Diphtheria is an acute infectious disease caused by bacteria. The bacteria usually enter the body through the respiratory tract where it multiplies in the mucous membranes and produces a toxin, or poison. This diphtheria toxin can travel through the bloodstream and can lead to potentially life-threatening complications affecting the heart, kidneys, and the central nervous system. The toxin can cause tissue damage that affects the heart's ability to pump blood or the kidneys' ability to clear wastes. It can also cause nerve damage, eventually leading to paralysis. Patients who don't get treated suffer a death rate of 40% to 50%. Children under 5 years old and adults over 60 are particularly at risk for contracting diphtheria, as are those living in crowded or unsanitary conditions, the undernourished, and children and adults who do not have up-to-date immunizations. Diphtheria is rare in the North America and Europe, where health officials have been immunizing children against it for decades. However, it is still common in developing countries where immunizations are not given routinely. The incubation period for diphtheria is 2 to 4 days, although it can range from 1 to 6 days.

Symptoms: In its early stages, Diphtheria can be mistaken for a bad sore throat accompanied by a low-grade fever and swollen neck glands. The toxin caused by the bacteria can lead to a thick coating in the nose, throat, or airway. This coating is usually fuzzy gray or black and can cause breathing problems and difficulty in swallowing. The patient may also complain of double vision, have slurred speech, or even show signs of going into shock (pale, cold skin; rapid heartbeat; sweating; and an anxious appearance).

Prevention: Diphtheria is highly contagious. It is easily passed from the infected person to others through sneezing, coughing, or even laughing. It also can be spread to others who pick up tissues or drinking glasses that have been used by the infected person. People who have been infected by the diphtheria bacteria can infect others for up to 4 weeks, even if they don't have any symptoms.

Preventing diphtheria depends almost completely on immunizing children with the combined diphtheria/tetanus/pertussis (DTP or DTaP) vaccine and non-immunized adults with the diphtheria/tetanus vaccine (DT). Most cases of diphtheria occur in people who haven't received the vaccine at all or haven't received the entire course.

The immunization schedule calls for DTP or DTaP vaccines at 2, 4, and 6 months of age, with booster doses given at 18 months and then at 4 to 6 years. Booster shots should be given every 10 years after that to maintain protection.

Although most children tolerate it well, the combined DTP vaccine sometimes causes mild side effects such as redness or tenderness at the injection site, a low fever, or general fussiness or crankiness. Severe complications, such as an allergic reaction or seizures, are rare (seizures occur in fewer than one in 2,000 children receiving the vaccine).

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Haemophilus influenzae type b (Hib) was the most common cause of bacterial meningitis (an infection of the membranes and fluid that cover the brain and spinal cord) and a leading cause of other serious invasive infections in children under 5 before the introduction of Hib vaccines. About 55% to 65% of affected children had meningitis, the remainder suffering from epiglottitis, bacteremia, cellulitis, pneumonia or septic arthritis. The case-fatality rate of meningitis is about 5%. Severe neurologic sequelae occur in 10% to 15% of survivors and deafness in 15% to 20% (severe in 3% to 7%). The risk of Hib meningitis is at least twice as high for children attending full-time day care as for children cared for at home. The risk is also increased among children with splenic dysfunction (e.g., sickle cell disease, asplenia) or antibody deficiency, and among Inuit children. Persons who have received a cochlear implant should also be considered at high risk of invasive Hib disease. Hib is spread by close, direct contact between infected people, such as sneezing, kissing or sharing drinks. Hib bacteria can survive for hours on contaminated objects. Healthy people can be carriers of Hib bacteria.

The bacteria can persist and multiply on the surface of the nose or throat without causing any symptoms in someone who has already developed immunity to Hib. In people who are not immune, symptoms can occur within a few hours or over a few days following infection. Surface infections of the respiratory tract can lead to infections in ears, sinus, eyes, airways and lungs, although there are many other causes for each of these infections. The most severe Hib infection invades the bloodstream which can lead to meningitis (infection of the membranes and fluid that cover the brain and spinal cord), bacteremia (infection of the bloodstream), epiglottitis (infection of the epiglottis), osteomyelitis and septic arthritis (joint & bone infection). Fever is a usual symptom, as well as aches, pains, irritability, and a general sense of feeling unwell.

