How Communicable Diseases Spread · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

How germs travel and how to stop them

Science · The Human Body · ages 15-16
Name ______________________   Date ____________

  1. A mosquito carries malaria between people. What is the mosquito called here?

    • A host cell
    • A vector
    • A pathogen

  2. Which list names the four pathogen types?

    • Bacteria, viruses, fungi, protists
    • Bacteria, viruses, insects, worms
    • Germs, dirt, cold air, bad food

  3. Most bacteria can reproduce without a host cell, but a virus cannot.

    Circle one:   True   False

  4. A village has rising malaria cases. Which control follows from the route, and why?

    • Hand out bed nets, since mosquitoes bite at night
    • Close schools, since touch spreads it
    • Boil drinking water, since water carries it

  5. Cholera spreads through dirty water and colds spread through touch. Which pairing of blocks fits?

    • Handwashing for cholera, bed nets for colds
    • Bed nets for both
    • Clean water for cholera, handwashing for colds

  6. Why does isolation of sick people slow a disease spread by direct contact?

    • It trains antibodies in healthy people
    • It kills the pathogen in the water supply
    • It removes the source that touch would carry onward

  7. A new fever spreads where people share river water, and tests show a protist in the water. What is the best first move?

    • Treat and protect the water supply
    • Hand out face masks
    • Spray against mosquitoes

  8. A poster says: flu is airborne, so everyone should boil drinking water. What is the error?

    • Flu is not communicable at all
    • Boiling water blocks the wrong route, since flu travels in coughs
    • Boiling water is useless against every disease
LightMySky · lightmysky.comW1-mt_o__-bF814q-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

How germs travel and how to stop them W1-mt_o__-bF814q-s1

  1. A vector · A vector is a living carrier that ferries a germ between hosts.
  2. Bacteria, viruses, fungi, protists · The four types are bacteria, viruses, fungi and protists.
  3. True · Viruses must hijack a host cell to copy themselves.
  4. Hand out bed nets, since mosquitoes bite at night · Nets block night bites, which is the exact path malaria travels.
  5. Clean water for cholera, handwashing for colds · Each block must cut the route its own germ travels.
  6. It removes the source that touch would carry onward · Without contact with the sick, the germ runs out of new hosts.
  7. Treat and protect the water supply · The evidence points at a waterborne route, so the water is the chain to cut.
  8. Boiling water blocks the wrong route, since flu travels in coughs · The block must match the route, and water treatment cannot catch coughs.
Worksheet · LightMySky