Microbiology Chapter 6

Front 1

Define reservoir of infection

Back 1

Sites where pathogens exist and are maintained as a source of infection, once they leave the host (place or location where the pathogen goes)

Front 2

Describe the three types of reservoirs of infection for human diseases.

Back 2

1. Animal reservoirs
2. Human carriers
3. Nonliving reservoirs

Front 3

Contrast human, animal, and nonliving reservoirs and give one example of each.

Back 3

Human carriers - Humans with active diesase are reservoirs of infection. Carriers asymptomatic but infective (w/o symptoms). S. aureus - from normal flora or infected persons by contact. Common cold viruses by inhalation of sneezed particles. HIV direct sexual contact or injection of contaminated products (IV drugs or blood transfusion) **After they get older their immune system gets compromised they are able to get disease**

Animals - Pathogens that infect domesticated or sylvatic (wild animals) can infect humans. Routes - direct contact with animal, animal wastes, eating animals, blood sucking arthropods. Rabies, plague, Brucella abortis, Plasmodium vivax, fungi that cause ringworm by contact with infected dogs and cats.

Nonliving reservoirs - Soil, food, water, air

Front 4

What is zoonotic disease?

Back 4

diseases spread from animal host to humans. >150 known

Front 5

Explain the three methods of disease transmission and give an example of each.

Back 5

*DID*
1. Direct contact - person to person, placental, fecal-oral
2. Indirect contact - formites (inadimate object carries pathogen)
3. Droplet transmission - mucous droplets, airborne transmission >1 meter
*STD example of direct
*Contaminated kleenex or sandwich is indirect

Front 6

Distinguish between direct contact, indirect contact, and droplet transmission.

Back 6

Direct contact - person to person spread; touching, handshaking, animal bite, sexual intercourse (rabies, anthrax, syphilis, genital herpes)

Indirect contact - agent of disease is transmitted from its reservoir to a susceptible host by means of nonliving object (for mite) such as bedding, dishes, money, thermometer, contaminated needles.

Droplet transmission - microbes spread in aerosol droplets (mucus droplets) discharged in air by sneezing, coughing, laughing, talking. Travel short distances (whooping cough, influenza, pneumonia) A meter or less away arms length distance over a meter is vehicle transmission.

Front 7

Distinguish between waterborne airborne and foodborne and vehicle transmission.

Back 7

Waterborne transmission - spread by water contaminated with untreated sewage (cholera) fecal-oral infection is major source of disease in world. **Fecal-Oral route most common**

Food-borne - pathogens transmitted in or on food that has been improperly prepared, cooked, or stored (botulism, tapeworm, and Hep A)

Air-borne - spread of agents in aerosol droplets that travel more than 1 meter from reservoir to host (measles virus, spores born by fungi that cause histoplasmosis)

Front 8

Describe the main differences between biological vector transmission.

Back 8

Vectors are animals that carry pathogens from one host to another; specifically arthropods.

Mechanical - passive transport of pathogens on insects feet or other body part (house flies walk across feces of infected person to food of noninfected person) not required as host by pathogen

Biological - vector such as insect carries pathogen in body; host is often part of pathogens life cycle, transmits pathogen to host when it bites host.

Front 9

Identify and discuss the main factors affecting disease transmission

Back 9

overall health of the host, age 5<70, gender, lifestyle, occupation, emotional state, climate

Front 10

Identify and describe the portal of exit that pathogens take from the host body

Back 10

openings, secretions (nasal, saliva, sputum, respiratory droplets), blood, vaginal fluids, semen, urine, feces

Front 11

Define a compromised host

Back 11

Host competence, risk factors for infection are immunocompromised, lifestyle, occupation, trauma, travel, age.
A person or something having something wrong with them

Front 12

Describe how neutropenia, organ transplants, and burns can affect host.

Back 12

neutropenia - when a person has fewer than normal neutrophils (WBC)
organ transplant - get put on drugs and more vulnerable to disease.
burns - skin is compromised and allows for port of entry

Front 13

Describe three conditions that create opportunities for normal microbiota to cause disease.

Back 13

Opportunistic disease, kidney disease, normal microbiota start turning

Front 14

Explain the "universal precautions" and their role in controlling nosocomial infections.

Back 14

handwashing, proper disinfecting, and cleaning of tubs, showers, bedding, etc. Proper handling of contaminated material. Education of staff

Front 15

Define nosocomial infections, and explain their importance.

Back 15

Hospital-acquired infections which range from mild to severe. A hospital can be seen as a high-density population made up of unusually susceptible people. 10% of patients admitted to a US hospital acquired a nosocomial infection.
1/3 infections are preventable.

Front 16

Define epidemiology and discuss its importance

Back 16

The study of factors and mechanisms involved in the frequency and spread of diseases and other health-related problems within populations of humans, other animals, or plants.

Front 17

Contrast between incidence and prevalence.

Back 17

incidence - of a disease is the number of NEW cases contracted within a set population during a specific time period (100,000/yr)
# new cases / # people @ risk

prevalence - of a disease, is the TOTAL number of people infected within the population at any time (old + new cases)
# of old + new cases / # people @ risk

Front 18

Morbidity

Back 18

number of individuals within a disease during a set period of time divided by the total population

Front 19

mortality

Back 19

number of deaths due to a specific disease during a specific period of time divided by the total population

Front 20

endemic

Back 20

disease that normally occurs at a relatively stable frequency within a given population or geographic area

Front 21

sporatic

Back 21

a disease that appears as a few scattered cases within a population or geographic area (random)

Front 22

epidemic

Back 22

a disease that occurs with a greater than usual frequency within an area population (flu)

Front 23

pandemic

Back 23

when an epidemic occurs on one or more continents at the same time H1N1 flu, aids

Front 24

common source outbreak

Back 24

group of people all exposed to a pathogen. arises from contact with contaminated substances (food, water)

Front 25

propagated epidemic

Back 25

amplification of infection as a result of person-to-person contact (cold/flu person to person contact)

Front 26

What is a nationally notifiable disease?

Back 26

A disease that is well-known. Health departments (local and state), Nationally (CDC) Worldwide (WHO)