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Health: The Ultimate Treasure - How to Prevent and Control Diseases?

Grade 8CBSE

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

🔑Concepts

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Health is defined by the WHO as a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity.

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Diseases are broadly classified into two categories: Communicable (Infectious) diseases which spread from an infected person to a healthy person, and Non-communicable (Chronic) diseases which do not spread.

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Pathogens are disease-causing organisms including Bacteria (e.g., Typhoid), Viruses (e.g., Common Cold, COVID-19), Fungi (e.g., Ringworm), and Protozoa (e.g., Malaria).

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Vectors are organisms, such as the female AnophelesAnopheles mosquito or houseflies, that carry pathogens from a host to a recipient without being affected themselves.

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Antibiotics are medicines that block biochemical pathways important for bacteria (like cell wall synthesis), but they are ineffective against viral infections because viruses use the host's machinery.

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Pulse Polio Programme is a large-scale immunization campaign to eradicate Poliomyelitis by vaccinating all children under the age of 55 years.

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The Body Mass Index (BMIBMI) is a tool used to determine if an individual has a healthy body weight relative to their height.

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Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine containing weakened or dead pathogens.

📐Formulae

BMI=Weight (kg)Height (m)2BMI = \frac{\text{Weight (kg)}}{\text{Height (m)}^2}

Underweight<18.5\text{Underweight} < 18.5

18.5≤Normal≤24.918.5 \le \text{Normal} \le 24.9

ORS Concentration (Approximate)=6 tsp Sugar+0.5 tsp Salt1 Litre Water\text{ORS Concentration (Approximate)} = \frac{6 \text{ tsp Sugar} + 0.5 \text{ tsp Salt}}{1 \text{ Litre Water}}

💡Examples

Problem 1:

Calculate the BMIBMI of a student who weighs 50 kg50\text{ kg} and has a height of 1.5 m1.5\text{ m}. Determine their health status.

Solution:

BMI=50(1.5)2=502.25≈22.22BMI = \frac{50}{(1.5)^2} = \frac{50}{2.25} \approx 22.22

Explanation:

Since the calculated BMIBMI is 22.2222.22, which falls within the range of 18.518.5 to 24.924.9, the student is considered to have a 'Normal' or healthy weight.

Problem 2:

If a city recorded 45004500 cases of Malaria in Year 1 and implemented vector control, resulting in 12501250 cases in Year 2, calculate the reduction in cases.

Solution:

4500−12503250\begin{array}{r} 4500 \\ - 1250 \\ \hline 3250 \end{array}

Explanation:

The reduction in Malaria cases due to vector control (like removing stagnant water and using nets) is 32503250 cases.

Problem 3:

Identify the causal organism and vector for Malaria.

Solution:

Causal Organism: PlasmodiumPlasmodium (a protozoan). Vector: Female AnophelesAnopheles mosquito.

Explanation:

The protozoan PlasmodiumPlasmodium enters the human bloodstream through the bite of an infected female AnophelesAnopheles mosquito, which acts as the carrier (vector).