Ear infections, sinusitis and pneumonia suspected to be caused by bacteria are treated with antibiotics. All serious infections caused by Hib must be treated with high doses of intravenous antibiotics for at least 7 days. Oral antibiotics may also be prescribed for family members to reduce the spread. Children who experience serious Hib infections before their second birthday often do not develop solid immunity and may be at risk of a second episode of Hib disease.

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Hepatitis B is a disease that affects the liver. The word hepatitis simply means an inflammation of the liver, without pinpointing a specific cause. Someone with hepatitis may be suffering from one of several disorders, including a viral infection of the liver; liver injury caused by a toxin (poison); liver damage caused by interruption of the organ's normal blood supply; or trauma. There are three types of Viral Hepatitis, A (a relatively mild infection), B and C.

In Canada, hepatitis is most commonly caused by the Hepatitis B virus (HBV). Hepatitis B is also called "serum hepatitis," because it spreads through infected body fluids, such as blood, saliva, semen, vaginal fluids, tears, breast milk, and urine. Infections may occur through a contaminated blood transfusion (uncommon in Canada), shared contaminated needles or syringes for injecting drugs, or sexual activity with an HBV-infected person. HBV-infected mothers can also pass the virus to their newborn babies. The incubation period is between 1 and 5 months.
 

Symptoms: Hepatitis, in its early stages, may cause flu-like symptoms. The symptoms may include malaise (a general ill feeling), fever, muscle aches, loss of appetite, nausea, vomiting, diarrhea. If hepatitis progresses, its symptoms begin to point to the liver as the source of illness. Chemicals normally secreted by the liver begin to build up in the blood. This causes jaundice (a yellowing of the skin and whites of the eyes), foul breath, and a bitter taste in the mouth. Urine turns dark or "tea-colored," and stools become white, light, or "clay-colored." There also can be abdominal pain, which may be centered below the right ribs (over a tender, swollen liver) or below the left ribs (over a tender spleen).

Duration: With hepatitis B, 90% to 95% of patients recover from their illness completely within 6 months, without long-term complications. In some cases, however, persons can go on to develop chronic hepatitis and cirrhosis of the liver. Some persons with hepatitis B may also become lifelong carriers of these viruses and can spread them to other people.

Prevention: Hepatitis B is contagious, and its virus can be found in virtually all body fluids. Its main routes of infection, however, are through sexual contact, contaminated blood transfusions, and shared needles for drugs. Over the past several years, improved medical technology has almost eliminated the risk of catching hepatitis from contaminated blood products and blood transfusions. However, as tattoos and acupuncture have become more popular, the risk of developing hepatitis from improperly sterilized equipment used in these procedures has increased.
A hepatitis B vaccine has been available since 1982 and is now being given to school aged children. Older children or adults who are not immunized can get the vaccine from their doctor.

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Infection usually clears up by itself and causes no signs or symptoms. However, of the more than 100 types of HPV, some are the leading cause of cancer of the cervix, vagina, vulva, penis and anus, and others cause genital or anal warts. 

HPV is very common. People usually get it during the first 5 years after they start being sexually active. Up to 29% of adolescents and young adults under the age of 25 will be infected with HPV. The virus must be present for many years before it develops into cancer.

Annual Pap testing has been very successful in reducing the death rate and is recommended for all sexually active females, whether they have been vaccinated or not. A vaccine can help protect girls from several types of HPV that cause cancer and warts. In Canada, girls 9 to 13 years old should get the vaccine, which is given in 3 doses in school-based programs. To be most effective, the vaccine needs to be given before any sexual activity starts. The vaccine hasn’t yet been approved for use in males, but more studies are being done to see if it should also be given to them as well. The HPV vaccine does not protect against other sexually transmitted infections. It also does not protect against all types of HPV. The vaccine does not work as well if girls have already been infected with the specific types of HPV that are in the vaccine.

