Epi Chp 2 Flashcards
List examples of direct transmission
A disease that can be transmitted person-to-person (direct transmission) by means of direct contact
List the modes of disease transmission
Direct or in direct
Explain indirect transmission
Indirect transmission can occur through a common vehicle such as a contaminated air or water supply, or a vector such as a mosquito.
What are the three categories of factors that may be associated with increased risk of human disease?
Host characteristics
Types of agents and examples
Environmental factors
Give examples of host characteristics that may be associated with increased risk of human disease
Age, sex, religion, race, customs, occupation, genetic profile, marital status, family background, previous disease, immune status
List types of agents and examples that are associated with increased risk of disease
Biological-bacteria, viruses
Chemical-poison, alcohol, smoke
Physical - trauma, radiation, fire
Nutritional-lack, excess
List environmental factors associated with increased risk of disease
Temperature, humidity, altitude, crowding, housing, neighborhood, water, milk, food, radiation, air pollution, noise
Transmission of disease is determined by what 3 things?
Agent
Host
Environmental factors
PH interventions are directed at ….?
Controlling or eliminating agent at source of transmission
Protecting portals of entry
Increasing host’s defenses
Explain herd immunity
thresholds that stop disease transmission for selected vaccine preventable diseases.
(the percent of the population that has to be vaccinated to allow for herd immunity differs per disease but overall –high 80%-high 90% )
explain why trends for food borne disease outbreaks have increased over the years.
increase in eating out
increased globalizations
increase in raw foods or organic foods
What are the different kinds/classifications of food borne outbreaks
Poison, Bacterial - staph aureus
Infections, Bacterial - salmonella
Viruses - Hep A
Parasites - trichinosis
Plants - mushrooms
Chemical - arsenic, lead, methyl mercury in Japan (Minamata disease- food chain)
Food Additives - carrageenan, mycoprotein
List the symptoms of food poisoning.
Nausea and vomiting
general weakness
abdominal pain/cramping
diarrhea
fever
What is the importance of an epidemic curve?
Incubation period
Time- probable time period people were exposed
Time trend - whether outbreak was time limited or is ongoing, time frame of the epidemic
Pattern of disease spread - the probable mode of transmission
Magnitude of disease - how many are affected
The overall shape of an epidemic curve may reveal what?
Common source - continuous or intermittent exposure
Point source
Propagated
what is the formula for determining the Attack rate?
of people who ate a food and became ill / # people who ate that same food
What are the three critical variables in investigating an outbreak or an epidemic?
when did the exposure take place
when did the disease begin
what was the incubation period for the disease
Give the formula for determining attack rate
Number of people at risk in whom a certain illness develops
_________________________________
The total number of people at risk
What formula is useful for comparing the risk of disease in groups with different exposures?
Attack rate
When trying to determine food specific attack rate what formula should be used?
Total number of people who ate that food
A person who acquires a disease from exposure (e.g. contaminated food) is called what?
Primary case
Define secondary case?
A person who acquires the disease from exposure to a primary case
The attack rate in susceptible people who have been exposed to a primary case are defined as ?
Secondary attack rate
When a disease appears to have occurred at more than an endemic level and we wish to investigate its occurrence we ask what three questions?
WHO was attacked by the disease
WHEN did the disease occur
WHERE did the cases arise
When confronted with several possible causal agents as is often the case in foodborne disease outbreaks, very helpful method for determining which of the possible agency is likely to be the cause is called?
Cross tabulation
