Coccidioidomycosis
Coccidioidomycosis
Definition
Coccidioidomycosis is an infection caused by inhaling the microscopic spores of the fungus Coccidioides immitis. Spores are the tiny, thick-walled structures that fungi use to reproduce. Coccidioidomycosis exists in three forms. The acute form produces flu-like symptoms. The chronic form can develop as many as 20 years after initial infection and, in the lungs, can produce inflamed, injured areas that can fill with pus (abscesses). Disseminated coccidioidomycosis describes the type of coccidioidomycosis that spreads throughout the body affecting many organ systems and is often fatal.
Description
Coccidioidomycosis is an airborne infection. The fungus that causes the disease is found in the dry desert soil of the southwestern United States, Mexico, and Central and South America. Coccidioidomycosis is sometimes called San Joaquin fever, valley fever, or desert fever because of its prevalence in the farming valleys of California. Although commonly acquired, overt coccidioidomycosis is a rare disease. Chronic infections occur in only one out of every 100,000 people.
Although anyone can get coccidioidomycosis, farm laborers, construction workers, and archaeologists who work where it is dusty are at greater risk to become infected. People of any age can get coccidioidomycosis, but the disease most commonly occurs in the 25-55 age group. In its acute form, coccidioidomycosis infects men and women equally.
Chronic and disseminated forms of coccidioidomycosis occur more frequently in men and pregnant women. Although it is not clear why, people of color are 10-20 times more likely to develop the disseminated form of the disease than caucasians. People who have a weakened immune system (immunocompromised), either from diseases such as AIDS or leukemia, or as the result of medications that suppressed the immune system (corticosteroids, chemotherapy ), are more likely to develop disseminated coccidioidomycosis.
Causes and symptoms
When the spores of C. immitis are inhaled, they can become lodged in the lungs, divide, and cause localized inflammation. This is known as acute or primary coccidioidomycosis. The disease is not spread from one person to another. Approximately 60% of people who are infected exhibit no symptoms (asymptomatic). In the other 40%, symptoms appear 10-30 days after exposure. These symptoms include a fever which can reach 104°F (39.5°C), dry cough, chest pains, joint and muscle aches, headache, and weight loss. About two weeks after the start of the fever, some people develop a painful red rash or lumps on the lower legs. Symptoms usually disappear without treatment in about one month. People who have been infected gain partial immunity to reinfection.
The chronic form of coccidioidomycosis normally occurs after a long latent period of 20 or more years during which the patient experiences no symptoms of the disease. In the chronic phase, coccidioidomycosis causes lung abscesses that rupture, spilling pus and fluid into the lungs, and causing serious damage to the lungs. The patient experiences difficulty breathing and has a fever, chest pain, and other signs of pneumonia. Medical treatment is essential for recovery.
In its disseminated form, coccidioidomycosis spreads to other parts of the body including the liver, bones, skin, brain, heart, and lining around the heart (pericardium). Symptoms include fever, joint pain, loss of appetite, weight loss, night sweats, skin lesions, and difficulty breathing. Also, in 30-50% of patients with disseminated coccidioidomycosis, the tissue coverings of the brain and spinal cord become inflamed (meningitis ).
Diagnosis
Many cases of coccidioidomycosis go undiagnosed because the symptoms resemble those of common viral diseases. However, a skin test similar to that for tuberculosis will determine whether a person has been infected. The test is simple and accurate, but it does not indicate whether the disease was limited to its acute form or if it has progressed to its chronic form.
Diagnosis of chronic or disseminated coccidioidomycosis is made by culturing a sample of sputum or other body fluids in the laboratory to isolate the fungus. A blood serum test is used to detect the presence of an antibody produced in response to C. immitis infection. Chest x rays are often used to assess lung damage, but alone cannot lead to a definitive diagnosis of coccidioidomycosis because other diseases can produce similar results on the x ray.
Treatment
In most cases of acute coccidioidomycosis, the body's own immune system is adequate to bring about recovery without medical intervention. Fever and pain can be treated with non-prescription drugs.
Chronic and disseminated coccidioidomycosis, however, are serious diseases that require treatment with prescription drugs. Patients with intact immune systems who develop chronic coccidiodomycosis are treated with the drug ketoconazole (Nizoral) or amphotericin B (Fungizone). Patients with suppressed immune systems are treated with amphotericin B (Fungizone). Amphotericin B is a powerful fungistatic drug with potentially toxic side effects. As a result, hospitalization is required in order to monitor patients. The patient may also receive other drugs to minimize the side effects of the amphotericin B.
