Deck 2: Basic Concepts of Infectious Disease

Question 1

What factor is most responsible for both the very young and the very old being most susceptible to infectious diseases?

A) the host genotype
B) different portals of entry for pathogens
C) the host immune system
D) the inability of these populations to communicate symptoms to health care providers

Answer 1

C

Question 2

Which of the following might be an effective means of limiting a disease spread via a urogenital route?

A) using fresh needles,that is,not sharing needles
B) wearing condoms during sexual activity
C) wearing a mask that covers the nose and mouth
D) washing hands before eating

Answer 2

B

Question 3

The most dangerous potential bioterrorism agents have what portal of entry into the human body?

A) respiratory
B) urogenital
C) parenteral
D) fecal

Answer 3

D

Question 4

Walter defecates in the company restroom,does not wash his hands thoroughly,and then uses the office coffee pot,transferring bacteria onto the handle of the pot.Marcia pours some coffee and then goes to her desk to eat a muffin,ingesting some of the bacteria she picked up from the coffee pot.What is the route of transmission of this infection?

A) fecal-oral
B) respiratory
C) urogenital
D) parenteral

Question 5

Lily (who has lice)brings a comb to school for picture day.After Lily combs her hair,Leticia asks to borrow the comb.Leticia later is diagnosed with lice.In this example,the comb is a(n)

A) carrier.
B) fomite.
C) incubator.
D) portal.

Question 6

A mosquito can transmit a viral pathogen into humans.What is the mode of transmission of the virus in this instance?

A) oral
B) respiratory
C) urogenital
D) parenteral

Question 7

Colonization occurs during which stage of an infectious disease?

A) incubation phase
B) invasive phase
C) decline phase
D) prodromal phase

Question 8

Which of the following might be an effective means of limiting a disease spread via a parenteral route?

A) not sharing needles
B) wearing condoms during sexual activity
C) wearing a mask that covers the nose and mouth
D) cooking foods thoroughly

Question 9

An island nation normally has low background level of cholera.After an earthquake,sanitation is disrupted and cholera cases spike to high levels on the island but not in other areas of the world.The spike in cholera cases is an example of a(n)

A) endemic disease.
B) epidemic disease.
C) pandemic disease.
D) opportunistic infection.

Question 10

What kind of relationship exists between microbiota and their human hosts?

A) mutualistic
B) pathogenic
C) endoparasitic
D) ectoparasitic

Question 11

Which of the following is NOT a fundamental attribute of a successful pathogen?

A) host attachment
B) immune avoidance
C) nutrient acquisition
D) wide host range

Question 12

Which of the following might be an effective means of limiting a disease spread via an oral route?

A) not sharing needles
B) wearing condoms during sexual activity
C) checking for and removing ticks after outdoor activity
D) washing hands before eating

Question 13

A mosquito can transmit a viral pathogen into humans.The mosquito is an example of a(n)

A) fomite.
B) symptom.
C) vector.
D) endoparasite.

Question 14

Giardia lamblia,a cause of diarrhea and other gastrointestinal symptoms,is acquired from contaminated drinking water.It can be treated with several different antimicrobial drugs.Into what risk level does G.lamblia fall?

A) risk group I
B) risk group II
C) risk group III
D) risk group IV

Question 15

During which phase of an infectious disease do disease symptoms begin to subside?

A) incubation
B) prodromal
C) decline
D) convalescent

Question 16

Human immunodeficiency virus (HIV)spreads directly from person to person via intimate contact.HIV exhibits

A) a simple infection cycle.
B) a complex infection cycle.
C) vehicle transmission.
D) indirect transmission.

Question 17

What factor favors an infectious disease to become pandemic instead of epidemic?

A) a localized animal reservoir
B) rapid mortality
C) a low infectious dose 50%
D) a short incubation period

Question 18

The acme of an infectious disease,when the symptoms are most severe,occurs during which phase of the infection?

A) incubation
B) invasive
C) decline
D) prodromal

Question 19

Which of the following is an example of a symptom?

