ch. 35

Select three signs (as opposed to symptoms) of an infectious disease.

fever blood in the stool rash

Because dust particles and droplet nuclei can travel distances greater than a meter, carrying along pathogens, both are considered transmission by ______ means.

indirect

Select the best example of indirect contact transmission.

HIV infection via IV drug use with a contaminated shared needle

Microbial pathogens that are able to grow and replicate within a host cell are typically called______ pathogens.

intracellular

Viral glycoproteins utilized for attachment are particularly effective when there is a complementary ____ on the host cell for them to bind to.

receptor

When a microorganism is restricted to infecting only a particular cell or tissue type, this is known as a(n)___.

tropism

True or false: An obligate intracellular pathogen is incapable of growth and replication outside of a host cell.

true

Select the best definition of pathogen.

any organism that causes disease

Bacteria such as Streptococcus pneumoniae and Haemophilus influenzae resist phagocytosis by producing an outer mucoid structure called a(n)

capsule

Select three types of adherence structures used by infectious agents for attachment.

capsules pili and fimbriae specialized adhesion molecules (e.g. viral glycoproteins)

The degree of harm (pathogenicity) inflicted on the host is best defined as a pathogen's .

virulence

Which of the following is a general class of molecules that enables a microorganism to cause host cell or tissue damage?

virulence factors

An infectious disease that is transmitted from an animal to a human is termed a(n) ______.

zoonosis

Select three obligate intracellular pathogens.

Chlamydia spp. smallpox virus rickettsias

The most specific term used to describe the presence of viable bacteria in the bloodstream is ______.

bacteremia

Select all examples of common vehicles that could be referred to as fomites.

bedding surgical instruments drinking vessels

L. monocytogenes, Shigella spp., and Rickettsia spp. are able to escape being digested by a phagocyte by triggering the assembly of an actin tail, which results in the bacteria ______.

being engulfed by an adjacent host cell

Select all potential advantages to the formation of biofilms by microbes.

better nutrient acquisition avoidance of host immune cells protection against antimicrobial agents protection against predators

A(n) is a complex heterogeneous community formed by microbes, usually within their natural environment, but they have also been found "stuck" to medical plastics such as catheters and heart stints.

biofilm

The infectious disease process induced by bacterial or fungal toxins in the is termed septicemia

blood

Bacteremia results when viable bacteria are present in the .

bloodstream

Factors such as nutrition, cleanliness, stress, genetic predisposition, and level of immune function ______.

can alter the ID50 value for individuals

Both the ID50 and LD50 for a given pathogen ______.

can be influenced by the susceptibility of the host

The term that most specifically describes the establishment of a site of microbial replication on or within a host is ______.

colonization

When a microorganism establishes a site on or within a host allowing replication, has occurred.

colonization

Pathogenicity

consequence of the interplay between microbe and host

During which phase of the infectious disease process do the signs and symptoms begin to disappear?

convalescence

Like droplet nuclei, resuspended particles known as ___ can remain airborne for long periods of time and travel long distances, carrying along attached pathogens and thereby playing an important role in airborne transmission.

dust

Infectivity can be defined as the ability of an organism to ______.

establish a discrete focal point of infection

Microbial pathogens that only grow and replicate outside of a host cell are typically called _______pathogens.

extracellular

Microbial pathogens that only grow and replicate outside of a host cell are typically called pathogens.

extracellular

The plague-causing bacterium Yersinia pestis and the fungus Aspergillus are two good examples of ______.

extracellular pathogens

A(n) intracellular pathogen may reside within the cells of a host organism or in the environment, independent and outside of a host organism.

facultative

Brucella abortus and Histoplasma capsulatum are two examples of ______.

facultative intracellular pathogens.

