microbio exam 2

A virus first interacts with a host cell during the attachment process that precedes viral entry into the cell. Which of the following are possible consequences of the specific interaction between viral attachment sites and host cell surface receptors?

-A particular virus may be able to infect humans but not mice.

-Some people are naturally (innately) resistant to certain viral infections.

-Viral infection of a cell may be prevented by blocking the attachment sites on a virus with antibody.

-A particular virus may be able to infect a liver cell but not a lung cell.

-Viral infection of a cell may be prevented by blocking the receptor sites on a host cell.

Select strategies that are likely to interfere with viral infection and replication but will NOT damage the normal functioning of host cells.

-blocking host cell receptors that serve as sites for viruses to attach

-blocking attachment sites on the virus surface

-inhibiting the release of viruses from the host cell

-inhibiting viral-encoded DNA polymerasei

A feature that may be found in viruses but never in bacteria is

-may contain and rna genome

How do all viruses differ from bacteria?

viruses are not composed of cells

Viruses are the only known infectious agents that are obligatory intracellular parasites.

false

Viruses that utilize reverse transcriptase belong to the virus families

Hepadnaviridae and Retroviridae

Which of the following is NOT utilized to culture viruses?

culture media

Each of the following can be used for the detection and/or identification of viruses except _____________

fermentation test (they dont ferment sugars)

Lysogeny can result in all of the following EXCEPT

Immunity to reinfection by any phage.

An envelope is acquired during which of the following steps?

Release

Which of the following places these items in the correct order for DNA-virus replication?
1. Maturation
2. DNA synthesis
3. Transcription
4. Translation

2341

Most RNA viruses carry which of the following enzymes?

RNA-dependent RNA polymerase

Dogs do not get measles because their cells lack the correct receptor sites for that virus.

true

Oncogenic viruses

cause tumors

Which of the following statements regarding latent viral infections is true?

Latent infections can persist for years in an individual without causing any symptoms.

A persistent infection is one in which

The disease process occurs gradually over a long period.

An infectious protein is a

prion

Which of the following statements concerning prion diseases is true?

Normal host cellular prion proteins (PrP^C) are converted into scrapie proteins (PrP^Sc).

This activity asks you to identify Koch’s postulates for determining the etiology of infectious diseases.

Which statements accurately describe Koch’s postulates?

-The pathogen must be isolated from the diseased host and grown in pure culture.

-The same pathogen must be present in every case of the disease.

-The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible laboratory animal.

-

The pathogen must be isolated from the inoculated animal and must be shown to be the original organism.

This activity presents experimental results obtained when a suspected pathogen was tested and asks you to identify appropriate conclusions based on each scenario.

A rabbit was found to have floppy ear disease, which causes long-ear infections. Its etiology (cause) is unknown. Unknown Microorganism X from the infected rabbit’s right ear is successfully isolated and cultured on laboratory growth media. The ear of a healthy laboratory mouse is then inoculated with isolated microorganism, and after a period of time, no disease is observed.  Which of the following statements accurately describe(s) the conclusion(s) that can be drawn from this experiment?

-A laboratory mouse might not be an appropriate, susceptible host; an experiment with a laboratory rabbit may be needed

-Microorganism X might not be linked to floppy ear disease, because the inoculated mouse remained healthy.

This activity asks you to sort statements that describe the benefits and limitations of using Koch’s postulates to determine the etiology of infectious diseases.

Benefits:

-the steps ares designed to link a pathogen to a specific infect disease

-lab findings provide experimental evidence that support the germ theory

-healthy susceptible animals can be used as model organisms for testing many infections

Limitation:

-some pathogens cause several diff diseases, so it harder to link one pathogen

-some infectious agents have specific growth requirement that prevent them from being artificially cultured in lab

-diff pathogens can produce the same signs and symptoms, making it difficult to dtermine which microorganism is causing a disease

Which of the following statements concerning pathology, infection, and disease is true?

Pathology refers to the study of structural and functional changes that occur in the body as a result of a disease.

Transient microbiota differ from normal microbiota in that transient microbiota

short amt of time

Which of the following is NOT an example of microbial antagonism

bacteria causing disease

The yeast Candida albicans does NOT normally cause disease because of

antagonistic bacteria

the rise in herd immunity amongst a population can be directly attributed to

vaccinations

epidemic level

highest level

Which of the following are a predisposing factor of disease?

occupation, genetic background, climate, lifestyle

hich of the following statements about the development of infectious diseases is correct?

The period of convalescence is the time during which the person regains health and fully recovers (back to the pre-disease state).

Biological transmission differs from mechanical transmission in that biological transmission

involves reproduction of a pathogen in an arthropod vector prior to transmission.

the situation

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever ≥ 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.

a zoonosis

A cold transmitted by a facial tissue is an example of

fomite

Which one of the following does NOT contribute to the incidence of healthcare-associated infections?

gram neg cell walls

Which of the following can contribute to postoperative infections?

using syringes more than once, normal microbiota on the operating room staff, errors in aseptic technique, antibiotic resistance

As a health care worker, you are keenly aware of how important it is to avoid harming patients. You worry about inadvertently transmitting an infectious disease to an already compromised individual. According to the CDC, what is the most important thing you can do to avoid this?

wash hands before and after

Emergence of infectious diseases can be attributed to all of the following EXCEPT

-climatic changes.

-ease of travel.

-new strains of previously known agents.

-antibiotic resistance.