A) a rash
B) swollen glands
C) jaundice (yellow tinge to the skin)
D) muscle aches

Question 20

Adhesins are proteins on the surface of microbes.Adhesins help most with which fundamental pathogen attribute?

A) host attachment
B) immune avoidance
C) nutrient acquisition
D) host mortality

Question 21

During which phase of an infectious disease are immunopathologies most likely to first appear?

A) incubation
B) invasive
C) decline
D) convalescent

Question 22

The ability of a microbe to cause disease is known as

A) emergence.
B) invasiveness.
C) pathogenicity.
D) virulence.

Question 23

Which of the following can weaken the host immune response?

A) too little sleep
B) moderate exercise
C) proper nutrition
D) avoiding alcohol and drugs

Question 24

The main reason that climate change can affect infectious disease patterns is by

A) causing the evolution of new animal species that can serve as hosts to emerging pathogens.
B) altering where organisms can live.
C) increasing the virulence of pathogens.
D) decreasing the virulence of pathogens.

Question 25

An infectious disease that rapidly increases in incidence throughout the world is known as a ________.

Question 26

CASE HISTORY
In 1884,Yong Ding was a 38-year-old male in Canton,located in southern China.Life was hard,but Yong Ding,a cook,still managed to support his family.As he walked to his restaurant each day,he barely noticed the small bands of rats scurrying through the streets.Disease was rampant that year;victims of the Shuyi (rat epidemic)were stacked like firewood in the streets,five bodies high in places,waiting to be taken to burial.Yong knew that the disease started as a swollen gland in the armpit and often had a black appearance (now called a bubo).He checked himself daily for these swellings and,seeing none,always felt relief.Then,one morning,he found one.Within days,Yong Ding began coughing blood as the agent (a mystery at the time)spread through his bloodstream to his lungs.Once that happened,Yong Ding knew death was not far behind.More than 60,000 died this way in what was to be the start of the Third Pandemic of bubonic plague.Yong Ding's body was one of many lining the street that year.
We now know that the cook Yong Ding was living through the Third Epidemic of bubonic plague.We also know that the rats that scurried randomly through the streets were infested with fleas,which carried the causative agent of the bubonic plague: Yersinia pestis.In this complex infection cycle,which organism was the vector?

A) Yersinia pestis
B) rats
C) fleas
D) humans

Question 27

The ability of a microbe to attach to a body surface is known as ________.

Question 28

Francisella tularensis is a highly infectious bacterium that can be contracted via multiple routes including inhalation.It causes severe disease but is treatable.Into what risk level does F.tularensis fall?

A) risk group I
B) risk group II
C) risk group III
D) risk group IV

Question 29

What is the difference between an emerging and a reemerging disease?

A) Emerging diseases are of viral origin,and reemerging diseases are bacterial.
B) Emerging diseases are ones for which vaccines exist;reemerging diseases lack vaccines.
C) Emerging diseases are new to humans;reemerging are known but are rapidly increasing in incidence and/or geographic range.
D) Emerging diseases evolve within humans,but reemerging diseases are of zoonotic origin.

Question 30

Which of the following is NOT true of climate change?

A) Climate change will not affect human disease patterns.
B) Climate change can alter insect vector distribution.
C) Climate change can foster emerging diseases.
D) Climate change can foster reemerging diseases.

Question 31

A disease that can spread to humans from nonhuman animals is known as a ________ disease.

Question 32

The typical signs and symptoms of a disease first appear during the ________ phase of an infectious disease.

Question 33

Which of the following is NOT a driver of emerging diseases?

A) decreased human drug use
B) climate change
C) microbial evolution
D) changing land use patterns

Question 34

A fever is often a host response to a pathogen.As such,fever is an example of ________.

Question 35

Transplacental transmission is an example of

A) fecal-oral transmission.
B) vehicle transmission.
C) indirect transmission.
D) direct transmission.

