Chapter 14 HW (Mastering)

If your county reported 89 cases of cryptosporidiosis last year and there were 769,000 people living in your county, what was the annual incidence rate of cryptosporidiosis in your county? .00089 89 11.6 0.000116

11.6

Which of the following is considered a major category of transmission of disease? Contact transmission Vehicle transmission Vector transmission Contact, vehicle, and vector transmission

Contact, vehicle, and vector transmission

When aerosols containing pathogens spread disease from a distance of less than one meter, it is considered waterborne transmission. contact transmission. airborne transmission. vector transmission

contact transmission

If a disease occurs at a fairly stable rate, it is said to be >pandemic >endemic >epidemic >sporadic

endemic

Which of the following would be considered a fomite? A tick A fly Contaminated water An infected toy

An infected toy

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? Select all that apply. A laboratory mouse might not be an appropriate, susceptible host; an experiment with a laboratory rabbit may be needed. It is not possible to isolate and culture microorganism X in the laboratory, because this microbe is found in nature. Microorganism X is the etiologic agent for floppy ear disease because it caused infection in the diseased rabbit. Healthy laboratory organisms rarely show signs and symptoms of infection and disease. Microorganism X might not be linked to floppy ear disease, because the inoculated mouse remained healthy. Microorganism X modified its cell wall structure while being cultured, and is no longer infectious to rabbits.

-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 identify Koch's postulates for determining the etiology of infectious diseases. Which statements accurately describe Koch's postulates? Select all that apply. 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 microscopic properties of pathogens isolated from the original (diseased) and inoculated (also diseased) animals should differ significantly. 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 same pathogen must be present in every case of the disease. -The pathogen must be isolated from the diseased host and grown in pure culture. -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.

Which of the following would be considered a vector? Water containing bacteria from fecal matter A fly carrying disease from fecal matter to food Water droplets that come from a sneeze from an infected individual Saliva that is transmitted between individuals during kissing

A fly carrying disease from fecal matter to food

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. Visitors currently being treated with antibiotics can pass them on to the patient. Health care workers being treated with antibiotics may pass the antibiotic on to the patient.

Antibiotics can be used in aerosols, thereby entering the environment.

What type of nosocomial infection is likely to arise from intravenous catheterizations? Surgical Lower respiratory Cutaneous Bacteremia Urinary tract

Bacteremia

Limitations to Koch's Postulates 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. For each of the following statements, determine whether it describes a benefit or a limitation of Koch's postulates. -laboratory findings provide experimental evident that support the germ theory of disease -healthy, susceptible animals can be used as model organisms for testing many types of infections, thus avoiding the unethical inoculation of healthy human hosts -The steps are designed to systematically link a pathogen to specific infectious disease -Different pathogens can produce the same signs and symptoms, making it difficult to determine which microorganism is causing a disease -Some pathogens cause several different diseases, which make it difficult to link on pathogen to one disease using Koch's postulates -Some infectious agents have specific growth requirements that prevent them from being artificially cultured in the laboratory

Benefit: -laboratory findings provide experimental evident that support the germ theory of disease -healthy, susceptible animals can be used as model organisms for testing many types of infections, thus avoiding the unethical inoculation of healthy human hosts -The steps are designed to systematically link a pathogen to specific infectious disease Limitation: -Different pathogens can produce the same signs and symptoms, making it difficult to determine which microorganism is causing a disease -Some pathogens cause several different diseases, which make it difficult to link on pathogen to one disease using Koch's postulates -Some infectious agents have specific growth requirements that prevent them from being artificially cultured in the laboratory

In the last segment of the animation, when does the first epidemic occur? >January of year three >April of year four >September of year three >January of year four >March of year two

January of year three

Which of the following examples would best fall under the science of epidemiology? Determining what water source in the county is contaminated with Cryptosporidium oocytes. Determining what factors lead to oocyte formation by intestinal Cryptosporidium. Determining what factors lead to the fastest Cryptosporidium growth rate. Determining the best treatment for an individual infected with Cryptosporidium.

Determining what water source in the county is contaminated with Cryptosporidium oocytes.

Experimental Approaches for Understanding Disease This activity asks you to view Foundation Figure 14.3 and determine the purpose of key components of this experiment. The key components include the diseased or dead animal, the healthy laboratory animal, the microscope, and the growth media. Robert Koch performed experiments to determine the specific microorganisms associated with specific diseases.

