stances such as contaminated glasses, toys, or water. It may also be transmitted via fleas, flies, mosquitoes, ticks, or other insects.
Control of a communicable disease rests on properly identifying the organism that transmits it, preventing its spread to the environment, protecting others, and treating the infected patients.
By law, many communicable diseases must be reported to the local health department. Communicable diseases include those caused by bacteria, such as chlamydia, fungi, parasites, rickettsiae and viruses.
Not all communicable diseases must be reported, since they are not all considered to be a danger to society. Some diseases which must be reported include bacterial meningitis, aids, food poisoning, measles, hepatitis, rabies, lyme disease, syphilis, malaria, and tuberculosis.
condylomata acuminata A type of wart that commonly occurs in the genital area. Found throughout the world, the condition is readily spread by sexual contact. The warts are also known as acuminate warts or veneral warts.
Cause This type of wart is caused by infection with human papillomavirus (hpv).
Symptoms The warts primarily appear in the moist genital folds and creases, and while just one wart may appear, they are commonly found in heaped-up bunches that form cauli-flower-like masses. The warts are subject to injury and can bleed, although they are generally painless. Women who are pregnant or who take birth control pills tend to have more vigorous growth of these warts.
Giant condylomata acuminata can invade local tissue, which may rarely develop into a form of skin cancer.
Treatment There is no known treatment that will eradicate human papillomavirus from the skin, and the virus has survived even laser treatment; recurrence, therefore, is common. Treatment is aimed at removing warts; sexual partners should be examined for warts. Condoms should be worn to reduce the chance of transmission.
Most lesions in moist areas can be treated with a chemical (podophyllin) that is painted on the lesion and then washed off several hours later. Extensive areas should not be treated at one time, since absorption of the resin can be toxic. For the same reason, pregnant women should not be treated. Dry lesions do not respond as well to the resin treatment.
Burning off the wart with liquid nitrogen is often effective, nontoxic, and does not require anesthesia. If done properly, it does not scar. Cutting out the wart may also be successful. While alpha interferon is available for treatment of resistant cases, it is not recommended because of its high likelihood of toxicity, low effectiveness, and expense.
A carbon dioxide laser and more conventional surgery may also be helpful in cases of extensive growths, especially for those who have not responded to other treatments.
In pregnant patients, freezing is most effective. Women taking birth control pills must stop taking the pills before the warts can be successfully treated.
Prevention Because these warts are easily spread, sexual contact should be avoided when warts are present. Because there is a strong association between cancer of the cervix and HPV, a woman with HPV should be screened often. Not all HPV strains cause cancer, but several of the more than 100 types are believed to be linked to malignancy.
congenital infectious disease Any infectious disease present at birth that was acquired by the infant either before birth or during its passage through the birth canal.
A wide variety of bacteria, viruses, and microorganisms can cross the placenta from the mother's blood into the infant's body. Organisms that cause particularly serious diseases include rubella, syphilis, toxoplasmo-
SIS, and CYTOMEGALOVIRUS. Often, the effect these microorganisms have on the fetus depends on the stage of pregnancy at which the infection was acquired. For example, a rubella infection at the 9th or 10th week of pregnancy may cause deafness, heart disease, and other damage. If the same infection occurs much later in pregnancy, no harm usually results.
The infant is also vulnerable to maternal infection while passing through the birth canal. At this time, any active infection in the mother's genital area can have serious repercussions to her child. Conditions acquired in this way include conjunctivitis, genital herpes, or chlamydial infection. Staph, or strep infections, meningitis, hepatitis b, or listeriosis may also be passed on.
Some of these diseases may be prevented by proper medical care. All girls should be immunized against rubella and pregnant women should have any sexually transmitted diseases treated immediately.
A baby who is born with an infectious disease is treated immediately, although some diseases that occurred in the uterus cannot be reversed at birth.
