MIC 205A Dr. Jan Decker
Exam 4
December 1, 2006
Part 1 MULTIPLE CHOICE: Read each question and the answers carefully. Pick the one BEST answer and darken the corresponding letter on the scantron. Each answer is worth 3 points, for a Part one total of 90 points.
- Human Papilloma Virus
- a. always causes cancer.
- b. dies very quickly on surfaces.
- c. remains latent in neurons between outbreaks.
- d. stimulates infected cells to produce DNA-replicating enzymes.
- To diagnose a Herpes simplex infection, one could NOT
- a. compare the DNA fingerprint of a patient sample containing the virus with the DNA fingerprint of known Herpes simplex.
- b. observe the patient’s signs of disease for typical signs of Herpes simplex.
- c. test Herpes simplex’s ability to metabolize glucose or amino acids.
- d. test the patient’s serum for the presence of antibodies to Herpes simplex.
- Measles is
- a. caused by a Herpes virus.
- b. transmitted by direct skin-to-skin contact.
- c. treatable with antibiotics.
- d. very contagious by droplets.
- The blood-brain barrier
- a. includes the skull and bones of the spine.
- b. keeps normal flora from leaving the CNS.
- c. refers to the capsules of Streptococcus pneumoniae, a cause of meningitis.
- d. restricts entry of microbes into the brain.
- The virulence factor that allows necrotizing fasciitis to spread quickly through the skin is
- a. antibiotic resistance.
- b. catalase.
- c. endotoxin.
- d. hyaluronidase.
- Plague is most contagious when it is
- a. bubonic.
- b. endotoxic.
- c. pneumonic.
- d. septicemic.
- A virus that infects the digestive tract but can then infect and destroy motor neurons to cause paralysis is
- a. Arbovirus.
- b. HIV.
- c. Polio Virus.
- d. Rubella Virus.
- Mycobacterium leprae and Mycobacterium tuberculosis BOTH
- a. are normal flora of the skin.
- b. are easily transmitted from one infected person to another.
- c. cause respiratory tract infections.
- d. survive inside macrophages.
- The ability of Rabies Virus to change the behavior of infected animals favors virus
- a. avoidance of the immune system.
- b. movement along neurons to the brain.
- c. survival in the host.
- d. transmission to new hosts.
- Salmonella can be acquired from
- a. eating infected eggs and meat.
- b. handling infected reptiles.
- c. ingesting as few as 10 organisms.
- d. All of the above are true.
- Secretory IgA is an important immune defense in the
- a. Cardiovascular System
- b. Nervous System.
- c. Respiratory Tract.
- d. Skin.
- For someone with a suspected central nervous system infection, the appropriate sample to test for the presence of pathogen would be
- a. a brain biopsy.
- b. a throat swab.
- c. blood.
- d. cerebrospinal fluid.
- HIV
- a. infects CD4 T cells.
- b. is a hemorrhagic fever virus.
- c. is a Herpes Virus.
- d. is the only virus that infects lymphocytes.
- Shingles is
- a. a painless form of chickenpox usually seen in people over 50.
- b. a rash in the skin closest to the nerve ganglion where Varicella-Zoster Virus has been latent.
- c. not able to be transmitted from person to person.
- d. the stage of a chickenpox infection during which infected lymphocytes carry the virus to the skin.
- Group A Strep (Streptococcus pyogenes) causes
- a. necrotizing fasciitis.
- b. pharyngitis.
- c. rheumatic fever.
- d. All of the above.
- High levels of ___________ in the blood cause septic shock.
- a. antibody
- b. bacterial exotoxins
- c. Gram negative bacteria
- d. viruses
- Lyme arthritis is caused by
- a. antigen-antibody complexes attracting neutrophils to the joints.
- b. Borrelia burgdorferi infecting joint cells.
- c. latent Lyme spirochetes moving through neurons into the joints.
- d. tick bites to the joints.
- Naegleria fowleri, the amoeba that causes Naegleria meningoencephalitis, is acquired by
- a. changing the litter box used by infected cats.
- b. having unprotected sex.
- c. inhaling respiratory droplets from infected humans.
- d. swimming in warm, non-chlorinated water.
- Influenza hemagglutinin is
- a. often antigenically different from one flu strain to the next.
- b. the envelope protein that allows Influenza Virus to bind respiratory mucosal cells.
