Everything you need to know about microbial diseases. Some of the frequently asked questions are as follows:-
Q.1. Name the microorganisms that form normal micro-biota of the skin.
Ans. They are Gram-positive pleomorphic rods known as diphtheroids (e.g., Propionibacterium acnes) which produce propionic acid that helps to maintain low pH of the skin ranging from 3 to 5. The acidic effect produced by these bacteria safeguards skin against many harmful microorganisms. The Corynebacterium xerosis, another diphtheroid is aerobic and inhabit the surface of the skin. The yeast Pityrosporum grows on oily skin secretions and causes scaling skin conditions known as dandruff.
Q.2. Give the main microbial diseases of the skin, causative agents, characteristics and treatment.
Ans. The common microbial diseases caused by bacteria, viruses, fungi and mites, and their cause, symptoms and treatment are listed in Table 16.1.
Q.3. Who was the last victim of small pox?
Ans. The last victim of small pox was an African in Somalia, who recovered from variola minor, in 1977.
Q.4. Which are the two main types of small pox?
Ans. Two main types of small pox are Variola major and Variola minor. Recovery from one type of disease provides immunity against both the types.
Q.5. Which are the two sites where the smallpox viruses are maintained?
Ans. One in USA and the second in Russia.
Q.6. What may be the after effect of use of aspirin to lower fevers in chicken pox and influenza?
Ans. Increases the chances of acquiring Reye’s syndrome.
Q.7. What is Reye’s syndrome?
Ans. Reye’s syndrome is an occasional complication after chickenpox, influenza and other viral infections. In it a few days after the initial infection recedes the patient persistently vomits and shows the signs of brain dis-function. It may follow coma, fatty degeneration of liver and death. Death and brain damage in those who survive is due to swelling in the brain that prevents the circulation of blood.
Q.8. What is a dermatophyte?
Ans. A fungus that colonizes on skin including hair and nail is called dermatophyte. Dermatophytes grow on the keratin, the skin protein found in dermis, hair and nails and cause infections called tinea or ringworms. Tinea capitis or ringworm of scalp results bald circular patches on the head of school children.
Q.9. List the bacterial, viral and protozoal diseases of the eye. Also give their causal organisms, symptoms and therapy.
Ans. These are given in Table 16.2:
Q.10. List the microbial diseases of the nervous system.
Ans. These are listed in Table 16.3.
Q.11. List the microbial diseases of cardiovascular and lymphatic systems. Also give their causal microorganism mode of transmission and therapy.
Ans. These are listed in Table 16.4.
Q.12. Name the bacterial diseases of upper respiratory system.
Ans. These are given in Table 16.5.
Q.13. Name a viral diseases of upper respiratory tract
Ans. Common cold is the viral disease of upper respiratory tract which is caused by coronaviruses or rhinoviruses from respiratory secretions. There is no therapy for it.
Q.14. Give bacterial diseases of lower respiratory system.
Ans. Bacterial diseases of lower respiratory system are given in Table 16.6.
Q.15. Give fungal diseases of the lower respiratory system.
Ans. See Table 16.7.
Q.16. Name a protozoal disease of lower respiratory system.
Ans. Pneumocystis pneumonia is caused by Pneumocystis carinii which is transmitted through respiratory route. Trimethoprim-sulphamethoxazole and pentamidine isethionate are used for treatment.
Q.17. Give food borne bacterial diseases of digestive system.
Ans. See Table 16.8.
Q.18. Give viral diseases of digestive system.
Ans. See Table 16.9
Q.19. Name the fungal diseases of the digestive system.
Ans. See Table 16.10
Q.20. Give the protozoal diseases of the digestive system.
Ans. See Table 16.11.
Q.21. Give the common helminthic diseases of digestive system. What are their causal organisms and how are they transmitted? Give their generally followed therapy.
Ans. See Table 16.12.
Q.22. How can Neisseria gonorrhoeae be microscopically recognized in the pus from a gonorrhoea patient?
Ans. A smear of the pus from a patient will show Neisseria gonorrhoeae as paired cocci contained within leukocytes which are Gram-negative.
Q.23. Give common bacterial diseases of the urinary system.
Q.24. Give bacterial diseases of the reproductive system in a tabulated form.
Ans. See Table 16.14 below.
Q.25. Give viral diseases of the reproductive system in tabular form.
Q.26. Name the most common fungal disease. Give its causative fungal species, transmission and therapy/treatment.
Ans. Candidiasis is caused by the fungus Candida albicans which is an opportunistic pathogen but may also be transmitted by sexual contact. Clotrimazole and miconazole are used.
Q.27. Name the disease caused by protozoan Trichomonas vaginalis.
Ans. It causes trichomoniasis (often vaginitis). The pathogen is usually transmitted by sexual contact and is generally treated with metronidazole.