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MEDICAL MICROBIOLOGY SHORT ANSWER QUESTIONS
These basic questions will be included in the mid-semester tests (in addition to simple-
choice and multiple-choice questions) and in the written entry test of the Final Examination in
the Department of Medical Microbiology. We would like to emphasize some important
aspects about these questions and answers.
It is important to realize that learning only this material does not give sufficient
knowledge for the tests and examinations. These questions are not to be used to start learning,
rather for measuring your knowledge. However, after a certain amount of learning, students
may use this material for self-testing, and also for identifying dark areas of their knowledge.
The teacher correcting the tests can give 1 point for each answer. As these are basic
questions, only completely good answers will be accepted. However, after careful
consideration, the teacher may give a point for an answer which is 75-80 % good. On the
other hand, if the student writes bad answer(s) in addition to good answers for a question, the
teacher may refuse to give the point, depending on the severity of the mistake.
If you find any mistakes in the questions or answers, or you think that there may be
additional good answers given to a question, please write me, preferably in e-mail (Dr. Veress
György: firstname.lastname@example.org). We cannot accept any complaints regarding these
Dr. György Veress Associate Professor Academic advisor
Describe the colour (in a Gram stained smear) of Gram positive and Gram negative
bacteria, respectively! Gram positives: dark blue/purple
Gram negatives: red/pink
Describe the 3 important parts of the bacterial lipopolysaccharide!
+ core polysaccharide
+ O-specific (polysaccharide) side chain
Which 2 roles are attributed to bacterial pili (fimbriae)?
; conjugation (sex fimbriae
Mention a bacterium and its virulence factor that is encoded by a lysogenic
bacteriophage! Corynebacterium diphtheriae – diphtheria toxin
Streptococcus pyogenes – erythrogenic toxin
Specify 2 genera containing obligate intracellular pathogens!
, (Coxiella, Ehrlichia)
Mention at least 5 possible transmission ways of infections!
(infectious aerosol) faecal-oral direct contact
(such as sexual) fomites
(inanimate objects) blood
List the possible shapes of bacteria. Write one example per category.
(spherical): Staphylococcus, Streptococcus rod
: Clostridium, Corynebacterium, Gram negative rods curved rod
: Vibrio helical
: Spirochetes (Treponema, Borrelia, Leptospira)
What are the essential components of bacterial cells? Specify at least 3!
cytoplasm, nucleoid (genome), cell membrane
, (cell wall)
Vector is an arthropod
that transmits infection
from human to human, or from animal to
examples. tick – Lyme disease; louse – epidemic typhus; mosquito – malaria
10. What is a reservoir? Write an example.
The normal host
of a pathogen (human or animal) serving as a continuous source of
to other hosts (such as humans).
Salmonella typhi – human; Yersinia pestis - rodents
11. Mention 3 reliable methods of sterilization!
autoclaving, hot air oven, gamma-radiation, filtration
(fluids), gas sterilisation
(not acceptable: boiling, pasteurisation, UV!)
(alkylating agents); phenol derivatives; detergents
= oxidising agents
Mention a group
of antimicrobial drugs that act on the bacterial ribosome and usually
has bactericidal effect! aminoglycosides
14. Describe precisely what toxoid means!
Inactivated bacterial exotoxin that is not toxic but immunogenic
15. Mention 2 broad-spectrum (effective against both Gram positive and Gram negative
bacteria) penicillin derivatives. ampicillin, amoxicillin, piperacillin
, azlocillin, mezlocillin
16. Mention an antifungal and an antibacterial drug that alter the function of the cell
membrane! antifungal: Amphotericin B, azoles; antibacterial: polymyxins
17. What are the possible mechanisms of acquired penicillin resistance of bacteria? Mention
at least 3 mechanisms!
(target) alteration 3
. reduced permeability
4. active efflux
18. Mention a drug belonging to macrolides!
, spiramycin, roxithromycin, clarithromycin, azithromycin
19. Mention 2 drugs belonging to aminoglycosides!
streptomycin, gentamycin, tobramycin, amikacin
20. Mention 2 groups of antimicrobial drugs that act on the 30 S subunit of the bacterial
ribosome! aminoglycosides, tetracyclines
21. Mention 3 groups
of antibacterial drugs inhibiting bacterial cell wall synthesis!
carbapenems, monobactams, glycopeptides
22. Which part of the bacterial cell carries the endotoxin?
of Gram negative bacteria
23. What role is attributed to the bacterial capsule in the infectious process?
24. Mention 2 infectious diseases that are transmitted to humans by tick bites!
tick-borne encephalitis; Lyme-disease
; Rocky-Mountain spotted fever;
recurrent fever (Borrelia recurrentis) etc.
25. Which type of hypersensitivity is involved in the tuberculin test?
type (type IV)
26. Mention 2 bacterial infectious diseases that can be prevented or treated by passive
transfer of specific immunoglobulins!
treatment: diphtheria, botulism, tetanus
27. What do the vaccine(s) against diphtheria and tetanus contain?
Diphtheria and tetanus toxoid
28. What does the vaccine against pertussis contain?
vaccine (toxoid + other purified proteins)
29. What does the vaccine against tuberculosis (BCG) contain?
live attenuated Mycobacterium bovis
30. What is the nature of antigen in the vaccines used to prevent infections by
Streptococcus pneumoniae, Haemophilus influenzae
and Neisseria meningitidis
? capsular polysaccharide
(either alone or conjugated to a carrier protein)
Mention 2 bacterial exotoxins that are neurotoxic!
tetanus toxin, botulinum toxin
Specify the 4 groups of bacterial
vaccines according to the nature of the antigen!
a., live, attenuated vaccines
b., killed bacterial vaccines
c., toxoid vaccines
d., subunit vaccines
(capsular polysaccharide or purified protein)
What is the mechanism of action of lysozyme? Where is lysozyme found in the host?
It destroys bacterial cell wall peptidoglycan by hydrolysing the glycosyl bonds
between NAM (N-acetylmuramicacid) and NAG (N-acetylglucosamine). It occurs in
tear, saliva, respiratory secretions.
Which Gram negative organelles or structures are associated with the O, H and K
antigens, respectively? O- LPS, H-flagella, K-capsule
Mention 2 bacterial exotoxins that act by ADP ribosylation!
