Level: JHS (Basic 7 – 9) | Subject: Integrated Science | Topic: Diseases – Causes, Prevention, and Control | Curriculum: Ghana NaCCA / GES
Disease is one of the most significant challenges facing Ghana’s development. Understanding how diseases are caused, how they spread, and how they can be prevented is not just academic knowledge – it directly affects the health and survival of families and communities across the country.
Classification of Diseases
| Type | Cause | Examples |
|---|---|---|
| Infectious (communicable) | Microorganisms (pathogens): bacteria, viruses, fungi, protozoa, worms | Malaria, tuberculosis, cholera, HIV/AIDS, typhoid, measles |
| Non-infectious (non-communicable) | Genetics, lifestyle, diet, environment | Diabetes, hypertension, sickle cell disease, cancer, asthma |
| Deficiency diseases | Lack of essential nutrients | Anaemia (iron), rickets (vitamin D), scurvy (vitamin C), kwashiorkor (protein) |
Malaria
Malaria is one of the leading causes of illness and death in Ghana, particularly among children under 5 and pregnant women.
| Aspect | Details |
|---|---|
| Causative organism | Plasmodium species (protozoan parasite) – mainly Plasmodium falciparum in Ghana |
| Vector (carrier) | Female Anopheles mosquito. The mosquito carries the parasite but is not the disease itself. |
| Mode of transmission | Bite of an infected female Anopheles mosquito, usually in the evening or at night |
| Symptoms | High fever, chills, sweating, headache, vomiting, muscle pain, anaemia. Can progress to cerebral malaria (affecting the brain) in severe cases. |
| Prevention | Sleep under insecticide-treated bed nets (ITNs); use mosquito repellents; eliminate stagnant water where mosquitoes breed; indoor residual spraying; take prophylactic antimalarial medicine when recommended |
| Treatment | Artemisinin-based combination therapies (ACTs) are the recommended treatment for uncomplicated malaria in Ghana |
Tuberculosis (TB)
| Aspect | Details |
|---|---|
| Causative organism | Mycobacterium tuberculosis (bacterium) |
| Mode of transmission | Airborne: droplets released when an infected person coughs, sneezes, or speaks. TB is NOT spread by touch, sharing food, or mosquitoes. |
| Symptoms | Persistent cough lasting more than 2 weeks, coughing up blood, night sweats, unexplained weight loss, fever, chest pain, fatigue |
| Prevention | BCG vaccination in infancy; improve ventilation in homes and public spaces; identify and treat infected people promptly |
| Treatment | A 6-month course of antibiotics (DOTS – Directly Observed Treatment Short-course). Completing the full course is critical to prevent drug resistance. |
Cholera
| Aspect | Details |
|---|---|
| Causative organism | Vibrio cholerae (bacterium) |
| Mode of transmission | Contaminated water and food (faecal-oral route). Usually linked to poor sanitation. |
| Symptoms | Sudden, severe watery diarrhoea (“rice-water stools”), vomiting, rapid dehydration. Can be fatal within hours if untreated. |
| Prevention | Drink only clean, treated water; wash hands with soap; cook food thoroughly; proper sewage disposal; avoid open defaecation |
| Treatment | Oral rehydration salts (ORS) to replace lost fluids; antibiotics in severe cases; IV fluids when patient cannot drink |
HIV/AIDS
HIV (Human Immunodeficiency Virus) is a virus that attacks the immune system. AIDS (Acquired Immune Deficiency Syndrome) is the most advanced stage of HIV infection, when the immune system is severely damaged and the body can no longer fight off infections.
| Aspect | Details |
|---|---|
| Causative organism | Human Immunodeficiency Virus (HIV) – a retrovirus |
| Mode of transmission | Unprotected sexual intercourse with an infected person; sharing needles or syringes; blood transfusion with infected blood; mother to child during pregnancy, birth, or breastfeeding |
| How it is NOT transmitted | Hugging, handshakes, sharing food, mosquito bites, coughing, sneezing, toilets, or swimming pools |
| Symptoms | Initial flu-like illness; then often symptom-free for years; later stage: weight loss, persistent fever, diarrhoea, oral thrush, opportunistic infections like TB and pneumonia |
| Prevention | Abstinence or faithful partnership; consistent use of condoms; avoid sharing needles; use screened blood only; pregnant women with HIV should receive treatment to protect baby (PMTCT) |
| Treatment | Antiretroviral therapy (ART) – medication that suppresses the virus and allows people with HIV to live healthy, long lives. ART does not cure HIV but makes it manageable. |
Sickle Cell Disease
Sickle cell disease is a non-infectious genetic disorder that is very common in Ghana and across sub-Saharan Africa.
- Cause: A mutation in the gene for haemoglobin (the protein in red blood cells that carries oxygen). People with sickle cell disease (genotype SS) have abnormally shaped, crescent (sickle-shaped) red blood cells.
- Effect: Sickle cells are rigid and can block small blood vessels, causing painful episodes called sickle cell crises, organ damage, anaemia, and increased risk of infection.
- Inheritance: The disease is inherited from both parents. If both parents carry the sickle cell trait (AS), there is a 25% chance with each pregnancy that the child will have sickle cell disease (SS).
- Common genotypes: AA (normal), AS (carrier – sickle cell trait, generally healthy), SS (sickle cell disease)
- Management: Adequate hydration, pain medication, folic acid supplements, blood transfusions when needed, hydroxyurea medication, and bone marrow transplant in some cases.
- Screening: Newborn screening programmes help identify affected babies early so management can begin promptly.
General Disease Prevention Principles
- Personal hygiene: Regular handwashing, bathing, and clean clothing reduce the spread of many pathogens.
- Environmental sanitation: Proper disposal of waste, use of latrines, and clean water supply are foundational to community health.
- Vaccination: Immunisation programmes protect against measles, polio, meningitis, hepatitis B, and many others.
- Adequate nutrition: A well-nourished immune system is better able to fight infection.
- Health education: Knowing how diseases spread empowers people to protect themselves and their families.
Practice Questions: Diseases and Prevention
1. What is the causative organism of malaria?
Reveal Answer
Answer: C – Plasmodium falciparum. Malaria is caused by the Plasmodium protozoan parasite, particularly P. falciparum in Ghana. It is transmitted by the female Anopheles mosquito, which is the vector, not the causative organism itself.
2. Tuberculosis is transmitted through:
Reveal Answer
Answer: C – Airborne droplets from an infected person’s cough or sneeze. TB is an airborne disease. Good ventilation and prompt treatment of infected individuals are key prevention strategies.
3. A child has parents with genotypes AS and AS. What is the probability that the child will have sickle cell disease (SS)?
Reveal Answer
Answer: B – 25%. When both parents are AS, the possible combinations are: AA (25%), AS (50%), SS (25%). There is a 1 in 4 (25%) chance that any child will inherit SS (sickle cell disease).
4. HIV cannot be transmitted through:
Reveal Answer
Answer: C – Hugging or handshakes. HIV is not transmitted through casual contact. This misconception has caused enormous stigma and discrimination against people living with HIV. HIV requires direct exchange of specific body fluids to be transmitted.
5. Which of the following is the most effective immediate treatment for cholera?
Reveal Answer
Answer: C – Oral rehydration salts to replace lost fluids. Cholera kills primarily through rapid, severe dehydration. Restoring lost fluids and electrolytes with ORS (a mixture of clean water, salt, and sugar) is the most critical and life-saving immediate treatment.
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