The Pathogenic Side of the Species

 

 

Diseases caused by the genus Aspergillus are named aspergillosis. This includes invasion and damage of tissues in an animal that can be widespread and rapidly fatal.  For emphasis, aspergillosis is the second most common fungal infection requiring hospitalization (Smith 1994). The fungus can cause infections in any type of tissue, even the brain, but the lungs are where it is most common. Two types of aspergillosis are observed: allergic and invasive aspergillosis, both mentioned further in detail below. The symptoms of each type vary from no symptoms to life-threatening.

 

 

Could it be you?

People infected with Aspergillosis are usually immunocompromised but can be in health individuals. For clarity, the term immunocompromised can describe persons with Asthma or Cystic Fibrosis, people who have had an organ transplant or bone marrow transplant, people on chemotherapy, or those taking high doses of corticosteroids, plus several others. To put this into perspective, up to five percent of adults with asthma get aspergillosis at some time in his or her life (Rhodes n.d.).

 

As well as humans, other animals can suffer from this type of infection. Colonization of Aspergillus fumigatus can be found in horses, cows, dogs, cats, and birds. In most of these animals listed above, infection rates average between five and ten percent of a population (Bennet, J.W. and M.A. Klich 1992), yet it is much higher in avian populations. Some reasoning for this is also mentioned in the adaptations section. The picture to the left is a duck lung infected with this species of Aspergillus.

 

 

 

How do you get this fungus in you?

In order to get aspergillosis, you must breathe in fungal spores of Aspergillus, commonly Aspergillus fumigatus. These spores are found everywhere, and most people breath these spores into their bodies everyday. They are most commonly found in environments with soil or dust (i.e. building renovation or construction). Rarely, skin infections can be caused from contact with contaminated biomedical devices as well. Incubation times vary, but there are a few symptoms to watch for if the spores do colonize in your body. Many develop symptoms much like allergic reactions such as runny nose, itchy eyes, or swelling of the throat in the case of allergic aspergillosis. People with invasive aspergillosis usually have nose stuffiness, headache, facial discomfort, cough (often with blood), fever, and chest pain, but in people with a normal immune system, the first three of these symptoms listed are most common. However, some people don’t have any symptoms at all.

 

How does the doctor know?

Diagnosis is based on x-rays, CT scans, and fungal cultures. The images can be read by the appearance of an aspergilloma, a tumor made of Aspergillus fungus. This is often found in a place where scars or unnatural crevices are present (i.e. a dip in the lung or bronchi membrane made by prior Tuberculosis infection).

 

 

How is it treated?

Antifungal drugs are used such as voriconazole, itraconazole, lipid amphotericin formulations, micrafungin, or posaconazole. Sometimes doctors will take patients off of immunosuppressant drugs, causing the natural immune system to recognize the invasion of disease. Other treatments include surgery, which can be quite difficult for the patient and the surgeon.  

 

Can you prevent it?

The spores are found everywhere, so it is impossible to totally prevent it. Several suggestions are advised for those who are immunosuppressed. This means minimizing dusty environment exposure, avoiding garden and lawn work, using HEPA filtration, or using N95 masks. If exposure is unavoidable, prophylactic antifungal medication is available too. The mycotoxins produced from this fungus cause disease, and unfortunately, acquired immunity occurrences are not known to happen in the animal species' mentioned here.

 

 

If this and other disease interest you, look at tooth-decaying bacteria, the cause of malaria, flesh-eating bacteria, the cause of Lyme disease, bubonic plague, pneumonia, or whooping cough. 

For more information regarding aspergillosis and Aspergillus fumigatus, visit the following links: http://www.doctorfungus.org/thefungi/aspergillus_fumigatus.htm, http://www.cdc.gov/nczved/dfbmd/disease_listing/aspergillosis_gi.html, or http://www.aspergillus.org.uk/indexhome.htm?languages/index.php~main.