Unit 3 Health Body and Immunity

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Unit 3

Health and Immunity

That microbes consist of bacteria, viruses and fungi.

That these microbes, once inside the body can cause disease in humans.

That there are three main types of bacteria.

How bacteria enter the body and the diseases they cause.

How viruses enter the body and the diseases they cause.

That some microbes like yeast and penicillin are beneficial.

A human's natural barriers to infection.

That humans have different types of immunity to diseases.

The role of the immune system in combating infection.

The role of the white blood cells: lymphocytes and neutrophils.

That vaccines and vaccination protect us against life threatening diseases like mumps, smallpox, measles and rubella.

Microbes, Bacteria, Viruses, Fungi, Disease, Immunity, White blood cells, Antibodies, Vaccines, Vaccination, Polio, Smallpox, Anthrax, Flu, AIDs, HIV, Measles, Infection, Edward Jenner, Joseph Lister, Antibiotics, Antiseptics & Disinfectants. Unit 3: Health and Immunity web: www.science-interactive.co.uk email: sales@science-interactive.co.uk Science Interactive LTD PO BOX 50764 LONDON NW6 9AT Click mouse to begin Science Interactive LTD Copyright 2005 Understand: Keywords:

Microbes and disease Our knowledge and understanding of disease and the causes of disease, just 200 years ago was no better than even the best theories around from over 2000 years ago. Microbes had not been discovered and scientists had not suspected that diseases like smallpox and tuberculosis could be caused by something that was beyond the vision of the human eye. Blood letting, ventilation and some very primitive and toxic treatments, like giving a patient poisonous arsenic were all many doctors could offer. What piece of laboratory equipment led to the discovery of microbes like bacteria ? Healthcare in the 19 th century: Science Interactive LTD Copyright 2005 In the 19 th century, bad air caused by poor ventilation was thought to carry and spread disease. The existence of microbes was still not known by doctors. Ventilation Medicines like arsenic and mercury were given to many ill people. Both elements are highly toxic. Many patients died as a result of taking these treatments. Blood letting was practised for over five centuries. The draining of blood was thought to purify the body of all disease. Many died during this treatment. Leonardo da Vinci studied human anatomy during the 14 th century recording the location of the major organs. He also study diseased organs in humans. Notes Diagram Organism Leonardo da Vinci Blood letting Arsenic

Disease causing microbes Bacteria, v_________ and fungi are all microbes which are able to cause disease in humans. Not all diseases are caused by microbes, for example heart disease is caused by a number of lifestyle factors like a high fat diet, smoking or excessive a________ intake. Microbes can be found anywhere, in the air, the soil, on food, or on unclean surfaces and in water. A particular risk of infection is associated with sharing unclean needles. Blood born viruses like HIV and hepatitis can be passed on from person to person. Why are intravenous drug users who inject drugs like heroin or crack at particular risk of contracting viruses like HIV and hepatitis? Microbes and disease: Science Interactive LTD Copyright 2005 Word bank: viruses alcohol Some types of fungi can cause disease or infections in humans. Athlete’s foot is caused by a fungi. They reproduce by producing spores. Fungi Blood borne viruses including HIV and hepatitis can be passed from person to person by needle sharing. Drug users have a high risk of contracting HIV. Needles Viruses are extremely small. Viruses are not whole cells. Their genes are found in a protective protein coat. They reproduce inside other cells. A bacteria is a single celled organism. All the bacteria in the world weigh more than any other class of species. They are the most successful species. Notes Diagram Bacteria Viruses

Bacteria Bacterial cells are found everywhere. They grow in super colonies, reproducing themselves asexually over very short periods of time. There are three main types of bacteria that cause disease in h_______ (see below). Most diseases caused by bacteria are not life threatening, however in the very young, old or the ill, they can kill. Anthrax, perhaps the most deadly bacteria, when inside the body, releases toxins that can destroy whole organs leading to your death. Since September 11 th many people including USA state senators and their employees have been targeted and even killed by terrorists using these biological weapons. Find out at google.co.uk about the source of Anthrax ? Bacterial types: Science Interactive LTD Copyright 2005 Word bank: humans Coccus bacteria are spherical in shape, and slightly smaller than the bacillus type of bacteria. They form the largest group of all bacteria. Coccus Spirillum bacteria get their name because of how these bacteria cells look like spirals. In this picture all three types of bacteria are present. Bacillus bacteria are shaped like rods and often have many hair like protrusion called flagella. They are the most common bacteria. Separate super colonies of bacteria starting from one single bacterial cell can be seen growing on the nutrient rich agar plate (in green) Notes Diagram Colony Bacillus Spiralum