Diphtheria toxin, cholera toxin, pertussis toxin
Describe the rules of collecting native urine for culturing bacteria! Describe also the
conditions for keeping the specimen before sending it to the laboratory! A midstream specimen, taken preferably in the morning, after thorough cleaning of
the external genital area. Keep it up to 1 h at room temperature or up to 24 h at +4
Describe the rules of collecting hemoculture specimens!
It is recommended to obtain 3 specimens
(with at least 30 min. between the specimens).
The specimens should be preferably taken before fever spikes (during rising fever),
from fresh peripheral venipuncture sites
. If possible, both aerobic and anaerobic
bottles should be used (3 x 2 bottles altogether). The site of venipuncture
and the plug of
containing the medium must be properly disinfected
. The amount of blood
injected to the bottle should be about 10 % of the liquid medium.
Mention two clinical specimens that are heavily contaminated with bacteria belonging
to the normal body flora! throat and nasal secretions, faeces, vaginal secretions.
Mention at least three of the physiological effects of septic shock (characterized by the
presence of large amount of bacterial endotoxin in the blood)! fever, hypotension, disseminated intravascular coagulation (DIC), complement
impaired organ perfusion, hypoglycaemia
What pathogenic role is attributed to lysogenic conversion?
Lysogenic conversion: transfer of genes from one bacterium to another by lysogenic
bacteriophages. The bacteria may gain exotoxins
(diphtheria toxin, Streptococcus
pyogenes erythrogenic toxin), or the structure of LPS epitopes may be altered
41. Describe the principle of acid fast staining procedures!
Mycobacteria contain a high amount of special lipids called mycolic acids
. They can be
stained by hot carbol-fuchsin, but they resist decolourisation with acid-alcohol
, so they
remain red. All other cells are stained blue by the counter stain (methylene blue).
42. Mention 2 non-essential bacterial organelles that enhance bacterial virulence! Describe
how their function contributes to pathogenicity! Capsule: antiphagocytic effect, adhesion to tissues
Fimbriae: binding to tissues
Flagellae: spreading the bacteria
43. Mention a differentiating culture medium and describe which groups of bacteria are
distinguished on the mentioned medium!
Eosin-methylene blue (EMB) agar: Inhibits Gram positive
bacteria and inhibits the
swarming of Proteus. Differentiates between lactose fermenters and non-fermenters
Lactose fermenters produce high amounts of acids, which is indicated as dark blue
colonies by eosin and methylene blue.
McConkey agar: Inhibits Gram positive bacteria
by bile salts and crystal violet. It
differentiates between lactose fermenters and non-fermenters
. Lactose fermentation is
indicated by neutral red. Lactose fermenters form pink to red colonies, while non-
fermenters form colourless colonies.
Describe the definition for facultative anaerobic bacteria!
They are able to grow and metabolize both in the presence and in the absence of
. In aerobic conditions they perform respiration, in anaerobic condition, they
Mention 4 extracellular enzymes of bacterial origin functioning as virulence factors!
(fibrinolysine), streptodornase (DNase), hyaluronidase, IgA
protease, collagenase, elastase, urease
What is the difference between prevalence and incidence of an infectious disease?
It can be differentiated in chronic diseases
. Prevalence: total number
of diseases (per
100,000 people). Incidence: number of new
cases in a year (per 100,000 people).
47. What is the difference between mortality and lethality of a disease?
Mortality: total number of deaths
caused by the disease in a population (usually 100,000
people). Lethality: rate of death
(in percent) among patients suffering from the disease.
Mention 2 groups of disinfectants acting on the microbial membrane structures!
a., (cationic) detergents (quaternary ammonium-compounds);
b., phenol compounds (cresol, hexachlorophene, chlorohexidine)
c., alcohol (ethanol, isopropanol)
Describe the principle of the Kirby-Bauer (disk diffusion) method used to determine
antibiotic sensitivity! Disks impregnated
with different antibiotics are placed on the surface of appropriate agar
media that has been inoculated with the bacterium isolated from the patient. After
overnight incubation, the antibiotics diffusing from the discs
may cause zones of
inhibition around the discs. The size of the zone
should be compared to standards to
determine antibiotic sensitivity.
Explain the purpose for using beta-lactamase inhibitors in antibacterial therapy!
Combination of beta-lactamase inhibitors (such as clavulanic acid or sulbactam
beta-lactamase sensitive penicillins (such as amoxicillin or ampicillin) can overcome
resistance mediated by many but not all beta-lactamases.
51. What are the main advantages and disadvantages of live attenuated vaccines as
Advantages: induce not only serum antibodies but also cellular immunity and local IgA
antibodies. Some may be applied orally. Usually fewer doses
Disadvantages: Attenuated strains may revert to virulent
in rare cases. They may cause disease in immunosuppressed
patients. Live attenuated microbes are usually heat
sensitive and must be refrigerated.
Mention 4 groups of antibiotics which have bactericidal effects!
penicillins, cephalosporins, aminoglycosides, fluoroquinolons etc
Which antibiotics inhibit bacterial DNA gyrase enzyme?
nalidixic acids, fluoroquinolons
What is the mode of action of the antibiotics sulfonamides and thrimethoprim,
They inhibit the synthesis of folic acid
. Sulfonamides: inhibit the synthesis of dihidro-
folate (they are PABA analogues). Trimethoprim: inhibition of dihidrofolate-reductase.
What is the mode of action of the antibiotic vancomycin?
Inhibits cell wall synthesis in Gram positive bacteria by blocking transpeptidation
Mention 4 groups of antibiotics inhibiting protein synthesis of bacteria!
Aminoglycosides, tetracyclines, chloramphenicol, macrolides, lincosamides
Regarding the joint effects of 2 antibiotics, what does synergism mean?
The effect of the two drugs together is significantly higher than the sum of the effects
of the two drugs acting separately.
Regarding the joint effects of 2 antibiotics, what does antagonism mean?
The effect of the two drugs together is significantly lower than the effect of the more
effective drug alone.
Selective inhibition of the growth of the microorganism without damage to the host.
In other words: the drug is highly toxic to the bacteria, but not toxic (or have very low
toxicity) to the human host.
