Primary Pupil Tip
Health & Diseases is a major topic in Grade 7 Integrated Science. Always remember the distinction between Vectors (living organisms that carry pathogens like mosquitoes) and Pathogens (microorganisms like bacteria, viruses, and plasmodium).
Table of Contents
1. Communicable vs Non-Communicable Diseases
In ECZ Grade 7 Integrated Science, diseases are classified into two main groups:
| Category | Definition | Examples |
|---|---|---|
| Communicable (Infectious) | Diseases that can spread from an infected person/animal to a healthy person via air, water, vector, or physical contact. | Malaria, Cholera, Tuberculosis, Bilharzia, COVID-19, Measles. |
| Non-Communicable (Non-infectious) | Diseases that cannot be passed from person to person; caused by malnutrition, genetics, lifestyle, or environment. | Kwashiorkor, Scurvy, Rickets, Diabetes, High Blood Pressure. |
2. Major Communicable Diseases & Vectors
A. Malaria
- Pathogen: Plasmodium parasite.
- Vector: Female Anopheles mosquito.
- Symptoms: High fever, chills, sweating, headache, vomiting.
- Control: Sleeping under Insecticide Treated Nets (ITNs), burying open water containers, clearing bushes around houses.
B. Cholera
- Pathogen: Vibrio cholerae bacteria.
- Transmission: Drinking contaminated water or eating unwashed food.
- Symptoms: Severe watery diarrhea ("rice-water stools"), vomiting, rapid dehydration.
- Control: Drinking boiled or chlorinated water, washing hands with soap before eating and after using latrines.
C. Bilharzia (Schistosomiasis)
- Pathogen: Blood fluke (schistosoma parasitic worm).
- Vector: Freshwater snails.
- Symptoms: Blood in urine, abdominal pain.
- Control: Avoiding swimming in stagnant freshwater ponds; destroying freshwater snails.
3. Water Purification Methods
Safe drinking water prevents water-borne disease outbreaks. Grade 7 candidates must know these 4 water treatment steps:
- Filtration: Passing dirty water through cloth or sand filters to remove solid debris.
- Boiling: Heating water to $100^\circ\text{C}$ for at least 10 minutes to kill all bacteria, viruses, and parasite eggs.
- Chlorination: Adding measured liquid chlorine or water purification tablets (e.g. Clorox/Liquid Chlorine) to kill germs.
- Settling / Sedimentation: Allowing heavy soil particles to settle at the bottom of the container.
4. Deficiency Diseases
| Deficiency Disease | Missing Nutrient | Symptoms | Dietary Source Solution |
|---|---|---|---|
| Kwashiorkor | Protein | Swollen belly, reddish hair, cracked skin. | Beans, eggs, groundnuts, kapenta, meat. |
| Marasmus | Total Energy (Carbs & Fats) | Extreme thinness, visible ribs, weak body. | Maize meal (nshima), cassava, sweet potatoes. |
| Scurvy | Vitamin C | Bleeding gums, slow wound healing. | Oranges, lemons, guavas, wild fruits (masuku). |
| Rickets | Vitamin D / Calcium | Soft, bowed legs in young children. | Milk, fish oil, sunlight exposure. |
Parent & Home Guidance
Involve your child in daily home hygiene practices like chlorinating drinking water, inspecting mosquito nets for holes, and identifying vitamin-rich local Zambian fruits during market trips.
Frequently Asked Questions
Malaria is transmitted by the female Anopheles mosquito. Prevention methods tested in Grade 7 ECZ exams include sleeping under Insecticide Treated Nets (ITNs), clearing stagnant water around homes, spraying larvicides, and wearing long-sleeved clothes at dusk.