Our bodies are pretty amazing. Day after day, they work hard — digesting
food, pumping blood and oxygen, sending signals from our brains and much more.
But there is a group of tiny invaders that can make our bodies sick — they're
called germs.
Some kids may think that germs are bugs or cooties or other gross stuff. Actually,
germs are tiny organisms, or living things, that can cause disease. Germs are so small
and sneaky that they creep into our bodies without being noticed. In fact, germs are
so tiny that you need to use a microscope to see them. When they get in our bodies,
we don't know what hit us until we have symptoms that say we've been attacked!
What Types of Germs Are There?
Germs are found all over the world, in all kinds of places. The four major types
of germs are bacteria, viruses, fungi, and protozoa. They can invade plants, animals,
and people, and sometimes they can make us sick.
Bacteria (say: BAK-teer-ee-uh) are tiny, one-celled creatures
that get nutrients from their environments in order to live. In some cases that environment
is a human body. Bacteria can reproduce outside of the body or within the body as
they cause infections. Some infections that bacteria can cause include ear infections,
sore throats (tonsillitis or strep throat), cavities, and pneumonia (say: new-MO-nyuh).
But not all bacteria are bad. Some bacteria are good for our bodies — they
help keep things in balance. Good bacteria live in our intestines and help us use
the nutrients in the food we eat and make waste from what's left over. We couldn't
make the most of a healthy meal without these important helper germs! Some bacteria
are also used by scientists in labs to produce medicines and vaccines
(say: VAK-seens).
Viruses (say: VY-rus-iz) need to be inside living cells to grow
and reproduce. Most viruses can't survive very long if they're not inside a living
thing like a plant, animal, or person. Whatever a virus lives in is called its host.
When viruses get inside people's bodies, they can spread and make people sick. Viruses
cause chickenpox, measles, flu, and many other diseases. Because some viruses can
live for a short time on something like a doorknob or countertop, be sure to
wash your hands regularly!
Fungi (say: FUN-guy) are multi-celled (made of many cells), plant-like
organisms. Unlike other plants, fungi cannot make their own food from soil, water,
and air. Instead, fungi get their nutrition from plants, people, and animals. They
love to live in damp, warm places, and many fungi are not dangerous in healthy people.
An example of something caused by fungi is athlete's foot, that itchy rash that teens
and adults sometimes get between their toes.
Protozoa (say: pro-toh-ZOH-uh) are one-cell organisms that love
moisture and often spread diseases through water. Some protozoa cause intestinal infections
that lead to diarrhea, nausea, and belly pain.