Transmission of bacterial disease one Bacteria can be found in every living o_________, on every surface and even in the air we breathe. Some bacteria are very useful, whilst others cause diseases like cholera and dysentery. There are a number of ways in which b________ can enter your body. By understanding how bacteria enters our body, we can reduce our risk of contracting or spreading a disease. Explain why most infections caused by bacteria are entirely avoidable in humans ? Bacterial infecting people: Science Interactive LTD Copyright 2005 Word bank: organism bacteria Water containing human waste is full of bacteria. Before water is fit to drink it is filtered, cleaned and sterilised using chlorine which is a strong antiseptic. Sewage Surfaces in kitchens and bathrooms can be home to many thousands of unwanted and harmful bacteria. Always keep these surfaces clean by using disinfectants. Touching an infected person can lead to the transmission of the disease causing bacteria. Bacterial infections causing nausea can be spread by touch. Fresh food and drink can be infected with bacteria. Some foods contain bacteria that can only be destroyed by cooking. How does this destroy bacteria ? Notes Diagram Food Touching Surfaces

Transmission of bacterial disease two Bacteria has to enter our bodies before they can cause d________. They can enter via the digestive system, the nose or cuts in our skin. Our lifestyles determine our risk to infection. In refugee camps, where there is little or no treatment of sewage, poor nutrition and many people living in unsanitary conditions, disease spreads rapidly killing many people. We all have a personal responsibility for how we live and how clean we are. Explain how modern intensive farming can lead to the transmission of viruses like ‘bird flu’ or ‘mad cows disease: BSE ’ in humans ? Bacteria infecting people: Science Interactive LTD Copyright 2005 Word bank: disease Using a tissue and covering your nose prevents you from infecting other people. Millions of microbes are expelled from your nose every time you sneeze. Sneezing Human waste is another source of bacterial infection. Decaying fruit, meat and vegetables play host to many different bacterial colonies. Why do we treat our waste ? Washing your hands before meals or after going to the toilet reduces the risk of infection from bacteria found in human waste like faeces. Animals are a potential source of infection. Most farm raised animals are given huge amounts of antibiotics to control their levels of disease and bacteria. Notes Diagram Animals Washing hands Waste

Infections in humans caused by bacteria one Once inside the body, bacteria start to multiply increasing their numbers rapidly. They have a ready nutrient source and suitable temperatures. Bacteria infections can affect us in two ways. By destroying tissue in a major organ. Tuberculosis bacteria destroys the l______ tissue . By releasing toxic chemicals into your body. Both Salmonella and Anthrax release toxins which cause the symptoms of the disease. Bacterial infections: Science Interactive LTD Copyright 2005 Word bank: lung Salmonella found in contaminated eggs and poultry can cause vomiting and diarrhoea. MRSA (Multi Resistant Staphylococcus Auras) is resistant to many antibiotics. E-coli found in contaminated foods can cause vomiting and diarrhoea. Thrush is a yeast like bacterium that affects the mouth and genital surfaces. Notes MRSA Bacteria Diagram Thrush E-Coli Salmonella

Infections in humans caused by bacteria two Most bacterial infections like thrush do not cause life threatening illnesses, however cholera, anthrax, dysentery and tuberculosis are all potentially lethal . In areas where there is limited access to a_________, poor living conditions and poor nutrition, these diseases can spread very quickly and cause widespread death. Diseases like cholera and dysentery spread through contaminated water in areas where there is no effective water treatment killing both the old and young. Bacterial infections: Science Interactive LTD Copyright 2005 Word bank: antibiotics TB affects the lung tissue. This X-ray shows widespread damage of the lung tissue (areas shown in white) Dysentery is found in dirty water. Can cause in the vulnerable, weak and young prolonged diarrhoea and fluid loss. Anthrax has been used by terrorists as a ‘biological weapon.’ Can be fatal if lungs are infected. Cholera is a common disease where humans live in areas with no or little sanitation. Sewage carries this disease. Notes Dysentery Bacteria Diagram Cholera Anthrax Tuberculosis