Question 36

Infectious dose is measured by determining how many microbes are required to cause

A) disease symptoms in half of an experimental group of hosts.
B) death in half of an experimental group of hosts.
C) disease symptoms in all of an experimental group of hosts.
D) death in all of an experimental group of hosts.

Question 37

Which of the following is most likely true of pathogens with a broad host range?

A) The pathogens are highly virulent in all hosts.
B) The pathogens are unlikely to be zoonotic diseases.
C) The pathogens are less likely than narrow host range pathogens to respond to antibiotics.
D) The pathogens recognize receptors that are very similar among different hosts.

Question 38

Known diseases that rapidly increase in incidence and/or geographic range are known as

A) emerging.
B) reemerging.
C) zoonotic.
D) etiologic agents.

Question 39

Which of the following host factors can prevent disease by limiting exposure?

A) too little sleep
B) moderate exercise
C) working in the health care field
D) proper hygiene

Question 40

A particular virus has a high infectious dose 50% and extremely low mortality,causing only mild symptoms.Which of the following is true of this virus?

A) It has high infectivity and high virulence.
B) It has high infectivity but low virulence.
C) It has low infectivity and low virulence.
D) It has low infectivity and high virulence.

Question 41

What distinguishes simple from complex infection cycles?

Question 42

List a few host factors that can influence the course of an infection by impacting immune status.

Question 43

Describe how bacterial adhesins affect the preferred entry portal of pathogens.

Question 44

Describe the difference between an infection and a disease.

Question 45

CASE HISTORY
Brandon,a 30-year-old stockbroker living in Chicago,visited his physician's office.When the nurse asked Brandon why he was there,he blushed and said he wanted to talk only to the physician about his problem.Once the doctor entered the room,Brandon explained he had a small round lesion on his penis.When asked about his sexual partners,Brandon initially said he was dating only one woman,but when pressed,he admitted he had been intimate with two women over the past month and one man.Upon examination,the lesion appeared to cause no pain but exuded a clear fluid.The physician quickly sent a sample of the fluid to the clinical laboratory.There the sample was found to contain highly motile,corkscrew-shaped bacteria.The diagnosis was syphilis,caused by the bacterium Treponema pallidum.Left untreated,the disease could eventually cause horrible disfiguration and death.Confident that he knew the cause,the physician gave Brandon a shot of long-acting penicillin.
What signs and/or symptoms of disease (distinguish between the two in your answer)did Brandon's doctor note as a part of this diagnosis?

Question 46

Describe how a pathogen could use an exit portal different from the portal it used to enter the host.

Question 47

Why do some public health departments widely spray insecticides in the spring and summer?

Question 48

In some parts of the world,human immunodeficiency virus is endemic.Endemic diseases require a reservoir to serve as a source of pathogen.________ are the reservoir for HIV.

Question 49

What is immunopathology?

Question 50

Why is the lethal dose 50% easier to determine than the infectious dose 50%?

Question 51

What distinguishes risk level III from risk level IV organisms?

Question 52

What is the difference between a sign and a symptom?

Question 53

CASE HISTORY
In 2004,three people in Boston came down with a virulent form of pneumonia.An investigation by public health officials discovered that all three worked at the same laboratory studying Francisella tularensis,a bacterium that is highly infectious (although not usually spread by person-to-person contact).Under specific conditions,the organism can be aerosolized and inhaled and cause deadly pneumonia-making it a possible bioterrorism agent.Its handling is highly restricted by U.S.Homeland Security.Scientists studying this bacterium must use extreme precautionary measures to ensure that it cannot escape the laboratory.The investigation determined that the Boston researchers had indeed contracted tularemia.The scientists appear to have handled the organism in several instances without wearing or using proper protective gear-for example,examining agar plates containing the organism outside a biosafety containment hood.From the type of disease and the laboratory procedures performed,it seemed that the victims,who all fully recovered,inhaled the organism while working with it.
When working with a Risk Group III level organism,the scientists should have known what types of precautions to take to decrease their risk of susceptibility.
What are protective measures they should have used to decrease their risk of susceptibility?