-The emergence of infectious diseases can be attributed to all of these (CORRECT)

Which of the following definitions is INCORRECT?

secondary infection: a long-lasting illness

primary infection: an initial illness

chronic: a disease that develops slowly and lasts for months

acute: a short-lasting primary infection

inapparent: infection characteristic of a carrier state

secondary infection

Which of the following statements is FALSE?

Antimicrobial therapy for hemodialysis-associated infections increases antibiotic resistance.

The USA100 strain accounts for most hospital-acquired MRSA.

The USA300 strain accounts for most community-acquired MRSA.

S. aureus is differentiated from other mannitol+ cocci by the coagulase test.

The M in MRSA stands for mannitol.

M in mrsa stands for mannitol

The CDC is located in

ATL

The science that deals with when diseases occur and how they are transmitted is called

epidemiology

from which phrase is the term “prions” derived?

Proteinaceous infectious particles

In what year did Stanley Prusiner discover prions?

1982

1979

1997

1928

1982

Which disease did Stanley Prusiner first identify as being caused by prions?

Kuru

Scrapie

Mad cow disease

Fatal familial insomnia

scrapie

How are prions different from other infectious agents?

they lack nucleic acid

How are viruses different from eukaryotic cells?

They do not contain protein.

They do not contain genetic material.

They require a host in order to reproduce.

They do not contain enzymes.

require a host

what is the function of the structural elements of a virus?

To package and protect the viral genome

To provide a source of energy for the virus

To use all of the cell proteins

to package and protect the viral genome

Epidemiology is defined as the study of

when a disease occurs.

where a disease occurs.

where and when a disease occurs, and how it is transmitted.

how a disease is transmitted.

where and when

What is the role of epidemiology?

To learn which organisms cause disease.

To learn what diseases can be caused by respiratory pathogens.

To learn which medicines are effective at killing pathogens.

To learn how to treat and prevent various diseases.

learn how to treat

Which of the following would be considered a fomite?

An infected toy

Contaminated water

A fly

A tick

an infected toy

Which of the following would be considered a vector?

A fly carrying disease from fecal matter to food

Water droplets that come from a sneeze from an infected individual

Water containing bacteria from fecal matter

Saliva that is transmitted between individuals during kissing

a fly carrying disease from fecal matter to food

When aerosols containing pathogens spread disease from a distance of less than one meter, it is considered

contact transmission.

waterborne transmission.

airborne transmission.

vector transmission.

contact transmission

Which of the following is considered a major category of transmission of disease?

Vehicle transmission

Contact, vehicle, and vector transmission

Contact transmission

Vector transmission

b

Which is an example of vehicle disease transmission?

Touching a telephone with cold viruses on its surface

The presence of Listeria on undercooked chicken served for dinner

The bite of a mosquito containing malaria

The transmission of MRSA from skin to skin contact

listeria on uncooked chicken

Staphylococcus epidermidis

an example of a microorganism that produces lactic acid and contributes to antagonism on the skin.

koch postulates class test q

-koch postulates :

- if i cannot reproduce acc signs or symptoms in lab u cant show connection 

signs

-signs: changes in the body that can be measured or observed as a result of disease 

(taking temps)

symptoms: changes in body that the patient feels

SYNDROME

: a specific group of signs and symptoms that accompany a disease (occurs tog)

Septicemia

 blood poisoning bacteria is multiplying inside the blood 

Exceptions to Koch's postulates

• Some pathogens can cause several different disease conditions.

• Some pathogens cause disease only in humans, making the laboratory-animal requirement problematic.

• Some microorganisms have never been successfully cultured.

incidence

the number of people who develop a disease during a particular period. (how many new cases)

Prevalence

the number of people who have a disease at a specified time, regardless of when it first appeared. It accounts for both old and new cases. (how many ppl have it?)

herd immunity

immunity in most a population

-when a good amt of people in a population are immune this can help lower the spread of said virus this also protects those who are susceptible

sporadic

occurs only occasionaly

endemic

constantly present in the pop

epidemic

disease caught by people in a given area above the endemic level

pandemic

worldwide epidemic (people all over the world)

HIT (herd immunity threshold)

-the level of immunity needed in the population to slow down the spread

R0

how many secondary infections will come from one susceptible person

-when the r0 is higher a larger part of the population will need immunity to reach the HIT

local infection

limited to one area of the body

systemic

spread throughout body

focal

starts as local then changes to systemic

Sepsis:

A toxic inflammatory condition arising from the spread of microbes, especially bacteria, or their toxins from an infection focus.

subclinical disease

no signs or symptoms

five stages of disease

-incubation:

The interval between the initial infection and the first signs and symptoms.

The pathogen is present, but noticeable symptoms have not begun.

-prodromal:

A short period after incubation characterized by early, mild symptoms.

You begin feeling that something is wrong.

-period of illness: The disease is at its most severe.

The most pronounced signs and symptoms occur here.

-period of decline: signs and symptoms subside and the patient is improving

-period of convalescence: The body returns to its prediseased state.

Recovery and restoration of normal functioning.

3 main types of reservoirs

human animal and environmental

-the pathogen is maintained here as a source of infection

zoonotic

-transmitted from animals to humans

An emerging infectious disease

is new, increasing in incidence, or showing the potential to increase in the near future.

descriptive epidemiology

collection and analysis of data: john snow

analytical

analyzes a particular disease to find case

-florence nightengale

experimental epidemiology

involves a hypothesis and controlled experiment

-ignaz semmelweis