Congo fever (Congo-Crimean hemorrhagic fever) An infectious disease (associated with a tick bite) that causes a fever and bleeding from mucous membranes and the skin. The disease, which was first observed in the Crimea by Russian scientists in 1944 and 1945, is fatal in about 30 percent of cases. The virus that causes this disease was isolated in Africa in the mid-1960s and named Crimean, but African researchers found the same organism and named it Congo; therefore, it is called either Congo fever or a combination of both names.
Cause The viral infection is usually transmitted to humans by a tick in the genus Hyalomma. The virus has been classified as a Nairovirus in the genus1 Bunyavirus. (The Nairovirus group includes the Hazara virus isolated from ticks in Pakistan, and to Nairobi sheep disease virus.) In Africa, the virus has been isolated from a variety of animals, including cattle, sheep, goats, hares, and hedgehogs and from a number of ticks found on these animals. More and more cases have been reported among medical and nursing staffs caring for patients in hospitals and in lab personnel studying these patients. In these cases, the infection was apparently acquired by contact with the patient's blood or blood-contaminated specimens. Exposure to the blood of infected animals (especially cattle and sheep) has led to severe, often fatal, infections.
Antibodies to the disease have been widely found in farm workers, cattle, sheep, and small mammals in southern Africa without evidence of disease.
Symptoms Within two to seven days after exposure, the onset of illness begins suddenly with fever, chills, severe muscular pains, headache, and vomiting. Between the third and fifth day of the infection, a red rash or hemorrhages in the skin appear, and blood pours from all body orifices. At this stage, the face is flushed and the tongue is dry and often coated with dried blood. As blood loss continues, the pulse starts to race and blood pressure drops. This is followed by signs of shock and collapse, with massive hemorrhage and cardiac arrest. In fatal cases, death usually occurs between seven and nine days after onset.
Among patients who recover, the fever falls between 10 and 20 days after infection begins and bleeding stops. However, recovery may take more than a month in these cases.
Diagnosis The diagnosis may be confirmed in the lab by a variety of methods for testing the blood for presence of the virus and its antibodies.
Treatment There is no cure. Treatment is aimed only at easing symptoms.
conjunctivitis The medical name for "pink eye," an inflammation of the transparent membrane covering the white of the eye and the lining of the eyelid. This common infection of childhood, also referred to as a "cold in the eye," causes redness, discomfort, and a discharge from the eye.
Cause Most conjunctivitis is caused by bacteria (staphylococci) spread by hand-to-eye contact or by viruses associated with a cold, sore throat, or illness such as measles. Viral conjunctivitis can spread like wildfire through schools and other group settings.
Newborns sometimes contract a type of conjunctivitis called neonatal ophthalmia, caused by infection in the mother's cervix during birth from either gonorrhea, genital herpes, or chlamydia. The infection may spread to the entire eye and cause blindness.
Symptoms All types of conjunctivitis lead to redness, itchy, scratchy, or painful feelings; discharge; and photophobia (discomfort from bright lights). There may be so much discharge that the eyelids stick together in the morning.
Treatment Antibiotic eye drops or ointments are given if a bacterial infection is suspected; however, this will not cure a viral infection. Warm water may wash away the discharge and remove crusts; in babies, the eye may be washed with sterile saline. In addition to eye drops, the discharge must be cleaned from the eyes (on an hourly basis for the first day).
Complications A doctor should be called immediately if any of these symptoms appear: swollen red eyelids, blurry vision, severe headache, fever higher than 101 degrees F, or a very painful eye. A doctor should be seen within 24 hours for any of the following symptoms: no improvement after drops or ointment, eye pain, decreased vision, or eyes that get more red or itchy after drops or ointment (which may be an allergic reaction).
