Epidemiology

What is epidemiology?

Science that deals with when and where diseases occur and how they are transmitted in the human population

What is communicable versus noncommunicable disease?

Communicable diseases are infectious and spread person to person, whereas noncommunicable diseases are chronic and do not transmit

What are fomites?

A non-living object that help spread infections

What are endemic diseases and an example?

A disease that is always present in a population within a georgraphic area; common cold

What is an epidemic disease and an example?

Many people in a given area acquire a disease in a short period of time; COVID-19, HIV

What is a pandemic disease and example?

Spread over the population of many continents; HIV and COVID-19

What is index case?

First case of a disease

What is direct transmission?

Spread between host via direct contact or droplet spread

What is mechanism transmission?

Indirect transmission on the surface of a mechanical vector, like an insect

What is biological transmission?

Indirect transmission via the saliva of a biological vector

What is a host?

An organism that harbors the pathogen

What is a pathogen?

A disease-causing microorganism which needs to come in contact with the host to cause disease

What is a reservoir?

Continual source of infection or disease that can be human, animal, or non-living

What is a carrier?

A person that harbors a disease but is not displaying any sign of disease

What is the formula to calculate infection rate?

number of infected individuals/ population at risk

What is the optimal growth range of psychrophilic bacteria?

15 degree C or below

What is the optimal growth range of psychrotrophic bacteria?

20-30 degree C

What is the optimal growth range of mesophilic bacteria?

25-40 degree C

What is the optimal growth range of thermophilic bacteria?

45-65 degree C

What is the optimal growth range of hyperthermophilic bacteria?

80 degree C or above

What are examples of dry heat?

Hot oven, bunsen burner flame

What are examples of moist heat?

Boiling, pasteurization, autoclaving

What temperature and time are needed for pasteurization?

63 C for 30 minutes or 72 C for 15 sec

What is the temp and time for boiling?

100 C for 10 min

What is the radiant energy spectrum from largest wavelength to smallest?

Radiowaves, Microwaves, Infrared radiation, Visible Light, Ultraviolet, X-Rays, and Gamma Rays

What damage can UV light induce and what fixes it?

Thymine dimer; photolyases

What are the types of UV Light?

UVA, UVB (synthesize Vitamin D), UVC

What are disinfectants?

Chemicals that lower the level of microbes on the surface of inanimate objects.

What are antiseptics?

They decrease the number of microbes on living tissue

What three strains of bacteria are used to do American Official Analytical Chemist Use-Dilution Test?

Samonella enterica, Staphylococcus aureus, and Pseudomonas aeruginosa

What are the characteristics of the genus Pseudomonas?

Gram-negative bacillus with one or more flagella, very diverse, but similarities are non-spore forming, non-coliform, catalase positive, and oxidase variable

What are the characteristics of Pseudomonas aeruginosa?

Oxidase-positive species with one flagellum. Typically create green colonies due to secondary metabolites, increasingly antibiotic resistant, and opportunistic pathogen

What is antibiosis?

Process of one organism inhibiting another

What are two methods of how antibiotics work?

Inhibition of cell wall formation (peptidoglycan) and inhibition of DNA synthesis, which prevents propagation so immune system can fight

What is minimal inhibitory concentration?

The lowest concentration of an antimicrobial agent that inhibits the visible growth of a microorganism

What bacterium is known to be mutualistic on the skin?

Propionibacterium

What type of bacterium is typically a parasitic?

Transient bacterium

What do normal skin microbiota need to be tolerant to?

Salt and dryness

What areas are more bacteria found in on the skin?

Moist areas

What are characteristics of Staphylococcus genus?

Gram positive, catalase producing, and facultative anaerobes

What are the characteristics of Staphylococcus aureus?

Gram-positive microbes on skin and respiratory tract that can be pathogenic. Positive for catalase and nitrate reduction

What do pathogenic Staphylococcus aureus produce?

Coagulase, which activates prothrombin into staphylothrombin, which activates fibrinogen to fibrin.

What plate mimics environment created by the skin?

MSA

What does MSA allow us to do?

Differentiate pathogenic and non-pathogenic species

What type of enzyme breaks down mannitol in MSA plate?

Exoenzyme