In the Home (Under the Microscope)

Under the Microscope

In the

Home Sabrina Crewe Consultant: Professor Anne K. Camper, Montana State University

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: Chelsea Clubhouse An imprint of Chelsea House 132 West 31st Street New York NY 10001 Library of Congress Cataloging-in-Publication Data Crewe, Sabrina. Under the microscope : in the home / Sabrina Crewe. p. cm. Includes index. ISBN 978-1-60413-823-8 (hardcover) ISBN 978-1-4381-3248-8 (e-book) 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 Wijaya), 26 bottom (Jasenka Lukša), 29 top (3445128471), 29 bottom (Nikola Spasenoski).

Contents 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

Index

32

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.

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?

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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.

T E t s

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We all share our homes with billions of microorganisms! 4

I a a l h s o m a

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

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

Looking closer

How Small Is Small? A dust mite is 0.2 to 0.5 millimeters long—so small that it can live in your carpet unnoticed. But it is still several thousand times bigger than the smallest microbes. We’ll find out more about dust mites next.

In this book, we’ll use a microscope to take a look at the hidden life-forms in your home. We’ll also see some familiar household objects under the microscope. You will discover a whole new world in your home! 5

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 Micro-Fact and cranny that traps dust. In just one ounce of household A bed may hold dust, there can be 30,000 to about 2 million 40,000 dust mites like the dust mites. one opposite! 6

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 Dust Dust 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?

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 allergycausing droppings are dust mites.

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. 

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 In this close-up areas where people eat, view of house dust, the dust contains crumbs parts have been colored so you can see them more clearly. of food, too.

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.

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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.

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. 10 10

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 Bugs Bed 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 11

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!

Escherichia coli (E. coli for short) bacteria are round and cluster together in bathrooms and elsewhere. Some forms of E. coli cause people to get very sick.

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 Micro-Fact living things with just one cell, Bacteria reproduce by but a bacterium is different dividing their cell into two because its cell does not have identical new cells. Some a nucleus, such as the one you bacteria can do this so fast would find in a plant or animal that one bacterium can cell. Instead, a bacterium cell become 4,000 bacteria has a nucleoid that controls the in just four hours. cell and what it does. 12

This diagram of a bacterium shows the basic structure of all bacteria.

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Most bacteria are harmless. In fact, These many perform staphylococci (colored green) are living important on a person’s skin and hair. tasks in the Lots of people carry these soil, air, bacteria around in their and living bodies. They can be picked up in bathrooms by other people. things. Some Many staphylococci are bacteria in harmless, but some can our homes, cause horrible skin infections. however, are pathogens— microorganisms that make people sick.

13

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 How Small full of food particles, and their Is Small? fibers provide a perfect surface for bacteria. Bacteria are only In one study of U.S. homes, between 0.001 and 0.004 scientists examined kitchen millimeters in size. That sponges and found 134,500 means you could fit bacteria per square inch. The millions of them on garbage cans in the same houses your fingernail.

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 of yeast. 14 14

Salmonella

People infected with Salmonella get upset stomachs and fevers. This picture shows Salmonella invading human cells.

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. 15

Getting Rid of Bacteria People 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 killing bacteria, too.

Fungi at Home Other microorganisms that thrive in your kitchen and all over the home are called fungi. Fungi are a little like plants, but they have different ways of growing and feeding. They reproduce by releasing spores. One kind of fungus you would recognize right away is a mushroom.

Microfungi Many fungi are tiny, and it’s only when they spread over a large area that you can see them without a microscope. These fungi are called microfungi. There are several types of microfungi that live in our homes. Once you know what they are and where to look, you can probably find some in your home.

Mold Think of a piece of fruit or slice of bread covered in mold. Mold is a kind of fungi. To our eyes, the mold looks like fluff or powder. But if we look at it under a microscope, we can see it is made up of a network of hyphae. Hyphae are the threads fungi use to grow and feed. The mold Aspergillus versicolor looks like a tree, with its branches holding spores. Aspergillus versicolor likes moist places, including carpets, mattresses, and walls. 16 16

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F g t f a c t f s s t t

Mildew Fungi in the home don’t just grow on food. They can spread Micro-Scientist through walls, carpets, and A mycologist is a scientist floors. Damp walls can get who becomes an expert on attacked by what we often all kinds of fungi, including call mildew, a group of fungi microfungi. Because of research that likes moisture. You might by mycologists, fungi are find this type of mildew in the used in many drugs shower or behind the kitchen that fight infections. sink. But when fungi experts use the word mildew, they mean fungi that grows on plants.

