Definition Histoplasmosis is an infection caused by a fungus, Histoplasma capsulatum. The lungs are the usual site of the infection.
What is going on in the body? Histoplasmosis occurs in many areas of the world. It is very rare in Australia with a few cases reported around Rockhampton. The fungus is found in soil that is contaminated with bird or bat droppings, and usually gets into the body when it is inhaled into the lungs.
What are the signs and symptoms of the infection? Some infected people have no symptoms. Most of the time the disease causes symptoms of cough, with or without fever. Other symptoms can include diarrhoea and a rash. The disease can disseminate or spread throughout the body in young children and in those who are immuno-compromised. They may develop an enlarged liver or spleen and swollen lymph nodes. Some individuals develop a central nervous system infection, which can cause changes in mental status and behaviour.
What are the causes and risks of the infection? The very young and people with weakened immune systems may have more severe disease. Persons with HIV infection are particularly vulnerable to histoplasmosis.
What can be done to prevent the infection? Soil that is contaminated with bird or bat droppings should be avoided.
How is the infection diagnosed? The organism can be cultured from infected specimens from the body. In addition, the fungus can be seen in tissue samples with the help of a microscope. There is also a test that can detect the fungus in urine or blood. Usually specific antibodies, or molecules that react with the fungus, can be detected in the blood. Special tests can be used to help identify the organism in the microbiology laboratory.
What are the long-term effects of the infection? Long term effects range from mild symptoms that go away by themselves, to severe respiratory insufficiency and even death.
What are the risks to others? The disease is not spread from person to person.
What are the treatments for the infection? Most cases of the infection have few complications and do not need to be treated. More serious cases should be treated with amphotericin B, fluconazole, or itraconazole.
What are the side effects of the treatments? The most common side effects of amphotericin B use are chills, fever, low blood pressure and kidney damage. Fluconazole and itraconazole may cause problems with the liver.
What happens after treatment for the infection? People with HIV infection may need to remain on life-long therapy to prevent relapse of the histoplasmosis.
How is the infection monitored? Any recurrence of symptoms should be reported to the doctor. Special blood tests can be used to detect relapse.
Author: Danielle Zerr, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
