34.

(a) What is mental illness? Explain any three methods of treatment of mental illness.

(b) What are Koch’s postulates? Why are they not applicable to viruses?

(c) Name the causative agent and the main symptom of each of the following diseases :

(i) Filariasis

(ii) Rabies

(iii) Chicken pox

Mental illness is characterised by abnormal behaviour and talk resulting in social and vocational days functioning.

Three methods of treatment of mental illness :

(i) Psychotherapy : It is a slow treatment, involving patience and care.

(ii) Chemotherapy : It involves use of tranquillisers to slow down the brain activity in very disturbed patients.

(iii) Shock treatment: It is used in selected cases and can produce dramatic results in severe depression.

(b) Koch’s postulates are:

(i) The disease causing organism must be found in all the animals that have the disease.

(ii) The pathogen should be isolated and grown in pure culture on an artificial culture medium.

(iii) The same organism should be recovered from the inoculated diseased animal.

They are not applicable to viruses because they cannot BE cultured artificially.

(c) (I) Filariasis : Causative agent = filarial worm (Wuchereria bancrofti)

Symptoms - Rarely, long-term damage to the lymph system causes swelling in the legs, arms and genitalia. It also increases the risk of frequent bacterial infections that harden and thicken the skin 

(II) Rabies.

Causative agent = Rhabdoviridae

Symptoms are severe headache, fever, severe and painful spasm of throat muscles.

(III) Chicken pox.

Causative agent = Varicella zoster 

Skin eruptions as red papules which grow into pustules and appear as tear drop vesicles.