Dry Rot Several fungi can cause a type of damage, called dry rot, to wood. Most homes are built partly from wood, and dry rot can spread through a home like mold through bread. The thin, tan-colored threads you can see are the hyphae of dry rot that have eaten this piece of wood. Wood invaded by dry rot eventually crumbles away.

1

Close-up on Clothes Let’s see what things in the the laundry room look like under the microscope.

Fabric and fibers When you look at some fabrics, such as cotton, you can easily see they are made up of woven fibers. But many human-made fabrics, such as polyester, look completely smooth. Up close, however, you can see that polyester is also made of tiny fibers. Sometimes, you’ll see fabric fibers A close-up are made of even smaller fibers. of the collar of a

cotton t-shirt shows cotton fibers with dirt trapped in them.

Stinky bacteria If clothes and other fabrics get a little stinky, it is usually because of some form of microscopic life in the fibers. Mildew and other fungi will get into clothes and give off a musty smell. When people sweat, bacteria on their skin cause an odor to develop. The odor and the bacteria are transferred onto their clothes. 1

So what can kill off stinky bacteria? People have been using bleach as a cleaning agent for about 200 years. Scientists eventually figured out why it works so well. A chemical in bleach destroys parts of the bacteria cell. This can kill the cells or make them inactive, so the bacteria can’t spread.

Micro-Cleaners Have you ever thought about how clothes get clean when we wash them? Most detergents are improved by tiny molecules called enzymes. Enzymes are in the cells of all living things, where they help to break down food. When enzymes are added to detergent, they do a similar job—they break down stains and dirt on clothes. The yellow stuff that comes out of these detergent granules as they dissolve in water includes enzymes.

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Pet Parasites Micro-Monster Cat fleas have strong hind legs that they use to leap onto animals. They can leap about 150 times farther than their own body length, which is 1 millimeter or less. With their flat bodies, cat fleas can move around quickly in fur. They are not fussy about what kind of fur, so they live on dogs as well as cats.

A living thing that lives on or in another living thing and feeds off it is called a parasite. As you can imagine, there are many parasites in the microscopic world. They live on plants, people, and even other parasites. The organism they live on or in is called the host. You can be pretty sure that your pets are hosts to many parasites.

Fleas and ticks Fleas are very small wingless insects that live on cats, dogs, and other animals. Fleas feed off their hosts by sticking their sharp mouthparts into animals’ skin and sucking the blood out. Most of the fleas living on pets in North America are cat fleas. Ticks are a kind of mite that tend to be larger than other mites. The American dog tick finds its host by waiting on a blade of grass or other plant. When a dog brushes against the plant, the tick hops onto the dog and stays. The tick inserts its mouthparts into the dog’s skin and

20

When a dog scratches its ear, the itch may be caused by hundreds of dog ear mites, like the one on the right, running around inside the ear.

starts sucking blood. They stick in so firmly that if you pluck the tick off, its head can stay behind in the flesh!

How Small Is Small? Fleas have their own parasites in the form of tiny mites that live on them! A mite that lives on a flea is just a fraction of a millimeter long.

Mites

The dog ear mite is only about 0.24 millimeters long. Like ticks and other mites, it’s an arachnid with eight legs. These mites infect the ears of dogs and other animals. Other mites tunnel into the skin of dogs and cats and cause nasty itching and swelling. When people say their pets have mange, they mean an infestation of mites. 21

Microbes in the Air Every time you cough, sneeze, or laugh, thousands of bacteria can fly out of your body and float around in the air. The air in your home has other microscopic particles in it, too, including fungi spores. Fungal spores are like seeds. They are blasted into the air by the parent fungus and float around until they settle somewhere where they can grow and spread.

Household Mini-Monsters Let’s take a look at some other microscopic life around the home. When you look up close, you’ll find creatures living everywhere!

House pseudoscorpions If your home is a little damp in places, you might well have house pseudoscorpions as roommates. “Pseudo” means false, and so a pseudoscorpion is not a real scorpion. Its scorpion-like pincers contain a poison that it uses on its prey.

Pseudoscorpions have scorpion-like pincers. The pincers hold poison that the bugs use to attack tiny lice, mites, and ants. 22

This booklouse was photographed against a background of paper fibers.

Booklice In spite of their name, booklice are not parasites like the ones that infest people. Booklice are wingless insects that like to eat mold and other fungi. So it’s not really the books they are eating, but the mold that’s on old books.

