in the home

A Hidden World in Your Home 4 Dust Mites 6 Looking Closer at Dust 8 Bugs in the Bed 10 In the Bathroom 12 In the Kitchen 14 Fungi at Home 16 Close-up on Clothes 18 Pet Parasites 20 House

In the

Home

Sabrina Crewe

Consultant:

Professor Anne K Camper,

Montana State UniversityUnder the Microscope

Copyright © 2010 by Infobase Publishing

All rights reserved No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval systems, without permission in writing from the publisher For information contact:

You can find Chelsea Clubhouse on the World Wide Web at http://www.chelseahouse.com

Text design by Sabine Beaupré

Illustrations by Stefan Chabluk

Originated by Discovery Books

Composition by Discovery Books

Cover printed by Bang Printing, Brainerd, MN

Book printed and bound by Bang Printing, Brainerd, MN

Date printed: May 2010

Printed in the United States of America

10 9 8 7 6 5 4 3 2 1

This book is printed on acid-free paper.

All links and Web addresses were checked and verified to be correct at the time of publication Because of the dynamic nature of the Web, some addresses and links may have changed since

publication and may no longer be valid.

Acknowledgments

We would like to thank the following for permission to reproduce photographs: Centers for Disease Control and Prevention, US Department of Health and Human Services: pp 11, 12; Dennis Kunkel Microscopy, Inc.: pp 9, 10, 13 bottom, 14, 16, 18, 22, 23, 27 top; MicroAngela: pp 20, 21 right; Rocky Mountain Laboratories, The National Institute of Allergy and Infectious Diseases: p 15; Science Photo Library: pp 5 (Andrew Syred), 7 (Andrew Syred), 17 (Jeremy Burgess), 19 (Andrew Syred), 25 (Susumu Nishinaga), 26 top (Volker Steger), 27 middle (Andrew Syred), 27 bottom (Eye of Science); Shutterstock Images: pp 4 (Rob Marmion), 8 (Photoroller), 21 left (Alice Mary Herden Vision-Vault LLC), 24 (Rudyanto Wijaya), 26 bottom (Jasenka Lukša), 29 top (3445128471), 29 bottom (Nikola Spasenoski).

A Hidden World in Your Home 4 Dust Mites 6 Looking Closer at Dust 8 Bugs in the Bed 10

In the Bathroom 12

In the Kitchen 14 Fungi at Home 16 Close-up on Clothes 18 Pet Parasites 20 Household Mini-Monsters 22 Bigger Bugs 24 Everyday Stuff 26 Size and Scale 28 About Microscopes 28 Micro-Detective 29 Glossary 30 Explore These Web Sites 31

Some words are bold the first time they appear

in the text These words are explained in the glossary at the back of this book.

Copyright © 2010 by Infobase Publishing

All rights reserved No part of this book may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying, recording, or by any information storage or retrieval

systems, without permission in writing from the publisher For information contact:

1 Microorganisms Juvenile literature 2 Microscopy Juvenile literature 3 Housing and health

Juvenile literature I Title

QR57.C743 2010

579.028’2 dc22

2009041203

Chelsea Clubhouse books are available at special discounts when purchased in bulk quantities for

businesses, associations, institutions, or sales promotions Please call our Special Sales Department

in New York at (212) 967-8800 or (800) 322-8755.

You can find Chelsea Clubhouse on the World Wide Web at http://www.chelseahouse.com

Text design by Sabine Beaupré

Illustrations by Stefan Chabluk

Originated by Discovery Books

Composition by Discovery Books

Cover printed by Bang Printing, Brainerd, MN

Book printed and bound by Bang Printing, Brainerd, MN

Date printed: May 2010

Printed in the United States of America

10 9 8 7 6 5 4 3 2 1

This book is printed on acid-free paper.

All links and Web addresses were checked and verified to be correct at the time of publication

Because of the dynamic nature of the Web, some addresses and links may have changed since

publication and may no longer be valid.