Patients with AIDS must continue to take itraconazole (Sporonox) or fluconazole (Diflucan) orally or receive weekly intravenous doses of amphotericin B for the rest of their lives in order to prevent a relapse. Because of the high cost of fluconazole, Pfizer, the manufacturer of the drug, has established a financial assistance plan to make the drug available at lower cost to those who meet certain criteria. Patients needing this drug should ask their doctors about this program.
Alternative treatment
Alternative treatment for fungal infections focuses on creating an internal environment where the fungus cannot survive. This is accomplished by eating a diet low in dairy products, sugars, including honey and fruit juice, and foods like beer that contain yeast. This is complemented by a diet consisting, in large part, of uncooked and unprocessed foods. Supplements of vitamins C, E, A-plus, and B complex may also be useful. Lactobacillus acidophilus and Bifidobacterium will replenish the good bacteria in the intestines. Antifungal herbs, like garlic (Allium sativum ), can be consumed in relatively large does and for an extended period of time in order to increase effectiveness.
KEY TERMS
Abscess— An area of inflamed and injured body tissue that fills with pus.
Acidophilus— The bacteria Lactobacillus acidophilus that usually found in yogurt.
Antibody— A specific protein produced by the immune system in response to a specific foreign protein or particle called an antigen.
Antigen— A foreign protein to which the body reacts by making antibodies.
Asymptomatic— Persons who carry a disease but who do not exhibit symptoms of the disease are said to be asymptomatic.
Bifidobacteria— A group of bacteria normally present in the intestine. Commercial supplements containing these bacteria are available.
Corticosteroids— A group of hormones produced naturally by the adrenal gland or manufactured synthetically. They are often used to treat inflammation. Examples include cortisone and prednisone.
Immunocompromised— A state in which the immune system is suppressed or not functioning properly.
Meningitis— An inflammation of the membranes surrounding the brain or spinal cord.
Pericardium— The tissue sac around the heart.
Prognosis
Most people who are infected with coccidiodomycosis only suffer from the mild, acute form of the disease and recover without further complications. Patients who suffer from chronic coccidiodomycosis and who have no underlying lung or immune system diseases also stand a good change of recovery, although they must be alert to a relapse.
The picture for patients with the disseminated form of the disease, many of whom have AIDS, is less positive. Untreated disseminated coccidiodomycosis is almost always fatal within a short time. With treatment, chance of survival increases, but the death rate remains high when meningitis or diffuse lung (pulmonary) disease is present. AIDS patients must constantly guard against relapse.
Prevention
Because the fungus that causes coccidioidomycosis is airborne and microscopic, the only method of prevention is to avoid visiting areas where it is found in the soil. Unfortunately, for many people this is impractical. Maintaining general good health and avoiding HIV infection will limit coccidioidomycosis to the acute and relatively mild form in most people.
Resources
ORGANIZATIONS
American Lung Association. 1740 Broadway, New York, NY 10019. (800) 586-4872. 〈http://www.lungusa.org〉.
Canadian HIV/AIDS Clearinghouse. 1565 Carling Avenue, Suite 400, Ottawa, ON K1Z 8R1. (877) 999-7740. 〈http://www.clearinghouse.cpha.ca/clearinghouse_e.htm〉.
Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. 〈http://www.cdc.gov〉.
National Aids Hotline. (800) 342-2437.
Project Inform. 205 13th Street, #2001, San Francisco, CA 94103. (800) 822-7422. 〈http://www.projinf.org〉.
Coccidioidomycosis
Coccidioidomycosis
Disease History, Characteristics, and Transmission
Introduction
Coccidioidomycosis, also called valley fever, is a fungal disease caused by the spores (tiny seeds) of the fungus Coccidioides immitis (CI). The fungus is classified as dimorphic, meaning that it exists both as a mold and yeast. It is found in infected soil of the Sonoran climates of the southwestern United States, northwestern Mexico, and other isolated areas within the Western Hemisphere.
The disease causes several respiratory problems in humans. However, humans cannot acquire the disease from other people, only through inhalation of these airborne particles and contact with infected soil. Scientists assume that a person develops immunity to the disease once recovered from it.
Sixty percent of the time the disease causes no symptoms to the infected person. It is only recognized later by medical professionals when a coccidioidin skin test comes back positive from the laboratory. It is rarely fatal to humans, except to those with weakened immune systems.
Disease History, Characteristics, and Transmission
Coccidioidomycosis was first described in the late 1800s. Only severe cases were reported. Milder cases began to be reported in the early 1900s. It is also called valley fever, San Joaquin Valley fever, desert fever, Posadas-Wernicke disease, and California valley fever.
WORDS TO KNOW
ACUTE: An acute infection is one of rapid onset and of short duration, which either resolves or becomes chronic.