Carpet beetles The black carpet beetle larva doesn’t just eat carpet. It will eat hair, feathers, fur, and bristles from your brush. It likes leather, wool, silk, and paper. In the kitchen, it will go for flour, cereals, rice, and pet foods—just about any packaged food!

How Small Is Small? House pseudoscorpions are 3 to 4 millimeters in length, while booklice are about 2 millimeters long. The carpet beetle larva is about 7 millimeters long, which is the length of this line . So you could see it crawling across the floor. 23

Bigger Bugs Flies and mosquitoes are always a nuisance when they get into the home. Flies can buzz at you, and they carry germs in the form of microbes. Mosquitoes bite, leaving itchy swellings, and they can also bring disease. Most of us aren’t really afraid of these insects, however, because they are so small. But when you put flies and mosquitoes under the microscope, they look more scary!

Flies Flies lay their eggs in places where there is food. It’s a good reason not to leave Micro-Fact food out in the kitchen, because when Flies spit digestive the eggs hatch, out come maggots. juices onto the food And maggots start eating the food to soften it up before right away. they eat it!

Woodworm beetle

Woodworm beetles are another household pest. They don’t attack people, but they do eat wood in furniture and floors. As they munch, woodworm beetles make tunnels that can destroy the wood. After a few days of feasting on your food, maggots like these will turn into fullfledged flies. 24

House centipedes House centipedes are myriapods, which are small creatures with bodies divided into sections and at least one pair of legs on each section. House centipedes have fifteen pairs of legs, some of them longer than their bodies. They like to live in closets and basements, under boxes, and in other cool, dark places.

Micro-Monster Under the microscope, you can see the mouthparts that mosquitoes use to attack you. When they stick their proboscis into your skin, mosquitoes are actually injecting chemicals. The chemicals make the blood come out easily, and it’s your blood that mosquitoes want!

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proboscis

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Everyday Stuff Take a look around your home, and imagine what the things you see would look like under a microscope. They might surprise you. Opposite are a few magnified objects you could find in your home. See if you can guess what they are. (The answers are on page 31.)

Sticky Bubbles The sticky strip on a sticky note is formed from microscopic bubbles of glue on the surface of the paper. When you press the note onto another surface, only some of the bubbles break to release glue, just enough to hold the note in place. After a while, all the glue bubbles will have burst and the note loses its stickiness. That’s why sticky notes stick many times, but not forever.

26

1

This gel is good for cleaning.

2

These tiny hooks help hold things together.

3

These fibers squeeze out a colored liquid when you are using this.

27

Size and Scale In this book, we measure some things in millimeters and even smaller measurements. This is because inches are just too big for measuring microorganisms and microscopic parts of things. Millimeters are pretty small, and micrometers and nanometers are so tiny that they are impossible to see with the naked eye and hard to imagine. There are more than 25 million nanometers in just one inch! 1 inch = 25.4 millimeters 1 millimeter = 1,000 micrometers or 1,000,000 nanometers 1 micrometer = 1,000 nanometers Only the smallest of microbes are measured in nanometers. Some of these have to be magnified many thousands of times before we can see them. Other microorganisms are huge compared to these small microbes, but we still need to magnify them to see them clearly.

About Microscopes Many of the images you have looked at were produced using an electron microscope. Electron microscopes can magnify things many thousands of times, so they are used to magnify bacteria and tiny parts of cells. At home or in school, we use optical microscopes. They usually magnify things anywhere between 20 and 1,000 times, depending on the lenses you are using. It’s always fun to take an everyday object, like a hair from your head or a piece of food, and look at it under the microscope. Some of the images we have seen are made by optical microscopes with cameras attached.

28

Micro-Detective How Well Do You Wash Your Hands? On page 15, we learned that bacteria are easily carried on your hands. Bad bacteria can grow on food without us knowing, and they can make us sick. That is why we have to wash our hands before handling food and after going to the bathroom. Unfortunately, most people don’t wash their hands well enough to do any good! A quick rinse under the faucet doesn’t do much to fight bacteria. Here’s an experiment to show you what kind of hand washing really does work. Rub some vegetable oil on your hands. This soap Imagine the oil is a film of bacteria. You won’t bubble will want to put your hands anywhere near your help wash off eyes, just like you wouldn’t with real bacteria. the bacteria. First, rub your hands quickly under cold water—the way you may wash your hands if you were in a hurry. They probably still feel pretty oily. Oil your hands again, and try washing them under warm water. Are they a little cleaner? Finally, after a third oiling, wash your hands in warm water again, but this time use soap and scrub well. You’ll probably get rid of the oil very easily.

