germ The popular term for any microorganism that causes disease. Either a virus or a bacterium is an example of a germ.
German measles The common name for rubella, this is a viral infection that is not very similar to measles, although it also causes a rash on the face, trunk, and limbs. Rubella, which causes a mild illness in children and a slightly more problematic one in adults, is really serious only when contracted by pregnant women in the early months of gestation. During this time, there is a chance the virus will infect the fetus, which can lead to a range of serious birth defects known as rubella syndrome.
Although rubella was once found throughout the world, it is now much less common in most developed countries because of successful vaccination programs. The United States has tried to eradicate the disease by vaccinating all school-age children; in 1969 when the vaccine became available, at least 60,000 Americans had rubella. By 1993, the number dropped to 192.
Cause Rubella is caused by the rubella virus, which is transmitted by particles in the air when an infected person coughs or sneezes. It can also be transmitted on contaminated objects, where the virus can survive for a short period of time on tissues, doorknobs, phones, and so on. It infects only humans.
Before the development of the vaccine, rubella was common in spring and winter, and peaked every six to nine years. There were huge rubella epidemics in the United States in 1935,1943, and 1964.
Symptoms The infection usually affects youngsters between the ages of 6 and 12 with the rash that starts on the face and spreads downward and out to arms and legs. The rash may run together to make large patches, but it does not itch. It lasts for a few days, with a slight fever and enlarged lymph nodes; some children may have a mild cough, sore throat, or runny nose before the rash appears. Sometimes the entire infection comes and goes without notice; at least 30 percent of children with rubella have no symptoms at all, although they are infectious to others.
Adolescents and adults may have slightly more pronounced symptoms, including headaches, fever, body aches, eye infections, or a runny nose about one to five days before the rash. Swollen glands in the neck and behind the ear typically appear 7 to 10 days before the rash. The virus may be transmitted from a few days before the symptoms appear until a day after symptoms fade.
Incubation period ranges from 14 to 23 days; the average is 16 to 18 days.
Rubella may be confused with other conditions characterized by rashes, such as SCARLET FEVER or drug allergy.
Diagnosis A lab test to confirm rubella is important, since the symptoms can be so mild they may be overlooked or mistaken for something else. This is especially true during an outbreak where pregnant women may be exposed.
Blood tests are available that reveal rubella immunity or an active rubella infection. If a person has been vaccinated, the blood test will show that the person is immune. Pregnant women need a rubella immunity test at the first prenatal visit; if not immune, the woman will receive rubella vaccine in the hospital after delivery.
If a pregnant woman gets an infection resembling rubella during pregnancy, and she is not immune, blood tests must be done to determine whether rubella is the cause of the illness.
Treatment There is no specific treatment for rubella, although acetaminophen may reduce the fever.
Complications Congenital rubella is the most serious complication of rubella infection, since it can cause fetal death or miscarriage. The risk is highest when the pregnant woman is infected in the first 12 weeks of pregnancy (miscarriage rate is as high as 85 percent during this time). At 14 to 16 weeks, the risk drops to just 10 to 24 percent, and after 20 weeks the risk is almost nonexistent.
Infants who survive infection in the womb may be born with a variety of birth defects, including deafness, eye problems (including blindness), heart defects, mental retardation, growth retardation, and bleeding disorders.
Rare complications in adults include bleeding disorders or ENCEPHALITIS.
Prevention Any child with rubella must be kept at home until well past the infectious stage; babies born with rubella have the infection virus in their nose, throat, and urine for as long as a year.
Vaccination can provide long-lasting immunity. It is given in the United States to all infants as part of the measles and mumps vaccine at about 15 months of age. There is not usually any reaction to the vaccine. The vaccine is a live attenuated virus that provides complete protection to more than 95 percent of those who receive it. Rubella infection itself also provides immunity,
The recommended vaccine, MMR (measles, mumps, rubella), is not effective when given earlier than 12 months because the baby may have maternal antibodies that will interfere with the vaccine's action. A first dose is given at 12 to 15 months; a second booster is given at age four to six, before the child starts school. Older children who missed these shots should receive one dose of MMR.
Women of childbearing age can be given the vaccine if they are not already immune. Anyone who is not sure of having received the vaccine or having rubella should be vaccinated. There is no risk to receiving the vaccine if a person is already immune.
