Immunology and infectious diseases FAQs
- What is botulism?
- What is cat scratch disease?
- What is chicken pox?
- What is conjunctivitis?
- What is diphtheria?
- What is encephalitis?
- What is infectious mononucleosis?
- What is listeriosis?
- What is meningitis?
- What is mumps?
- What is pertussis ("whooping cough")?
- What is pneumonia?
- What is polio?
- What is rabies?
- What is Reye's syndrome?
- What is strep throat?
- What is tetanus?
- What is tonsillitis?
- What is West Nile virus?
Botulism is a form of potentially serious poisoning that can be contracted by swallowing or through open wounds. It is caused by a bacterium that occurs in soil, untreated water, and improperly preserved food, such as home-canned vegetables, honey, corn syrup, cured pork, or smoked or raw fish. Symptoms include weakness, nausea, vomiting, abdominal cramps, double vision and even paralysis. Infants are susceptible to a strain of botulism that survives in honey or corn syrup. Severe cases can lead to respiratory failure by weakening muscles essential for breathing. Botulinus anti-toxin is given to victims, and treatment may require emergency hospitalization.
Cat scratch disease is a bacterial infection transmitted through a scratch by a cat or other animal. After appearance of a blister or bump a few days following the scratch, lymph nodes under the arms or around the neck begin to swell and may become tender or even painful. Other organs may be affected as well. Cat scratch disease is treated with antibiotic medications.
Chicken pox, medically known as “varicella,” is a highly contagious viral infection that causes a blistered rash on the skin and in the mucous membranes of the body. Some children develop hundreds of these itchy blisters which may, in turn, become infected by bacteria. Chicken pox often causes abdominal pain and fever of 101 to 103 degrees Fahrenheit. After the blisters break, scabs form.
Chicken pox usually isn’t serious for most children, but it can be life-threatening for children who have leukemia or a weakened immune system. They may be given acyclovir, an antiviral medicine. Even though most people can contract chicken pox only once, the virus that causes the disease can remain dormant within nerve cells for decades before emerging in adulthood as shingles, another skin infestation. A vaccine is largely effective in preventing chicken pox.
Conjunctivitis, also called “pinkeye,” is an inflammation of the conjunctiva characterized by redness and sometimes by irritation or itching. The conjunctiva is a clear membrane that lines the inner surface of the eyelids and the white of the eye. The inflammation can be caused by bacteria, viruses or irritants, and sometimes coincides with allergic conditions. Bacterial conjunctivitis is treated with antibiotic drops or ointment.
In infants, a blocked tear duct can cause a condition called neonatal conjunctivitis, which can be treated easily. Some types of bacterial conjunctivitis contracted by newborns during birth can cause eye damage without proper treatment.
Diphtheria is a highly contagious bacterial illness characterized by a thick coating in the nose, throat, or airway that can cause breathing and swallowing difficulties. Other symptoms include double vision, slurred speech, rapid heartbeat, sweating and paleness. The diphtheria toxin can damage the heart, kidneys or nerves, and in severe cases can cause the threat of paralysis. Without treatment involving anti-toxin and antibiotics, the disease can be fatal. Fortunately, diphtheria is rare in the United States and Europe because it can be prevented by immunization with the “DTaP” (diphtheria-tetanus-acellular pertussis) series of injections.
Encephalitis is inflammation of the brain typically caused by a virus, but sometimes resulting from a bacterial infection. Insects transmit some forms of encephalitis through bites. While mild cases may cause no more than fever, headache or loss of energy, severe cases can cause much more intense reactions, including nausea, vomiting, stiffness, mental confusion, memory loss, double vision, personality changes, difficulty walking, speech or hearing problems, hallucinations, convulsions (seizures), or even coma. Antiviral drugs such as acyclovir are used to treat some forms of encephalitis. Corticosteroids can help to reduce brain swelling, and anticonvulsants may be administered as well.
Mononucleosis is an infectious illness caused by Epstein-Barr virus (EBV), which is related to the herpes virus. It is transmitted by human saliva. Older children and adolescents who contract infectious mononucleosis may develop a fever, sore throat, enlarged lymph nodes, muscular soreness or stiffness, breathing difficulty, loss of appetite, and perhaps an enlarged spleen, which is on the left side of the body below the ribs. Extreme fatigue is also common. Young children may feel just mildly out of sorts. Although infectious mononucleosis can cause complications—including spleen damage, heart muscle inflammation and reduced production of red and white blood cells—it usually subsides and disappears after time. Rest is often the most effective treatment.
Listeriosis is a rare illness caused by Listeria monocytogenes bacteria. It affects newborn babies as well as older children and adults with weakened immune systems. Listeriosis can be contracted through water or food, notably delicatessen cold cuts, undercooked meats, milk, soft-ripened cheeses, shellfish, and coleslaw made with contaminated cabbage. Symptoms include fever, breathing difficulty, vomiting, diarrhea, fatigue and irritability. Listeriosis is treated with intravenous antibiotics. Without proper care, it can be fatal.
Meningitis is an inflammation of the “meninges,” the name for the sheaths that cover the brain and spinal cord. It also can affect the fluid that circulates in and around the brain and spinal cord. Meningitis can be caused by bacteria, viruses, fungi, and other microorganisms. It occurs most commonly among children younger than 5 years of age, and typically affects the respiratory system. A spinal tap usually is administered to properly diagnose the disease, and antibiotics are used for treatment.