Prevention Careful hand washing may prevent conjunctivitis, since the disease is spread from hand to eye very easily. Anyone with the disease should have separate washcloths and towels. It is also important that swimming pools and hot tubs be properly chlorinated. Children with conjunctivitis should be kept at home until 24 hours after antibiotics have been taken or until the eye is better.
contagious disease Any communicable disease. (Previously, the term referred to any disease transmitted by direct physical contact.) Some of the contagious diseases are actinomycosis, amebiasis, candidiasis, chicken pox, cholera, colds, conjunctivitis, diphtheria, gastroenteritis, giardiasis, hepatitis, herpes, influenza, meningitis, mononucleosis, mumps, paratyphoid fever, pediculosis, pneumonia, ringworm, roundworm infection, rubella, shigellosis, strep throat, syphilis, tuberculosis, typhoid fever, and whooping cough.
coronavirus Any one of a family of viruses that includes several types capable of causing respiratory illness and the common cold, especially during the winter and spring. Coronaviruses rarely cause fatal illness in humans. Named for their appearance, which includes a sort of thorny crown when visualized under an electron microscope, they are among the most common of the cold viruses.
It takes only about three days after exposure to these viruses for symptoms to appear, and they last up to about a week (a few days shorter than is typical for a cold caused by a rhinovirus). However, the coronavirus tends to cause more nasal congestion and is capable of reinfecting the same person.
corticosteroid drugs An extremely important group of drugs, commonly called steroids, that are similar to the natural corticosteroid hormones produced by the adrenal glands. These drugs, which are used to fight a variety of inflammatory conditions, include beclomethasone, betamethasone, cortisone, dexamethasone, hydrocortisone, prednisolone, and prednisone.
Side effects The severity of effects depends on the dose, the form of the drug, and the length of treatment. The effect of the steroids is to prepare the body for stress; they do this by increasing blood pressure, blocking histamine release, increasing sugar in the bloodstream, reducing the body's response to infection or inflammation, boosting appetite, and storing more fat. Short-term use of steroids, therefore, can produce beneficial "side effects," especially by decreasing inflammation (such as in the case of the asthmatic who stops wheezing).
Long-term treatment, which is often necessary in certain diseases, can cause high blood pressure, obesity, diabetes, and soft bones. High-dose steroid use can cause acute psychosis, which stops when the medication is discontinued.
Corynebacterium diphtheriae A bacterium that causes diphtheria, found in the mouth, throat, and nose of an infected individual. The bacteria are easily transmitted to others during coughing or sneezing or through close contact with discharge from nose, throat, skin, eyes, and lesions.
Diphtheria is usually a disease of the throat that mimics strep throat (although diphtheria may be more severe), characterized by a dense white membrane over the tonsils and the back of the throat.
In the United States, diphtheria is uncommon because of childhood immunizations. The immunity of adults is kept current by the practice of giving diphtheria vaccine whenever a tetanus booster is given.
cowpox An infection that usually affects cows caused by the vaccinia virus. An attack of cowpox in humans used to confer immunity against smallpox, since the two viruses were so similar. In fact, this was the basis for the smallpox vaccination. Vaccinia virus (for which the term vaccine was named) continued to be used as a smallpox vaccine until smallpox was eradicated in the 1970s. See also monkeypox.
Coxiella burnetii Another name for Rickettsia burnetii, the organism that causes q fever.
coxsackievirus Any of 30 different enteroviruses associated with a variety of symptoms that primarily affect children during warm weather. The germ resembles the polio virus (especially in size).
Among the diseases associated with these viruses are herpangina; hand, foot and mouth disease; myocarditis; and aseptic meningitis. There is no known way to prevent infection with these viruses other than avoiding infected patients. Treatment is usually aimed at easing symptoms.
crabs The popular term for pediculosis pubis, or lice in the pubic hair. The pubic louse may also be found in eyebrows, beards, eyelashes, chest hairs, and armpits, but it is not found in hair on the head.
While the scientific name for the pubic louse is Phthirius pubis, it gets its common name from its crablike appearance; it even has tiny pincer claws that it uses to hang onto the hairs. The pubic louse is a cousin of the body louse and the head louse and infects only humans.