60. How can one identify the different surface antigens of Gram negative bacteria?
with slide agglutination tests using antibodies of known specificity
61. What is the mechanism of action of diphtheria toxin?
Inhibition of protein synthesis
in eukaryotic cells by ADP-ribosylation of ribosomal
62. What is the mechanism of action of tetanus toxin?
It causes spastic paralysis
by blocking the release of inhibitory neurotransmitters
(glycine) in synapses
63. What roles can be attributed to specific antibodies in antibacterial immunity? Specify at
a. neutralisation of exotoxins and enzymes
b. complement-dependent bacteriolysis
d. interfering with attachment
of bacteria to mucosal surfaces
64. Starting from a fixed smear, specify the main steps of Gram stain in the appropriate
order! 1. Crystal violet 2. Lugol solution (iodine) 3. Differentiation: ethanol wash 4. Counterstaining: safranin or fuchsin (wash with tap water after each step)
65. Starting from a fixed smear, specify the main steps of the acid-fast stain (Ziehl-Neelsen)
1. Stain with carbol-fuchsin (with heating) 2. Differentiation: wash with acid-ethanol 3. Counterstaining with methylene-blue (wash with tap water after each step)
66. What is the difference between agglutination and precipitation?
Both are serological reactions where specific binding of the antigen with the antibody
directly results in a reaction visible by the naked eye. The difference is in the nature of the
antigen. Agglutination: particulate antigen
(RBC, bacteria, latex particles). Precipitation: antigen is in solution
before the reaction.
67. What does titer mean in serological tests?
The highest dilution
of the serum sample that gives a positive
reaction in the test.
68. How can one differentiate between past and current infections in serological tests?
Current infections are indicated by: either IgM class
specific antibodies or, in the case of
paired serum specimens (taken from the same patient at least 7-10 days apart), a significant (at least 4-fold) rise in the titer
of specific antibodies.
Specify the main steps of an ELISA test in which we detect antibodies from patients’
serum samples using known antigens!
1. Binding antigen
to plastic surface (in wells of a 96-well plate)
2. Adding diluted serum sample
(specific antibodies bind to the antigen)
(secondary antibody conjugated with an enzyme)
4. Adding the substrate
of the enzyme, reading the colour reaction
70. How can one determine the minimal inhibitory concentration of an antibiotic to a
Inoculate the bacterial isolate into a series of test tubes containing 2-fold dilution series of
the drug. After overnight incubation, the lowest concentration of drug that prevents
of the organism is the MIC.
Mention 5 diseases that can be caused by Staphylococcus aureus
Impetigo, furunculus, pneumonia, osteomyelitis, food poisoning etc
Mention 2 toxin-mediated staphylococcal diseases!
toxic shock syndrome (TSS), scalded skin syndrome, food poisoning
Mention 3 toxic products produced by Staphylococcus aureus
TSST (toxic shock syndrome toxin), enterotoxin, exfoliatin, leukocidins, hemolysins
Which is the most virulent species of Staphylococcus?
Which enzymatic virulence factor is characteristic exclusively for Staphylococcus
How can we identify the source of infection in a staphylococcal food poisoning?
by phage typing
Which antibacterial drug is the first choice in serious infections caused by methycillin
resistant Staphylococcus aureus (MRSA) strains? glycopeptides (vancomycin, teicoplanin)
In which disease is Staphylococcus saprophyticus
considered an obligate pathogen!
cystitis in young women
Which cell constituents determine the group-specific, and the type specific antigens of
, respectively? group specific: C- polysaccharide
type specific: M protein
Mention 3 enzymes produced by Streptococcus pyogenes
that enhance the spread of
the bacterial infection in the body! Streptokinase (fibrinolysin), hyaluronidase, streptodornase (DNAse)
List 3 diseases caused by Streptococcus pyogenes
in the skin or in subcutaneous
tissues! impetigo (pyoderma), cellulitis, erysipelas, fasciitis, myositis
Mention a toxin-mediated streptococcal disease, specify the name of the toxin and its
mechanism of action! Scarlet fever - erythrogenic toxin – superantigen causing capillary destruction
Glomerulonephritis, rheumatic fever
, erythema nodosum, chorea minor.
14. Which product of Streptococcus pyogenes has a major pathogenic role in
poststreptococcal diseases? M protein
: may induce hypersensitivity reactions
How long does immunity against scarlet fever exist? Which immune effector
mechanism is involved? Life-long immunity. Antitoxic antibodies are involved.
What is the drug of first choice in Streptococcus pyogenes infection?
What is the patomechanism of post-streptococcal rheumatic fever?
type II hypersensitivity (cytotoxic antibodies)
What is the patomechanism of post-streptococcal glomerulonephritis?
type III hypersensitivity (immune complexes)
Which Streptococcus species plays major role in the meningitis of newborn babies?
Group B Streptococcus (S. agalactiae)
What is (are) the major causative agent(s) for subacute bacterial endocarditis?
What are the characteristics of Enterococci that can be used in their identification?
D group polysaccharide antigen; tolerance to bile and hydrolysis of esculin (BEA
medium: bile esculin agar); growth in the presence of 6,5 % NaCl
What are the specific morphologic features of Streptococcus pneumoniae
Gram positive diplococcus, lancet shape, capsule.
Mention 3 diseases that can be caused by Streptococcus pneumoniae
Pneumonia, meningitis, sinusitis, otitis media, sepsis, (
ulcus serpens corneae)
What fast diagnostic procedure can be used in acute Neisseria gonorrhoeae
Demonstration of bacteria (intracellular in PMNs) from urethral discharge by Gram
or methylene blue stain
; PCR amplification of bacterial DNA
What kind of immunity develops after Neisseria gonorrhoeae
Partial immunity of short duration; no protection from reinfection
Specify at least 2 of the most important manifestations of disseminated gonorrhoeal
infections! arthritis, skin eruptions,
What is the major manifestation of Neisseria gonorrhoeae
infection in newborns?
How can it be prevented? Blenorrhoea (ophtalmia) neonatorum, silver acetate eye drops or erythromycin
Mention at least 3 major virulence factors of Neisseria gonorrhoeae
pilus, outer membrane proteins, LOS (lipooligosaccharide), IgA protease
Mention at least 2 major virulence factors of Neisseria meningitidis
polysaccharide capsule, LPS, IgA protease
What is the site of entry of Neisseria meningitidis
infection? What diseases are caused
by this bacterium?
The site of entry is the nasopharynx
(transmitted by airborne droplets). Meningococcemia
(characterized by skin lesions), and acute (purulent) bacterial meningitis
What kinds of prophylactic measurements are available against Neisseria meningitidis
infections? Chemoprophylaxis: rifampin or ciprofloxacin.
Vaccination: capsular polysaccharide (types A, C, Y and W135). No vaccine against
Which rapid diagnostic methods can be used in the presumptive diagnosis of purulent
bacterial meningitis? Gram or methylene blue stain of CSF sediment
Demonstration of bacterial capsular antigens by latex agglutination (from CSF)
Which capsular serotype is included in the vaccine against Haemophilus influenzae?