Mumps, formally known as “epidemic parotitis,” is a contagious viral disease characterized by painful swelling of salivary glands. Unvaccinated children between the ages of 2 and 12 are most likely to contract mumps, which also causes fever, headache and throat soreness. Children should be given a vaccination to prevent measles, mumps and rubella (MMR immunization) between the ages of 12 and 15 months, and again when they’re between 4 and 6 years of age. While no specific treatment for mumps exists, application of ice or heat, or gargling with warm salt water, can help reduce discomfort. Here’s good news: after recovering from mumps, a child will have lifelong immunity from the disease.
Pertussis, widely known as “whooping cough” is a contagious bacterial infection of the respiratory system. It’s called “whooping cough” because children infected with it gasp for air between the fierce bouts of coughing that it causes. More than half of the victims of whooping cough are infants. Particularly intense coughing can cause infants with whooping cough to stop breathing for several seconds at a time. Whooping cough, which can lead to pneumonia, is treated with antibiotic medications. Once deadly, it can now be prevented with a vaccine.
Pneumonia is an infection of the lungs that can be caused by various microorganisms, including viruses, bacteria, fungi and parasites. Symptoms can include fever, chills, coughing, labored or rapid breathing, chest or abdominal pain, and perhaps a blue or gray appearance in the lips or fingernails—indicating a shortage of oxygen in your child’s lungs. The viral and bacterial agents that can cause pneumonia are contagious and can be spread by coughing, sneezing, drinking and eating utensils, and other objects touched by an infected child. Some types of viral and bacterial pneumonia can be prevented by vaccination. Pneumonia often can be treated with oral antibiotics.
Poliomyelitis—also known as “polio” or “infantile paralysis”—is a serious viral disease that in severe cases can cause permanent paralysis or death. This contagious illness, which is rare in the Western Hemisphere, affects the central nervous system—the brain and the spinal cord. Sometimes the disease causes only mild symptoms resembling those of the flu. Dangerous paralytic polio, however, first manifests itself with fever, muscle weakness or spasms and breathing difficulties that rapidly worsen. Complete recovery is likely in the majority of cases, in which the spinal cord and brain are not affected.
Rabies is a viral infection that is rare in the United States but is usually fatal if untreated. Children and adults can contract the disease when bitten by infected animals, typically dogs or bats. The virus causes inflammation in the brain. Symptoms include swallowing difficulty, drooling, restlessness, muscle spasms, numbness, and loss of muscle function or feeling. A child who is bitten by an animal suspected of having rabies may be given vaccine treatment. Immunization within two days of the bite is usually effective in preventing rabies symptoms from developing.
Reye’s syndrome is a potentially deadly illness capable of causing damage to the brain and liver. Reye’s syndrome can induce vomiting, loss of muscle function, double vision, hearing loss, delirium, behavioral changes, seizures or even a coma. It has been linked to use of aspirin to treat chicken pox or influenza. Treatment may include intravenous fluids to boost electrolytes and blood glucose, or steroids to reduce swelling within the brain.
Strep throat is a painful inflammation of the throat resulting from an infection by Group A streptococci bacteria. Children with the condition typically develop a fever of 101 degrees Fahrenheit or greater, accompanied by swollen glands in the neck, chills and body aches and perhaps by abdominal pain, nausea and vomiting. A strep infection can sometimes cause a red skin rash—known as “scarlet fever.” Strep throat can be treated successfully with penicillin or other antibiotics. Treatment is important because strep throat infections sometimes can lead to kidney problems or rheumatic fever, which can result in heart disease or arthritis.
Tetanus is a disorder caused by a bacterium that causes sever muscular spasms or stiffness, notably in the jaw—giving rise to its common name, “lockjaw.” The toxic material in tetanus interferes with the proper function in the nervous system. The infection that causes tetanus often begins in a contaminated wound such as a cut or burn, or following exposure to unsanitary conditions. While fatalities are high among newborns who contract neonatal tetanus through unsanitary conditions during childbirth, older children can be treated successfully with antibiotics and antitoxin to neutralize the poisonous material in the bacteria. Medication also may be given to control muscle spasms. The most effective weapon, however, is prevention, by means of the “DTP” (diphtheria-tetanus-pertussis) series of injections.
Tonsillitis is an infectious condition in the tonsils, which are located at the back of the throat. Children with tonsillitis first develop a sore throat, followed often by difficulty in swallowing, chills, fever above 101 degrees Fahrenheit, and swollen glands in the neck. It can be caused by a bacteria or virus, but only bacterial tonsillitis can be treated with antibiotics. Tonsillitis caused by a strep infection can be treated with penicillin. All forms of tonsillitis are quite contagious. A doctor may recommend tonsillectomy—surgical removal of the tonsils—for children who experience frequent episodes of tonsillitis.
What is West Nile virus?
West Nile virus, which was unknown in the Western Hemisphere before 1999, is spread by mosquitoes that feed on infected birds. After an initial outbreak in New York, it spread westward and now has been detected in California. In humans, West Nile virus can cause various complications, the worst of which is encephalitis—inflammation of the brain that can create havoc throughout the nervous system. Fortunately, fewer than 1 percent of mosquitoes are infected with West Nile virus, and fewer than 1 percent of people who are infected with West Nile virus will become seriously ill. Mild cases of the diseases are characterized by flu-like symptoms including fever, headache and body aches. No vaccine for the virus exists. While spraying clothing with permethrin or DEET can be effective in warding off mosquitoes, keep in mind that repellents with concentrations greater than 10 percent DEET can be toxic to children.