Destroying microbes and preventing infection We can reduce the risk of i_________ caused by microbes by having good hygiene at home, particularly in places where we eat, sleep and store food. We should always wash our hands after the toilet, bathe regularly, dress wounds, refrigerate food and keep surfaces free from food and grease. Also we should use disinfectant products on all s________, particularly in the kitchen and bathroom. In hospitals for example, equipment, injected drugs, dressings and surfaces need to be sterile, free from microbes. Destroying microbes: Science Interactive LTD Copyright 2005 Word bank: infection surfaces Gamma radiation is also used to sterilise heat sensitive products. Blood is sterilised using gamma radiation, killing all microbes before its transfusion. Radiation Antiseptics like iodine and other products like mouthwash can be used to destroy microbes found on living tissue. They are weaker than disinfectants. Heating above 100 o C is one way of destroying microbes. An autoclave oven is used by hospitals to sterilise equipment used during surgery. Disinfectants products are chemicals like household bleach that destroy microbes. They can be used on surfaces like floors, walls and tops. Notes Diagram Disinfectants Washing Antiseptics

Viruses Viruses by far cause many of the killer diseases like flu, AIDs, smallpox and measles. Viruses are not whole c_____ like fungi and bacteria and are unable to reproduce themselves outside host cells. They consist of a few g_____ protected by a protein coat. They use the host cell to reproduce themselves. During replication inside the host cells, they also cause its destruction. If the virus is left unchecked, whole organs and their cells can be destroyed. Smallpox, a common killer in the late 19 th and early 20 th century has now been eradicated by vaccination. Viruses in detail: Science Interactive LTD Copyright 2005 Word bank: cells genes Viruses are very small. This picture had been magnified 10,000 times. The HIV virus has replaced smallpox as the single biggest killer. Viruses that are carried by your breath can spread very quickly amongst the population. Viruses inject their genes into the host cells in order to reproduce. In doing so they destroy that cell. Mass destruction can lead to organ failure. Viruses kill by destroying your vital organs. Viruses are not true cells. They require a host cell to reproduce themselves. Host cells are destroyed during this process. Mass destruction can be fatal. Notes Diagram Virus structure Viral replication inside human cells HIV virus

Transmission of viral diseases Many viral diseases are spread from person to person without the need for physical contact. Flu, Smallpox and Polio infect the cells of your body through the water droplets that enter through your n_____ or mouth. Vaccination is the only effective treatment for these types of v______. Some viruses like HIV rely on the exchange of bodily fluids, for example during unprotected sex or needle sharing. Fortunately, the HIV virus that causes AID s is extremely fragile and cannot exists outside the human body. You can reduce your risk of contracting AID s by practising safe sex or never sharing needles. Viral transmission: Science Interactive LTD Copyright 2005 Word bank: nose viruses Blood borne viruses including HIV and hepatitis can be passed from person to person by needle sharing. Drug users have a high risk of contracting HIV. Sharing needles Some viruses are transferred from animal to human. Mad cow’s disease has crossed from cow to human. 20 people have died from BSE infected beef. Viruses like HIV and syphilis are transmitted during sex. HIV is fatal. Protect yourself and reduce the risk of infection by wearing a condom. Viruses like flu are carried in the air from person to person. They enter your body via your mouth or nose. They replicate inside your throat or lung cells. Notes Diagram Air and water droplets Unprotected sex Animal flesh

Viral infections one Viruses are sometimes called non-living entities. They are 10 to 100 times smaller than a typical bacterial cell. They are made up of genetic material wrapped in a protein coat. The virus tricks the host cell, for example your throat or lung cells into duplicating the virus many times over. In most cases the host cell is destroyed. In severe cases, widespread cell death can lead to o______ failure and death. There are over 200 forms of the common c_____ virus. This abundance is caused by rapid mutations of the cold virus. Viral infections: Science Interactive LTD Copyright 2005 Word bank: organ cold Polio virus releases toxins which damage the nervous system. Can cause life long paralysis and disability . Herpes is a sexually transmitted disease affecting the genitals and mouth. Using a condom can protect you. BSE, a virus that jumped species from cow to human. 20 people in the U.K. have died because of BSE. Smallpox was once a big killer. Because of Worldwide vaccination it has now been completely eradicated. Notes Herpes Virus Diagram Smallpox BSE Polio

