Mastering Microbiology Chapter 14
The following choices list several types of diseases, along with factors that may contribute to their emergence. Which disease and associated factor do NOT match?
emergence of avian influenza A (H5N1): use of antibiotics
Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a
nosocomial infection
GROWTH MEDIA
nutrient-rich environment for isolating and culturing microorganisms
Expected prevalence of a disease is
the expected occurrence of a disease based on past observations.
In the last segment of the animation, how many regions of the world experience the pandemic during April of year four?
Five
Which of the following statements is true regarding hand washing?
Frequent and proper hand washing should be routinely done by patients and by healthcare workers, both prior to and after interaction
How can surgeons help to limit nosocomial infections?
They should perform surgeries and invasive procedures only when absolutely necessary.
What is the role of epidemiology?
To learn how to treat and prevent various diseases
Which of the following best describes why West Nile Virus is considered to be an emerging infectious disease?
West Nile virus outbreaks have increased in number and affected areas since 1937.
Which of the following would be considered a vector?
a fly carrying disease from fecal matter to food
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. the situation is an example of
a zoonosis
A nosocomial infection is
acquired during the course of hospitalization
Which of the following would be considered a fomite?
an infected toy
Symptoms of disease differ from signs of disease in that symptoms
are changes felt by the patient.
In the figure, when is the prevalence the highest?
February
A rabbit was found to have Floppy Ear disease that causes long-ear infections, but its etiology (cause) is unknown. Unknown Microorganism X from the infected rabbit's right ear was successfully isolated and cultured on laboratory growth media. The ear of a healthy laboratory mouse was then inoculated with isolated microorganism, and after a period of time, no disease is observed. Which of the following statements BEST describe the conclusion(s) that can be drawn from this experiment?
-Microorganism X might not be linked to Floppy Ear disease, since the inoculated mouse remained healthy. - A laboratory mouse might not be an appropriate, susceptible host; an experiment with a laboratory rabbit may be needed.
What features of West Nile virus make it an emerging disease of special concern?
-West Nile virus is an arthropod-borne virus transmitted by mosquitoes. - West Nile virus has a high mortality rate in immunosuppressed humans and infects many species of birds in southern Europe, the Mediterranean basin, and North America. - West Nile virus is maintained in nature through biological transmission between susceptible hosts by blood-feeding arthropods.
During his research on West Nile virus, Bill learned that this virus is placed within a functional grouping known as arboviruses. What is meant by the term arbovirus?
-an arborovirus is an arthropod-borne virus -an arborovirus is maintained in nature through biological transmission
LIMITATION
-some infectious agents have specific growth requirements that prevent it from being artificially cultured in the lab -some pathogens cause several different diseases, which makes it difficult to link one pathogen to one disease using Koch's postulates -different pathogens can produces the same signs and symptoms, making it difficult to determine whic microorganism is causing a disease
Which of statements best describe Koch's postulates?
-the same pathogen must be present in every case of the disease -the pathogen must be isolated from the inoculated animal and must be shown to be the original organism -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 diseased host and grown in pure culture
BENEFIT
-the steps are designed to systematically link a pathogen to a specific infectious disease -laboratory findings provide experimental evidence that support the germ theory of disease -healthy susceptible animals can be used as model organisms when testing many types of infections, thus avoiding the unethical inoculation of healthy human hosts.
According to the animation, surgical infections account for what percentage of nosocomial infections?
20%
Which of the following would be an example of disease transmission via INDIRECT contact?
A student sneezes on her test booklet. The instructor grades it and catches her cold.
How might a patient who is not being treated with an antibiotic still be exposed to an antibiotic?
Antibiotics can be used in aerosols, thereby entering the environment.
What type of nosocomial infection is likely to arise from intravenous catheterizations?
Bacteremia
Which of the following is considered a major category of transmission of disease?
Contact, vehicle, and vector transmission
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. The etiologic agent of the disease in the situation is
Coxiella burnetti
Which of the following is an example of the symbiotic relationship known as mutualism?
E. coli within the large intestine
The brain tissue of the birds indicated the possibility of encephalitis. What is encephalitis, and why should this type of infection cause concern among health care professionals?
