4. The most common cause of traveller s diarrheoa is a. Rotavirus b. E coli c. Shigella d. Giardia e. Salmonella

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1 INFECTIOUS DISEASE 1. Mumps virus is a a. Adenovirus b. Herpes virus c. Paramyxovirus d. Pox virus e. Picornavirus 2. All of the following cause a clinical effect via the production of exotoxin except a. Clostridium difficile b. Staph aureus c. E coli d. Pseudomonas aeruginosa e. Vibrio cholera 3. Which virus causes molluscum contagiosum a. Adenovirus b. Herpes virus c. Parvovirus d. Pox virus e. Picornavirus 4. The most common cause of traveller s diarrheoa is a. Rotavirus b. E coli c. Shigella d. Giardia e. Salmonella 5. Pneumocystis carinii a. Produces pneumocystis pneumonia in normal persons b. Causes a Ghon s focus in the lung c. Causes a patchy atelectasis d. Is a fungus e. Attaches selectively to type II alveolar cells 6. Bacterial endotoxin a. Is exemplified by streptokinase b. Is the cause of the severe form of diphtheria c. Is the cause of gas gangrene d. Is from the outer wall of gram positive bacteria e. Induces production of TNF

2 7. Tetanus toxin a. Is composed of a light and heavy chain b. Acts directly on motor neurons c. Stimulates inhibitory neurons d. Never affects BP e. Is produced by gram negative rods 8. regarding streptococcal infections a. commonly cause boils b. do not produce glomerulonephritis c. cause minimal destruction of host tissue d. do not produce capsular virulence factors e. streptococcus pneumoniae is the commonest cause of meningitis in children 9. All of the following infectious disorders are associated with splenomegaly except a. Leprosy b. Toxoplasmosis c. Tuberculosis d. Typhoid fever e. CMV 10. regarding the Clostridium species a. wound infections caused by C.perfringens generally occur 7-10 days following surgery b. C.tetani produces an endotoxin which causes muscle spasm c. The toxin of C.botulinum blocks serotonin and dopamine receptors d. Vaccination against C.tetani has not significantly reduced the incidence of tetanus e. All are spore producing 11. In aseptic meningitis a. The glucose in the CSF is raised b. The most commonly identified agent is an enterovirus c. There is a more fulminant course than bacterial meningitis d. Microscopically there is a large infiltration of lymphocytes e. There is no brain swelling 12. In TB a. Mycobacteria are aerobic, spore forming bacilli b. CD4+ T cell result in formation of granulomas by killing macrophages c. The major cause of tissue damage is granulomas d. The granulomas in patients with AIDS are well formed e. The CD8 T cells secrete cytokines inducing macrophage transformation

3 13. Streptococcus a. Viridans is β haemolytic b. Produces an endotoxin which causes scarlet fever c. Causes erysipelas which involves significant tissue necrosis d. Causes 50% of community acquired lobar pneumonias e. Glomerulonephritis becomes chronic in less than 10% children 14. Clostridia a. Perfringins produces toxin A b. Tetani neurotoxin produces both a heavy and a light chain c. Is a gram positive coccus that grows under both aerobic and anaerobic conditions d. Botulinum releases a potent neurotoxin that causes convulsive contractions of skeletal muscles e. Clostridial cellulites causes severe myonecrosis 15. Staphylococci a. Are typical encapsulated diplococci b. Produce multiple haemolytic toxins including α toxins c. Rarely cause pyogenic infections in bone d. Are the most common cause of hospital acquired infections e. Lung infections are rarely opportunisitic 16. Mycobacteria tuberculosis a. Are aerobic, non-spore forming, non-motile cocci b. Induce type II hypersensitivity c. Cause formation of epitheliod cell granulomae d. Are killed by macrophages in primary infection e. Induce formation of a Ghon complex after secondary infection 17. virulence factors of Staph include a. surface proteins that adhere to host cell b. enzymes that degrade host proteins c. exfoliative toxins d. enterotoxins that stimulate emetic receptors in abdominal viscera e. all of the above 18. Clostridium perfringens (2 CORRECT) a. Causes myonecrosis via theta toxin b. Is locally invasive c. Produces a cytotoxin d. Causes diarrhea e. Is spread nosocomially

4 19. In infectious diseases a. Bacterial exotoxin is a mucoprotein on the inner cell wall b. The molecular mechanisms of most exotoxins are unknown c. Microbes that propagate in the lumen of the intestine are accessible to IgA antibodies d. Macrophages in bronchi play a major role in protecting the lungs from bacterial infection e. Bacterial adhesions that bind bacteria to host cells have a broad range of host cell specificity 20. Staph aureus a. Has receptors on its surface that allow binding to host endothelial cells b. Has a capsule that allows it to attach to artificial materials c. Has a lipase that degrades lipids on the skin surface d. Has enterotoxins that stimulate emetic receptors in the abdominal viscera e. All of the above 21. In malaria a. Plasmodium vivax causes severe anaemia b. Inoculated sporozoites immediately invade spleen c. Parasites mature in RBCs d. Plasmodium falciparum infection initially causes hepatomegaly e. Cerebral malaria is caused by parasites invading gray matter 22. All of the following are DNA viruses except a. CMV b. HIV c. VZV d. HSV e. EBV 23. rickettsial infections a. involve endothelial cells 24. the pathogenicity of Mycoplasma TB is due to a. impaired antibody response/cell mediated b. hypersensitivity response to products of TB bacteria c. due to expanding granuloma d. due to caseous necrosis e. direct host cell killing by the bacillus

5 25. Staph aureus can cause all of the following except a. Food poisoning b. Osteomyelitis c. Carbuncles d. Scarlet fever e. Scalded skin syndrome 26. With respect to streptococcal infection a. May result in glomerulonephritis 3 weeks post infection 27. Non-thrombocytopenic purpura is associated with a. Aplastic anaemia b. SLE c. Meningococcaemia d. HIV e. EBV ANSWERS 1. C 2.?D 3. D 4. B 5. D 6. E 7. A 8. C 9. A 10. E 11. B 12. C 13. E 14. B 15. B 16. C 17. E 18. B + C 19. E 20. E 21. C 22. B B 25. D C