Viral infections two Viruses able to infect and r_________ inside humans can be extremely harmful causing many diseases like, flu, AID s, measles, smallpox and polio. A human left untreated, who has contracted smallpox will normally die within 4 to 5 days. The polio virus, although not as fatal as smallpox can cause permanent disability. Many viruses are now vaccinated against, with smallpox being completely eradicated by the World Heath Organisation since 1979 . Think of all the vaccinations that you have received since you were born ? Viral infections: Science Interactive LTD Copyright 2005 Word bank: replicate HIV transmitted by sharing needles or having unprotect sex attacks the immune system. There is no known cure. Syphilis is transmitted by having unprotected sex. Left untreated it can kill. Using a condom prevents infection. Measles, mumps and rubella are all vaccinated against in children given the MMR vaccine. The flu virus has up to 200 forms and is difficult to vaccinate against. Only the young and old are vaccinated. Notes Syphilis Virus Diagram Flu Measles AIDs

Useful microbes Some b________ are useful and have been used by humans for many centuries. In the food industry, y_______ is used in the manufacture of bread and alcohol . These industries alone are worth many billions of pounds. Many different moulds and fungi are used in the manufacture of cheeses, including the blue cheeses like Stilton and Roquefort . These moulds and fungi give blue cheese their characteristic flavour, smell and colour. Can you think of any other useful microbes found in foods ? Useful microbes: Science Interactive LTD Copyright 2005 Word bank: bacteria yeast Mould and fungi are added to cheeses and allowed to grow using the nutrients contained in the milk. Many cheeses are produced this way. Fungi - Cheese Penicillin and its mould produces a chemical that stops the growth of many bacteria. It is used as an antibiotic to help your immune system fight bacterial infections. Yeast in an oxygen free atmosphere is able to ferment glucose found in grape or grain producing alcohol as a waste product. This is how beer and wine are made. Yeast respires glucose contained in wheat flour producing carbon dioxide gas. This causes the bread to rise and gives that spongy – light texture. Notes Diagram Yeast - Bread Yeast - Alcohol Penicillin

Yeast Yeast is a very important microbe and supports two multibillion pound industries: Bread making: Yeast is used during bread making. The carbon dioxide gas produced during the respiration of wheat sugars and carbohydrates cause the bread dough to rise. This gives the bread its light texture. Alcohol manufacture: Yeast is an essential bacteria used to ferment sugar from grape or wheat into a_________. Fermentation must be done in an oxygen free environment. Fermented alcohol (beer and wine) have been around for many centuries. Yeast: An important microbe: Science Interactive LTD Copyright 2005 Word bank: alcohol Yeast is used in the manufacture of wine, beer and spirits. Sugar contained in grapes or grain is fermented by the yeast producing alcohol. After fermentation, the alcohol is separated from the dead yeast cells and allowed to mature over time. Distilling alcohol increases its content in spirits like vodka, gin, whisky and brandy. Fermentation Bread dough (flour, water, salt, sugar and yeast) is left to rise in a warm place for around 30 minutes before baking. The carbon dioxide produced during sugar fermentation causes the bread to rise. The yeast is destroyed during baking in a hot oven. Bread made without yeast is called unleavened bread e.g. Pitta bread. Notes Diagram Before rising After rising Final products

Barriers against infection Your body has a variety of ways of preventing disease causing microbes from entering the body. These barriers provide the first line of d________ against microbial entry into your body. Should these barriers fail, the i_______ system and immune cells (lymphocytes and neutrophiles) responds to the presence of these microbes in our blood stream or tissues. Although oil produced by our skin helps prevent bacterial build up, during adolescence it is over produced encouraging bacterial infection of the pores, leading to teenage spots. Human barriers: Science Interactive LTD Copyright 2005 Word bank: defence immune The oil that is produced by your hair follicles prevents your skin from drying out and cracking. It is also antiseptic, capable of preventing a lethal build up of bacteria growing on your skin. Skin Any bacteria that is ingested through the digestive system is destroyed by your stomach acid. This acid destroys the bacterial membranes. The pH of stomach acid is a very low two. Your air passage including the trachea are lined with thousands of ciliated epithelial cells. These hair like cells trap dirt and microbes and prevent them entering the lung. Your eye tear duct produces a liquid that contains an antiseptic. When you blink this liquid spreads over the surface of the eye keeping the surface of your eye free of any bacterial cells. Notes Diagram Eye Lungs Stomach

