Chapter 35 Homework

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

Reservoir

Select two extracellular pathogens.

Aspergillus, a fungus Yersinia pestis

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

Bedding Drinking vessels Surgical instruments

______ 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.

direct, indirect

The best description of an epidemiologist is someone who is a

disease detective

Superantigens cause disease by

dramatically stimulating a large portion of circulating host T cells, causing them to overexpress and release cytokines

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 the best definition of pathogen.

any organism that causes a disease

The proportional number of cases of a disease that develop in a population that was exposed to an infectious agent is the

attack rate

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

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

In an AB exotoxin molecule, the B portion

binds to the target receptor on a host cell

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

bloodstream

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

capsule

When a disease maintains a steady, low-level frequency in a population, it is characterized as ______.

endemic

Lipopolysaccharide (LPS) is also called ___ because it is bound to the outer membrane of Gram-negative bacteria, and it is harmful to humans.

endotoxin

The study of the occurrence, determinants, distribution, and control of health and disease is called

epidemiology

Among the most lethal substances known, heat-labile proteins secreted mainly by Gram positive bacteria are called

exotoxins

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

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

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

false Reason: Facultative intracellular pathogens can reside within host cells or in the environment.

Bacterial meningitis, which occurs occasionally in the human population at irregular intervals, is a good example of which category of disease?

sporadic

What category of disease occurs occasionally and at irregular intervals?

sporadic

Which type of bacterial exotoxin stimulates a large proportion of the host T cell population to produce excessive amounts of cytokines?

superantigen

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

suppress

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

Large segments of bacterial chromosomal and plasmid DNA encoding virulence factors are known as pathogenicity "islands" because

they appear to have been inserted intact into existing DNA

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

tissue damage

Which term describes the ability of a microorganism to produce substances that alter host cell metabolism in a negative way?

toxigenicity

Which term refers to a substance that alters the normal metabolism of host cells with negative effects on the host organism

toxin

Which is an example of vertical transmission of a pathogen?

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

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

tropism

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

virulence

Select three typical systemic effects of lipid A on host organisms

weakness shock fever also, inflammation diarrea

The WHO stands for the

world health organization

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

zoonosis

toxins produced by fungi are generally called

mycotoxins

Select all correct descriptions of lipid A (endotoxin).

only weakly immunogenic component of the outer membrane of Gram-negative bacteria heat stable

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

opportunistic pathogen

A sudden, unexpected occurrence of a disease, usually in a limited segment of a population, is a(n)

outbreak

An increase in the occurrence of a disease within a a large population, affecting at least two countries around the world, is a(n)

pandemic

The global occurrence of H1N1 influenza outbreaks in 1918 and 2009 are good examples of

pandemics

Select the best term for a large segment (10-200 kilobases) of bacterial chromosomal and plasmid DNA that encodes virulence factors.

pathogenicity island

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

pathogenicity or virulence

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 total number of cases of a disease divided by the number of individuals in the population is the ______ rate

prevalence

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

In an AB exotoxin molecule, the A portion

produces the negative effect of the toxin inside the cell

A low ID50 value means ______.

relatively small numbers of microorganisms are required to establish an infection

What type of shock can result from exposure to relatively large amounts of the lipid A component of Gram-negative bacteria, and the subsequent release of large amounts of cytokines like IL-1 and tumor necrosis factor

septic shock

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

septicemia

Match each pathogen with the strategy used to evade the immune responses of the host. N. gonorrhoeae H. influenzae S. pyogenes

1)Produces proteases that digest host proteins such as IgA 2) Produces a capsule that prevents deposition of host complement 3) Expresses M protein on their surface to prevent detection

example of indirect contact transmission.

HIV infection via IV drug use with a contaminated shared needle

Select all correct statements regarding the Centers for Disease Control and Prevention.

It carries out health promotion and education activities. It employs many specialists in disease prevention and environmental health.

Select the best description of vector-borne transmission.

Lyme disease contracted through a bite from a tick

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.

best definition of lethal dose 50 (LD50)

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

Examine the table, then select all statements that correctly describe changes in the leading causes of death in the U.S. from 1900 and 2016.

The percentage of deaths due to heart diseases has increased. The percentage of deaths due to pneumonia and influenza has decreasec

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.

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

True

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

Virulence

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

True or false: Bacterial endotoxins produced by different species have very distinct structures and produce variable effects on different target cells.

false, Endotoxins produce similar effects on the same types of host cells regardless of the bacterial species that produce them.

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

fomites

Select all correct descriptions of bacterial exotoxins.

heat-labile (inactivated at 60-80 degrees C) often encoded on plasmids or prophages among the most toxic substances known

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

horizontal/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 winter months, the common cold can be described as a(n) ___ disease because it gradually increases in frequency beyond the endemic level, but not to the epidemic level.

hyperendemic

During the illness period of an infectious disease process, host ___ responses are typically triggered

immune

An opportunistic pathogen is one that is particularly likely 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

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.

incubation period---> prodromal stage---> illness period---> convalescence

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) ______. Multiple choice question.

infectious disease

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

intracellular

The number of new cases of a disease during a specified period divided by the number of individuals in the population is the ______ rate.

morbidity