Acknowledgments

We would like to thank the following for permission to reproduce photographs: Centers for Disease

Control and Prevention, US Department of Health and Human Services: pp 11, 12; Dennis Kunkel

Microscopy, Inc.: pp 9, 10, 13 bottom, 14, 16, 18, 22, 23, 27 top; MicroAngela: pp 20, 21 right; Rocky

Mountain Laboratories, The National Institute of Allergy and Infectious Diseases: p 15; Science Photo

Library: pp 5 (Andrew Syred), 7 (Andrew Syred), 17 (Jeremy Burgess), 19 (Andrew Syred), 25 (Susumu

Nishinaga), 26 top (Volker Steger), 27 middle (Andrew Syred), 27 bottom (Eye of Science); Shutterstock

Images: pp 4 (Rob Marmion), 8 (Photoroller), 21 left (Alice Mary Herden Vision-Vault LLC), 24 (Rudyanto

A Hidden World

in Your Home

Who lives in your home? You, of course, and other

members of your family, and maybe you have a pet But

did you know that your home is also home to an invisible

population of microscopic living things?

Billions of microorganisms

There are billions of microorganisms in your home

Microorganisms are living things that are too small to

be seen without a microscope They come in many sizes,

starting with tiny and getting even tinier Microorganisms

live in your bed, in your kitchen, and even on your pets

The biggest microorganisms are very small insects and

other animals The smaller ones—which are not animals—

are often known as microbes Some microbes are like

miniature animals, while others are more like plants Even

smaller are the bacteria that are everywhere around us

There are more bacteria on Earth than any other living things, and yet we can’t see them

microscope You will discover

a whole new world in your home!

bacteria

We all share our homes with billions of microorganisms!

There are more bacteria on

Earth than any other living

things, and yet we can’t

home We’ll also see

some familiar household

objects under the

microscope You will discover

a whole new world in your home!

In real life, this tip of a pin

is only 0.03 millimeters across It has been magnified 1,500 times

If you looked at it without

a microscope, you would never know that it was covered

in bacteria.

bacteria

Dust Mites

The first microscopic creature we’re going to look at is the dust mite There are millions of them in every part of your home where dust collects

Pieces of you

You may be surprised to learn that most of this dust comes from living things—especially you Much of the dust in our homes consists of human skin! Every hour, a person will shed about 1.5 million flakes of dead skin The flakes are tiny, but that’s still a whole lot of skin

Delicious skin

Skin is the favorite food of the dust mite These microscopic animals eat by squirting juice from their digestive systems onto flakes of skin The juices turn the skin into liquid, and the dust mites suck it up

Not surprisingly, the dust mite’s favorite places are those where they will find the most skin flakes, such as under your bed or in your pillows and mattress Dust mites live all over

the house, however: in carpets, couches,

and armchairs These places trap a lot

of dust, so you can find many mites there, too In fact, you will be sure to find them in any nook and cranny that traps dust In just one ounce of household dust, there can be 30,000 to 40,000 dust mites like the one opposite!

Micro-Fact

A bed may hold

about 2 million

dust mites

Dust Mites

The first microscopic creature we’re going to look at is the

dust mite There are millions of them in every part of your

home where dust collects

Pieces of you

You may be surprised to learn that most of this dust comes

from living things—especially you Much of the dust in our

homes consists of human skin! Every hour, a person will

shed about 1.5 million flakes of dead skin The flakes are

tiny, but that’s still a whole lot of skin

Delicious skin

Skin is the favorite food of the dust mite These microscopic

animals eat by squirting juice from their digestive systems

onto flakes of skin The juices turn the skin into liquid, and

the dust mites suck it up

Not surprisingly, the dust mite’s favorite places are those

where they will find the most skin flakes, such as under your

bed or in your pillows and mattress Dust mites live all over

the house, however: in carpets, couches,

and armchairs These places trap a lot

of dust, so you can find many mites there, too In fact, you will be

sure to find them in any nook and cranny that traps dust In

just one ounce of household dust, there can be 30,000 to

40,000 dust mites like the one opposite!

