5. Fungal infections
Fungi are a type of plant that can infect people. Yeasts, molds, and mushrooms are all examples of fungi.
Some fungi reproduce by spreading microscopic spores. These spores are often present in the air, where they can be inhaled or come into contact with the surfaces of a person's body. Consequently, fungal infections usually begin in the lungs or on the skin. Of the wide variety of spores that land on the skin or are inhaled into the lungs, most do not cause infection. Except for some superficial skin conditions, fungal infections are rarely passed from one person to another.
Certain types of fungi (such as Candida) are normally present on body surfaces or in the intestines. Although normally harmless, these fungi sometimes cause local infections of the skin and nails, vagina, mouth and sinuses. They seldom cause serious harm, except in people with a weakened immune system or with foreign material (such as an intravenous catheter) in their body.
Sometimes, the normal balances that keep fungi in check are upset and infections occur. For example, the bacteria normally present in the digestive tract and vagina limit the growth of certain fungi in those areas. When a person takes antibiotics, those helpful bacteria can be killed—allowing the fungi to grow unchecked. The resulting overgrowth of fungi can cause symptoms, which are usually mild. As the bacteria grow back, the balance is restored, and the problem usually resolves.
Some fungal infections (for example, histoplasmosis, blastomycosis, and coccidioidomycosis) can be serious in otherwise healthy people.
Some fungal infections are more common in certain geographic areas. For example, in the United States coccidioidomycosis occurs almost exclusively in the Southwest, whereas histoplasmosis is especially common in the Ohio and Mississippi River valleys. Blastomycosis is particularly common in the eastern and central United States and in Africa.
Because many fungal infections develop slowly, months or years may pass before a person seeks medical attention. In people with a weakened immune system (for example, people who have received an organ transplant, are being treated for cancer with immunosuppressive drugs, or who have AIDS), fungal infections can be very aggressive—spreading quickly to other organs and often leading to death.
Several drugs effective against fungal infections are available, but the structure and chemical makeup of fungi make them difficult to kill. Antifungal drugs may be applied directly to a fungal infection of the skin or other surface, such as the vagina or the inside of the mouth. Antifungal drugs may also be taken by mouth or injected when needed to treat more serious infections. Several months of treatment are often needed.
Notes:
immunosuppressive drugs имунно-подавляющие лекарства
inhale вдыхать
upset нарушать
resolve a problem решать проблему
TextA Histoplasmosis
Histoplasmosis is infection caused by the fungus Histoplasma capsulatum that occurs mainly in the lungs but can sometimes spread throughout the body.
The spores of Histoplasma are present in the soil and are particularly common in the eastern and midwestern United States. Farmers and others who work with soil are most likely to inhale the spores; severe disease can result when large numbers of spores are inhaled. People with human immunodeficiency virus (HIV) infection are more likely to develop histoplasmosis, especially the form that spreads throughout the body.
Symptoms and Diagnosis
Most people with histoplasmosis do not have any symptoms. However, three forms of histoplasmosis do cause symptoms: acute, progressive disseminated, and chronic cavitary.
In acute histoplasmosis, symptoms usually appear 3 to 21 days after a person inhales the spores. The person may feel sick and have a fever and a cough. Symptoms usually disappear without treatment in 2 weeks and rarely last longer than 6 weeks. This form of histoplasmosis is very rarely fatal.
Progressive disseminated histoplasmosis does not normally affect healthy adults. This infection usually occurs in infants and in people with a weakened immune system (such as those with AIDS). Symptoms are vague at first. People may experience fatigue, weakness, and a general feeling of illness (malaise). Symptoms may worsen very slowly or extremely rapidly. The liver, spleen, and lymph nodes may enlarge. Less commonly, the infection causes ulcers to form in the mouth and intestines. In rare cases, the adrenal glands may be damaged, causing Addison's disease. Without treatment, this form of histoplasmosis is fatal in 90% of people. Even with treatment, death may occur rapidly in people with AIDS.
Chronic cavitary histoplasmosis is a lung infection that develops gradually over several weeks, producing a cough and increased difficulty in breathing. Symptoms include weight loss, a mild fever, and a general feeling of illness (malaise). Most people recover without treatment within 2 to 6 months. However, breathing difficulties may gradually worsen, and some people may cough up blood, sometimes in large amounts. Lung damage or bacterial invasion of the lungs eventually may cause death.
To make the diagnosis, a doctor obtains samples of an infected person's sputum, bone marrow, urine, or blood. Samples may also be taken from the liver, lymph nodes, or any mouth ulcers that are present. These samples are sent to a laboratory for culture and analysis.
Prognosis and Treatment
People with the acute form of histoplasmosis rarely require drug treatment. Those with the progressive disseminated form do need treatment and often respond well to amphotericin B given intravenously or to itraconazole given by mouth. In the chronic cavitary form, itraconazole or amphotericin B may eliminate the fungus, although the destruction caused by the infection leaves behind scar tissue. Breathing problems similar to those caused by chronic obstructive pulmonary disease usually remain. Therefore, treatment should begin as soon as possible to limit lung damage.