34. Which are the portals of entry of Bacillus anthracis
Skin, lungs, gastrointestinal tract
Mention 3 important bacteria involved in nosocomial (hospital-acquired) infections!
Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Escherichia
Mention four E. coli pathogenetic groups involved in enteric diseases!
Enteropathogenic E. coli
(EPEC) Enterotoxic E. coli
(ETEC) Enteroinvasive E. coli
(EIEC) Enterohemorrhagic E. coli
Enteroaggregative E. coli
What are the most important extraintestinal infections caused by E. coli? Mention at
least 3 of them! urinary tract infections, neonatal meningitis, nosocomial wound infections
38. The most frequent causative agent of urinary tract infections is:
Which 2 diseases are caused by E. coli O157:H7?
hemorrhagic colitis +/- HUS (hemolytic uraemic syndrome)
What is the reservoir of Salmonella typhi
humans (with disease, or healthy carriers)
41. Which bacteria cause most frequently typhoid fever and enteric fever, respectively?
Salmonella typhi (typhoid)
Salmonella paratyphi A, B, C (enteric fever)
42. When typhoid fever is suspected, what kinds of clinical samples should be used to isolate
the causative agent in the first 2 weeks of the disease? Blood,
43. What is the route of infection in Salmonella gastroenteritis?
Ingestion of contaminated food
(such as eggs, cream, mayonnaise, creamed foods, etc.) containing a sufficient number of Salmonella
44. Which antibacterial drugs should be administered in gastroenteritis caused by
Salmonella? Antibiotics are not usually necessary unless the infection is generalised. In case of
extraintestinal infection (very young, very old or immunosuppressed patients):
ampicillin, gentamicin, trimethoprim/sulfamethoxazole, or ciprofloxacin.
45. List the 4 Shigella species causing human disease!
Shigella dysenteriae, S. flexneri, S. boydii, S. sonnei
46. Mention 2 bacterial species belonging to different genera that cause bacillary dysentery
Shigella dysenteriae, (Shigella flexneri, Shigella boydii, Shigella sonnei), enteroinvasive
E. coli (EIEC)
Mention 3 bacterial species belonging to different genera that cause enteritis or
enterocolitis! Campylobacter jejuni, Escherichia coli, Salmonella enteritidis, Shigella, Yersinia
Mention 2 bacteria causing intestinal infections which have animal reservoirs!
Salmonella (not Typhi and Paratyphi!), Campylobacter jejuni, Yersinia
enterocolitica, Listeria monocytogenes, E. coli O157
49. What are the modes of transmission for the 2 different epidemiologic forms of plague?
- Bubonic plague
is transmitted by the bite of infected rat fleas from rats to humans.
- Primary pneumonic plague
spreads directly from human to human via respiratory
What are the possible portals of entry of Francisella tularensis
? Specify at least 4!
tick bite, mucous membranes, skin abrasions, resp. tract, gastroint. tract
51. How do humans acquire brucellosis? Where do the bacteria replicate in the human body?
Via contaminated milk products or through skin abrasions (contact with animals).
Organisms spread to the mononuclear phagocytes of the reticuloendothelial system
(lymph nodes, liver, spleen, bone marrow).
What are the reservoirs of the different Brucella species, respectively?
B. abortus: cattle
B. melitensis: goat, sheep
B. suis: swine
53. What is the mechanism of action of cholera toxin?
Cholera toxin activates the adenylate cyclase enzyme in cells of the intestinal mucosa
leading to increased levels of intracellular cAMP
, and the secretion of large amount of
water, Na+, K+, Cl-, and HCO -
3 into the lumen
of the small intestine.
54. What is the principle of the treatment for cholera?
Rapid intravenous or oral replacement of the lost fluid and ions.
isotonic maintenance solution should continue until the diarrhea ceases.) In severe cases:
administration of tetracycline (in addition to rehydration).
55. Mention 4 diseases caused by Haemophilus influenzae
epiglottitis (obstructive laryngitis)
otitis media and sinusitis
56. Which disease is caused by Haemophilus ducreyi
Chancroid (soft chancre or ulcus molle)
57. What can serve as source of infections caused by Pseudomonas aeruginosa
Pseudomonas species are normally present in the environment
and can be isolated from
the skin, throat, and stool
of some healthy persons. They often colonize hospital food,
sinks, taps, mops, and respiratory equipment.
58. Mention 4 diseases that are frequently caused by Pseudomonas aeruginosa
urinary tract infections
wound infections (burns)
pneumonia, sepsis (immunosupression)
Mention at least 3 drugs which may be effective to treat infections caused by
certain penicillins: piperacillin/tazobactam combination
a 3rd generation cephalosporin: ceftazidim
a 4th generation cephalosporin: cefepime
certain aminoglycosides: gentamycin, tobramycin, amikacin
60. Which 2 diseases are caused by Legionella pneumophila?
- legionellosis, legionnairs’ disease (
- Pontiac fever (
mild, flu like illness without pneumonia)
61. List 3 important virulence factors of Bordetella pertussis
filamentous hemagglutinin, pertussis toxin, adenylate-cyclase toxin, tracheal
62. Mention 3 bacterium species causing food poisoning!
Staphylococcus aureus, Bacillus cereus, Clostridium perfringens, Clostridium
botulinum, Vibrio parahaemolyticus
, (Salmonella serotypes causing enterocolitis)
63. Which bacterium has the highest germ number in the colon?
64. Mention 4 bacterial genera that are obligate anaerobes!
Clostridium, Bacteroides, Prevotella, Porphyromonas, Fusobacterium, Actinomyces,
Bifidobacterium, Peptostreptococcus, Propionibacterium
65. Which is the most important gas gangrene Clostridium? What is its main virulence factor?
66. Mention 3 Clostridium species causing gas gangrene! How are they acquired?
Clostridium perfringens, C. novyi, C. septicum, C. histolyticum, C. tertium, C.
bifermentans, C. sporogenes
The site of infection is usually a wound that comes into contact with Clostridium
that germinate in an anaerobic environment
How can be tetanus prevented in patients who have wounds possibly contaminated with C.
Wound should be cleaned and debrided
; tetanus toxoid booster injection given
; tetanus immunoglobulin
(TETIG) in previously unvaccinated patients and in case of
heavy contamination of wound; penicillin may be added prophylactically
What are the main symptoms of tetanus infection? Specify at least 3!