Diseased or dead animal- original source of the infectious microbial agent Healthy laboratory animal- organism injected with a potential infectious agent Microscope- tool used to view and identify individual microorganisms Growth media- nutrient-rich environment for isolating and culturing microorganisms

Which of the following situations would be likely to lead to an opportunistic infection? E. coli is conveyed from its normal location in the colon to the urinary tract, where it is not normally found. Staphylococcus is present on the skin, where it is normally resident. Staphylococcus is conveyed from the skin into the urinary tract; it is normally found in both locations. The pathogen Vibrio cholerae enters the intestine, where it is not normally found.

E. coli is conveyed from its normal location in the colon to the urinary tract, where it is not normally found

Etiology and Infectious Disease This activity asks you to match each key term related to etiology and infectious disease with its description. Match to etiology, infections disease, germ theory of disease, or Koch's postulates. Based on the information contained in the introduction, match each of the following concepts with its best description. 1. The study of the cause of a disease 2. disease directly caused by microorganisms and not by other means, for example, genetic or degenerative diseases 3. this theory states that microorganisms cause infected diseases 4. experimental requirements for identifying the agent of an infectious disease

Etiology- the study of the cause of a disease Infectious disease- disease directly caused by microorganisms and not by other means, for example, genetic or degenerative diseases Germ theory of disease- this theory states that microorganisms cause infected diseases Koch's postulates- experimental requirements for identifying the agent of an infectious disease

In the last segment of the animation, how many regions of the world experience the pandemic during April of year four? >Four >Two >Six >Five

Five

How can health care workers reduce the occurrence of nosocomial infections? Limit the number of visitors who can see the patient Reduce the number of times they visit a patient Administer all medications orally instead of through injections Practice more stringent aseptic techniques

Practice more stringent aseptic techniques

Which of the following represents an instance of commensalism? Salmonella colonizes the gallbladder without any effect on the gallbladder. E. coli lives in the host's intestine and releases vitamins that are absorbed by the host. Pseudomonas aeruginosa grows in the upper respiratory tract, inducing difficulty in breathing. Clostridium difficile damages the cells lining the intestine.

Salmonella colonizes the gallbladder without any effect on the gallbladder

In the sixth segment of the animation, why is the disease epidemic in North America? >Only a few cases are occurring in this region. >The disease has spread to North America from Europe >The disease occurs at a higher rate than what would normally be expected in this region >The disease occurs at a lower rate than what would normally be expected in this region

The disease occurs at a higher rate than what would normally be expected in this region

Which statement best describes microbial antagonism? The normal microbiota prevents a pathogen from establishing an infection by producing toxic substances that prevent pathogenic bacteria growth. A member of the normal microbiota causes disease by infecting an area of the body in which it is not normally found. The normal microbiota prevents a pathogen from establishing an infection by occupying the available space. The normal microbiota prevents a pathogen from establishing an infection by both taking up space and producing toxic substances.

The normal microbiota prevents a pathogen from establishing an infection by both taking up space and producing toxic substances

Which is an example of vehicle disease transmission? The transmission of MRSA from skin to skin contact The presence of Listeria on undercooked chicken served for dinner Touching a telephone with cold viruses on its surface The bite of a mosquito containing malaria

The presence of Listeria on undercooked chicken served for dinner

Why are invasive procedures likely to increase the risk of nosocomial infections? Invasive procedures require long term hospital stays, thereby increasing the number of visitors seen by the patient. Invasive procedures must use antibiotics. These procedures are carried out by health care workers, who carry resistant microbes. These procedures allow microbes from the skin to enter the bloodstream of the patient.

These procedures allow microbes from the skin to enter the bloodstream of the patient.

Which mode of transmission best describes the spread of Cryptosporidium from reservoir to host? Vector transmission via flies. Vehicle transmission via air. Contact transmission via droplets. Vehicle transmission via water.

Vehicle transmission via water.

Expected prevalence of a disease is >the expected occurrence of a disease based on past observations >the total number of cases of a disease over a period of time >the anticipated geographical spread of a disease based on past observances >the number of new cases of a disease over a period of time

the expected occurrence of a disease based on past observations

Cryptosporidiosis is caused by _________ . the protozoan Cryptosporidium, spread via the fecal oral route the bacterium Cryptosporidium, spread via the fecal oral route the protozoan Cryptosporidium, spread via insect bite the bacterium Cryptosporidium, spread via insect bite

the protozoan Cryptosporidium, spread via the fecal oral route