Notes:
histoplasmosis микоз, вызываемый диморфным грибом, гистоплазмоз
histoplasma capsulatum возбудитель гистоплазмоза
Text B Coccidioidomycosis
Coccidioidomycosis (San Joaquin fever, valley fever) is infection caused by the fungus Coccidioides immitis that usually affects the lungs.
The spores of Coccidioides can be found in soil in the southwestern United States, Central America, and South America. Farmers and others who work with soil are most likely to inhale the spores and become infected. People who become infected while traveling may not develop symptoms of the disease until after they leave the area.
Coccidioidomycosis occurs either as a mild lung infection that disappears without treatment (acute primary coccidioidomycosis) or as a severe, progressive infection that spreads throughout the body and is often fatal (progressive coccidioidomycosis). The progressive form is often a sign that the person has a weakened immune system, usually because of AIDS.
Symptoms and Diagnosis
Most people with acute primary coccidioidomycosis have no symptoms. If symptoms develop, they appear 1 to 3 weeks after the person becomes infected. The symptoms are usually mild and include a cough, fever, chills, chest pain, and sometimes shortness of breath. The cough may produce sputum and even occasionally blood. Some people develop "desert rheumatism"—inflammation of the surface of the eye (conjunctivitis) and joints (arthritis) and the formation of skin nodules (erythema nodosum).
The progressive form of the disease is unusual and may develop weeks, months, or even years after the acute primary infection. Symptoms include mild fever and losses of appetite, weight, and strength. The lung infection may worsen, causing increased shortness of breath. The infection also may spread from the lungs to the bones, joints, liver, spleen, and kidneys. Infection of the brain and the tissues covering the brain (meninges) is often chronic.
A doctor may suspect coccidioidomycosis if a person develops symptoms after living in or recently traveling through an area where the disease is common. Chest x-rays usually reveal abnormalities, but further testing (of blood, sputum, or pus samples) may be needed to confirm the diagnosis.
Prognosis and Treatment
Acute primary coccidioidomycosis typically goes away without treatment, and recovery usually is complete. However, some doctors prefer to treat the person if coccidioidomycosis affects the lungs. Oral fluconazole or intravenous amphotericin B is given to people with the progressive form of the disease. Alternatively, the doctor may treat the infection with itraconazole or ketoconazole. If a person develops meningitis (infection of the tissues covering the brain and spinal cord), intravenous fluconazoleis given. Alternatively, amphotericin B may be injected into the spinal fluid. Untreated meningitis is always fatal. Although drug treatment can be effective in localized infections—for example, in the skin, bones, or joints—relapses often occur after treatment is discontinued. Treatment must therefore be continued for years, often for life.
Notes:
coccidioidomycosis кокцидиоидомикоз
confirm the diagnosis подтвердить диагноз
go away прекращаться
Text C Candidiasis
Candidiasis (candidosis, moniliasis, "yeast infection") is infection caused by species of Candida, especially Candida albicans.
Candida is normally present on the skin, in the intestinal tract, and—in women—in the genital region. Usually, Candida in these areas does not cause problems. Sometimes, however, the fungus can cause infection of the skin or the mucous membranes of the mouth or vagina. Such infections can develop in people with a healthy immune system, but they are more common or persistent in people with diabetes, cancer, or AIDS and in pregnant women. Candidiasis is also common in people who are given antibiotics, because the bacteria that normally compete with Candida are killed and the fungus is able to grow unchecked.
Some people, mainly those with a weakened immune system, develop candidiasis that spreads through the bloodstream to other parts of the body.
Symptoms and Diagnosis
Infection of the mouth (thrush or trench mouth) causes creamy, white, painful patches to form inside the mouth. Skin infections can cause a burning rash. Patches in the esophagus cause pain with swallowing.
More serious infections, such as those in the heart valves, can cause fever, heart murmur, and enlargement of the spleen. An infection of the retina and inner parts of the eye can cause blindness. An infection of the blood (candidemia) or kidney can cause fever, very low blood pressure (shock), and a decrease in urine production.
Many candidal infections are apparent from the symptoms alone. To confirm the diagnosis, however, a doctor must identify the fungi in a skin sample under a microscope. Samples of blood or spinal fluid that have been cultured may also reveal the presence of the fungus.
Prognosis and Treatment
Candidiasis that occurs only on the skin or in the mouth or vagina can be treated with antifungal drugs that are applied directly to the affected area (for example, clotrimazole and nystatin ). A doctor may prescribe the antifungal drug fluconazole to be taken by mouth.
Candidiasis that has spread throughout the body is a severe, progressive, and potentially fatal infection that is usually treated with intravenous amphotericin B , although fluconazole is effective for some people. Caspofungin and voriconazole , drugs that are still being studied, may be useful as well.
Certain medical conditions, such as diabetes, can worsen candidiasis. In people with diabetes, control of the blood sugar levels facilitates cure of the infection.
Notes:
candidiasis кандидоз
“yeast infection” дрожжевая инфекция
Candida albicans дрожжеподобный белый гриб
candidemia наличие белых грибов в крови, кандидемия
apparent несомненный, очевидный