Human immunity You can have two types of immunity: Innate and acquired immunity. Innate immunity is your body’s response to an i_________. When you are infected by a microbe, your white blood cells will respond by engulfing the microbes and produce the right sort of antibodies. Acquired immunity can come from vaccinations, breast feeding or booster jabs. During breast feeding, your mother’s milk contains a__________ which can help you fight any disease until your own immune system develops. Can you remember any of the vaccinations that you have been given ? Types of immunity: Science Interactive LTD Copyright 2005 Word bank: infection antibodies Blood Plasma Cells Neutrophils Lymphocytes Red Blood Cells Breast feeding Boosters We can acquire immunity in three ways: During vaccination, vaccines are given to us when we are young to protect us against diseases like smallpox. Breast feeding allows the newborn to have all the same antibodies as their mothers. Boosters are given when there is an outbreak of a disease or to the young and old. These are given by injection. White blood cells find and destroy microbes, reducing our risk of dying from infection. Although less numerous than red blood cells, there are an essential part of our immune system. Notes Diagram Innate immunity Vaccination

Blood fighting infection one Blood also contains white blood cells, platelets and antibodies that are all part of the immune system which is responsible for fighting disease. White blood cells are a collection of cells that help recognise, fight and destroy foreign material like b________ and viruses. Lymphocytes produce antibodies which help clump bacteria together so they can be engulfed by neutrophils (also called phagocytes) When a new m_________ enters the body, new antibodies are made which recognise only that microbe. After the microbe has been destroyed, these antibodies remain in the blood, giving you immunity to that microbe. Why do babies have the same immunity as their mothers ? Immune response in blood: Science Interactive LTD Copyright 2005 Word bank: bacteria microbe Antibodies produced by lymphocytes in response to a specific microbe are able to recognise and clump together these invaders. It takes about 2 – 5 days for lymphocytes to make these antibodies. Stage three Phagocytes or neutrophils begin to search, and destroy microbial cells. They release enzymes which rip open and destroy the microbes. They also neutralise any microbial toxins. Stage four Microbes use the blood and other tissues to begin to multiply. They have a ready source of oxygen and nutrients. If the microbes continue to multiply, the toxin they produce would kill you. Microbes enter your body from sources like unclean hands or food that has not been cooked or handled properly. Describe four other ways of microbial transmission ? Notes Diagram Stage one Stage two

Blood fighting infection two The skin is the largest o_______ in the body. One of its main functions is to act as a ‘physical barrier’ to the entry of microbes. If cut, you are at risk of infection caused by the entry and subsequent multiplication of bacteria in the circulatory system. Once cut, the skin rapidly heals, helped by the c__________ response. This is where platelets and fibrinogen, both carried in the blood, form a tightly knitted scab, that prevents further blood loss and closes the wound. Why are haemophiliacs at greater risk from infection through cuts and abrasions ? Forming a scab: Science Interactive LTD Copyright 2005 Word bank: organ clotting Two Three When you cut healthy skin, a three stage response occurs before scab formation takes place. One: The skin is cut, bleeding occurs. Two: Platelets are pumped to the injury site. Three: Platelets and fibrinogen form a scab which prevents further bleeding and closes the wound. White blood cells are also rushed to the injury site to destroy what ? A key role of the skin is to help maintain core body temperature at 37 o C. The skin also has many other roles. It protects your body against disease and bacterial infection by acting as a physical barrier. Notes Diagram Human skin One