CHRONIC: Chronic infections persist for prolonged periods of time—months or even years—in the host. This lengthy persistence is due to a number of factors including masking of the diseasecausing agent (e.g, bacteria) from the immune system, invasion of host cells, and the establishment of an infection that is resistant to antibacterial agents.
DIMORPHIC: This refers to the occurrence of two different shapes or color forms within the species, usually occurring as sexual dimorphism between the males and females.
ENDEMIC: Present in a particular area or among a particular group of people.
IMMUNOCOMPROMISED: A reduction of the ability of the immune system to recognize and respond to the presence of foreign material.
No signs of symptoms occur in over half of reported cases. When symptoms are apparent, they range from mild to severe. Forty percent of the time, they are similar to influenza or the common cold. More serious cases result in pneumonia-like symptoms. Symptoms can initially include cough, headache, fever, skin rash (lower legs), and muscle and joint pain and stiffness. Other symptoms include chest pain, chills, night sweats, neck or shoulder stiffness, bloodtinged sputum, loss of appetite and weight loss, wheezing, change in behavior, joint swelling (ankles, feet, legs), arthritis, and light sensitivity. Most cases resolve on their own and are not treated medically.
The disease occurs in acute, chronic, and disseminated forms. Acute coccidioidomycosis is rare, with few or no symptoms. Some symptoms include cough, chest pain, breathing difficulties, fever, and fatigue. According to the National Institute of Health, only about 3% of people contract the acute form. Seven to 21 days is the usual incubation period. Almost all cases resolve themselves without medical help.
With chronic infection, the fungus enters internal tissues and organs, such as the meninges (protective covering of brain and spinal column), joints, heart, and bone. It can also produce neurologic damage and tumors. People with compromised immune systems are especially affected by the chronic form of the disease. Coccidioidomycosis is not always recognized upon examination, but it does show up as nodules or cavities in the lungs. If diagnosis takes years, these lung abscesses can rupture. The chronic form occurs in 5–10% of infected patients.
Disseminated coccidioidomycosis is the most common form of the disease. It spreads to the lungs, bones (ankles, knees, feet, pelvis, wrists), organs (adrenal glands, gastrointestinal tract, liver, thyroid), meninges, brain, skin, and heart. Meningitis, the most serious complication, occurs in 30–50% of the cases.
Transmission occurs by inhalation of airborne dust containing the fungal spores. The fungus can also be contracted through the skin from infected soil. When they travel into lungs, the spores grow into spherical cells called spherules. The spherules enlarge, divide, and explode into numerous particles about 2–5 micrometers (one micrometer equals one millionth of a meter) in size.
Inhalation becomes more likely when soil is disturbed by artificial means (farming, excavation, construction) or by natural events (earthquakes, dust storms). Hispanic-, African-, and Asian-Americans are at higher risk than other ethnic groups. Pregnant women during the third trimester of pregnancy and immunocompromised individuals are also at higher risk.
Scope and Distribution
The disease is found in semiarid and desert regions of the southwestern United States (specifically, Arizona, California, Nevada, New Mexico, Texas, and Utah) and the northern part of Mexico. It is found in alkaline soils, climates with hot summers, and areas with annual rainfalls of 5–20 inches (13–50 cm). Between 1995 and 2005, California, New Mexico, and Arizona had the highest incidence of coccidioidomycosis, according to the NETSS (National Electronic Telecommunications System for Surveillance) of the Centers for Disease control and Prevention (CDC). It is prevalent in California's San Joaquin Valley. It also occurs in parts of Central American and South America.
According to the CDC's Division of Bacterial and Mycotic Diseases, about 15 cases out of 100,000 occur in Arizona. Ten to fifty percent of people living in areas where the disease is common are found to be positive when tested. In the United States, about 100,000 people are infected with the fungus each year, but less than 10% of these people will develop the disease.
Treatment and Prevention
Diagnosis can be made in a variety of ways, including recovery of Coccidioides immitis from cultures and smears of sputum or other body fluid; blood tests showing the body's reaction to fungal presence; skin tests (such as Spherulin test); and chest x-ray. Their reliability, however, may vary depending on the disease's stage. Chest x rays are used to find lung abnormalities, however, the specific disease causing the abnormalities is difficult to identify from the x ray alone.
Coccidioidomycosis patients with flu-like symptoms are given antifungal medicines. In particular, amphotercin B (Abelcet®, Fungisome®) is used. However, this drug is toxic, especially when injected underneath the skull to treat meningitis. Thus, oral antifungal medicines are increasingly used, including ketoconazole (Nizoral®), fluconazole (Diflucan®), and itraconazole (Sporanox®). One-year treatments are common. Severe cases involving lung and bone damage may require surgery.
