MCB 100 Homework #5 (Exam 3)

Virulence factors allow microbes to be pathogens. This means that a bacterium with more virulence factors _____. A. can more easily infect hosts and cause disease B. cause a more severe immune response by the host C. can infect a greater variety of hosts D. will be more deadly

A. can more easily infect hosts and cause disease

Based on the data supplied, what was the approximate mortality rate for this outbreak? A. 14% B. 0.14% C. 43% D. 1%

A. 14%

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? Select all that apply. A. An arbovirus is an arthropod-borne virus. B. An arbovirus is a virus isolated in Ann Arbor, Michigan. C. An arbovirus is maintained in nature through biological transmission. D. An arbovirus is a virus that originated from plants.

A. An arbovirus is an arthropod-borne virus. C. An arbovirus is maintained in nature through biological transmission

What additional information would you request from those who survived the disease? A. How tall are they and were the misters on when they shopped the produce aisle? B. Did they purchase any ice cream? C. Did they purchase any deli meats? D. Did they purchase any hamburger?

A. How tall are they and were the misters on when they shopped the produce aisle?

The release of lipid A may lead to _____. A. fever, blood clotting, inflammation, and shock B. fever, blood clotting, muscle contraction, and anemia C. seizures, anemia, inflammation, and shock D. hypothermia, blood clotting, pus formation, and shock

A. fever, blood clotting, inflammation, and shock

A patient is sickened after being infected with Escherichia coli (E. coli) from consuming contaminated lettuce; this is a type of _______________ disease transmission. A. vehicle B. droplet C. direct contact D. indirect contact

A. vehicle

Why may some bacteria use extracellular enzymes to form blood clots? A. The blood clots cause disease, which is the intended purpose of the bacteria. B. Blood clot can hide bacteria from the immune system. C. A blood clot leads to tissue necrosis or death, a necessary condition for infection. D. The blood clots are a necessary food source for the bacteria.

B. Blood clot can hide bacteria from the immune system.

Dr. John Snow's investigation of the cholera epidemic of 1854 most closely matches which approach to epidemiology? A. Experimental epidemiology B. Descriptive epidemiology C. Analytical epidemiology

B. Descriptive epidemiology

How could this epidemic be stopped without firing the worker? A. Alert townspeople to cook all vegetables thoroughly. B. Educate the worker about personal hygiene; use an outhouse or designated bathroom. Instruct him to thoroughly wash his hands with clean soap and water after using the facilities. C. Alert townspeople to drink only pasteurized milk. D. Alert townspeople to thoroughly cook pork.

B. Educate the worker about personal hygiene; use an outhouse or designated bathroom. Instruct him to thoroughly wash his hands with clean soap and water after using the facilities.

Is Legionellosis contagious? A. Yes. It is highly contagious and spreads through households in a matter of days. B. No. Legionellosis is not contagious. C. No. Legionellosis is a zoonotic disease. D. No. Legionellosis is caused by vitamin C deficiency.

B. No. Legionellosis is not contagious

Which type of toxin, when secreted, may lead to the disruption of the cells within the gastrointestinal tract? A. endotoxin B. enterotoxin C. cytotoxin D. neurotoxin

B. enterotoxin

What do we call the person determined to be the first case of a disease in an outbreak? A. immunocompromised B. index case C. contagious D. prodromal case

B. index case

How was this carrier identified? A. sputum sample B. urine culture C. nasal swab D. throat swab

B. urine culture

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? A. Encephalitis is an inflammation of the meninges. It is a concern to health care professionals because of how quickly the infection will spread to the rest of the body. B. Encephalitis is an inflammation of the peripheral nervous system. It is a concern to health care professionals because of how quickly the infection will spread to the rest of the body. C. 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. D. Encephalitis is an inflammation of the spinal cord. It is a concern to health care professionals because the infection will spread to the brain.

C. 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

Which of the following is the best mode of controlling the spread of West Nile infections? A. Kill all mosquitoes to prevent the transmission of West Nile virus. B. Kill all birds to prevent the amplification and transmission of West Nile virus. C. Limit exposure to mosquitoes to prevent the transmission of West Nile virus. D. Limit exposure to birds to prevent the transmission of West Nile virus.

C. Limit exposure to mosquitoes to prevent the transmission of West Nile virus

Some bacteria secrete chemicals that prevent the phagocytic digestion of a bacterium by interfering with the fusion of _____ to the phagosome. A. pseudopods B. the bacterium C. a lysosome D. a lipopolysaccharide layer (LPS)

C. a lysosome

In the last segment of the animation, how many regions of the world experience the pandemic during April of year four? A. Four B. Two C. Six D. Five

D. Five

In the last segment of the animation, when does the first epidemic occur? A. April of year four B. January of year four C. March of year two D. January of year three E. September of year three

D. January of year three

Which of the following best describes why West Nile Virus is considered to be an emerging infectious disease? A. West Nile virus causes an infection and death in birds such as crows and blue jays. B. West Nile virus causes a latent viral infection that can emerge later in life. C. West Nile virus was first isolated in Uganda in 1937 and has caused significant outbreaks every year since then. D. West Nile virus outbreaks have increased in number and affected areas since 1937.

D. West Nile virus outbreaks have increased in number and affected areas since 1937

What type of epidemiological study is exemplified in this case? A. zoonotic B. experimental C. descriptive D. analytical

D. analytical

If a disease occurs at a fairly stable rate, it is said to be A. sporadic. B. epidemic. C. pandemic. D. endemic.