Blood fighting infection three White blood cells (neutrophils) constantly roam around the circulatory system. Unlike red blood cells, they do not carry o_______, but form part of your immune system. Neutrophils are able to find, attach and engulf m_______. When the invading microbes are fully engulfed, they are digested and destroyed by enzymes inside the cell. These white blood cells are also able to neutralise any microbial toxins, therefore preventing these toxins from poisoning your body. HIV affects your white blood cell count...how does this leave you vulnerable to other diseases ? Neutrophils engulfing bacteria: Science Interactive LTD Copyright 2005 Word bank: oxygen microbes Blood Plasma Cells Neutrophils Lymphocytes Red Blood Cells Images of a neutrophil (phagocyte) in action. They have long thread like features which literally trap the bacteria and draw them in to be engulfed by the neutrophil. HIV destroys these cells ! Neutrophils (Phagocytes) in action An essential role of blood is to fight disease. Lymphocyte antibodies and neutrophils search and destroy microbes. Without an immune system we couldn't survive in our environment. Notes Diagram Components of the blood

Blood fighting infection four Despite millions of neutrophils, which search and destroy microbes that enter the bloodstream, some microbes are difficult to find and evade detection by these immune cells. The other white blood cells, lymphocytes produce a__________ which are specific to an individual microbe. They work by binding onto the surface of the microbe and clumping them together. This makes their detection by neutrophils easier. Your body also remembers this microbe and continue to produce antibodies for the rest of your life, ready for the next time. Why do they say that you never catch the same cold twice ? Antibodies in your blood: Science Interactive LTD Copyright 2005 Word bank: antibodies Antibodies are able to clump together microbes in the blood by binding themselves to the their surface. This aids their detection by neutrophils which then destroy them. Antibodies helping neutrophils Several days after infection, your lymphocytes start to produce large numbers of antibodies which roam around the bloodstream looking for invading microbes. Bacteria enter and multiply in the blood. They spread out and try to avoid detection by your neutrophils. What happens if they are left to continue to multiply in the bloodstream ? Notes Diagram Bacterial infection Producing antibodies

Microbes and your health When microbes like viruses or bacteria enter your body, you develop s_________ alongside the disease. These symptoms are a result of either toxins produced by rapidly multiplying bacteria or viruses destroying your cells found in organs like your lung. Your body temperature rises, you may feel generally unwell, sleepy and experience a____ or pains. During the illness period, your body begins to make new antibodies and neutrophils to search and destroy the microbes. Look at the graph and see how you body responds to illness or disease caused by microbes. Microbes and your health: Science Interactive LTD Copyright 2005 Word bank: symptoms aches Measurements of body temperature, microbes and antibody levels were taken during a 14 days period. 1: How long would you have felt ill during the 14 days ? 2: How many days did the microbe replicate itself in the body before your immune system kicked in ? 3: Why did the number of microbes start to decrease after 5 days ? 4: Explain why the level of antibodies in your blood remain high, even during recovery ? Notes

Life long protection one Dangerous diseases like smallpox, rubella, whooping cough, tuberculosis, polio and measles have, in the past killed many people. Vaccines against these diseases have been developed to give you immunity. The MMR (mumps, measles and rubella) vaccine is given to all children in the UK before the age of five. Worldwide vaccination against measles now covers the majority of children in all countries. Since the introduction of the MMR vaccine in the UK , no children have died from measles. Worldwide there has also been a greater reduction in the number of childhood deaths. Why do children still die from measles in some counties ? Lifelong protection: Science Interactive LTD Copyright 2005 Measles vaccine Since 1989, the number of reported cases of measles worldwide has fallen rapidly after the introduction of the measles vaccine in 1978. Measles use to kill up to 100 children a year in the UK, now there are no reported cases of child deaths. How did the WHO eradicate smallpox ? Notes Diagram Worldwide vaccination against measles

Life long protection two Vaccination against common viruses like mumps, measles and rubella stimulates the white blood cells into producing antibodies that are able to recognise surface antigens on the virus surface. The vaccine contains parts of the virus or inactive whole viruses incapable of harming you. If you are then exposed to the virus, the white blood cells know which antibodies to produce straight away, therefore destroying the virus before you suffer the s__________ of the disease. Following vaccination you should be immune and protected for life. Vaccination: Science Interactive LTD Copyright 2005 Word bank: symptoms If the virus enters your body, your white blood cells immediately begin to produce the right antibodies, destroying the virus before you suffer the symptoms. Exposure Dead viruses are injected into the bloodstream. In the UK, you are immunised against polio, mumps, measles, smallpox and rubella. Vaccines contain dead or harmless microbes. White blood cells make antibodies specific to the virus. These cells remember when they are next exposed to the same virus. Once a particular antibody has been made by white blood cells, they stay in the body for the rest of your life, ready to destroy any more microbes. Why are scientist’s currently developing a vaccine against bird flu ? Notes Diagram Vaccines and the immune response