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Influenza, commonly called "the flu", is a highly contagious viral infection of the respiratory tract. Compared with most other viral respiratory infections, such as the common cold, influenza infection often causes a more severe illness. There are three types of influenza viruses. Type A usually is responsible for the large influenza epidemics. Type A is constantly changing, with new strains appearing regularly, therefore being previously infected with Influenza type A does not produce immunity to these new strains and re-infection can occur. This results in a new epidemic every few years. Types B and C are not as widespread. Type B causes smaller, more localized outbreaks. Type C is less common and usually causes only a mild illness.

Symptoms: The main symptoms of influenza are fever, chills, headache, muscle aches, loss of appetite and tiredness. Symptoms may also include cough, sore throat, runny nose, nausea, weakness and depression. Although nausea, vomiting, and diarrhea can sometimes accompany influenza infection, especially in children, gastrointestinal symptoms are rarely prominent.

Duration: Most people who get the flu recover completely in 1 to 2 weeks, but some people develop serious and potentially life-threatening medical complications, such as pneumonia. Flu-related complications can occur at any age; however, the elderly and people with chronic health problems are much more likely to develop serious complications after influenza infection than are younger, healthier people.

Prevention: Influenza is spread by virus-infected droplets coughed or sneezed into the air. The simplest way to prevent influenza is to avoid crowds during an epidemic. Persons with influenza should avoid spreading germs to others by washing hands often and thoroughly, and discarding used tissues properly. A Flu vaccine is available and is recommended especially if you have chronic lung or heart disease, diabetes, cancer, kidney disease, anemia or are 65 or older. The Centers for Disease Control and Prevention report that influenza vaccine ("flu shots") can reduce the chance of contracting this disease by 60% to 80%. Because the viruses that cause flu frequently change, yearly vaccinations are recommended.

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Measles causes a skin rash, cough, fever and can lead to ear infections, pneumonia, diarrhea, seizures, brain damage and death. Measles, also called rubeola, is best known for its typical skin rash. It is, however, a respiratory infection caused by a virus. Measles can lead to many different complications: croup, bronchitis, bronchiolitis, pneumonia, conjunctivitis, myocarditis, hepatitis, and encephalitis. Measles can also make the body more susceptible to ear infections or pneumonias caused by bacteria. Symptoms and complications of measles are usually most severe in adults.

Symptoms: The first symptoms are irritability, runny nose, eyes that are red and sensitive to light, hacking cough, and a fever as high as 40.6C (105F). The length of these early symptoms, is usually three or four days before the rash appears.

Once the measles rash begins, early symptoms usually disappear, except for the cough, which may last throughout the course of the measles infection. Typically, the measles rash begins on the forehead, then spreads downward over the face, neck, and body. It usually takes three days for the rash to make its way down to the feet. The rash itself looks like large flat red to brown blotches that often flow into one another to completely cover the skin, especially on the face and shoulders. The rash fades in the same order that it appeared, forehead first and feet last. A unique sign of measles is Koplik's spots. These are small, red, irregularly-shaped spots with blue-white centers found inside the mouth. Koplik's spots usually appear one to two days before the measles rash and may be noticed by a physician looking for the cause of a child's fever and cough.

Duration: The total time for the rash, from beginning to end, head to toe, is usually about six days. As the rash disappears, the healing skin may look brown temporarily, before it sheds in a finely textured peel.

Prevention: Infants are generally protected from measles for six to eight months after birth, due to immunity that was passed on from their mothers. Children receive the measles vaccine as part of the mumps-measles-rubella immunizations (MMR) at 12 months and again at 4-6 years. Measles vaccine made before 1979 may not have been as effective as vaccine made today. Because of this, doctors often recommend that persons vaccinated before 1980 receive another measles vaccination if a measles outbreak occurs in their area, especially if they are in school.