Pubic lice don't live more than a few days away from humans, which makes reinfesta-tion less likely.
Cause Crabs are caught through close body contact with an infected person (usually a sex partner) although it is possible to catch lice by sharing a bed, clothing, or towels with someone who has lice. Pubic lice are more common among those who live in crowded places with poor laundry facilities.
The pubic louse lays tiny round eggs (called "nits") that hatch in about a week; 8 to
10 days after that, the louse matures. Once it is attached to the hair, the louse hangs upside down and bores into the skin to feed on the blood vessels close to the skin's surface.
Symptoms Severe itching begins in the pubic area about a week after exposure to lice, with reddened skin as a result of scratching. Nits are visible attached to the base of the pubic hairs, and the lice leave a bluish stain on the skin on the upper thigh. In particularly bad infestations, there may be swelling of the lymph glands in the groin. The longer the infestation has been going on, the more lice there will be and the worse the itching.
Diagnosis Inspection of the pubic area will reveal nits. Tests are not necessary.
Treatment Pubic lice are eliminated the same way as other types of lice, using perme-thrin 1% that is available without prescription or pyrethrins; over-the-counter shampoos are available with RID. Lindane 1% is no longer considered to be the treatment of choice because of concerns about side effects.
After treatment, all visible nits should be removed with a nit comb. The patient should be checked daily for the first week after treatment to make sure all nits are gone. If itch remains after seven days, another treatment is needed. Close physical contact (including sex) should be avoided until the treatment is complete. Nits in eyebrows or eyelashes should not be treated (they are too close to the eyes); instead, nits in these areas should be removed with tweezers. All bedding, towels, and clothing should be washed in hot sudsy water, then dried in the dryer for 20 minutes on high. Anything that can't be washed should be left isolated for three to four days, since lice can't survive long without a human host.
Prevention All sex partners and roommates should be treated, since lice can be passed on to others as long as there are live, unhatched nits attached to the pubic hairs. Vigilant checks for nits should continue for one week.
croup Inflammation and narrowing of the air passages (in young children), causing a hoarse, barking cough and a wheezing on breathing in. Once very common in children up to age four, croup is a frightening but not terribly serious illness. In older children and adults, the air passages are too wide and the cartilage in the air passages too stiff for swelling or inflammation to cause the walls to collapse.
One bout of croup does not confer immunity, and some children get several attacks. However, most cases are mild and children recover uneventfully.
Cause Croup is caused by one of several different types of viral infections (often a cold) that affect the larynx, windpipe, and airways into the lungs. The most common is parainfluenza virus (which usually occurs in late fall). respiratory syncytial virus (rsv) and influenza may appear in winter and early spring. adenoviruses, rhinovirus, and sometimes measles may lead to croup. While croup can't be passed on to anyone else, it is possible to catch a virus that can cause croup.
Some babies appear to be more likely to get croup than others, possibly because of a sensitive larynx; premature infants may also be prone to croup. Twice as many boys get croup as girls; some infants never get it, and others get it every time they have a cold.
Children outgrow the tendency toward croup, but there is no immunity.
Symptoms Croup begins like a cold. About one to seven days later, fever, cough, and breathing problems often appear at night. The child may awake with the characteristic barking cough, with shallow, fast, and noisy breathing. The high-pitched sounds occur during inhaling, not exhaling.
The child may feel better during the day but suffer the barking cough during the night for three or four nights.
Diagnosis A doctor can diagnose croup from the symptoms; tests are not needed, although a neck X-ray may be used to rule out foreign bodies or obstructions.
Treatment Cool mist vaporizers or cool night air help a child to breathe; the child should be kept upright while breathing in the cool air. Steam from a shower will work if no vaporizer is available.