- c. the target of host neutralizing antibodies.
- d. All of the above are true.
- Tubercles found in TB are
- a. a sign of disseminated TB.
- b. composed of antibody-agglutinated Mycobacterium tuberculosis.
- c. composed of infected macrophages surrounded by Th1 cells and fibroblasts.
- d. the inflammation seen in a positive TB test.
- Which virus below does NOT cause an STD?
- a. Herpes simplex 2
- b. HIV
- c. Hepatitis B
- d. Human Herpes Virus 8
- Most pneumonia is caused by
- a. Legionella pneumophila.
- b. Mycoplasma pneumoniae.
- c. Pneumonia virus.
- d. Streptococcus pneumoniae.
- Lysozyme is
- a. an enzyme that breaks down peptidoglycan.
- b. an important defense in the stomach.
- c. a packet of digestive enzymes inside the macrophage.
- d. an iron-binding protein.
- In order to identify a bacterium as E. coli 0157, once would need to
- a. do appropriate biochemical tests for E. coli.
- b. do a serological test with antibodies to the 0157 antigen.
- c. Gram stain the bacterium and observe it under the light microscope.
- d. Any one of these tests would be sufficient to identify E. coli 0157.
- Typhoid Mary was a carrier of Salmonella typhi, which means that she
- a. was a vector for the bacterium.
- b. was infected but did not have symptoms of typhoid.
- c. was infected but not infectious to other people.
- d. All of the above are true about carriers.
- Giardia lamblia is a
- a. bacterium.
- b. helminth.
- c. protozoan parasite.
- d. virus.
- Normal flora are an important defense in the ___________ system.
- a. cardiovascular
- b. gastrointestinal
- c. lower respiratory
- d. nervous
- Urinary tract infections are
- a. most often caused by E. coli and S. saprophyticus.
- b. often nosocomial.
- c. usually opportunistic.
- d. All of the above are true.
- Syphilis
- a. has become antibiotic-resistant.
- b. is caused by the Syphilis Virus.
- c. is more easily detected in females than in males.
- d. rapidly becomes systemic.
- Which statement below is TRUE?
- a. Herpes simplex 1 always causes cold sores and Herpes simplex 2 always causes genital herpes.
- b. Herpes simplex virus cannot be transmitted unless lesions are visible.
- c. One hundred percent of cervical cancer is caused by HPV.
- d. The same type of HPV causes genital warts and skin warts.
EXTRA CREDIT!!!
(3 points) Tell me about one thing you knew that I did not ask on this test (either in the multiple choice or the essay questions).
Part 2 ESSAY: Answer TWO of the questions below in the space provided. Each correct answer is worth five points, for a Part 2 total of 10 points.
31. Pima County Health Department has been tracking West Nile Virus infections in Tucson. Briefly describe two techniques that they could use to confirm that someone has WNV.
DNA fingerprinting to see if viral nucleic acids match those from WNV. [Will need to be preceded by RT-PCR to copy viral RNA genome into DNA and make more copies; not needed for full credit on answer.]
Testing serum of patient for antibodies to WNV, probably ELISA. [Virus is too small for fluorescent antibody or agglutination tests.]
Culture must be done in tissue culture, examine viral morphology under EM. [Less definite because other viruses resemble this one]
32. Describe the natural defenses of the skin. List one normal bacterial inhabitant of the skin and the disease it causes.
- Keratin: waterproof and good barrier for entry
- Skin sloughing: attached bacteria fall off with old skin
- Sebum: low pH, high lipid
- Sweat: low pH, high salt, lysozyme to digest peptidoglycan cell wall of baceria
- Propionibacterium acnes: acne
- Staphylococcus aureus: necrotizing fasciitis
- Streptococcus pyogenes: necrotizing fasciitis
- Candida albicans: yeast infection
33. Explain the synergistic effects between Influenza virus and Streptococcus pneumoniae.
Influenza virus infects and kills the ciliated epithelial cells of the lower respiratory tract, causing inflammation. The fluid in the lungs from the inflammation provides a great environment for the Streptococcus pneumoniae to grow. [Streptococcus pneumoniae also has a capsule that resists phagocytosis.] Together each microbe causes a more severe disease than either does alone (that is synergism).
Don’t forget the Extra Credit Question on the previous page!