Currently, outbreaks of measles are occurring most often on college campuses, among young persons who have either not been adequately immunized against measles, or whose immunity has decreased since childhood.

Measles vaccine should not be given to pregnant women, or to persons with active tuberculosis, leukemia, lymphoma, or depressed immune systems. Also, persons with severe allergies to eggs, or to the antibiotic neomycin, may risk life-threatening reactions to measles vaccine.

Measles vaccine occasionally causes side effects in persons with no underlying health problems. In about 10 percent of cases there is a fever between five and 12 days after vaccination, and in about five percent of cases there is a rash.

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Meningitis is an infection of the fluid of a person's spinal cord and the fluid that surrounds the brain. People sometimes refer to it as spinal meningitis. Meningitis can be caused by a virus (viral meningitis) or a bacterium (bacterial meningitis) and the severity of illness and the treatment differ.

Bacterial meningitis can be quite severe and may result in brain damage, hearing loss, or learning disability. For bacterial meningitis, it is also important to know which type of bacteria is causing the meningitis because antibiotics can prevent some types from spreading and infecting other people. Before the 1990s, Haemophilus influenzae type b (Hib) was the leading cause of bacterial meningitis, but new vaccines being given to all children as part of their routine immunizations have reduced the occurrence of meningitis due to H. influenzae. Today, Streptococcus pneumoniae and Neisseria meningitidis are the leading causes of bacterial meningitis. Early diagnosis and treatment are very important. If symptoms occur, the patient should see a doctor immediately. Bacterial meningitis can be treated with a number of effective antibiotics. It is important, however, that treatment be started early in the course of the disease. Appropriate antibiotic treatment of most common types of bacterial meningitis should reduce the risk of dying from meningitis to below 15%, although the risk is higher among the elderly.

Symptoms: High fever, headache, and stiff neck are common symptoms of meningitis in anyone over the age of 2 years. These symptoms can develop over several hours, or they may take 1 to 2 days. Other symptoms may include nausea, vomiting, discomfort looking into bright lights, confusion, and sleepiness. In newborns and small infants, the classic symptoms of fever, headache, and neck stiffness may be absent or difficult to detect, and the infant may only appear slow or inactive, or be irritable, have vomiting, or be feeding poorly. As the disease progresses, patients of any age may have seizures.

Prevention: Some forms are bacterial meningitis are contagious, however they are not as contagious as the common cold or Influenza, and transmission of the disease usually occurs with close or prolonged contact with an infected person. People in the same household or day-care center, or anyone with direct contact with a patient's oral secretions (such as a boyfriend or girlfriend) would be considered at increased risk of acquiring the infection. People who qualify as close contacts of a person with meningitis caused by N. meningitidis should receive antibiotics to prevent them from getting the disease.

There are vaccines against Hib and against some strains of N. meningitidis and many types of S. pneumoniae. The vaccines against Hib are very safe and highly effective. By age 6 months of age, every infant should receive at least 3 doses of an Hib vaccine. A fourth dose ("booster") should be given to children between at 18 months of age.

There is also a vaccine that protects against four strains of N. meningitidis, but it is not routinely used in Canada and is not effective in children under 18 months of age. The vaccine against N. meningitidis is sometimes used to control outbreaks of some types of meningococcal meningitis.

A vaccine to prevent meningitis due to S. pneumoniae (also called pneumococcal meningitis) can also prevent other forms of infection due to S. pneumoniae. The pneumococcal vaccine is not effective in children under 2 years of age but is recommended for all persons over 65 years of age and younger persons with certain chronic medical problems.

Viral (Aseptic) Meningitis is an illness in which there is inflammation of the tissues that cover the brain and spinal cord and is the most common type of meningitis. It is caused by an infection with one of several types of viruses. Viral meningitis is generally less severe than bacterial meningitis and resolves without specific treatment. Viral (aseptic) meningitis is rarely fatal in persons with normal immune systems.