A doctor should be called if the coughing doesn't get better or if the illness is severe (fever over 101 degrees F and severe breathing problems). For serious cases, doctors may check oxygen levels in the blood and provide oxygen together with epinephrine. A tube may be inserted down the throat or they may insert a tube through the throat (tracheostomy). The infant may be placed in a croup or mist tent, but such a tent should not be constructed at home.
Complications Croup that enters the windpipe and small airways leading into the lungs is called acute tracheobronchitis, a more serious condition that can interfere with breathing and may require hospitalization.
Epiglottitis is a rare (but dangerous) condition that may be confused with croup. Epiglottitis is caused by a sudden bacterial infection of the epiglottis that causes so much swelling in the upper throat that the child's airway is blocked. A doctor should be called if there are any of these warning signs of epiglottitis:
• fever higher than 103 degrees F
• drooling with open mouth
• agitation, restlessness, flaring nostrils
• muffled speech
• rapid, difficult breathing
• respiratory noise
• failure to breathe
• movement in and out in the areas between the ribs during breath
• severe sore throat
• refusal to swallow
Prevention If the child has a tendency toward developing croup, there are some ways to prevent the disease from occurring:
• keep a cool-mist vaporizer in the room during sleep
• give clear fluids to baby with a cold cryptococcosis A rare fungal infection caused by inhaling Cryptococcus neoformans, a type of fungus found throughout the world, especially in soil contaminated with pigeon droppings. Untreated, this infection may be progressive and ultimately fatal. The disease is also known as Buschke's disease or European blastomycosis.
Cause Although the infection usually affects adults, it can occur at any age. In North America, it is most likely to be found among those already ill with cancer (such as leukemia or lymphoma) or those with impaired immune systems, such as patients with AIDS. Infection with this fungus is unusual in patients who are otherwise healthy.
Symptoms Cryptococcosis is characterized by the development of fever and other symptoms depending on the specific organ involved. Because the lungs are the first site of infection, initial symptoms may include coughing. The fungus spreads from the lungs to the central nervous system, skin, skeletal system, and urinary tract. After the fungus spreads to the meninges, neurologic symptoms may develop, including headache, blurred vision, and difficulty in speaking.
While meningitis is the more usual and serious form of the disease, it can also cause a range of granular lesions, including ulcers, abscesses, tumors, papules, nodules, and draining sinuses into the skin, lungs, and so on.
Diagnosis The diagnosis is made by isolating and identifying the fungus in specimens of sputum, pus, spinal fluid, or tissue biopsy.
Treatment Fluconazole freely passes into the central nervous system and is the drug of choice; intravenous amphotericin B and oral flucytosine also may be helpful.
Cryptococcus A genus of yeasty fungus that reproduce by budding instead of by producing spores. Many harmless types of this fungus are found in soil, on the skin, and in the mucous membranes of healthy humans. However, there are a few disease-causing species, including C. neoformans, the cause of cryptococcosis.
cryptosporidiosis One of the more recently discovered types of food poisoning caused by a protozoan Cryptosporidium, which means "hidden spore" in Greek. The tiny invisible microbe infects cells lining the intestinal tract, and it was not identified as a cause of human disease until 1976. It is a major threat to the water supply of the United States.
In the United States, the number of outbreaks that occur each year aren't well documented. However, in 1993, more than 400,000 Milwaukee residents got sick after drinking water contaminated with Cryptosporidium.
Some immunity follows infection, but the degree to which this immunity occurs is not clear. See also traveler's diarrhea, diarrhea and infectious disease, antidiarrheal drugs.
Cause This parasite lives its entire life within the intestinal cells; it produces worms (oocysts) that are excreted in feces. These infectious oocysts can survive outside the human body for long periods of time, passing into food and drinking water, onto objects, and spread from hand to mouth. Unfortunately, chlorine does not kill the protozoan; instead, drinking water must be filtered to eliminate it. Many municipal water supplies do not have the technology to provide this filter.
