Last one year i felt sick three times. The illness were -typhoid, dysentry, viral fever.

(a) One change in habit that would avoid the illness is drinking safe and pure filtered/boiled water and avoid eating uncovered food. 

(b) One change in surroundings to avoid diseases is that there should be no accumulation of garbage and stagnant water in the surroundings.

A doctor/nurse/health-work can avoid getting sick by following these habit -:

(i) Wearing a mask  to cover mouth and nose to avoid infection when in contact with or near a diseased person.

(ii) Using gloves to avoid direct contact with wounds infections and disesed people.       

(iii) Drinking safe water and eating healthy and nutritious food to keep the immune sustem strong.

(iv)  Maintaining personal hygiene  i.e., personal cleanliness, washing hand with dettol/savlon etc. after handling equipment, clothes etc. of patients. 

(v)  Keep the surroundings clean.  

The three most ommon diseases in the neighbourhood are dysentry, malaria, viral fever.

The three preventive measures that could be taken by the local authorities are 

1. Keeping the area clean i.e., removal of garbage from the streets/ houses and storage in a covered place till it is disposed off. Proper  sanitation and cleaning of drains and proper disposal of sewer water.

2. Cleaning and removal of stagnant water and breeding places of mosquitoes like ditches with stagnant water. Pouring of oil over the stagnant water to kill the larvae of mosquitoes. Spraying of chemicals/smoke in neighbourhood to kill mosquitoes.

3. Ensure supply of safe drinking water. Regular cleaning of the water supply resources. 

(a) The symptoms like fever, loose motions, vomiting and signs like behavioural changes like constant crying, irritation etc, can tell that the baby is sick. 

(ii) The symptoms like vomoting, fever, loose motions indicate that the baby is suffering from diarrhoea. But to pinpoint the disease the baby should be taken to a doctor and further laboratory tests should be done in order to diagnose the disease.