Aspergillosis is a medical condition of a hyper sensitive reaction by an individual’s immune system upon exposure to a fungus known as “Aspergillus.”
The most common symptom is airway inflammation and other lung conditions. However, other conditions due to Aspergillosis may also include a localized infection involving the nails, feet, external auditory canal and eyes, etc. This is one of the most commonly misdiagnosed aliments. A report published in the Aspergillus Website Newsletter - September 2012 reveals that it is one of the top four misdiagnosed conditions with deadly consequences. The common symptoms of infected individuals includes, but are not limited to, cough, coughing up blood or brownish mucus plugs, fever, wheezing, weight loss, blood in urine, bone pain, chest pain, chills, decreased urine output, headaches, increased phlegm production, shortness of breath, skin sores (lesions), vision problems, etc.
Out of hundreds of known species of Aspergillus, A. fumigatus is most common in invasive, as well as, non-invasive types of “Aspergillosis.” A. flavus and A. niger are reported as the second and third most common causes of “Aspergillosis,” respectively. Other important species of Aspergillus that can cause “Aspergillosis” are A. terrus, A. amstelodomi, A. candidus, A. carneus, A. flavipes, A. nidulans, A. neveus, A. ochraceus, A. oryzae, A. repens, A. restrictus, A. sydowi, A. ustus, and A. versicolor.
Several of the above mentioned species have been reported in and around indoor environments; therefore, Aspergillus exposure is not uncommon in residential and commercial places. It has generally been observed that dwellers with a compromised or weak immune system are more prone to acquire this infection in comparison to individuals with robust immunity.
This fungus is a ubiquitous mycoflora of the environment, although, it also is reported from clinical specimens. It frequently occurs in soil, dead leaves, stored grain, breads, peanuts, dry fruits, rotting vegetables, cheese, compost piles, or in other decaying vegetation. In indoor environments, this fungus can be transported from outside or may propagate on building materials such as cellulose rich sheet rocks, etc. and can generally be isolated from floors, carpets, mattress dust, Heating Ventilation Air Conditioning (HVAC) system, etc.
This fungi can adapt to extreme conditions for their growth; however, the most favorable growth factors include, but are not limited to, moisture above 60% and a temperature around 25ºC (this is a thermophilic fungus and some species can grow at temperatures as high as 50ºC) besides organic rich compounds. Some species of these fungi are known to produce mycotoxins.
In routine investigations on environmental samples collected in and around indoor sites, the Environmental Diagnostics Laboratory at Pure Air Control Services, Inc. of Clearwater, FL (USA) has observed that Aspergillus species is one of the 10 most frequently reported fungi from indoor environments. This fungus may be categorized as environmental or clinical, based on its source. In either case, depending upon its viability, this microorganism is capable of rapid multiplication and dissemination. The air dispersal of this fungus is rather common and significant especially due to their small spore size (3-5µm). Individuals can inhale these spores easily and may sensitize themselves for Aspergillosis. Therefore, continuous environmental surveillance is essential to monitor these infectious particles from a health and hygiene point of view in and around closed structures (home, offices, etc.).
A number of techniques and methods are available for testing, both qualitatively and quantitatively, to understand the extent of Aspergillus in and around building environments such as healthcare settings, work places, offices, residences, and other habitations. The management of controlling, spreading, potential risk of exposure, and prevention of Aspergillus related infections can be facilitated by knowing the existence of these entities in our surroundings.