Rubella is common in many countries; anyone who travels abroad should be sure they are immune to rubella or receive the vaccine before leaving. The national recommendations for rubella elimination are as follows:
• vaccination for all children
• premarital screening, vaccination for those who need it
• prenatal screening and postpartum vaccination if needed
• routine vaccination in a medical setting
• proof of immunity for hospital workers and college students
There are some people who should not receive the vaccine. These include pregnant women or women who plan to become pregnant within the next three months; anyone with a high fever or a severe allergy to neomycin. There is no penicillin in rubella vaccine, and it is safe for those allergic to eggs.
germicide A drug that kills microorganisms.
Giardia lamblia A type of protozoa (found in the intestinal tract and in feces of humans, sheep, cattle, and beaver) that causes foul-smelling, explosive diarrhea called GIARDIASIS. The protozoa was named for the 19th-century French biologist Alfred Giard, who discovered it. It is most often found in tropical areas and in those who travel to the tropics. Recently, it has become more common in the developed countries, where it is especially common in preschools and among people living in institutions. See also DIARRHEA AND INFECTIOUS DISEASE; ANTIDIARRHEAL DRUGS.
giardiasis The most common cause of water-borne intestinal infection in the United States, giardiasis is an infection of the small intestine caused by the giardia lamblia protozoa, which is found in the human intestinal tract and in feces. In recent years, outbreaks of giardiasis have been common among people in institutions, preschool children, at catered affairs, and large public picnic areas. Recent tests have revealed the parasite in 7 percent of all stool samples tested in a nationwide study. See also DIARRHEA AND INFECTIOUS DISEASE; ANTIDIARRHEAL DRUGS; TRAVELER'S DIARRHEA.
Cause Giardiasis is spread by contaminated food or water or by direct personal hand-to-mouth contact. Children can spread the infection by touching contaminated toys, changing tables, utensils, or their own feces. For this reason, the infection spreads quickly through a day care center or institution for the developmentally disabled. Unfiltered streams or lakes that may be contaminated by human or animal feces are a common source of infection to campers.
Symptoms Giardiasis is not fatal, and about two thirds of infected people have no symptoms. When they do occur, symptoms appear about one to three days after infection and are uncomfortable. The infection interferes with the body's ability to absorb fats in the intestinal tract, so the stool is filled with fat. Symptoms include explosive diarrhea, foul-smelling and greasy feces, stomach pains, gas, loss of appetite, nausea, and vomiting. In some cases, the infection can become chronic.
Diagnosis Giardiasis is diagnosed by examining three stool samples for the presence of the parasites. Because the parasite is shed intermittently, half of the infections will be missed if only one specimen gets checked. Stool collection kits are available for this purpose.
A different test looks for the proteins of Giardia in the stool sample.
Treatment Acute giardiasis usually runs its course and then clears up, but antibiotics will help relieve symptoms and prevent the spread of infection. Medications include metronidazole, furazolidone, and paromomycin. Occasionally, treatment fails; in this case, the patient should wait two weeks and repeat the medication. Anyone with an impaired immune system may need to com bine medications. Healthy carriers do not need to be treated.
Complications Some children get chronic infection and suffer with diarrhea and cramps for long periods of time, losing weight and growing poorly. Those most at risk for an infection are people with impaired immune function, malnourished children, people with low stomach acid, and older people.
Prevention The best way to avoid giardiasis is to stay away from drinking untreated surface water. While chlorine in water treatment will not kill the cysts, filtered public water supplies eliminate it. Also
• maintain good personal hygiene
• don't eat unwashed fruit or vegetables unless they can be peeled
• boil water if in doubt; campers should boil stream water for three minutes before drinking
• if an outbreak occurs in a child care center, the director should notify the local health department. Children with severe diarrhea must stay at home until the stool returns to normal gingivitis See GUM DISEASE.
glanders An endemic infection (found in Asia, Africa, and South America) that afflicts horses and donkeys and may occasionally be transmitted to humans. The disease has been eradicated in Europe and North America.
Cause The infection is caused by the bacterium Pseudomonas mallei transmitted to humans from horses or other domestic animals.
