23. Infectious Diseases and how to Prevent them
Complete solutions to the Exercise. Maharashtra State Board (Balbharati), Standard 5 EVS 1.
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Exercises
Uncovered food is not safe to eat. Flies and other insects settle on it and leave micro-organisms behind, and dust from the air falls into it. Eating such food can cause diseases of the stomach and intestines.
I would recommend not allowing water to stagnate.
Mosquitoes lay their eggs in still water. If no water is allowed to collect in tyres, pots, coolers, tins or puddles, the mosquitoes have nowhere to breed and the trouble is stopped at its very source. Insecticides only kill the mosquitoes that are already there, so they have to be sprayed again and again. They also cost money, and the chemicals harm other living things in the water and can pollute it.
Emptying and drying containers once a week costs nothing, harms nothing, and can be done by everyone in the neighbourhood.
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A disease caused by micro-organisms, which spreads from one person to another, is called an infectious disease.
In an epidemic, a large number of people in the same area fall ill with the same infectious disease at about the same time. Hospitals are crowded, daily life and work are disturbed, and special measures have to be taken to stop the disease from spreading further.
Vaccination is a way of preventing disease. When a vaccine is given, our body builds up resistance to that particular disease, so that we do not fall ill with it later.
| Vaccine | Protects against |
|---|---|
| BCG | Tuberculosis |
| Hepatitis B (birth dose) | Hepatitis B |
| OPV (oral polio vaccine) | Polio |
| IPV (injectable polio vaccine) | Polio |
| Pentavalent (DPT + HepB + Hib) | Diphtheria, whooping cough, tetanus, hepatitis B and Hib |
| Rotavirus vaccine | Severe diarrhoea in babies |
| PCV | Pneumonia |
| MR | Measles and rubella |
Note: BCG, the birth dose of hepatitis B and the zero dose of OPV are given at birth itself. The rest follow at fixed ages during the first year and a half, as written in the baby’s immunisation card.
False. Diseases of the intestines spread through impure water and contaminated food, not through the air.
False. Diseases are caused by micro-organisms and by unclean surroundings, food and water. Believing otherwise is a superstition, and it is harmful, because it keeps a patient away from the treatment that would cure them.
| Medium | Diseases |
|---|---|
| Through food | Gastro, diarrhoea |
| Through water | Cholera, typhoid, jaundice |
| Through air | Tuberculosis, diphtheria |
Note: malaria fits none of the three columns. It does not spread through food, water or air — it is carried from a patient to a healthy person by the bite of a mosquito.
Cholera spreads through water that has been contaminated by micro-organisms. Boiling the water kills those micro-organisms and makes it safe to drink. During an epidemic the chance of the water being contaminated is high, so boiling it protects us and also helps to stop the disease from spreading further.
Mosquitoes lay their eggs in still water, and the young ones grow there. Puddles standing in our surroundings therefore become breeding places for them. Mosquitoes carry diseases such as malaria and dengue from one person to another, so allowing water to collect near our homes puts everybody in the neighbourhood at risk.