explain how cholera, malaria, TB and HIV are transmitted

Infectious Diseases: How They Spread 🚀

Cholera 💧

Cholera is caused by the bacterium Vibrio cholerae. It travels through the water highway—think of it as a river full of tiny, invisible cars that can crash into your body if the water is contaminated.

Transmission Mode Typical Example
Drinking contaminated water Tap water in unsanitary areas
Eating raw seafood Crab or mussels from polluted waters
Poor hand hygiene Not washing hands before meals
Exam Tip: Remember the “Water, Food, Hygiene” triad when answering transmission questions. Use the word “contaminated” to highlight the source.

Malaria 🦟

Malaria is a parasite that uses the mosquito as a delivery truck. The female Anopheles mosquito bites you, drops the parasite into your bloodstream, and then the parasite multiplies in your liver before invading red blood cells.

  1. Infected mosquito bites → parasite enters bloodstream.
  2. Parasite travels to liver → multiplies.
  3. Parasite returns to blood → infects red blood cells.
Exam Tip: Use the phrase “vector-borne” to describe malaria. Highlight the role of the mosquito and the life cycle stages.

Tuberculosis (TB) 🛬

TB is caused by the bacterium Mycobacterium tuberculosis. Think of it as a sneaky thief that hides in the air and enters your lungs when you breathe in infected droplets.

Transmission Key Point
Coughing or sneezing Droplets travel up to 1–2 m
Close contact in poorly ventilated spaces Increased risk in dorms, prisons
Sharing utensils (rare) Not a primary route
Exam Tip: Emphasise the “airborne” nature of TB and the importance of ventilation and masking in control strategies.

Human Immunodeficiency Virus (HIV) 🧬

HIV attacks the immune system by targeting CD4+ T cells. It spreads through direct contact with infected fluids—think of it as a stealthy virus that needs a doorway (blood, sexual fluids, or breast milk) to enter the body.

  • Blood‑to‑blood contact (e.g., needles, transfusions)
  • Unprotected sexual activity
  • Mother to child during pregnancy, birth, or breastfeeding
Exam Tip: When answering, mention the “high‑risk behaviours” and the role of pre‑exposure prophylaxis (PrEP) and antiretroviral therapy (ART) in prevention and treatment.

Revision

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