namibia UniVERSITY OF SCIEnCE AnD TECHnOLOGY

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1 namibia UniVERSITY OF SCIEnCE AnD TECHnOLOGY FACUL TV OF HEALTH AND APPLIED SCIENCES DEPARTMENT OF HEALTH SCIENCES QUALIFICATION: BACHELOR OF BIOMEDICAL SCIENCES QUALIFICATION CODE: SOBMES LEVEL: 7 COURSE CODE: MMB310S COURSE NAME: MEDICAL MICROBIOLOGY SESSION: JUNE 2016 PAPER: THEORY DURATION: 3 HOURS MARKS: 120 FIRST OPPORTUNITY EXAMINATION QUESTION PAPER EXAMINER(S) PROF SR MOYO MODERATOR: DR J OJULONG INSTRUCTIONS 1. Answer all the questions as specified under each section (A, B, and C). 2. Write clearly, neatly and legibly. 3. Do not use the left margin of the exam paper. This is for the examiner. 4. No books, notes and any other additional aids are allowed. 5. Mark all answers clearly with their respective question number. THIS QUESTION PAPER CONSISTS OF _7 _PAGES (Including this front page) 1

2 Section A [15 marks] Answer all questions in this section QUESTION 1 [10] Select the correct answer out of a choice of 4 (A, B, C and D) there is only one correct answer. Write only the number and the correct letter next to it. Example: Namibia shares a common border with A. Uganda B. Botswana C. Tanzania D. Swaziland 1.1 Mycobacterium tuberculosis will not stain with Gram stain due to (1) A. hard cell wall B. drug resistance C. presence of mycolic acid lipid layer D. all the above 1.2 The very first step of viral infection is (1) A. B. c. D. Release attachment Uncoating Replication 1.3 With regard to coccidioidomycosis, histoplasmosis and blastomycosis (1) A. B. c. D. They are all dimorphic fungi which cause human disease. They are dermatophytes They are spread through direct contact from human to human. None of the above. 1.4 What is the most striking structural feature of Cryptococcus neoformans? (1) A. Presence of a wide polysaccharide capsule B. Its relationship to HIV infection C. Like candida it is a yeast D. It causes disease in humans. 2

3 1.5 How is the direct diagnosis of tinea infection usually made? {1) A. Complement fixation test B. Isolation and identification c. KOH preparation D. Lactophenol cotton blue stain 1.6 Trichomonas vagina/is is transmitted through? {1) A. Sexual intercourse B. Inhalation c. Ingestion D. All the above 1.7 In which geographical areas does kala-azar occur? {1) A. Africa only B. Mediterranean basin, South Russia and Middle East. c. Europe only D. Africa, Europe and Asia 1.8 Trypanosoma cruzi is the cause of American trypanosomiasis. What is the other name given to this disease? {1) A. Triatoma B. Black sickness c. Chaga's disease D. None of the above 1.9 In HIV testing the golden standard test is the (1) A. ELISA B. Agglutination test c. Complement fixation {CFT) test D. Western blot 1.10 How is the laboratory diagnosis of toxoplasmosis made? {1) A. Culture in cell lines B. CFT c. Haemagglutination inhibition test D. ELISA detection of lgm antibodies 3

4 QUESTION 2 [5] Fill in the correct answer in the spaces provided to complete the given statements This question carries a total of 5 (10 X Yz) marks. Example: In the bacterial growth curve the third phase is the... decline phase and the last is called the... death phase. 2.1 Regarding viral hepatitis, the presence of the... agent in a patient serum is an indirect diagnostic test for..... (1) 2.2 Cholera is an example of a major... disease that can be controlled by application of appropriate water... measures. (1) 2.3 Brucella is a... pathogen that may enter the body either by ingestion of contaminated... or through the skin by direct contact in an occupational setting such as an abattoir. (1) 2.4 Trichomonas vagina/is exists only as a..., there is no... form. (1) 2.5 Human papillomavirus and 18 are associated with cervical... in humans. (1) Section B [25 marks] Answer all questions in this section. QUESTION 3 [25] Answer True (T) or False (F) for each statement. Just write the number of the statement and next to it True or False. There are a total of 25 marks in this section. Example: Concerning the bacteria T IF they multiply by binary fission T IF they all have a capsule T IF their strengthening layer is the cell wall T IF they are all motile and they have flagella T IF they have no nuclear membrane 4