Symptoms: The symptoms of meningitis may not be the same for every person. The more common symptoms are fever, severe headache, stiff neck, bright lights hurt the eyes, drowsiness or confusion, and nausea and vomiting. In babies, the symptoms are more difficult to identify. They may include fever, fretfulness or irritability, difficulty in awakening the baby, or the baby refuses to eat.

Duration: Usually, with viral meningitis, the symptoms last from 7 to 10 days and the person recovers completely. Bacterial meningitis, on the other hand, can be very serious and result in disability or death if not treated promptly. Often, the symptoms of viral meningitis and bacterial meningitis are the same. For this reason, if you think you or your child has meningitis, see your doctor as soon as possible.

Prevention: The viruses that cause viral meningitis are contagious. If you are around someone who has viral meningitis, you have a moderate chance of becoming infected, but a very small chance of developing meningitis (1:1000). The most effective method of preventing meningitis is to wash hands thoroughly and often.

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Mumps is caused by a virus that can infect many parts of the body, especially the parotid salivary glands. These glands, which produce saliva for the mouth, are found toward the back of each cheek, in the area between the ear and jaw.

Symptoms: Mumps causes fever, headache, and swollen glands under the jaw. Mumps can lead to hearing loss, meningitis (infections of brain and spinal cord coverings) and males may have painful swollen testicles. The parotid glands become increasingly swollen and painful over a period of 1 to 3 days. The pain gets worse when the child swallows, talks, chews, or drinks acidic juices (like orange juice). As the glands swell, there may be a fever of up to 39.4 °C (103°F) with headache and loss of appetite.

In two out of three cases, both left and right parotid glands are affected. The second gland usually swells about 4 to 5 days after the first. In rare cases, mumps will attack other groups of salivary glands. If this happens, the swelling and pain may be under the tongue, under the jaw, or down the front of the chest. Mumps can also involve the brain, pancreas, and other organs.

Mumps in males who are young adults or older may result in the development of orchitis, an inflammation of the testicles that ultimately can lead to a decreased sperm count. In males who have orchitis, one testicle usually becomes swollen and painful about 7 to 10 days after the parotids swell. There is a high fever, with chills, headache, nausea, and vomiting. After 3 to 7 days, testicular pain and swelling subside, usually about the same time as the fever passes. In some cases, both testicles are involved.

Mumps may also lead to encephalitis or meningitis. Symptoms appear 3 to 7 days after parotid swelling begins and may include: high fever, stiff neck, headache, nausea, vomiting, drowsiness, convulsions, and other signs of brain involvement.

In 25% to 30% of mumps cases, signs and symptoms are so mild that no one suspects a mumps infection.

The incubation period for mumps can be 12 to 25 days, but the average is 18 days.

Duration: Children usually recover from mumps in about 10 to 12 days. It takes about 1 week for the swelling to disappear in each parotid gland, but both glands don't usually swell at the same time.

Prevention: Mumps can be prevented by vaccine. This vaccine is given as part of the mumps-measles-rubella (MMR) immunizations at 12 months, and again at 4 to 6 years.

The mumps vaccine is effective in over 95% of persons who receive it and the protection that develops from vaccination is long lasting. It should not be given to pregnant women; people who have certain types of cancer; those who are having radiation or chemotherapy treatment for cancer; or people with depressed immune systems.

People who have not been immunized and who get the mumps are usually protected against having mumps for the rest of their lives.

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Pertussis is a very contagious bacterial infection of the respiratory system caused by Bordetella pertussis bacteria. Pertussis is most severe and complications are most frequent in children under 1 year. In some cases coughing spells are so bad that it is hard for infants to eat, drink, or breathe. It can lead to pneumonia, seizures (jerking and staring spells), brain damage, and death. Mortality is generally considered to be 1 in 200 cases. The pertussis vaccine has reduced the reported incidence of the disease by 90%. Currently, about 50 percent of all whooping cough infections occur in children less than one year old, and only 15 percent occur in children older than 15.