Encephalitis is an inflammation of the brain tissue. It is a concern to health care professionals because an infection in the brain means the virus has breached protective measures.
In the last segment of the animation, when does the first epidemic occur?
January of year three
Which of the following is the best mode of controlling the spread of West Nile infections?
Limit exposure to mosquitoes to prevent the transmission of West Nile virus.
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.
How can health care workers reduce the occurrence of nosocomial infections?
Practice more stringent aseptic techniques
Which of the following characteristics of a catheter should be considered, to help minimize the spread of nosocomial infections?
Single-use
In the sixth segment of the animation, why is the disease epidemic in North America?
The disease occurs at a higher rate than what would normally be expected in this region.
Koch's postulates established criteria for proving that a specific organism causes a specific disease. Which of the following is NOT one of the criteria given by Koch's postulates?
The pathogen must be isolated from inoculated animals and must be different from the original organism.
Which 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).
Which is an example of vehicle disease transmission?
The presence of Listeria on undercooked chicken served for dinner
If mosquitoes are the mode of transmission for West Nile virus, why did the students in Bill's virology class focus on finding the virus in the dead birds rather than collecting mosquitoes to examine?
The students tried to isolate and identify West Nile virus from birds because they are an amplifying host for the virus, making it more likely that the virus can be isolated from these animals.
Why are invasive procedures likely to increase the risk of nosocomial infections?
These procedures allow microbes from the skin to enter the bloodstream of the patient.
When aerosols containing pathogens spread disease from a distance of less than one meter, it is considered
contact transmission
the figure shows the incidence of influenza during a typical year. Which letter on the graph indicates the endemic level?
d
INFECTIOUS DISEASE
disease directly caused by microorgansims and not by other means, for example, genetic or degenerative diseases
If a disease occurs at a fairly stable rate, it is said to be
endemic
Malaria is an infectious disease caused by infection with a protozoan. In certain tropical regions, malaria is constantly present. We would say that malaria is a(n) _________ disease in these regions.
endemic
The graph in the figure shows the incidence of polio in the United States. The period between 1945 and 1955 indicates a(n
epidemic level
KOCH'S POSTULATES
experimental requirements for identifying the agent of an infectious disease
One effect of washing regularly with antibacterial agents is the removal of normal microbiota. This can result in
increased susceptibility to disease
In which of the following patterns of disease does the patient experience no signs or symptoms?
incubation and convalescence
A patient acquires an infection by touching a contaminated door handle. Which mode of transmission best describes this scenario?
indirect contact transmission
The major significance of Robert Koch's work is that
microorganisms cause disease.
HEALTHY LABORATORY ANIMAL
organism injected with a potential infectious agent
DISEASED OR DEAD ANIMAL
original source of the infectious microbial agent
Which of the following is a fungal zoonosis that can be transmitted by direct contact?
ringworm
Koch observed Bacillus anthracis multiplying in the blood of cattle. What is this condition called?
septicemia
Which of the following is classified as a latent disease?
shingles
The health of the patient
should be the primary concern of the healthcare worker.
The yeast Candida albicans does not normally cause disease because of ______.
the normal microbiota
ETIOLOGY
the study of the cause of a disease
If a patient notices a healthcare worker not following suggested precautions
they should immediately bring it to the attention of the healthcare worker
GERM THEORY OF DISEASE
this theory states that microorganisms cause infectious diseases
MICROSCOPE
tool used to view and identify individual microorganisms
Plague is transmitted through the bite of an infected flea. Which of the following best describes this mode of transmission?
vector transmission
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. The method of transmission of the disease in the situation was
vehicle
A dog develops a diarrheal disease after drinking water from a creek during a hike with his owner. Which of the following best describes this method of disease transmission?
vehicle transmission
As a health care worker, I am keenly aware of how important it is to avoid harming my patients. I worry about inadvertently transmitting an infectious disease to an already compromised individual. According to the CDC, what is the MOST important thing I can do to avoid this?
wash my hands before interacting with any patient
Epidemiology is defined as the study of
where and when a disease occurs, and how it is transmitted