Patients with the acute form usually recover completely. Relapses can occur with chronic or severe forms. The highest death rates occur with the disseminated form of the disease. The most frequent complications are infectious relapses, accumulation of fluid between lung and chest cavity membranes, and drug complications.
IN CONTEXT: REAL-WORLD RISKS
Coccidioidomycosis is considered a re-emerging infectious disease. It has been difficult to determine the total number of cases each year, since many cases are unreported. Generally, it is estimated that about 7,500 new cases occur each year in the United States.
SOURCE: Centers for Disease Control and Prevention (CDC)
Impacts and Issues
Coccidioidomycosis has plagued humans for many years. A cure has long been sought, but not yet attained. Currently, the disease is impossible to control and very difficult to treat. Researchers are trying to find an effective vaccine for the disease that would provide lifelong immunity. Although symptoms may subside, persons recovering from coccidioidomycosis often require repeated follow-up examinations from one to two years after symptoms disappear.
In the 1990s, one outbreak in California signaled a dramatic increase in the number of identified cases of coccidioidomycosis and illustrated the costs of an outbreak to the community. Even though most of the infections were self-limited, the cost of direct medical expenses and time lost from work was estimated to be more than $66 million during the outbreak in one California county alone. This particular outbreak was linked to heavy rainfall that ended a five-year drought in California. The rainfall enabled the Coccidioides immitis that had remained dormant throughout the drought to multiply to a higher density than usual, since many competing organisms were killed by the drought conditions. Scientists continue to study climate change and weather patterns to better understand their relationship to outbreaks of coccidioidomycosis.
According to the Arizona Daily Star newspaper, Arizona health officials have issued public information statements about the disease, since the state has been in the midst of an outbreak since 2005. A record 5,493 Arizonans were diagnosed with the disease in 2006, but as in years past, health officials say thousands of other cases went unreported. An estimated 60% of all Arizonians have been infected with the fungus, and about 33% of persons diagnosed with pneumonia in Arizona actually have coccidioidomycosis. An ongoing campaign in Arizona is aimed at educating the medical community to consider coccidioidomycosis whenever anyone seeks medical treatment for flu or pneumonia symptoms in regions where coccidioidomycosis is endemic. The University of Arizona is also tracking the outbreak, and is studying the effectiveness of a new drug, nikkomycin Z, that has shown potential to cure the disease when tested in mice.
See AlsoAirborne Precautions; Colds (Rhinitis); Influenza; Mycotic Disease; Pneumonia.
BIBLIOGRAPHY
Books
Kumara, Vinay, Nelso Fausto, and Abul Abbas. Robbins and Cotran Pathologic Basis of Disease. 7th ed. Philadelphia: Saunders, 2004.
Ryan, K. J., and C. G. Ray. Sherris Medical Microbiology: An Introduction to Infectious Diseases. 4th ed. New York: McGraw Hill, 2003.
Periodicals
Hector, R., and R. Laniado-Laborin. “Coccidioidomycosis—A Fungal Disease of the Americas.” PloS Medicine, January 25 2005. <http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0020002> (accessed March 8, 2007).
Web Sites
Centers for Disease Control and Prevention. Division of Bacterial and Mycotic Diseases. “Coccidioidomycosis.” <http://www.cdc.gov/ncidod/dbmd/diseaseinfo/coccidioidomycosis_t.htm> (accessed March 8, 2007). Valley Fever Connections. “Valley Fever.” <http://www.valley-fever.org> (accessed March 8, 2007).
Coccidioidomycosis (Valley Fever)
Coccidioidomycosis (Valley Fever)
Can Coccidioidomycosis Be Prevented?
Coccidioidomycosis (kok-sih-dee-oyd-o-my-KO-sis), also know as valley fever, is a disease that can occur after breathing in the spores* of a fungus found naturally in the soil of dry regions, such as the southwestern United States.
- *spores
- are a temporarily inactive form of a germ enclosed in a protective shell.
KEYWORDS
for searching the Internet and other reference sources
Coccidioides immitis
Desert rheumatism
Fungal infection
San Joaquin Valley fever
What Is Coccidioidomycosis?
During World War II, American trainees sent to Arizona and parts of southern California for flight training took thousands of days of sick leave because of coccidioidomycosis, a disease caused by Coccidioides immitis (kok-sih-dee-OYD-eez IH-mih-tus), a fungus that hibernates a few inches beneath semi-dry soil. The disease’s other name, valley fever, comes from the San Joaquin Valley region of California, where the fungus was first identified.