Arachnids

Dust mites are arachnids, which means they are

in the same family of animals as spiders and scorpions Arachnids have eight legs, no

antennae, and no wings

Looking Closer

at DustDust is everywhere in our homes Even if you clean your room every week, you will soon find specks of dust on your dresser and gray fluff under the bed We already know that skin

is a big part of dust, but what else do we find when we look at dust through a microscope?

Other stuff in dust

Most of us live in cities, and dirt is in the air all around us A lot of this dirt comes from vehicle engines and power plants Some of it comes into your home through windows and doors and settles on surfaces Grains of pollen, sand, and soil also float into your house from outside

Dust Allergies

You may know people

who have allergies

to dust—maybe

you have an allergy

yourself Pollen

in dust can cause

allergies, but there

isn’t that much pollen

inside your home

Usually, dust allergies

are caused by feces

(droppings) from

microanimals that

live in our homes Top

of the list for

allergy-causing droppings

are dust mites

The things bugs leave behind make a lot of dust, too: spiders’ webs, droppings from insects, and microscopic pieces of dead bugs You’ll also find a lot of fibers from

clothes, towels, and carpet Other strands in dust include hairs from people and pets In areas where people eat, dust contains crumbs

of food, too

In this close-up

view of house dust, the

parts have been colored so

you can see them more clearly

The yellow shape is a grain of

pollen Other microscopic plant

parts are green The dark brown

strand is a dog hair, and the orange

strand is a cat hair The purple,

pink, and blue fragments are

all fibers from cloth Most of

the brown stuff is dead

skin from people

and animals.

Bugs in the Bed

If you thought dust mites were gross, you might not want

to read this Bed bugs are so ugly up close that they make dust mites look cute Luckily for us, most homes don’t

have bed bugs living in them!

Bigger bugs

Bed bugs are much bigger than dust mites They are

about 5 millimeters long, so you can easily find them

without a microscope But when you put them under the microscope, you can see what they are really like!

Bed bugs are insects but, unlike many other insects, they have no wings During the day, bed bugs live

close to beds or in mattresses, pillows, or comforters—

anywhere safe and dark At night they come out to eat

This bed bug

uses its proboscis to

pierce skin and suck out blood The proboscis has been colored pink in this photo Bed bugs use their feelers on top of their head to find their way

to a blood source.

This bed bug

uses its proboscis to

pierce skin and suck out

blood The proboscis has

been colored pink in this

photo Bed bugs use their

feelers on top of their

head to find their way

to a blood source.

Blood eaters

The bed bug’s favorite meal

is human blood In fact, one of these mini-beasts can eat six times its own weight in blood

Then it can go months without another meal You won’t feel them when they pierce your skin to suck your blood, but the bites will itch the next day

Bed bugs put out a horrible smell if something scares them They secrete oil that has

a sweet, sickly odor You can

usually smell an infestation

of bed bugs in your home because of this odor, even if you don’t have bites

Baby Bed BugsBed bugs live from six months to one year During that time, a female bed bug can lay two or three eggs a day, which means several hundred new bed bugs! After

a couple of weeks, the eggs hatch nymphs The nymphs grow into adult bed bugs in about two months

If you look closely, you can see that this bed bug has its proboscis stuck

in a person’s skin.

proboscis

In the

Bathroom

Bacteria are everywhere:

in the yard, in our bodies,

and in the air If you want

to find billions of bacteria

in one place, take a look

in the bathroom!

Busy bathroom

It doesn’t matter how clean

your bathroom is—it will still be

busy with bacteria Some parts

of a toilet bowl can have 3 million

bacteria per square inch An average

faucet handle on a bathroom sink has

more than 6,000 bacteria per square inch

What are bacteria?