True or false: A disease syndrome is one defining symptom of a particular disease.

false

True or false: A facultative intracellular pathogen is incapable of growth and replication outside of a host cell.

false

The best term to describe an inanimate vehicle (e.g. surgical instrument, bedding, or drinking vessel) that can spread a pathogen to multiple hosts is a ______.

fomite

Regarding airborne transmission of infections, which of the following are characteristics of droplets (not droplet nuclei)?

form when saliva and mucus are placed under force 5 micrometers or more in diameter fall to the ground and other surfaces after remaining in the air for only a short distance from their point of origin

Inanimate materials (e.g. food, water, biological materials) that indirectly transmit pathogens to new hosts are called ___.

formite

The spread of a pathogen via some type of contact between two individuals is generally called transmission, whereas transmission occurs when an unborn child acquires a pathogen from an infected mother.

horizontal or direct vertical

In one example of a relationship between two organisms, a(n) is a larger organism that supports the survival and growth of a smaller organism.

host

During the illness period of an infectious disease process, host___ responses are typically triggered.

immune

An opportunistic pathogen is one that is particularly like to cause disease in what type of host?

immunocompromised

The time period between when a pathogen enters a host and the development of symptoms is called the_________ period and it will vary from disease to disease.

incubation

When a pathogen is growing and multiplying within or on a host (which may or may not result in overt symptoms) this is known as a(n) ______.

infection

When the presence of a pathogen or its products results in the impairment or loss of function of a host system, this is a(n) ______.

infectious disease

Select the strategy each pathogen uses to evade the immune responses of the host.

influenza viru--> changes surface proteins by genetic recombination N.gonorrhoeae--> phase variation of pili proteins; also produces proteases S.pyognes--> produces a capsule that resembles host tissue components; also produces protein G Staphylococcus--> produces proteins A to interfere with immune system recognition.

Microbial pathogens that are able to grow and replicate within a host cell are typically called pathogens.

intracellular

A congenital infection is one that ______.

is present at birth

Microbes within biofilms coordinate gene expression to upregulate mechanisms that make the biofilm community ______ sensitive to antibiotics and ______ resistant to host defense mechanisms. Multiple choice question.

less; more

Regarding airborne transmission of infections, droplets that are 5 micrometers or more in diameter can form when saliva and mucus are placed under force, e.g. during sneezing. When these droplets evaporate, smaller particles called droplet ___ can form.

nuclei

Because they require host cells for replication, all viruses are considered to be________ intracellular pathogens.

obligate

An organism that infects a host when it gets out of its typical niche (normal location in the body) is a(n) ______.

opportunistic pathogen

Select two symptoms (as opposed to signs) of an infectious disease.

pain loss of appetite

Non-pathogen-related ways of bypassing host mucous membranes and epithelia are termed ______.

passive penetration

The ability of an organism (usually a microbe) to cause disease is its .

pathogenicity

A body surface where infectious agents may gain access to host tissue is called a of entry.

portal

In relation to infectious diseases, the skin, respiratory system, gastrointestinal tract, urogenital system, and conjunctiva of the eye are all examples of ______.

portals of entry through which infectious agents may gain access to host tissues

The____ stage of an infectious disease is the period after signs and symptoms have set in, but are not yet specific enough for formal diagnosis.

prodromal

One mechanism used by some bacteria to evade specific immune responses (e.g. antibodies) is to ______.

produce capsules that resemble host tissue components, acting as a disguise of sort

A low ID50 value means ______.

relatively small numbers of microorganisms are required to establish an infection

A(n) ___ is the natural environmental location where a pathogen normally resides.

reservoir

Select three mechanisms by which pathogens can actively penetrate host mucous membranes and epithelial tissue.

secretion of enzymes that attack extracellular matrix and basement membranes disruption of host cell surface via microbe-secreted substances secretion of enzymes that degrade the glycocalyx of cells

Which term best describes the infectious disease process caused by bacterial or fungal toxins in the blood?

septicemia

By forming a biofilm in or on human tissues, pathogens may be more dangerous because they ______. Multiple choice question.

shift into slower-growing, antibiotic-resistant persister cells

In the context of infectious diseases, objective changes in the body that can be directly observed or measured (such as fever) are called___

signs

In the context of infectious diseases, objective changes in the body that can be directly observed or measured (such as fever) are called_______ .

signs

The best definition of the convalescence period of an infectious disease is when ______.

signs and symptoms of the illness begin to disappear, and the patient recovers

Select three mechanisms of passive penetration of host mucous membranes and epithelia by microorganisms.

small wounds created during feeding by arthropod vectors burns, wounds, or abrasions on the skin's surface initial entry through lesions, ulcers, or small breaks in mucous membranes