Symptoms: The incubation period for whooping cough is usually 7-10 days, with a range of 5-21 days. The first symptoms of whooping cough are similar to those of a "common cold," with a runny nose, dry cough and mild fever. After about 1-2 weeks, coughing begins to come in long spells which may last for over a minute. Between coughing spells the child may gasp for air with a characteristic "whooping" sound - although infants may not "whoop" as loudly as older children. Severe coughing spells can lead to vomiting. Coughing can continue for several weeks.

Because adults and adolescents with whooping cough may have milder symptoms, their whooping cough infection may be more likely to be misdiagnosed as "bronchitis."

Duration: Whooping cough can be a prolonged infection. There are usually 1-2 weeks of "common cold" symptoms, followed by 2-4 weeks of severe coughing, followed by 3-4 weeks of a convalescent period when coughing occurs less often. In some children, the convalescent stage may last for months.

Prevention: People become infected with B. pertussis by inhaling contaminated droplets of an infected person's cough or sneeze. It is probable that 70-100 percent of non-immunized family members will probably develop whooping cough if they live in the same household as someone who has the infection. For this reason, persons living in the same household are also usually given prophylactic (disease-preventing) antibiotics.

Infections can be prevented by the pertussis vaccine, which is part of the DPTP (Diphtheria, Pertussis, Tetanus, and Polio) immunization. DPTP immunizations are routinely given in five doses before a child's sixth birthday. In about half the children who receive it, the traditional pertussis vaccine causes mild side effects, including fever, irritability and soreness at the injection site. Recently, an improved pertussis vaccine, called DTaP, has been approved for use in children aged 15 months and older. This vaccine is less likely to cause side affects and will probably soon replace the old DTP, even in infants.

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Pneumococcal bacteria are the most common cause of bacterial infections in children and a frequent cause of infections in adults. There are more than 90 strains of pneumococci. Because the strains are different, the immune system must develop a specific immune response to each one. Pneumococcal infection is the most common complication of both seasonal and pandemic H1N1 influenza. Some people are at greater risk of serious complications from the disease including the very young, people 65 and older, and people with health conditions such as heart or lung disease, kidney failure, diabetes, HIV infection, anatomic or physiologic asplenia, or certain types of cancer. Pneumococci infections can cause local respiratory infections of the respiratory tract which remain on the surface and surrounding tissues e.g. ear infections, sinusitis, pneumonia, or invasive infections involving the bloodstream (bacteremia) that spreads to organs and tissue.

Infection starts in the nose or throat where it may persist for weeks or months. Many people will not develop any symptoms, but others may develop serious pneumococcal disease including acute otitis (infection of the ear), acute sinusitis (sinus), acute bronchitis or pneumonia (lung), bacteremia or septicemia (blood), meningitis (central nervous system), endocarditis (heart), septic arthritis (joint), osteomyelitis (bone), peritonitis (abdominal lining). Many people do not develop any symptoms but may be carriers of pneumococcal bacteria.

The pneumococci may persist in the nose and throat for weeks to months. The ‘silent’ infection induces a specific immune response against the strain causing the infection, but may not produce any protection against other pneumococcal strains. So as the body becomes immune to one strain a new strain will silently infect the person and the process of building immunity to another strain starts again.

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Polio is a contagious disease caused by infection with the poliovirus. Transmission of the virus occurs by direct person to person contact, by contact with infected secretions from the nose or mouth, or by contact with infected feces. The virus enters through the mouth and nose, multiplies in the throat and intestinal tract, and then is absorbed and spread through the blood and lymph system. Incubation ranges from 5 to 35 days (average 7 to 14 days). Severe cases may cause permanent paralysis or death. In the pre-vaccine era, paralytic poliomyelitis was a common childhood disease in Canada and approximately 11,000 people were left with paralysis following infection between 1949 and 1954. Although Canada has been polio free for almost two decades, a polio-free status was officially certified for North and South America in 1994. The worldwide elimination of polio will be a major achievement and will mark the second time that a human disease has been eliminated by immunization (smallpox was eliminated in 1977).

Symptoms: There are three basic patterns of polio infection: subclinical infections, non-paralytic, and paralytic.