Bacteria are living things made of

only one cell There are other

living things with just one cell, but a bacterium is different because its cell does not have

a nucleus, such as the one you

would find in a plant or animal cell Instead, a bacterium cell has a nucleoid that controls the cell and what it does

Micro-Fact

Bacteria reproduce by

dividing their cell into two

identical new cells Some

bacteria can do this so fast

that one bacterium can

become 4,000 bacteria

in just four hours

Escherichia coli

(E coli for short)

bacteria are round and cluster together in bath- rooms and elsewhere

Some forms of E coli

cause people to get very sick.

In the

Bathroom

Bacteria are everywhere:

in the yard, in our bodies,

and in the air If you want

to find billions of bacteria

in one place, take a look

in the bathroom!

Busy bathroom

It doesn’t matter how clean

your bathroom is—it will still be

busy with bacteria Some parts

of a toilet bowl can have 3 million

bacteria per square inch An average

faucet handle on a bathroom sink has

more than 6,000 bacteria per square inch

What are bacteria?

Bacteria are living things made of

only one cell There are other

living things with just one cell, but a bacterium is different

because its cell does not have

a nucleus, such as the one you

would find in a plant or animal cell Instead, a bacterium cell

has a nucleoid that controls the cell and what it does

Most bacteria are harmless In fact, many perform important tasks in the soil, air, and living things Some bacteria in our homes, however, are

pathogens—

microorganisms that make people sick

This diagram

of a bacterium shows the basic structure of all bacteria.

Escherichia coli

(E coli for short)

bacteria are round and cluster together in bath- rooms and elsewhere

Some forms of E coli

cause people to get very sick.

These staphylococci (colored green) are living

on a person’s skin and hair

Lots of people carry these bacteria around in their bodies They can be picked up

in bathrooms by other people.

Many staphylococci are harmless, but some can cause horrible skin infections.

In the Kitchen

Another place to find billions of bacteria is in the kitchen The kitchen is full of food for bacteria as well as for you

Close-up on cloths and sponges

You might think your garbage can would have the most

bacteria in the kitchen But compared to a

kitchen sponge or cloth, the trash is pretty clean There are reasons for this Sponges are damp, they are full of food particles, and their fibers provide a perfect surface for bacteria

In one study of U.S homes, scientists examined kitchen sponges and found 134,500 bacteria per square inch The garbage cans in the same houses

A close-up look

at this blue kitchen sponge reveals bacteria (pink specks and clusters) and other microorganisms lurking in its fibers The long purple and red strands

are microfungi So are

the yellow-green balls

millimeters in size That

means you could fit

millions of them on

your fingernail

In the Kitchen

Another place to find billions of bacteria is in the kitchen

The kitchen is full of food for bacteria as well as for you

Close-up on cloths and sponges

You might think your garbage can would have the most

bacteria in the kitchen But compared to a

kitchen sponge or cloth, the trash is pretty clean There are reasons for

this Sponges are damp, they are full of food particles, and their

fibers provide a perfect surface for bacteria

In one study of U.S homes, scientists examined kitchen

sponges and found 134,500 bacteria per square inch The

garbage cans in the same houses

had only an average 411 bacteria per square inch

Good and bad bacteria

Most kitchen bacteria are harmless and can help keep food safe because they compete with pathogens The pathogen

Salmonella lives on meat and in

eggs When you cook meat and eggs, the bacteria are killed, but some can remain on kitchen surfaces Then they can be carried

on your fingers or a spoon to other

food and give you food poisoning.

long purple and red strands

are microfungi So are

the yellow-green balls

of yeast

People infected with

Salmonella get upset

stomachs and fevers

This picture shows

Salmonella invading

human cells.

Getting Rid

of BacteriaPeople often try bleach, lemon juice, and water to get rid of bacteria on sponges, but none of these cleaning agents do a complete job If you put the sponge in a microwave for two minutes, however, the heat will kill more than 99 percent of the bacteria The super-hot water of a dishwasher does a good job of

Salmonella