Invasiveness can be defined as the ability of an organism to ______.

spread to adjacent or deeper tissues

The human immunodeficiency virus (HIV) is an example of a pathogen that has evolved to ______ the host's immune response. Multiple choice question.

suppress

A disease____ is a set of signs and symptoms that are characteristic of the disease.

syndrome

The best definition of the illness period of an infectious disease is when ______.

the disease is most severe, and the patient displays characteristic signs and symptoms

In the context of infectious diseases, a reservoir is ______.

the natural environmental location in which the pathogen resides

The best definition of the incubation period of an infectious disease is when ______.

the pathogen has entered the host and is multiplying, but hasn't reached high enough levels to cause clinical manifestations

The best definition of the prodromal stage of an infectious disease is the period when ______.

there is an onset of signs and symptoms, but they are not yet specific enough for disease diagnosis

Which is an example of vertical transmission of a pathogen?

transmission of a German measles virus across the placenta to a developing fetus

True or false: When it comes to parasitic organisms, smaller parasites most often live in or on a larger host organism to survive.

true

A(n)___ is an organism that facilitates the spread of disease from one host to another. Examples include mosquitoes, ticks, and fleas.

vector

Direct living transmitters of a pathogen, such as arthropods, are called .

vectors

An organism's ______ is the degree of harm (pathogenicity) inflicted on its host.

virulence

Because their expression is associated with the production of disease in their host, bacterial toxins, superantigens, and attachment factors are all be considered to be factors.

virulence

Arrange the four stages of a (nonfatal) infectious disease according to the order in which they occur, with the earliest stage that follows the initial infection at the top.

1. incubation period 2. prodromal stage 3. illness period 4. convalescence

See the graph showing the four stages of a typical infectious disease, and match the letter of each labeled area with its correct name.

A--->incubation period B-->prodromal stage C--->illness period D--->convalescence

Select two facultative intracellular pathogens.

Brucella abortus Histoplasma capsulatum

______ contact transmission typically results from an actual physical interaction with the infectious source (e.g. person to person contact). ______ contact transmission depends upon something acting to "transfer" the infectious agent between hosts. Multiple choice question.

Direct; Indirect

What does it mean to say a microbe has a specific tropism?

The microbe infects only specific cell or tissue types as dictated by the correct receptor being present on them.

Select the definition of infectious dose 50 (ID50).

The number of microbes required to induce disease in 50% of the inoculated hosts.

Select the best definition of lethal dose 50 (LD50).

The number of microbes required to kill 50% of inoculated host organisms.

Hepatitis B virus (HBV) produces large amounts of proteins that are not associated with the complete, infectious virus. How do these these proteins benefit the virus?

They act as decoys for the host immune response

What do these infectious diseases have in common: Lyme disease, malaria, plague, Rocky Mountain Spotted fever, and West Nile virus?

They are all transmitted by arthropod vectors.

What do German measles, gonorrhea, herpes, syphilis, and toxoplasmosis have in common?

They can all be congenital infections.

A good example of transmission of a zoonosis is ______.

a human contracting rabies from a raccoon bite

A high LD50 value means ______.

a relatively large number of microorganisms is required to kill an infected organism

After they are ingested by phagocytes, certain bacteria like Listeria monocytogenes are able to move within their host cell, and spread to other cells, by triggering assembly of what specific host cell protein?

actin

Microorganism-secreted substances that alter host tissues allow for what type of penetration of host mucous membranes and epithelia?

active

The image illustrates different microbial molecules that are specifically involved in ______.

adherence

In___ transmission, a pathogen is often sneezed or coughed into the air and suspended in dust, droplet nuclei, or larger respiratory droplets.

airborn

In ___ transmission, a pathogen is often sneezed or coughed into the air and suspended in dust, droplet nuclei, or larger respiratory droplets.

airborne

Suppose a student infected with influenza virus is sitting three feet across from you in class, coughing frequently. You do not touch the student or share any items with her. A few days later, you come down with influenza. What was the most likely route of transmission?

airborne

Select two extracellular pathogens.

Yersinia pestis Aspergillus, a fungus

True or false: All viruses are facultative intracellular parasites. True false question.

false