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Health and Hygiene - Communicable diseases (Causes and Prevention)

Grade 5ICSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Communicable diseases are infectious diseases that spread from one person to another through various agents called pathogens or germs, such as BacteriaBacteria, VirusesViruses, ProtozoaProtozoa, and FungiFungi.

Transmission through Air: Germs are released into the air through droplets when an infected person coughs or sneezes. Examples include the Common Cold and InfluenzaInfluenza.

Transmission through Water and Food: Diseases like Cholera and Typhoid spread when food or H2OH_2O is contaminated by flies or improper sewage disposal.

Transmission through Vectors: Some insects act as carriers of germs. For example, the Female Anopheles mosquito carries the protozoan PlasmodiumPlasmodium which causes Malaria.

Transmission through Direct Contact: Diseases like Ringworm or Chickenpox spread by touching an infected person or using their personal belongings.

Prevention: Communicable diseases can be prevented by maintaining personal hygiene, keeping the surroundings clean, and through vaccination (immunization).

Oral Rehydration Solution (ORS): A simple mixture used to treat dehydration caused by diseases like Diarrhoea, consisting of clean H2OH_2O, sugar, and NaClNaCl (salt).

📐Formulae

Disease Transmission=Pathogen+Mode of Transport (Vector/Air/Water)+Host\text{Disease Transmission} = \text{Pathogen} + \text{Mode of Transport (Vector/Air/Water)} + \text{Host}

ORS Preparation1 litre H2O+6 teaspoons Sugar+0.5 teaspoon NaCl\text{ORS Preparation} \approx 1 \text{ litre } H_2O + 6 \text{ teaspoons Sugar} + 0.5 \text{ teaspoon } NaCl

Boiling Water100C (Kills most pathogens)\text{Boiling Water} \rightarrow 100^\circ C \text{ (Kills most pathogens)}

💡Examples

Problem 1:

Identify the pathogen and the vector for the disease Malaria.

Solution:

Pathogen: PlasmodiumPlasmodium (a Protozoan); Vector: Female Anopheles mosquito.

Explanation:

The mosquito does not cause the disease itself but carries the PlasmodiumPlasmodium parasite from an infected person to a healthy person.

Problem 2:

Why is it recommended to boil H2OH_2O during a Cholera outbreak?

Solution:

Boiling H2OH_2O at 100C100^\circ C kills the bacteria Vibrio choleraeVibrio\ cholerae.

Explanation:

High temperatures denature the proteins in bacteria, making the water safe for consumption and preventing waterborne transmission.

Problem 3:

Match the disease with its causative agent: (a) Typhoid, (b) Common Cold.

Solution:

(a) Typhoid - BacteriaBacteria (Salmonella typhiSalmonella\ typhi); (b) Common Cold - VirusVirus (RhinovirusRhinovirus).

Explanation:

Typhoid is a bacterial infection of the intestinal tract, whereas the common cold is a viral infection of the respiratory system.