Fungal Endocarditis: A Disease of the Heart
Pathogenic fungi cause disease by parasitizing their plant, animal or human host. In humans, some of these fungi are normally present on, or in, our bodies and only cause a problem when the bodily defenses that control them are weakened or damaged. For example, Candida albicans, a yeast which normally lives harmlessly on our skin and mucus membranes, can, in certain conditions, grow out of control and cause the mouth disease "thrush" or other "yeast infections". A specific disease or set of symptoms can sometimes be caused by one of several different potential pathogens (disease-causing organisms). Sore throats can be caused by both bacteria and viruses. Endocarditis is a heart disease that can be caused by either bacteria or fungi.
Endocarditis is an inflammation of the heart muscle, the heart’s valves, or the lining of the heart’s chambers. The disease can be caused by many different pathogens, among them the filamentous fungus, Aspergillus fumigatus, and the yeast, Candida albicans. The symptoms are very general, and typical of many physical problems. Only a physician can make an accurate diagnosis. The symptoms can include fever, weakness, chest pain, unexplained weight loss, aches, a heart murmur, blood in the urine or abnormal urine color, and straight, narrow red lines of broken blood vessels under the nails. A variety of tests, possibly including blood culture, a complete blood count (CBC) or a CT ("cat") scan of the chest, can be used to diagnose this disease. Some cases are "culture-negative", meaning no fungus or bacterium can be found. Aspergillus fumigatus and Candida albicans are opportunistic pathogens. They exploit weaknesses or lapses in the body’s defense mechanisms. Our skin is an important defense against pathogens.
These fungi enter the body through wounds, such as surgical incisions, the insertion of catheters (tubes) into already existing wounds, or the sharing of contaminated needles by drug users. As organisms, Aspergillus fumigatus and Candida albicans do not resemble one another at all. Aspergillus fumigatus is a member of a large genus of filamentous fungi. Most Aspergillus are harmless, although other species have caused allergic reactions, since many produce huge amounts of air-borne spores, called conidia, in wet or humid rooms. We often breathe in the spores in such rooms, but Aspergillus fumigatus does not cause infections when inhaled. Candida albicans belongs to the group of fungi called yeasts. It is a very distant relative of a yeast in another genus, Saccharomyces cerevisiae, used in making bread. Candida albicans does not produce air-borne spores. It spreads to new places by being carried there. The treatment of fungal endocarditis can require surgery to remove colonies of fungi from the heart, and anti-fungal drug therapy for 6-8 weeks. (As an additional note: dental patients with some types of congenital [inherited] heart problems are usually given antibiotics before a procedure to protect them from a bacterial form of this disease.)