Subclinical infections are most common (95%) and may go unnoticed. Slight fever, headache, general discomfort or uneasiness, sore throat and vomiting can occur.

Major poliomyelitis affects the central nervous system (brain and spinal cord) and may occur after recovery from a subclinical infection. Major poliomyelitis is divided into nonparalytic and paralytic.

Symptoms of non-paralytic polio are moderate fever, headache, stiff neck, vomiting, diarrhea, excessive tiredness, irritability, pain or stiffness of the arms, legs, abdomen, muscle tenderness and spasm in any area of the body, neck pain and stiffness, and skin rash.

Symptoms of paralytic polio include fever, occurring 5 to 7 days before other symptoms, headache, stiff neck and back, muscle weakness, spasms and pain, unusual sensations and areas where mild touch may be painful. Breathing, swallowing and urination may be difficult. Disability is more common than death.

Duration: For a subclinical infection, 72 hours or less. Non-paralytic form symptoms last one to two weeks.

Prevention: Immunization with the Polio vaccine effectively prevents poliomyelitis in most persons (immunization is over 90% effective). Children are immunized against poliomyelitis with the DPTP vaccine (diphtheria, pertussis, tetanus and polio) at 2,4,6 and 18 months with a booster injection at 4-6 years.

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Rubella, commonly known as German measles, is an infection that primarily affects the skin and lymph glands. It is caused by the rubella virus, which can be found in the throat, blood, and stool of an infected person. The virus usually enters the body through the nose or throat, but it can also pass through a pregnant woman's bloodstream to infect her unborn child. Since this is a generally mild disease in children, the primary medical danger of rubella is the infection of pregnant women. When rubella occurs in a pregnant woman, it may cause congenital rubella syndrome with serious malformations of her developing fetus. Children infected with rubella before birth (a condition known as congenital rubella) are at risk for the following: growth retardation; malformations of the heart, eyes, or brain; deafness; and liver, spleen, and bone marrow problems. The incubation period for rubella is 14 to 21 days; 18 days is the average incubation period.

Symptoms: It may begin with 1 or 2 days of mild fever (99 degrees F to 100 degrees F) and swollen glands that are usually found either in the neck or behind the ears. On the second or third day, a rash appears that begins at the hairline and spreads downward on the rest of the body. As the rash spreads downward on the body, it usually clears on the face. The rubella rash appears as either pink or light red spots, about 2 to 3 mm in diameter, which may merge to form evenly colored patches. The rash doesn't itch, and lasts up to 5 days (the average is 3 days). As the rash passes, the affected skin may be shed in flakes.

Other symptoms of rubella may include: mild conjunctivitis (inflammation of the lining of the eyelids and eyeballs); stuffy or runny nose; swollen lymph glands in other regions of the body; pain and swelling in the joints (especially in young women); and in males, pain in the testicles.

Duration: The rubella rash may last from 1 to 5 days, but 3 days is the most common duration. Children with rubella usually recover in 1 week, but adults may take longer.

The rubella virus passes from person to person through droplets and fluids from the nose and throat. Persons with rubella are contagious from 1 week before the rash appears until 1 week after it fades.

Prevention: Rubella can be prevented by a rubella vaccine, which is usually given to children at 12 months as part of the scheduled Measles-Mumps-Rubella (MMR) immunization. A second dose of MMR is generally given at 4 to 6 years of age, but should be given no later than 11 to 12 years of age. The rubella vaccine should not be given to pregnant women or to a woman who may become pregnant within 3 months of receiving the vaccine.

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Tetanus is the result of an infection that affects the muscles and nerves. It is usually due to a contaminated wound. Tetanus is caused by a type of soil bacteria called Clostridium tetani, which produces a toxin (poison) called tetanospasmin which interferes with the normal activity of nerves, especially nerves that send messages to the muscles.

Neonatal tetanus causes these same symptoms in newborns. Neonatal tetanus occurs after a baby is delivered in unsanitary conditions, especially if the umbilical cord cut is contaminated. Prior to immunizations, neonatal tetanus was a common cause of newborn death. In infants, neonatal tetanus is almost always fatal.

