Which of the following is not a portal of entry for pathogens?

a. mucous membranes of the respiratory tract

b. mucous membranes of the digestive canal

c. skin

d. blood

e. parenteral route

Describe how hemolysins, leukocidins, coagulase, kinases, hyaluronidase, siderophores, and IgA proteases might contribute to pathogenicity.

Explain how drugs that bind each of the following would affect pathogenicity:

a. iron in the host's blood

b. N. gonorrhoeae fimbriae

c. S. pyogenes M protein

The ID₅₀ for Campylobacter sp. is 500 cells; the ID₅₀ for Cryptosporidium sp. is 100 cells. Which of the following statements is false?

a. Both microbes are pathogens.

b. Both microbes produce infections in 50% of the inoculated hosts.

c. Campylobacter is more virulent than Cryptosporidium.

d. Campylobacter and Cryptosporidium are equally virulent; they cause infections in the same number of test animals.

e. Cryptosporidium infections are acquired more easily than Campylobacter infections.

Compare and contrast the following aspects of endotoxins and exotoxins: bacterial source, chemistry, toxigenicity, and pharmacology. Give an example of each toxin.

An encapsulated bacterium can be virulent because the capsule

a. resists phagocytosis.

b. is an endotoxin.

c. destroys host tissues.

d. kills host cells.

e. has no effect; because many pathogens do not have capsules, capsules do not contribute to virulence.

Label this diagram to show how the Shiga toxin enters and inhibits protein synthesis in a human cell. <IMAGE>

Describe the factors contributing to the pathogenicity of fungi, protozoa, and helminths.

Which of the following genera is the most infectious? <IMAGE>

How can viruses and protozoa avoid being killed by the host’s immune response?

Which of the following does not represent the same mechanism for avoiding host defenses as the others?

a. Rabies virus attaches to the receptor for the neurotransmitter acetylcholine.

b. Salmonella attaches to the receptor for epidermal growth factor.

c. Lymphocryptovirus (mononucleosis) virus binds to the host receptor for complement protein.

d. Surface protein genes in N. gonorrhoeae mutate frequently.

e. none of the above

NAME IT The Fc region of this protein causes degranulation when it binds to basophils.

Desensitization to prevent an allergic response can be accomplished by injecting small, repeated doses of

a. IgE antibodies.

b. the antigen (allergen).

c. histamine.

d. IgG antibodies.

e. antihistamine.

Use the following choices to match the type of hypersensitivity to the examples in questions 7 through 10.

a. type I hypersensitivity

b. type II hypersensitivity

c. type III hypersensitivity

d. type IV hypersensitivity

e. all of the above

Reaction to an incompatible blood transfusion.

What does pluripotent mean?

a. ability of a single cell to develop into an embryonic or adult stem cell

b. ability of a stem cell to develop into many different cell types

c. a cell without MHC I and MHC II antigens

d. ability of a single stem cell to heal different types of diseases

e. ability of an adult cell to become a stem cell

Cytotoxic autoimmunity differs from immune complex autoimmunity in that cytotoxic reactions

a. involve antibodies.

b. do not involve complement.

c. are caused by T cells.

d. do not involve IgE antibodies.

e. none of the above

Antibodies against HIV are ineffective for all of the following reasons except

a. the fact that antibodies aren’t made against HIV.

b. transmission by cell–cell fusion.

c. antigenic changes.

d. latency.

e. persistence of virus particles in vacuoles.

Which of the following is not the cause of a natural immunodeficiency?

a. a recessive gene resulting in lack of a thymus gland

b. a recessive gene resulting in few B cells

c. HIV infection

d. immunosuppressant drugs

e. All of the above are causes of natural immunodeficiency.

Why does an ANA (antinuclear antibody) test diagnose lupus?

Use the following choices to match the type of hypersensitivity to the examples in questions 7 through 10.

a. type I hypersensitivity

b. type II hypersensitivity

c. type III hypersensitivity

d. type IV hypersensitivity

e. all of the above

Localized anaphylaxis.

Use the following choices to match the type of hypersensitivity to the examples in questions 7 through 10.

a. type I hypersensitivity

b. type II hypersensitivity

c. type III hypersensitivity

d. type IV hypersensitivity

e. all of the above

Allergic contact dermatitis.

Use the following choices to match the type of hypersensitivity to the examples in questions 7 through 10.

a. type I hypersensitivity

b. type II hypersensitivity

c. type III hypersensitivity

d. type IV hypersensitivity

e. all of the above

Due to immune complexes.

Which of the following pairs is mismatched?

a. leading infectious cause of blindness—Chlamydia

b. chickenpox—shingles

c. HSV-1—encephalitis

d. Buruli ulcer—stomach acid

e. none of the above

Discuss the usual mode of entry of bacteria into the skin. Compare bacterial skin infections with infections caused by fungi and viruses with respect to mode of entry.

Use the following information to answer questions 1 and 2. A 6-year old girl was taken to the physician for evaluation of a slowly growing bump on the back of her head. The bump was a raised, scaling lesion 4 cm in diameter. A fungal culture of material from the lesion was positive for a fungus with numerous conidia.

The girl’s disease was

a. rubella.

b. candidiasis.

c. dermatomycosis.

d. a cold sore.

e. none of the above

What bacteria are identified by a positive coagulase test? What bacteria are characterized as group A beta-hemolytic?

Use the following information to answer questions 1 and 2. A 6-year old girl was taken to the physician for evaluation of a slowly growing bump on the back of her head. The bump was a raised, scaling lesion 4 cm in diameter. A fungal culture of material from the lesion was positive for a fungus with numerous conidia.

Besides the scalp, this disease can occur on all of the following except

a. feet.

b. nails.

c. the groin.

d. subcutaneous tissue.

e. The disease can occur on all of these areas.

Use the following information to answer questions 3 and 4. A 12-year old boy had a fever, rash, headache, sore throat, and cough. He also had a macular rash on his trunk, face, and arms. A throat culture was negative for Streptococcus pyogenes.

The boy most likely had

a. streptococcal sore throat.

b. measles.

c. rubella.

d. smallpox.

e. hand-foot-mouth disease.

DRAW IT On the following figure, show the sites of the following infections: impetigo, folliculitis, acne, warts, shingles, sporotrichosis, pediculosis.

<IMAGE>

Use the following information to answer questions 3 and 4. A 12-year old boy had a fever, rash, headache, sore throat, and cough. He also had a macular rash on his trunk, face, and arms. A throat culture was negative for Streptococcus pyogenes.

All of the following are complications of this disease except

a. middle ear infections.

b. pneumonia.

c. birth defects.

d. encephalitis.

e. All are complications of this disease.