Life long protection three Lifelong protection is not always provided by a vaccine or even a booster jab. It is provided by how we live or really what we avoid. We take r______ everyday, but risking your health by having unprotected sex, or even sharing n__________ with other intravenous drug takers doesn’t make sense. For diseases like HIV, we have no cure or vaccine to protect us and therefore we must all take responsibility for our own health. Its simple, avoid taking drugs and having unprotected sex. Find out how HIV destroys your immune system ? Protecting yourself: Science Interactive LTD Copyright 2005 Word bank: risks needles Blood borne viruses including HIV and hepatitis can be passed from person to person by needle sharing. Drug users have a high risk of contracting HIV. Sharing needles Sadly, in the early 80s, most governments across Europe did not test blood products for viruses like HIV. Many hundreds of innocent people have since died. Infected blood Viruses like HIV and syphilis are transmitted during unprotected sex. Protect yourself and reduce the risk of infection by wearing a condom. The Aids virus, first discovered in the early eighties has and continues to kill many millions of people every year. There is no known cure. Notes Diagram Aids virus Unprotected sex

Protecting us against disease Vaccinations, boosters and antibiotics can all be helpful in controlling diseases caused by microbes. Since the discovery by Edward Jenner of the smallpox vaccine and penicillin by Alexander Fleming, doctors now have more and more weapons for the fight against d_________ in humans caused by microbes. Smallpox has been completely eradicated and polio is no longer recorded in the developed w______. HIV causing AIDs has no known cure. It attacks the immune system itself, making it more difficult to develop a vaccine. Why would a vaccine against HIV and AID ’s be a huge scientific breakthrough ? Treating disease: Science Interactive LTD Copyright 2005 Word bank: diseases world Antibiotic drugs prescribed by doctors like penicillin are chemicals that inhibit or destroy microbes. Penicillin and other antibiotics have helped save millions of lives since its discovery by Alexander Fleming in 1928. Antibiotics Boosters are injections that contain ‘ready made’ antibodies. These have been made inside another animal. They are normally given if there is an outbreak of a disease, or to the very young and old. Vaccines contain dead viruses which are injected into the bloodstream. This allows antibodies to be made by white blood cells. This offers protection in the future from the same microbe. Notes Diagram Vaccines Boosters

1: Define the following terms: Microbe, Bacteria, Virus, Fungi, Immunity, Antibodies & Vaccine. 2: Look at the diagram of the three types of microbes. Complete the table. 3: Explain why you should: a) Never share a bath towel with someone. b) Always wash your hands before handling food. c) Always wash your hands after going to the toilet. d) Always refrigerate food and throw away after the ‘use by’ date. e) Always cook meat thoroughly. f) Never share needles and always practice safe sex using the barrier method e.g. condoms. Extension questions and homework Science Interactive LTD Copyright 2005 How are they spread Fungi Viruses Bacteria What symptoms do they produce Examples Microbe

4: Look at the information in the table below. It shows the patient’s temperature when suffering from a bacterial infection: a) What symptom of the disease is shown by the data. b) How long was the incubation period. c) What caused the fever and how long did it last. 5: a) What is an antibiotic and how was the first antibiotic discovered. b) In hospitals, patients are treated for bacterial infection by doctors using antibiotics. Some of the bacterial strains become resistant to antibiotics like penicillin. How might this happen. 6: What is the difference between the following; a) An antiseptic and a disinfectant. b) An antibody and an antibiotic. c) A vaccine and vaccination. 7: Complete the following: Cholera and dysentery are diseases caused by ______________. Humans can develop these diseases by drinking ______________ water. Flu and the common colds are caused by ____________ which can be spread from person to person. Internet: Go to google.co.uk and find about how penicillin was discovered, who discovered it and what it is used for. Also find out about resistant MRSA bacteria and the overuse of antibiotics by doctors and hospitals. Science Interactive LTD Copyright 2005 37 o C 2 39 o C 6 37 o C 16 38 o C 14 40 o C 10 39 o C 8 37 o C 40 o C 38 o C 37 o C Body temperature 18 12 4 0 Day