Spastic paralysis: muscle spasms; lockjaw(trismus), rhisus sardonicus (grimace of the
, opisthotonus (spasm of the back); respiratory paralysis
69. What is the mechanism of action of the botulinus toxin?
Blocks release of acetylcholine
in peripheral nerve synapses;
flaccid paralysis: diplopia (double vision), dysphagia (difficulty to swallow),
dysphonia (hoarseness), respiratory paralysi
71. What kind of therapy is used to treat botulism?
Treatment: respiratory support + trivalent antitoxin
72. Explain whether or not antibiotic treatment is useful in botulism!
Not, because antibiotics are not effective against preformed toxins
73. What diseases may be associated with Helicobacter pylori? Specify at least 3!
Gastritis, peptic and duodenal ulcers, gastric carcinoma, MALT lymphoma
What is the most important virulence factor of Corynebacterium diphtheriae?
75. What is the mechanism of action of the diphtheria toxin?
Inhibits protein synthesis. Inhibits peptide elongation in eukaryotic ribosomes by
ADP ribosylation of EF-2 (elongation factor-2)
76. How long does immunity against diphtheria exist? Which immune effector mechanism is
involved? Antitoxic antibodies, long lasting immunity
77. Which assays should be done in the lab in order to prove diphtheria?
Smears of the throat swab should be stained with methylene blue or Neisser stain
bacteria are cultured on Löffler’s or tellurite
; toxin production
must be demonstrated by agar precipitation
78. What feature of Mycobacteria make them acid fast?
The cell envelope contains a high amount (60 – 70 %) of complex lipids
: mycolic acid,
cord factor. Once the cells are stained (by carbol-fuchsin) they resist decolorisation by
Mention 2 atypical Mycobacterium species!
M. kansasii, M. marinum, M. avium-intracellulare complex, M. fortuitum-chelonei
80. How can one demonstrate the presence of Mycobacterium tuberculosis in clinical
samples? Acid-fast staining (Ziehl-Neelsen)
Culture on selective media (Löwenstein-Jensen agar, liquid BACTEC medium)
PCR amplification of bacterial DNA
81. Why is multi-drug therapy used for tuberculosis?
To prevent the overgrowth of drug-resistant mutants during the long treatment
period (if bacteria resistant to one drug emerge, they are most probably inhibited by
the other drugs).
82. What is the main immune defense mechanism against Mycobacterium tuberculosis
83. Mention 3 antituberculotic drugs that are of first choice against Mycobacterium
tuberculosis! isoniazid (INH), pyrazinamid, rifampin, (ethambutol, streptomycin)
What disease is caused by Mycobacterium avium-intracellulare?
What patients are
characteristically susceptible to infection? It causes TB, especially in immunosuppressed patients
(such as AIDS patients).
What is the reservoir of Mycobacterium tuberculosis
What is the reservoir of atypical Mycobacteria?
environment (soil, water)
What are the 2 distinct forms of leprosy?
Tuberculoid, lepromatous forms
Mention 3 Gram-negative bacteria belonging to different genera causing zoonosis!
Brucella, Francisella tularensis, Yersinia pestis, Pasteurella
Mention 2 Gram-positive bacteria belonging to different genera causing zoonosis!
Listeria monocytogenes, Bacillus anthracis, Erysipelothrix rhusiopathiae
90. Mention 3 bacterial species belonging to different genera that are frequent causes of
urinary tract infections! E. coli, Klebsiella, Proteus, Pseudomonas aeruginosa, Enterococcus faecalis
91. Mention one aerobic and one anaerobic bacterium of the normal flora of the skin!
aerobic: Staphylococcus epidermidis
anaerobic: Propionobacterium acnes
Give two genuses for each category of bacteria!
Gram positive aerobic: Staphylococcus, Streptococcus, Bacillus, Corynebacterium,… Gram positive anaerobic: Clostridium, Actinomyces, Propionibacterium, Lactobacillus
Give two genuses for each category of bacteria!
Gram negativ aerobic: Vibrio, Neisseria, Haemophilus… Gram negativ anaerobic: Bacteroides, Prevotella, Porphyromonas, Veillonella…
Give 2 genuses for each category of bacteria!
Gram positive coccus: Staphylococcus, Streptococcus Gram negative coccus: Neisseria, Veillonella Gram positive rod: Clostridium, Bacillus
Give 2 genuses for each category of bacteria!
Gram negative rod: E. coli, Salmonella, Shigella Spirochetes: Treponema, Borrelia, Leptospira
Describe the color and the shape of Clostridia in a Gram stained smear of gas
gangrene exudate! Gram positive
(dark blue) rod
(it usually does not form spores in vivo)
Mention 2 antibiotics which can be used in the empirical treatment against Gram
negative obligate anaerobic bacteria! Metronidazol, amoxicillin + clavulanic acid, imipenem
Which 3 bacterial species are the most important causative agents of neonatal (< 1
month of age) meningitis? Streptococcus agalactiae, E. coli, Listeria monocytogenes
Which 3 bacterial species are the most important causative agents of meningitis
among babies (> 1 month of age) and children? Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae
What is the causative agent of febris undulans (undulant fever)?
What is the precise definition of bacterial food poisoning?
Acute disease, usually with vomiting and diarrhea, caused by preformed toxins
produced by bacteria contaminating the food
. The period between consumption of food
and the appearance of symptoms is short (< 4-6 hours).
What are the main symptoms in the different stages of syphilis?
Primary syphilis: nontender ulcer
Secondary lesions: maculopapular rash
on skin, and condylomata lata
Tertiary stage: granulomas (gummas
), central nervous system involvement (tabes
dorsalis, paralysis progressiva
), cardiovascular lesions (aortitis, aorta aneurysm
When syphilis is diagnosed in the lab, which antigens are used in the non-treponemal
and in the specific treponemal antibody tests, respectively?
Non-treponemal antibody tests: cardiolipin
Specific treponemal antibody tests: Treponema pallidum
Which are the two different kinds of antibodies which may indicate syphilis? Give
examples for tests demonstrating them!: Reagin (nonspecific antibody)
– RPR, VDRL
(flocculation tests) Immobilisin (specific antibody)
– TPHA (T. pallidum hemagglutination), FTA-ABS
(fluorescent treponemal assay – with antibody absorption),
TPI (T. pallidum
What is the advantage and disadvantage of the FTA-ABS syphilis serologic test
compared to the VDRL test?