Because the parasite is transmitted by the fecal-oral route, the greatest risk occurs in those infected people who have diarrhea, those with poor personal hygiene, and diapered children.
Symptoms Between 1 to 12 days after infection, the most common symptom is a watery diarrhea together with stomach cramps, nausea and vomiting, fever, headache, and loss of appetite. Some people with the infection don't experience any symptoms at all.
Healthy patients usually exhibit symptoms for about two weeks, but those with impaired immune systems may have a severe and lasting illness. In the Milwaukee outbreak, those affected noticed symptoms between 2 and 10 days after exposure. Some deaths were reported.
Diagnosis The infection is diagnosed by identifying the parasite during examination of the stool. If cryptosporidiosis is suspected, a specific lab test should be requested, since most labs don't yet routinely perform the necessary tests.
Treatment There is no standard treatment, but some patients may respond to some antibiotics (paromomycin). Intravenous fluids may be necessary, and antidiarrhea drugs may help.
Prevention Eradication of the organism from drinking water depends on adequate filtration, not chlorination. Scientists are studying new ways to protect water supplies, including reverse osmosis, membrane filtration, or radiation.
Cryptosporidium A type of parasite that causes the waterborne infection cryptosporidiosis. This organism is about l/60th the size of an average dust particle and has been found in up to 87 percent of surface water samples across the United States.
The egglike form of the organism, called oocysts, are passed into the feces of infectious animals, finding their way into water supplies, where they can then enter human intestines. Once in the intestine, they release an infective spore that begins another reproductive cycle.
A healthy infected human will experience watery diarrhea and cramps that pass in about a week, but those with impaired immune systems may have a much more serious (or fatal) case.
Boiling water for one minute is the only way to kill this bacteria, since they can live in chlorinated water. (Consumers who live above 6,562 feet should boil water for three minutes.)
cutaneous larva migrans Also known as creeping eruption, this disease is caused by hookworm larvae that normally parasitize dogs, cats, or other animals.
Cause Hookworm infestation occurs whenever human skin touches soil contaminated with cat or dog feces; shaded, moist, and sandy areas—such as beaches, children's sandboxes, and areas underneath houses—are the most likely spots to find larvae. Eggs passed in the feces hatch into infective larvae that can penetrate human skin (even through beach towels). The larvae penetrate the skin of the feet and move randomly, leaving intensely itchy red lines (sometimes accompanied by blisters).
Because several different parasites produce similar symptoms, there may be confusion about the diseases included under the umbrella of "cutaneous larva migrans." It usually refers to disorders caused by cat or dog hookworm larvae.
Symptoms Skin lesions usually appear in areas that often contact soil, such as feet, hands, and buttocks, appearing like a red papule a few hours after the larvae penetrates the skin. After a latency period of a few days to a few months, the larvae migrate, causing a red, raised, intensely itchy red line that may loop and meander all over the skin. Bacterial infection from scratching may occur. About half of the larvae die within three months even without treatment.
Treatment Thiabendazole can be administered on the skin over the tracks, and to nor-mal-appearing skin around the lesions (because there may be larvae outside the visible lines).
Older methods of treatment such as freezing the track with carbon dioxide or liquid nitrogen is unreliable and painful.
Side effects Thiabendazole taken internally is effective but associated with a high probability of side effects such as dizziness, nausea, and vomiting.
Cyclospora cayetanensis A parasitic microbe that infects the intestine and causes intense diarrhea, weight loss, and fatigue. It was identified as a cause of human disease only in recent years. The United States is currently battling its fourth epidemic of cyclospora, which began in the spring of 1996.
In a recent outbreak, contaminated raspberries sickened more than 1,000 people in 11 states east of the Rocky Mountains. Scientists found it hard to track the source of the problem because it takes a week between ingestion and symptoms.
The first outbreak in the United States probably occurred in 1979, although it was never properly identified; it came to the attention of officials in Chicago in 1989. This was followed by reports of outbreaks in Morocco, Peru, and New Guinea. The first full description of the disease was reported in the American Journal of Tropical Medicine and Hygiene in 1991.