After regular rainfall, the coccidioides fungus blooms into tiny mold spores. If the soil is stirred by events such as dust storms, earthquakes, farming, excavation, or construction work, these microscopic spores spring into the air, where they are easily breathed into the lungs of people and animals.
Coccidioidomycosis cannot be passed from person to person. People must inhale the spores of the fungus in order to contract the disease. Most people who inhale the spores develop only a mild case of disease, in which the infection results in symptoms similar to those of a cold or the flu that go away on their own. Many people are not even aware that they are infected when the symptoms are mild. For those with weakened immune systems and for people of African or Filipino ancestry (who, for some unknown reason, get more severe forms of the disease), coccidioidomycosis can be much more serious, spreading from the lungs to other parts of the body and even to the brain. Severe cases may result in meningitis*. Coccidioides infection that has spread throughout the body and occurs with arthritis* is sometimes called desert rheumatism (ROO-muh-tih-zum). In general, the more fungal spores inhaled by a person, the more serious the disease tends to be.
- *meningitis
- (meh-nin-JY-tis) is an inflammation of the meninges, the membranes that surround the brain and the spinal cord. Meningitis is most often caused by infection with a virus or a bacterium.
- *arthritis
- (ar-THRY-tis) refers to any of several disorders characterized by inflammation of the joints.
Is Coccidioidomycosis Common?
The fungus that causes coccidioidomycosis is found mainly in the desert climates of the southwestern United States, parts of Mexico, and Central and South America. The infection is considered endemic* in these regions. People who live in or visit “cocci country” and who often spend time outside for work or play are more likely to develop the disease, especially near areas of development and construction during the summer and fall. Up to 50 percent of people living in such areas have antibodies* against Coccidioides immitis in their blood, which indicates that they have been exposed to the fungus, although many of them never developed signs of the disease.
- *endemic
- (en-DEH-mik) describes a disease or condition that is present in a population or geographic area at all times.
- *antibodies
- (AN-tih-bah-deez) are protein molecules produced by the body’s immune system to help fight specific infections caused by microorganisms, such as bacteria and viruses.
Signs and symptoms
About 60 percent of people infected by Coccidioides immitis develop no symptoms. When symptoms do occur, they are usually mild and include fever, aches, chills, headache, and tiredness. Those with weakened immune systems, such as people with AIDS, certain types of cancer, and diabetes, have a greater risk of developing a more severe form of the infection.
Diagnosis
A doctor diagnoses coccidioidomycosis by culturing* a patient’s sputum* or by doing a skin test. If injecting the test material into the skin of the forearm causes a large circular welt to appear on the arm within 2 days, it is considered a positive test for the fungus. Blood tests may show antibodies to the fungus, which helps confirm the diagnosis. A chest X ray is sometimes taken to look for signs of infection or inflammation in the lungs.
- *culturing
- (KUL-chur-ing) means subjecting to a test in which a sample of fluid or tissue from the body is placed in a dish containing material that supports the growth of certain organisms. Typically, within days the organisms will grow and can be identified.
- *sputum
- (SPYOO-tum) is a substance that contains mucus and other matter coughed out from the lungs, bronchi, and trachea.
Treatment
Most mild cases of the disease can be managed with bed rest, over-the-counter pain relievers such as acetaminophen (uh-see-tehMIH-noh-fen), and sometimes oral (by mouth) anti-fungal medication. In more serious cases in which the fungus has spread throughout the body, intravenous (in-tra-VEE-nus, or given directly into a vein) antifungal medicines and hospitalization may be necessary. Mild cases of coccidioidomycosis last about 2 weeks, but recovery may take up to 6 months in more severe cases.
Complications
Pneumonia*, arthritis, meningitis, and other serious problems can result if the infection spreads throughout the lungs or to other parts of the body, such as the liver, heart, brain, bones, or joints.
- *pneumonia
- (nu-MO-nyah) is inflammation of the lung.
Can Coccidioidomycosis Be Prevented?
No specific activities can prevent a person from becoming infected with the coccidioides fungus, other than avoiding the regions where it is found. Planting grass and paving roads may reduce dust in problem areas but will not kill the fungus.
See also
Arthritis, Infectious
Meningitis
Pneumonia
Resources
Organizations
U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA 30333. The CDC offers information about coccidioidomycosis at its website.
Telephone 800-311-3435 http://www.cdc.gov
U.S. National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894. The National Library of Medicine has a website packed with information on diseases (including coccidioidomycosis) and drugs, consumer resources, dictionaries and encyclopedias of medical terms, and directories of doctors and helpful organizations.
Telephone 888-346-3656 http://www.nlm.nih.gov