5 3.1. In the case of enteroviruse A) T IF Hepatitis A is a picornavirus (enterovirus 72), which is transmitted through the oral-faecal route B) T IF The eradication of the polio virus from the face of the world is close to being achieved through the efforts being spearheaded by WHO. C) T IF Only type 1 of the three polio serotypes is pathogenic and causes poliomyelitis. D) T IF Laboratory diagnosis of polio by isolation in cell culture is detected by observing cytopathic effect (CPE). E) T IF Echoviruses and Coxsackie viruses are the leading causes of aseptic meningitis in humans Concerning hepatitis viruses A) T I F The delta agent uses the surface antigen of hepatitis B virus (HBsAg) as its coat. B) T IF Hepatitis B virus is much more easily transmitted as compared to HIV C) T I F In case of kidney dialysis of a patient, it is very important to know whether or not the patient has hepatitis infection so as to protect other patients who may need to use the dialysis machine. D) T IF 50% of the people infected by hepatitis proceed to chronic status E) T IF One of the complications of hepatitis infection is hepatocellular carcinoma With regard to mycology A) T IF Germ tube test is a test for confirmation of dermatophytes in the laboratory B) T IF Malassezia furfur causes pityriasis versicolor, a superficial scaly skin infection with depigmentation. C) T IF Dimorphic fungi form different structures at different temperatures D) T IF Trichophyton, the main cause of tinea captis is a yeast like fungus. E) T IF Cryptococcus neoformans is an important cause of meningitis in immunocompromised patients 3.4. Concerning laboratory diagnosis of parasites A) T IF The thin film is used for identification of species in plasmodium diagnosis B) T IF Wet preparation of HVS (high vaginal swab) is used for the diagnosis Trichomonas vagina/is although culture may also be used C) T IF In Giardia infection the human face like trophozoites are seen in sputum samples 5

6 D) T IF Schistosoma haematobium is recognizable by its lateral spine E) T IF Schistosoma mansonii is recognizable by its terminal spine and infect the urinary tract Concerning nematodes A) T IF Enterobius (pinworm), Trichuris (whipworm) and Ascaris (giant round worm) are all intestinal nematodes. B) T IF Wuchereria, Loa and Onchocerca, called "filarial worms" are all tissue Nematodes. C) T IF Ancylostoma duodenale and Necator americanus both cause hookworm Infection. D) T IF In Enterobius the diagnosis may be made by getting the eggs from perianal skin using the "scotch tape" technique. E) T IF Because of migration through the anus at night by the female mature worm to lay its eggs into the perianal skin and the environment, causing itching, Enterobius vermicularis is known to cause auto infection particularly in children. Section C [80 marks] Choose and answer four (4) out of the five possible question in this section. QUESTION Discuss sources of waterborne diseases 4.2 What is Giardiasis and how is it diagnosed in the laboratory 4.3 Discuss viruses as a source of food borne infections (10) QUESTION 5 Analyze the distinction between sporogony and schizogony in the life cycle of plasmodium. 6

7 D) T IF Schistosoma haematobium is recognizable by its lateral spine E) T IF Schistosoma mansonii is recognizable by its terminal spine and infect the urinary tract Concerning nematodes (5} A) T IF Enterobius (pinworm), Trichuris (whipworm) and Ascaris (giant round worm) are all intestinal nematodes. B) T IF Wuchereria, Loa and Onchocerca, called "filarial worms" are all tissue Nematodes. C) T IF Ancylostoma duodenale and Necator american us both cause hookworm Infection. D) T IF In Enterobius the diagnosis may be made by getting the eggs from perianal skin using the "scotch tape" technique. E) T IF Because of migration through the anus at night by the female mature worm to lay its eggs into the perianal skin and the environment, causing itching, Enterobius vermicularis is known to cause auto infection particularly in children. Section C [80 marks] Choose and answer four (4) out of the five possible question in this section. Answer these in the answer book provided. QUESTION Discuss sources of waterborne diseases 4.2 What is Giardiasis and how is it diagnosed in the laboratory 4.3 Discuss viruses as a source of food borne infections (10) QUESTION 5 Analyze the distinction between sporogony and schizogony in the life cycle of plasmodium. 6

8 QUESTION 6 With the aid of a diagram, describe the sequence of events in the HIV replication circle. QUESTION Analyse the main differences between HSV-1 and HSV-2 What is cytopathic effect (CPE)? How is its significance in the laboratory? (15) QUESTION Describe 2 tests used in the diagnosis of cryptococcal meningitis 8.2. What are dermatophytes? Describe two pathogens in this group of fungi How do you make diagnosis of tinea in the laboratory? (10) EN D