Specific (treponemal) tests such as FTA-ABS are more specific
, but they can not be used
to follow the efficacy of treatment
(because the specific antibodies persist even after
effective eradication of bacteria)
What is the drug of first choice in the treatment of syphilis?
What is the reservoir and what is the vector for Borrelia recurrentis
Reservoir: human; vector: louse
What is used for the laboratory diagnosis of relapsing fever?
of bacteria from peripheral blood smear
by microscopy (Giemsa
stain or dark field illumination)
What is the first characteristic symptom of Lyme disease? What is the causative
agent? Erythema (chronicum) migrans. Borrelia burgdorferi.
Mention 2 antibacterial drugs that are of first choice in early stage Lyme disease?
Tetracyclines, amoxicillin, cefuroxim
Which symptoms are characteristic for the early and the late phases of disease by
? Early: erythema chronicum migrans
Late: arthritis, cardiac (myocarditis, pericarditis) and neurological involvement
(meningitis, peripheral neuropathies)
What is the reservoir of Leptospira interrogans
rodents, household animals (dog, swine etc.)
Mention 2 obligate intracellular bacterial genuses!
Rickettsia, Chlamydia, (Coxiella, Ehrlichia)
Mention 4 bacteria causing atypical pneumonia!
What diseases are caused by Rickettsia prowazekii?
Louse-borne epidemic typhus
Recurrent form: Brill-Zinsser disease
Mention an antibacterial drug active against rickettsial infections!
What are the reservoir and vector of Rickettsia prowazekii
reservoir: human; vector: louse
What are the reservoir and vector of Rickettsia typhi
reservoir: rodents; vector: flea
What is the causative agent of epidemic typhus?
How can be Chlamydiae and Rickettsiae cultivated?
These are obligate intracellular
bacteria, can be cultured in experimental animals,
embryonated eggs, and cell culture
Mention an antibacterial drug active against chlamydial infections!
Tetracycline, erythromycin, azithromycin
List the serotypes of Chlamydia trachomatis and the diseases caused by them!
Types A,B and C: trachoma (chronic conjunctivitis)
Types D-K: genital tract infections (NGU, PID),
Types L1-L3: lymphogranuloma venereum (STD)
Mention an antibacterial drug effective against Mycoplasma pneumoniae infections!
Erythromycin, azythromycin, tetracycline
Why are penicillins not effective against Mycoplasma pneumoniae infections?
Because of the absence of a cell wall, penicillins are ineffective (penicillins inhibit cell
It is based on the cross-reaction
of an antigen present in many rickettsiae with the O
antigen polysaccharide found in certain Proteus vulgaris strains
(OX19 OX2, OXK).
The test is a tube agglutination test
in which these Proteus strains are used as antigens to
demonstrate antibodies from the patient’s serum sample.
Mention 4 bacteria frequently causing sexually transmitted diseases (STD)!
Treponema pallidum, Neisseria gonorrhoeae, Haemophilus ducreyi, Chlamydia
, (Calymmatobacterium granulomatis)
Which bacterial species can cause hepatitis (jaundice)?
Mention 2 bacteria causing aseptic (serous) meningitis!
Treponema pallidum, Leptospira interrogans, Borrelia burgdorferi
Mention a bacterial pathogen which eludes the host immune response by frequent
antigenic changes! Borrelia recurrentis, Neisseria gonorrhoeae
What is the causative agent of febris recurrens (recurrent fever)?
The same species is capable of existing in two morphological forms
(yeast or mold),
depending upon enviromental conditions (temperature, nutrients).
Which are the 4 fungal species causing systemic infections?
Coccidioides immitis, Histoplasma capsulatum, Blastomyces dermatitidis, Paracoccidioides
Mention 3 species causing opportunistic fungal infections!
Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, Mucor spp., Rhizopus
Mention 3 diseases caused by dermatophytons!
Tinea corporis, tinea capitis, onychomycosis, tinea barbae
Mention 3 fungal genera belonging to the dermatophytons!
Trichophyton, Microsporum, Epidermophyton
What is the route of transmission of Sporothrix schenkii?
Traumatically introduced into the skin
Mention a Candida infection associated with mucosal surfaces!
Which species is the most important causative agent of fungal meningitis?
Mention 3 manifestations of Candida albicans
infections that are characteristic in
AIDS patients? generalised oral candidiasis (GOC), oesophagitis, endocarditis
What are the different forms of pulmonary aspergillosis?
1. Aspergillus ball
(in preformed cavities)
2. invasive aspergillosis
3. allergic bronchopulmonary
What is the usual source of infection in systemic mycoses?
What is the usual site of entry of fungi causing systemic mycoses?
Which morphological form of Coccidioides immitis can be found in the human body?
Which human pathogenic fungus has a capsule?
Mention a worm species for which ab ano ad os
auto-reinfection is characteristic in
childhood! Enterobius vermicularis
Mention 2 worm species that migrate through the human lungs in the larval stage!
Which 2 protozoa may infect the human foetus transplacentally?
What is the laboratory diagnosis of malaria?
blood smears. Thick smear
is used to screen for the agent, thin smear
used to identify the species.
How long is the erytrocytic cycle of Plasmodium vivax
and P. ovale
How long is the erytrocytic cycle of Plasmodium malariae
What is the causative agent of malignant malaria?
Mention an antimalarial drug active against hypnozoites!
How can one diagnose the African sleeping sickness disease?
blood smears are used for direct demonstration
Serology may be helpful
What are the causative agents of African sleeping sickness?
Trypanosoma brucei gambiense
Microscopic demonstration of E. histolytica cysts and trophozoites from feces
How can one diagnose Trichomonas vaginalis infection?
of protozoa in wet mount or stained smear
of clinical specimens
(vaginal, urethral or prostatic secretions).
How can one diagnose intestinal taeniasis?
Demonstration of characteristic proglottis
and eggs (ova) in faeces.
How can one diagnose Hymenolepis infection?
Demonstration of eggs (ova) in faeces
Demonstration of eggs
(ova) in faeces
Demonstration of eggs
(ova) in faeces
How can one diagnose Enterobius infection?
Demonstration of eggs
(ova) recovered from perianal skin
(Scotch tape technique). Not
Mention 4 tissue infecting filarial nematodes!
How is human Fasciola hepatica
By eating aquatic vegetation containing encysted larvae
(Rarely: by eating raw sheep liver containing adult worms)
What disease is caused if humans are infected per os
with Taenia solium
(encysted larvae in brain, eyes, etc.)