Cause Little is known about the parasite's life cycle, the way it spreads, and whether birds or animals that feed on berries are involved. The organism is a distant cousin of CRYTOSPOR1DIUM, the protozoan that infiltrated a Milwaukee water supply in 1993 and caused an epidemic of stomach problems and 40 deaths, but this new organism is twice as large. Because the organism is a parasite of the small bowel, patients continue to lose weight even after the diarrhea stops because they can't absorb nutrients.
The organism does not appear to be halted by iodine or chlorine and can even elude filtration systems. The only thing that kills it is boiling the water in which it lives.
Symptoms About a week after ingestion, the disease begins with severe diarrhea, stomach cramps, nausea, and vomiting. It then progresses to weeks of mild fever, debilitating fatigue, and loss of appetite; patients can lose 15 to 20 pounds. While the disease is not normally fatal, some patients have been hospitalized because of dehydration.
Treatment The antibiotic combination of sulfa and trimethoprim can shorten the term of the illness, although most other diarrhea-causing organisms are now resistant to the drug. Those with impaired immune systems require higher doses and longer therapy.
Prevention Scientists advise those in epidemic areas not to eat strawberries or raspberries, especially for those with impaired immune systems. All fruit and vegetables should be thoroughly washed before eating.
cysticerosis See tapeworms.
cytomegalovirus (CMV) infection A disease caused by cytomegalovirus, one of the herpes family of viruses. The CMV is the largest, most complex virus that infects humans. First discovered in 1956, this extremely common infection has affected almost all children, yet rarely produces symptoms. By adulthood, up to 85 percent of Americans have been infected.
While not usually a serious disease, those with impaired immunity may have more severe symptoms. Cytomegalovirus also may cause significant problems during pregnancy if a woman has an acute infection, which would be transmitted to her unborn child. This can lead to minor impairments affecting hearing, vision, or mental capacity; a few of these babies are born with severe brain damage, including mental retardation or severe hearing loss.
Once a person has been infected, the virus remains latent in the body like other herpes viruses and can be reactivated later on during periods of stress or weakened immunity.
Cause CMV is present in almost all body fluids, including urine, saliva, semen, breast milk, and blood. It can be sexually transmitted, although most people don't get it this way. It is commonly found in day care centers, where it is passed around in children's saliva or urine-soaked diapers and transmitted from unwashed hands or shared toys.
Women with toddlers in day care are often infected, since CMV transmission happens often in these institutions. While young children rarely have symptoms, they excrete the virus in their urine and saliva for months to years. Anyone who works with young children is exposed to CMV. It is also possible to acquire CMV from transfused blood or transplanted organs, since so many individuals have an infection without having symptoms.
A person having an organ transplant or chemotherapy for cancer takes drugs that suppress the immune system; if such a patient had been infected with CMV earlier in life, the dormant virus can reactivate, resulting in life-threatening illness. If a patient taking these drugs has a first exposure to the virus, the new infection can cause a serious illness. In aids patients, reactivation of a CMV infection can lead to serious eye infections called retinitis, pneumonia, hepatitis, encephalitis, and colitis.
Symptoms Very few adults (including pregnant women) have symptoms when infected; if they do, symptoms will be mild, including achiness, low fever, and sore throat. Young children may experience a mild cold or flulike illness with fever.
However, if a woman is first exposed to this virus early in pregnancy, the resulting infection can cause serious fetal abnormalities. About 40,000 infants in the United States are infected each year, but almost all babies infected before birth are normal. About 10 percent of babies infected before birth are sick with the symptoms listed above. Of these 10 percent, 20 to 30 percent have a "congenital CMV syndrome" with serious symptoms that may be fatal. These symptoms include problems of major organs, including the liver, brain, eyes, and lungs together with convul
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