D. endemic

Hyaluronidase and collagenase both allow bacteria to _____. A. escape detection by a host B. adhere to body cells C. interfere with complement D. invade a host's tissues

D. invade a host's tissues

Ethical considerations make it problematic to apply Koch's postulates or the scientific method in strict form to the investigation of diseases that affect only humans. The field of epidemiology provides alternatives for the study of disease in humans. Dr. John Snow is considered the founder of epidemiology based on his work during the 1854 cholera epidemic in London. How does his work fit into the modern field of epidemiology? Match the terms for disciplines in epidemiology with the most appropriate definition.

Experimental epidemiology: Design and conduct a test of a hypothesis about a disease. Descriptive epidemiology: Observe and collect data concerning a disease. Analytical epidemiology: Make a detailed investigation of data collected concerning a disease.

The scientific method is a four-step framework for the process of scientific investigation. Scientists have successfully applied the scientific method to address problems and questions for more than a century. The application of the scientific method has helped move science from philosophical debate to an understanding of the world around us based on reproducible facts and phenomena. Place the steps of the scientific method in the correct sequence from left to right.

Left to right: Observation leads to formulation of a question. Formulate a hypothesis to address a question. Design and conduct experiments. Scientist decides to accept, reject or modify a hypothesis.

Dr. John Snow was a physician in London who was interested in understanding cholera. Based on his observations he believed water was somehow involved. In 1854 there was a serious outbreak of cholera in London during which hundreds of people became ill and died. Dr. Snow visited patients and provided what treatment he could. While in the patients' homes he asked questions of the family about their activities prior to the patient becoming ill. Based on the answers he received he concluded one water well in London was the source of the cholera cases. Drag the description of Dr. Snow actions or activities to the step of the scientific method it most closely fits.

Observation leads to formulation of a question: Observations suggest to Dr. Snow water is involved in cholera Formulation of a hypothesis to address a question: Observations suggest to Dr. Snow water is involved in cholera. Design and conduct experiments: Not Applicable Collect and analyze data: Dr. Snow collects information about patients' activities prior to becoming ill. Scientist decides to accept, reject or modify a hypothesis: Dr. Snow concludes a specific well is the source of the cholera cases.

Identify the mode of transmission associated with the particular pattern of disease occurrence in a population. Drag the appropriate labels to their respective targets.

Red line: Transmission category = vehicle transmission, Example = waterborne Blue line: Transmission category = direct transmission, Example = Droplet

What features of West Nile virus make it an emerging disease of special concern? Select all that apply. A. West Nile virus is an arthropod-borne virus transmitted by mosquitoes. B. 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. C. West Nile virus is maintained in nature through biological transmission between susceptible hosts by blood-feeding arthropods. D. West Nile virus has a positive, single-stranded RNA genome that is 11,000 to 12,000 nucleotides long.

A. West Nile virus is an arthropod-borne virus transmitted by mosquitoes. B. 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. C. West Nile virus is maintained in nature through biological transmission between susceptible hosts by blood-feeding arthropods.

A patient with West Nile viral encephalitis asks his nurse practitioner how he could have contracted the disease. The NP explains that the causative virus is carried by infected mosquitoes from birds to people. This is an example of disease transmission through A. a biological vector. B. bodily fluid. C. indirect contact. D. a mechanical vector.

A. a biological vector

An example of a mechanical vector is: A. a housefly at a picnic. B. a hypodermic needle. C. a diseased, blood-sucking insect. D. a contact transmission.

A. a housefly at a picnic

How would you classify this abrupt jump in cases of Legionellosis in Louisiana? A. epidemic B. pandemic C. endemic D. zoonotic

A. epidemic

What are the clinical signs and symptoms of typhoid fever? A. fever and rose-spotted rash B. coughing and double vision C. nausea and headache D. abdominal cramps and malaise

A. fever and rose-spotted rash

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

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

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? A. The students tried to isolate and identify West Nile virus from birds because they are large animals. It would be difficult to isolate West Nile virus from mosquitoes because they are small. B. The students tried to isolate and identify West Nile virus from birds because they had access to dead birds that were known to be infected with West Nile virus. C. 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. D. The students tried to isolate and identify West Nile virus from birds because it is faster to isolate the virus from a bird than to isolate it from a mosquito.

C. 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

What is the reservoir for this disease organism, Salmonella enterica serotype Typhi? A. cats B. dogs C. humans D. horses

C. humans

Bacterial capsules work by _____. A. preventing synthesis of digestive chemicals by phagocytes B. preventing the action of complement C. protecting the bacterium from engulfment D. killing the phagocyte

C. protecting the bacterium from engulfment

In early spring 2009, the CDC reported several dozen cases of novel H1N1 influenza ("swine flu") in the United States. By the end of the year millions of people had been infected. The pattern of novel H1N1 cases in the United States represents a(n) ________ disease. A. opportunistic B. pandemic C. endemic D. epidemic E. sporadic

D. epidemic

A major difference between exotoxins and endotoxins is that endotoxins are _____. A. not actually toxic B. secreted by bacteria C. able to kill cells directly D. physically part of the bacterial structure

D. physically part of the bacterial structure

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

D. the expected occurrence of a disease based on past observations

Jerica takes her young son to the pediatrician for regular childhood immunizations. While there, they wait in a room full of sneezing, sniffling, coughing youngsters. Despite making sure that her son stays at least six feet (two meters) from the other children and doesn't touch any play toys in the waiting room, microbes could still spread to her son by A. vector transmission. B. indirect contact transmission C. droplet transmission. D. vehicle transmission.

D. vehicle transmission

Match the field of epidemiology with the step of the scientific method it most closely fits.

Descriptive epidemiology: Observation leads to formulation of a question Experimental epidemiology: Formulation of a hypothesis to address a question Analytical epidemiology: Scientist decides to accept, reject, or modify a hypothesis