How is human Trichinella spiralis
By eating raw or undercooked meat containing encysted larvae
Mention 2 protozoa that are susceptible to metronidazol!
What are the 3 modes of transmission for human Toxoplasma gondii
Eating undercooked meat
containing tissue cysts, Contact with cat feces
containing oocysts Transplacental
Mention 2 helminths whose larvae enter the human body by penetratring the intact
Which developmental form of Echinococcus granulosus
can occur in humans?
What is the definitive (ultimate) host of Echinococcus granulosus
Which species are the causative agents of malaria?
Plasmodium vivax, P. ovale, P. malariae, P. falciparum
What is the definitive (ultimate) host of Plasmodium species?
female Anopheles mosquito
What are the definitive, and the intermediate hosts of Taenia saginata, respectively?
definitive host: human
intermediate host: cattle
What is the infectious form of Strongyloides stercoralis
What is the infectious form of Trichuris trichiura
Which form of Taenia saginata
is infectious for humans?
cysticercus (in beef)
Is autoreinfection possible in Ascaris lumbricoides
infection? If yes, when?
No, the eggs must mature in the soil for several days to become infectious
Is autoreinfection possible in Strongyloide stercoralis
infection? If yes, when?
yes, in immunosuppression
(for example: AIDS)
Is autoreinfection possible in Enterobius vermicularis
infection? If yes, when?
yes, the eggs become infectious in a few hours, and ab ano ad os autoinfection may
(especially in children)
Which virus family is characterized by a single-stranded DNA genome?
Which virus family is characterized by a double-stranded RNA genome?
Which viruses are susceptible to acyclovir? What is the mechanism of effect of the
alpha herpesviruses – HSV1, HSV2, VZV
; inhibitor of viral DNA polymerase
DNA chain terminator
Explain why acyclovir is selectively toxic to cells infected by alpha-herpesviruses!
These viruses encode their own thymidine kinase
enzymes, which are needed for
activation (phosphorylation) of the drug
. Cellular thymidine kinase does not activate
In which cells do Herpes simlex viruses establish latent infection?
Sensory ganglion cells (trigeminal or sacral ganglia)
What is the possible, late complication (years after acute infection) of the childhood
chickenpox? Herpes zoster (shingles)
7. What are the possible consequences of fetal infections caused by B19 parvovirus?
fetal death or hydrops fetalis
Which isotype of antigen-specific immunoglobulins in the newborn's blood indicates a
congenital infection? IgM
What diseases do cytomegalovirus cause in congenital infections?
cytomegalic inclusion disease
– spontaneous abortion, CNS damage (deafness, blindness,
mental retardation), hepatosplenomegaly, jaundice
What diseases do cytomegalovirus cause in immunocompetent persons?
Mention 2 diseases that cytomegalovirus can cause in immune compromised persons!
pneumonia, chorioretinitis, colitis
Which antiviral drug is active against cytomegalovirus infection?
, (foscarnet, cidofovir)
Describe the heterophil antibody test used in Epstein-Barr virus diagnostics!
– in mononucleosis caused by EBV, the serum of the patient
agglutinates sheep red blood cells
Which virus causes exanthema subitum (roseola infantum)?
Which virus causes erythema infectiosum?
Human parvovirus B19
Reverse transcription is involved in the replication of which DNA virus?
Hepadnaviridae – HBV
What is the mechanism of antigenic shift in influenza viruses?
reassortment of genome segments
Which antigens of the influenza virus are recognized by neutralizing antibodies?
Which virus(es) is(are) susceptible to amantadine?
Influenza A virus
What is the possible late complication of measles infection (several years after the
acute infection)? SSPE – subacute sclerosing panencephalitis
What is the portal of entry of the viruses belonging to Paramyxoviridae?
Respiratory tract – aerosol infection
Which age group is mostly affected by respiratory syncitial (RS) virus infection?
babies (6 week – 6 month old)
What are the possible complications of adulthood mumps virus infection? Specify at
least 2 of them! Orchitis, meningitis, pancreatitis
What is the route of infection of rabies virus? How does rabies virus spread in the
infected body? By the bite of a rabid animal
, (rarely by infectious aerosol)
spread of the virus in the host – along the axons
What medication does a person need after exposure to rabies virus?
– human diploid cell vaccine (killed virus
) and passive immunization – rabies immune globulin
What is the portal of entry of polioviruses? Which areas of the central nervous system
are affected by poliovirus infection? oropharynx and gastrointestinal tract
damage in motor neurons in the anterior horn of the spinal cord + brain stem
Which viruses belong to the Enterovirus genus?
Polioviruses, coxsackie A and B viruses, echoviruses, enteroviruses 68 - 71
Mention 4 diseases caused by Coxsackie viruses!
febrile rashes, herpangina, myocarditis, pericarditis, meningitis, pleurodynia, hand-
What disease do rotaviruses cause? At which age?
gastroenteritis in young children
List the 3 antigens of hepatitis B virus against which antibodies may develop during or
after the acute phase of infection? HBsAg, HBeAg, HBcAg
Which hepatitis B-specific antibody is never present in chronic hepatitis?
What are the main modes of transmission of HBV (hepatitis B virus) infection?
sexual contact; perinatally from mother to newborn; by blood or blood product
What are the 2 serological markers that are necessary and sufficient to prove acute
hepatitis B virus infection? HBsAg, Anti-HBc IgM
Describe the active and passive prophylaxis against hepatitis B!
active immunization: recombinant HBsAg vaccine
passive immunization: HBIG (hepatitis B immune globulin)
Which hepatitis viruses are acquired orally?
Which hepatitis viruses are acquired via parenteral routes?
HBV, HCV, HDV,
Mention 4 diseases that can be caused by adenoviruses!
pharyngitis, pharyngoconjunctival fever, acut respiratory disease, bronchitis,
atypical pneumonia, hemorrhagic cystitis, gastrointestinal infection
Kuru, Creutzfeldt-Jacob disease, Gerstmann-Straussler-Scheinker syndrome, fatal
What are the serious complications of HSV infection in newborns?
disseminated infections, encephalitis, skin, eye, mouth infection
Mention 3 DNA virus families containing no
Parvoviridae, Papovaviridae, Adenoviridae
Mention 3 DNA virus families containing envelope!
Herpesviridae, Hepadnaviridae, Poxviridae
Mention 3 RNA virus families containing no
Picornaviriade, Caliciviridae, Reoviridae
Mention 3 RNA virus families containing envelope!