Symptoms Glanders causes an ulcer or abscess where it enters a wound in the skin. If untreated, it may spread to the bones, liver, central nervous system, and other tissues and may be fatal.
Treatment Early treatment with an antibiotic clears the infection.
gonorrhea The most commonly reported communicable disease in the United States, most often affecting the genitourinary tract and (sometimes) the pharynx, eyes, or rectum. Since 1980 the number of people with gonorrhea has been declining; still, in 1993, 440,000 Americans were infected. Many more cases go unreported. People are at risk if they have more than one sex partner or don't use condoms. Most victims (75 percent) are between the ages of 15 and 24. Gonorrheal infections must be reported to local health departments in the United States.
Cause The disease is caused by a spherical bacterium, neisseria gonorrhoeae, that is always grouped in pairs. It is passed from one person to the next during sex. It is not possible to get gonorrhea from toilet seats or swimming pools.
A woman who has unprotected sex with an infected man has an 80 to 90 percent chance of being infected herself—a much higher rate than with other STDs. But a man who has unprotected sex with an infected woman has only a 20 to 25 percent chance of becoming infected. Men have less risk because it's harder for bacteria to enter the body through the penis than through the vaginal walls.
Symptoms Between three to five days after exposure, symptoms will appear in the genital or rectal area, or in the throat (depending on the sexual practice). Up to 80 percent of infected men experience painful urination, frequent urge to urinate, and white or yellow thick pus from the penis. About half of infected women have swelling of the vagina, abnormal green-yellow vaginal discharge, vaginal bleeding between periods, pelvic discomfort (itching and burning), and pain when urinating. Very few pregnant women have symptoms.
As the infection spreads—which is more common in women than in men—there may be nausea and vomiting, fever, and rapid heartbeat, or peritonitis. Inflammation of the tissues surrounding the liver also may occur,
116 Gonyaulax catanella causing pain in the upper abdomen. Severe cases of gonorrhea are also more common in women and are characterized by signs of blood poisoning, with tender lesions on the skin of the hands and feet and inflammation of the tendons of the wrists, knees, and ankles. If the disease spreads to the conjunctiva of the eyes, there may be scarring and blindness.
In both men and women, infection in the throat causes a mild, red, sore throat.
Treatment For many years, penicillin was the drug of choice, but in the late 1970s the bacteria became resistant. The most resistant strains are found in New York, California, and Florida, but resistance is seen in all states and most of Canada.
Today, treatment involves two antibiotics: a shot of ceftriaxone and doxycycline pills. The pills will also cure CHLAMYDIA, which has similar symptoms to gonorrhea (many people have both infections). Alternatively, instead of a shot a doctor may give a single dose of cefixime, ciprofloxacin, or ofloxacin. Pregnant women get a shot of ceftriazone and erythromycin pills.
An infant born with the symptoms of gonorrhea must be hospitalized and given ceftriaxone.
Complications PELVIC INFLAMMATORY DISEASE develops in almost 40 percent of untreated women and causes scars in the tubes, infertility, and tubal pregnancies. Untreated pregnant women may experience an infection in the amniotic fluid, smaller babies, or premature birth. Babies born to infected mothers may have gonorrhea conjunctivitis during delivery; untreated infants can become blind. For this reason, drops are placed in all babies' eyes at birth to prevent gonorrhea and chlamydia conjunctivitis.
In men, untreated gonorrhea can lead to infections of the testicles or scar the urethra, which can lead to sterility.
Gonyaulax catanella A (species of) plankton protozoa that produce a toxin ingested by shellfish along the North American coasts. Eating these toxic shellfish can lead to SHELLFISH POISONING. These protozoa also cause so-called RED TIDE because large numbers of the protozoa color the sea red.
Treatment There is no known antidote for shellfish poisoning caused by toxin-producing plankton. Administration of prostigmine may be effective, together with artificial respiration and oxygen as needed.
gram-negative shock See SEPTIC SHOCK.
granuloma Grouping of cells associated with chronic inflammation, which can occur in any part of the body. Granulomas are usually a reaction to certain infectious agents, although they may occur with no known cause.