Because of improved surgical techniques and because of maternal antibodies passed to the baby in the womb, newborn tetanus is now rare in developed countries.

Tetanus, although rare, is a serious illness and can lead to death. However, when the infection is diagnosed and treated early, recovery is possible. Tetanus is not contagious.

Symptoms: The incubation period for tetanus is 3 to 14 days, with most symptoms beginning around day seven. In neonatal tetanus, symptoms start within the first 2 weeks of life. Tetanus often begins with muscle spasms in the jaw, together with difficulty in swallowing, and stiffness or pain in muscles of the neck, shoulder, or back. Spasms soon spread to muscles of the abdomen, upper arms, and thighs. It can lead to "locking" of the jaw so the person cannot open his mouth or swallow.

Duration: Recovery usually takes at least 4 to 6 weeks.

Prevention: In children, tetanus can be prevented through immunization with DPTP (Diphtheria, Pertussis, Tetanus, and Polio) vaccine at ages 2,4,6 and 18 months with a booster at 4-6 years. After childhood, a tetanus booster is recommended every 10 years.

Neonatal tetanus can be prevented by making sure that all pregnant women have proper immunization before delivery and by delivering all newborns in sanitary conditions.

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Chicken pox is an infection that is caused by the varicella-zoster virus (VZV). VZV spreads in nasal discharge and in fluid from inside the chicken pox blisters. Chicken pox is very contagious, and 90% of people who are not immune will catch it when they are exposed. Epidemics are most common in the late winter and early spring, and children between ages 5 and 9 account for half of all cases. Varicella causes a blister-like rash on the surface of the skin and mucous membranes. Some persons have only a few blisters, although others have several hundred. As blisters itch and break, scabs form and the blisters can become infected by bacteria (a "secondary" bacterial infection). Normally, chicken pox is a mild illness, but it can cause serious complications, including pneumonia, encephalitis, and serious bacterial infections of chicken pox blisters. Usually a person has only one attack of chicken pox in his or her lifetime. But the virus that causes chicken pox can stay dormant in the body and can cause a different type of skin eruption, called shingles, later in life. The incubation period for chicken pox is from 7 to 21 days after exposure, with most cases appearing between 14 and 17 days. If, for example, one child in a family breaks out with chicken pox picked up at school, his brothers and sisters probably will exhibit symptoms of chicken pox about 2 weeks later. People with diseases or problems with their immune system should not come in contact with chicken pox. Neither should pregnant women. Generally, chicken pox is a mild illness, but it can be deadly in persons who have leukemia or other diseases that weaken the immune system.

The contagious period for chicken pox begins 2 days before the skin blisters appear and lasts until all the blisters are crusted over. A child with chicken pox should be kept out of school for about 1 week

Symptoms: Chicken pox blisters usually appear first on the torso and face, then spread to almost everywhere else on the body, including the scalp and penis, and inside the mouth, nose, ears, and vagina. Chicken pox blisters are about 5mm to 10mm wide, have a reddish base, and appear in crops over a 2- to 4-day period. Some children have a fever, abdominal pain, or a vague sick feeling along with their skin blisters. These symptoms usually last for about three to five days, and fever stays in the range of 101 degrees Fahrenheit to 103 degrees Fahrenheit (37.8 degrees Celsius to 39.4 degrees Celsius). Younger children often have milder symptoms and fewer blisters than older children or adults.

Duration: Chicken pox usually lasts 7 to 10 days in children, longer in adults.

Prevention: In children aged less than 10 years, varicella is now the main cause of death due to diseases potentially preventable by routine childhood vaccinations. A vaccine has been available in Canada since December of 1998. The vaccine prevents illness in 70% to 90% of those who receive it. Those who do develop chicken pox after vaccination have milder symptoms with fewer skin blisters. The varicella vaccine may be given to healthy children by injection at age 1 year or older. Systematic immunization programs are presently under consideration by Health Canada.

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