Orthomyxoviridae, Paramyxoviridae, Rhabdoviridae, etc.
What is the portal of entry of mumps virus?
Upper respiratory tract
Mention at least two viruses capable of causing pneumonia.
RSV, influenza virus A and B, parainfluenza virus, adenovirus,
What is the causative agent of subacute sclerosing panencephalitis (SSPE)?
What is(are) the nature(s) of antigen(s) in the combined vaccine against measles,
German measles and mumps? live attenuated viruses
What is the nature of antigen in the rabies vaccine for human use?
Which viral variants are included in the human influenza vaccine?
The vaccine contains 2 influenza A strains (H3N2, H1N1) and 1 influenza B strain.
What is the nature of antigen in the vaccine against hepatitis B?
Subunit vaccine, containing HBsAg
What is(are) the nature(s) of antigens in the vaccines against poliovirus?
IPV: inactivated polio vaccine: killed viruses (types 1, 2 and 3)
OPV: oral polio vaccine: live attenuated viruses (types 1, 2 and 3)
52. What is the causative agent of PML (progressive multifocal leucoencephalopathy)?
JC virus (Polyomaviridae)
53. Which influenza virus types are characterised by antigenic shift?
54. Which influenza virus types are characterised by antigenic drift?
Influenza A and B
55. What is the nature of the immune response in diseases caused by prions?
There is no immune response
, as prions are self proteins.
56. Mention at least 3 diseases caused by herpes simplex viruses (HSV1, HSV2)!
oropharyngeal herpes (gingivostomatitis, herpes labialis), keratoconjunctivitis,
encephalitis, herpes genitalis
57. What are the possible consequences of fetal infections caused by rubella virus? Specify at
least 3 of them! Congenital malformations involving the heart (patent ductus arteriosus, septum
defects), the eyes (cataract, glaucoma) and the brain (deafness, mental reardation).
58. Which ifluenza A subtypes cause most human infections currently?
Which are the two most important targets of antiretroviral chemotherapy?
HIV reverse transcriptase and protease
60. Mention 3 nucleoside type reverse transcriptase inhibitors used in the therapy of AIDS!
azidothymidine (zidovudine), dideoxyinozine (didanosine), dideoxycytidine
(zalcitabine), stavudine, lamivudine, abacavir
61. Mention 2 non nucleoside type reverse transcriptase inhibitors used in the therapy of
AIDS! nevirapine, delavirdine, efavirenz
62. Mention 2 protease inhibitors used in the therapy of AIDS!
indinavir, saquinavir, ritonavir, nelfinavir, amprenavir
63. What is the principle of the „highly active antiretroviral therapy” (HAART) currently used
in the treatment of AIDS! Combination of two nucleoside reverse transcriptase inhibitors (such as zidovudine
and lamivudine) and a protease inhibitor (such as indinavir). Or combination of two
nucleoside reverse transcriptase inhibitors (such as zidovudine and lamivudine) and
a nonnucleosid reverse transcriptase inhibitor (such as efavirenz).
2 NRTI + PI/NNRTI
What are the criteria to classify a virus as robovirus? Write an example, too!
Robovirus: rodent reservoir
Arenaviridae – Lassa, Junin, Machupo, LCM virus; Bunyaviridae – Hantaan virus,
Puumala virus, Sin Nombre virus; Filoviridae – Marburg, Ebola virus
What are the criteria to classify a virus as arbovirus? Write an example, too!
Arbovirus: arthropode vector
Flaviviridae – yellow fever, Dengue-fever; Bunyaviridae – Rift-valley fever, Crimean-
Congo hemorrhagic fever; etc.
Which hepatitis virus infections increase the risk of hepatocellular carcinoma?
HBV, HCV, HDV
Which virus can cause haemorrhagic fever with hepatitis and nephritis?
yellow fever virus
Describe the 2 different epidemiological cycles of yellow fever!
Jungle yellow fever: reservoir: monkeys; vector: Haemagogus mosquitos; humans:
Urban yellow fever: reservoirs: humans; vectors : Aedes aegypti mosquitos
How can we prevent tick borne encephalitis?
Active immunization: killed virus vaccine, passive: specific immune globulin
Which viruses can cause human tumors? Mention at least 4!
HPV, EBV, HHV-8, HBV, HCV, HTLV
Mention 3 opportunistic infections characteristic for AIDS!
Viruses: HSV-1, HSV-2, VZV, HCMV, EBV, HHV-8, HPV
Protozoa: Toxoplasma gondii, Pneumocystis carinii
Bacteria: Mycobacterium tuberculosis, atypical Mycobacteria, Salmonella septicaemia
Fungi: Candida, Cryptococcus neoformans
Describe the principals of the laboratory diagnosis of HIV infection!
Demonstration of antiviral antibodies. Presumptive diagnosis: ELISA
Verification: Western-blot assay
Mention three sexually transmittable viral infections!
HPV, HSV-1, HSV-2, HIV, HBV, HCV, molluscum contagiosum
Mention two viruses capable of getting through the placenta.
Rubella virus, HCMV, parvovirus B19, HIV, HTLV-1
Mention 2 viral infections whose preventive strategy involves passive immunization!
Rabies, tick-borne encephalitis, HBV, VZV, measles
List three viruses capable of causing (meningo)encephalitis!
Rabies, HSV, VZV, tick-borne encephalitis, Japanese B encephalitis, eastern and
western equine encepahalitis,
mumps, poliovirus, coxsackie virus, echovirus
What is the nature(s) of antigen in the vaccine against yellow fever?
Live attenuated virus (17D strain)
What disease does Epstein-Barr virus cause? What are the Epstein-Barr virus
associated tumors? Mononucleosis infectiosa
(heterophil positive) Nasopharyngeal carcinoma, Burkitt’s lymphoma, other B-cell lymphomas
79. Mention 3 types of human cancers caused by EBV?
Nasopharyngeal carcinoma, Burkitt’s lymphoma, other B-cell lymphomas
80. What type of human cancer is caused most frequently by HHV8?
81. What types of human cancers are caused by high-risk HPV types?
genital cancers, most importantly cervical cancer
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Why are We Losing the Battle Against AIDS?Why are We Losing the Battle Against AIDS? unacceptable truth: an entire generation of young Swazis is dying. WHY ARE WE LOSING Why, after having known about this problem for more than fifteen years,does it seem as if AIDS cannot be conquered in Africa? After having made a THE BATTLE AGAINST AIDS? study of this topic, I consider the following as