Certain infections, such as LEPROSY and SYPHILIS can lead to infective granulomas in many different organs of the body. A pyogenic granuloma is a common benign skin tumor that develops after a minor injury. Pyogenic granulomas can be surgically removed or treated with cryosurgery. See GRANULOMA, INFECTIOUS; GRANULOMA INGUINALE.
granuloma, infectious A lumpy lesion of GRANULOMA tissue that may develop in diseases such as TUBERCULOSIS, SYPHILIS, ACTINOMYCOSIS, LEPROSY, or other tissue-invading organisms.
granuloma inguinale A chronic bacterial infection of the genital region, usually assumed to be a sexually transmitted disease. This relatively rare disease occurs most frequently in men living in tropical and subtropical areas.
In the United States, homosexuals are at greater risk; it is relatively rare in heterosexual partners of those affected. Past infection does not confer immunity, and there is no evidence of natural resistance.
Cause The disease is caused by the bacteria Calymmatobacterium granulomatis, a small gram-negative rod-shaped bacillus. It is spread by sexual contact with an infected individual. Granuloma inguinale is communicable as long as the infected person remains untreated and bacteria from the lesions are present.
Symptoms Within 8 to 80 days after infection, lumps or blisters in the genital area appear, becoming a slowly widening sore. Untreated, the lesions will spread, deepen, multiply, and may become infected.
Diagnosis Microscopic examination and identification of a smear taken from a lesion and stained.
Treatment Several antibiotics, including streptomycin, will cure the disease; the sores usually will completely heal within five weeks. All patients who are suspected of having this disease are also tested for SYPHILIS, since infection with both diseases is common.
Complications If left untreated, granuloma inguinale can cause extensive destruction of the genitals and may spread to other parts of the body.
group A strep See STREPTOCOCCUS, GROUP A.
group B strep See STREPTOCOCCUS, GROUP B.
Gulf War syndrome, bacterial cause Some experts suggest that bacteria may cause at least some of the cases of Gulf War syndrome, a constellation of symptoms including joint and muscle pain, memory loss, depression, skin rashes, and chronic fatigue suffered by veterans of the 1991 Gulf War. The U.S. government insists there is no single Gulf War syndrome. A number of causes have been given for the problems, ranging from chemical weapons exposure to interaction between medications and vaccines.
gum disease Infection at the roots of the teeth that cause bleeding and receding gums that—if unchecked—can lead to tooth loss. Gingivitis is an early, reversible stage of gum disease characterized by inflammation of the gums. Mild gum disease is very common in young adults; it is especially common among pregnant women and diabetics because of their changing hormone levels.
Cause Gingivitis occurs when plaque (which contains bacteria) is allowed to collect around the base of the teeth. Experts believe that toxins produced by bacteria within the plaque irritate the gums, causing them to become infected, tender, and swollen.
Symptoms Bleeding gums are nearly always a symptom of gingivitis. Other symptoms include a reddish purple color of the gums, and a soft, shiny, swollen appearance.
Treatment Good oral hygiene is the main way to both treat and prevent gum disease. In severe cases of gum disease (periodontitis), the dentist will surgically remove part of the gum margin (a technique called gingivec-tomy) as a way of removing the pockets of infected gums. It is performed in the dentist's office using local anesthetics.
Complications Untreated gum disease may lead to periodontitis, the advanced stage of gum disease, in which infected pockets form between the gums and the teeth. As the infection spreads, the supporting tissues of the teeth and the surrounding bone erode, loosening the teeth.
Acute necrotizing ulcerative gingivitis (trench mouth) may develop following infection with anaerobic bacteria in those with chronic gingivitis, especially those with lowered resistance to infection. This is a serious condition that can destroy gum tissue; it requires antibiotics. (See VINCENT'S DISEASE.)
New research Scientists at the University of Michigan School of Dentistry have discovered that it is possible to treat severe root-level bacterial infections with antibiotics, not surgery. The new treatment being studied at the school includes drug capsules to be taken for two to four weeks, depending on the severity of the problem, followed by as many as three rounds of topical antibiotics. These topical drugs are administered by temporarily gluing on experimental drug-impreg-nated cellulose film into the root surface.
Using this regimen, researchers avoided surgery or extraction for 88 percent of their subjects, including 67 percent of those with teeth identified by other dentists as too infected to save.
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