29

Glossary arachnid—group of animals with eight legs and bodies divided into two parts: the cephalothorax and the abdomen bacteria—microorganisms with only one cell that are the smallest and most numerous life-forms on Earth cell—tiny unit that all livings things are made of enzyme—molecule that helps processes take place by speeding up reactions food poisoning—any one of several sicknesses that come from eating spoiled or infected food fungi—organisms similar to plants but with no ability to make food, so they live on other organisms (living or dead) hyphae—threads that most fungi use to grow and spread through their food source infestation—presence of a large number of pests, such as insects or bacteria larva—stage of an insect after it has hatched from an egg but is not yet an adult microanimal—tiny bug or other animal too small to be seen clearly without a microscope microbe—microorganism that is not a microanimal. Microbes also include viruses even though they are not really organisms. microfungi—fungi that are microscopic or are made up mostly of microscopic parts micrometer—measurement of length that is one-thousandth of a millimeter microorganism—any living thing that is too small to be seen properly without a microscope mildew—type of fungi that forms a layer in damp places around the home; or a type of fungi that grows on plants mite—tiny creature related to spiders, many of which live on animals or in food molecule—microscopic part that makes up all living and nonliving things. All cells are made of molecules. 30

nanometer—measurement of length that is one-millionth of a millimeter nucleus—part of a cell that controls the cell’s form and functions organism—any living thing, such as a plant, animal, or bacterium parasite—organism that lives on or in another living thing and feeds off it pathogen—microbe that causes sickness or disease proboscis—long tube used for sucking food that is part of some insects’ mouthparts spore—reproductive part of a fungus yeast—microfungi with only one cell that feeds on sugars and reproduces by forming buds that break off to form a new cell.

Explore These Web Sites MicroAngela’s Electron Microscope Image Gallery http://www.pbrc.hawaii.edu/bemf/microangela Look at fantastic images of microanimals in the home and elsewhere. Bacteria Cells—the Inside Story http://www.eurekascience.com/ICanDoThat/bacteria_ cells.htm Find out more about bacteria cells. Cells Alive! Microbiology http://www.cellsalive.com/toc_micro.htm Watch cells, parasites, and bacteria in motion. _________________________________________________________ Answers for pages 26–27 1. Toothpaste 2. Velcro fastening 3. Fiber-tip pen 31

Index allergies, 8 animals, 4 arachnids, 7 bacteria, 4, 5, 29 in the air, 22 in the bathroom, 12–13 Escherichia coli, 12 functions of, 13, 15 killing, 15, 19, in the kitchen, 14–15 Salmonella, 15 size of, 4, 14 on skin, 18 staphylococci, 13 bathrooms, 12–13 bed bugs, see insects beds, 4, 6, 10 carpet, 5, 6, 9, 16, 17, 23 cells, 19 bacteria, 12, 13, 19 human, 15 parts of, 13 clothes, 9, 18–19 cooking, 15 dog ear mite, 21 dry rot, 17 dust, 6, 7–8 dust mites, 5, 6–7, 10

enzymes, 19 fabric, 18 food, 9, 14, 15, 16, 17, 19, 23, 24, 28, 29 food poisoning, 15, 29 fungi, 16–17, 18, 23 spores, 16, 22 hair, 9, 13, 23, 28 house centipedes, 25 household objects, 5, 23, 26–27

maggots, 24 microanimals, 8, 9 microbes, 4, 5, 24 in the air, 22 measuring, 28 microfungi, 16–17 microorganisms, 4, 16 measuring, 28 types of, 4 microscopes, 4, 5, 10, 24, 26, 28 mildew, 17, 18 mold, 16, 17, 23

insects, 4, 9, 10, 22 bed bugs, 10–11 black carpet beetle, 23 booklice, 23 eggs of, 11, 24 fleas, 20, 21 flies, 24 house pseudo scorpions, 22, 23 mosquitoes, 24, 25 parts of, 9, 25 woodworm beetle, 24

parasites, 20–21 pathogens, 13, 15, 29 pets, 4, 9, 20–21 plants, 4, 20

kitchen, 4, 14–15, 17, 23, 24

ticks, 20, 21

larvae, 23

32

reproduction in bacteria, 12 in fungi, 16 skin, 10 animal, 9, 20, 21 human, 6, 7, 11, 13, 17, 25 sticky notes, 26

water, 19 wood, 17, 24