same migration pattern from year to year, breeding periodically and continuing their travels using genetic memory. A pathogenic fungus has established itself in one of their breeding grounds. Many of the butterflies die. When the population returns the next year, the fungus appears to be gone. The breeding ground functioned as a reservoir.

true

(TRUE/FALSE): A population of butterflies follow the same migration pattern from year to year, breeding periodically and continuing their travels using genetic memory. A pathogenic fungus has established itself in one of their breeding grounds. Many of the butterflies die. When the population returns the next year, a similar event occurs. The breeding ground functioned as a reservoir.

true

(TRUE/FALSE): Wildebeast are natural carriers of AHV-1, Malignant Catarrhal Fever, in Africa. Epizootic surges coincide with wildebeast calving. The adult Wildebeast have a cell associated infection that is not horizontally transmissible. The young carry the infection in a cell-free state in their secretions. Cattle are routinely infected through interactions with Wildebeast. The Wildebeasts are a reservoir.

reservoir

A __________________ must

1. be naturally infected with the pathogen

2. maintain the pathogen over time (year-to-year; generation to generation)

3. can transmit the disease to a new, susceptible host

false

(TRUE/FALSE): Animals acting as reservoirs are symptomatic.

acceptable level of control

When thinking about reservoirs from a practical disease control standpoint, the first question to ask is: can we establish an ________ ________ ___ _______ without consideration of a reservoir?

populations

When thinking about reservoirs from a practical disease control standpoint, if an acceptable level of control cannot be accomplished without establishment of a reservoir, epidemiologists must determine what ____________ constitute the reservoir.

false

(TRUE/FALSE): All sick animals are reserviors

false

(TRUE/FALSE): Asymptomatic animals are not infectious.

true

(TRUE/FALSE): Clinically ill animals that are reservoir competent are probably infectious.

Typhoid Mary

_______________ __________, an Irish immigrant who worked as a cook in the early 1900s, is a famous example of an asymptomatic carrier.

Snow

Dr. John ________’s cholera map was the first known epidemiological spot map.

anthrax

Dr. Koch first isolated and infected naiive animals with the bacterium responsible for ___________ to prove it as the causative agent of disease. This was the beginning of modern germ theory.

germ theory

Dr. Koch first isolated and infected naïve animals with the bacterium responsible for anthrax to prove it as the causative agent of disease. This was the beginning of modern _______ ________.

malaria

Ronald Ross discovered that ____________ was transmitted by mosquitoes in 1897.

yellow fever

Walter Reed discovered that _________ ________ was transmitted by mosquitoes in 1900.

Severity is dose dependent

Why did the individual who pressure washed the game chamber after the hare hunt die when others who were exposed to tularemia did not?

index patient

The first individual diagnosed with a disease in an outbreak.

retrospective

The investigation into the Tularemia outbreak in Germany was performed as a ______________ cohort study.

cohort

The investigation into the Tularemia outbreak in Germany was performed as a retrospective __________ study.

case definition

Criteria used to determine if someone is affected by a disease or condition.

Outbreak

A sudden rise in the number of cases of a disease.