The field of science that deals with study of Fungus is called as mycology where “myco” is derived from the Greek term “mykos” meaning fungus.
What are the Properties of Fungus?
- Fungi are uni-cellular or multi-cellular Eukaryote organisms.
- The cell wall are rigid and are made up of Chitin, Mannan and other polysaccharides.
- The cell membrane contain Ergosterol.
- They possess true nuclei with nuclear membranes and paired chromosomes.
- They divide asexually or sexually or may even multiply by both processes.
- The fungi are environmental saprophytes, meaning, they are present in organic matters in the environment.
- Not all fungi cause disease into humans, only some are pathogenic to humans, and some may be cause disease only if the body immunity gets low.
Broad classification of fungi
Fungi can be divided into any of the following broad categories based on their anatomical arrangement
- Yeast like
- Dimorphic fungi – can stay as fungi in some temperatures, and as moulds in some temperatures.
Why are Fungal disease so rare?
Fungi were recognized as causative agents of human disease even before bacteria. Fungi causing Favus (Trichophyton Schonleinii) and Thrush (Candida Albicans) were described as early as in 1839.
If you look around you, how many times have you heard of someone dying of fungal infections or entering a life threatening situation due to fungal infection ? The answers to these questions will be “rarely“. This is because, the immune system of a normal healthy individual is strong enough to eliminate and kill most of the fungal infections quickly or over a short interval of time.
Most of the fungi are present as saprophytes in soil. Fungal infections are extremely common and only some of them cause fatal or severe diseases. Human mycotic infections are mainly opportunistic.
Only some fungi are capable of causing diseases in a healthy human body. And most fungal infections are caused in patients with decreased immune system. these individuals with a decreased immune system are termed as “immunocompromissed individuals“
Who are at increased risk of fungal infections?
- People with uncontrolled diabetes
- Patients with long stay in ICU or on ventilators
- Patients with Kidney or Liver failure
- Patients who are high dose Steroids.
- Patients who are cancer patients or are receiving cancer treatment such as radiotherapy and chemotherapy
In todays world, the widespread use of anti-bioitcs, steroids, and immunosuppressive agents has reportedly led to an increase in opportunistic fungal infections.
FUNGI causing Diseases in Humans-
- Superficial Fungal infections
- Ptyriasis versicolor (tinea versicolor)
- Tinea nigra
- Deep fungal infections
- Fungal infection below the skin epidermis-
- Subcutaneous zygomycoses
- Systemic fungal infections
- Primary systemic fungal infectiosn
- Opportunistic fungal infections
As the name suggests, these infections occur only in individuals when their immunity gets low. Hence are called opportunistic infections as they wait for the opportunity to cause infections. In a healthy individual they might now even show the slightest of symptoms.
- Zygomycosis –
- Pneumocystis jirovenci
Some Common fungal infections
As discussed above, fungal infections are quite common, and many of your might have had a fungal skin infection which with minor treatment of maybe without any treatment went off. Here is the list of some common fungal infections which are quite common in the society-
- Dandruff (aka Seborrheic dermatitis) – tinea versicolor or pityriases versicolor
- Ringworm (aka tinea) – dermatophytoses
- Madura foot (aka maduramycosis) – mycetomase
- Histoplasmosis – histoplasma capsulatum
- Candidiasis – candida albicans, candida tropicalis, candida glabrata, candida krusei and others
- Fungal infection of transplant reciepients and cancer pateitns – cryptococcosis
- Mucormycosis (aka Black fungus disease)- rhizopus, mucor, absidia
- ABPA (allergic bronchopulmonary aspergillosis) – aspergillus
How are fungal infections detected?
In most cases, the detection of fungal infections is clinical in case of skin infections.
In case of deeper or systemic fungal infections, a sample of the affected organ may be required. This is is eiither taken using a swab or a biopsy. This sample taken is then undergone staining and culture. These processes help in enhancement of fungi and help us to see them better under microscope.
In some cases, the presence of anti-bodies in blood is used in order to get a clue about the fungal infection in the body. This is done by means of various processes called as agglutination, compliment fixation, immuno-fixation, counter immunoelectrophoresis, ELISA or indirect fluorescent antibody.
A specific group of drugs known as Anti-Fungal are used to kill the fungi.
These anti fungal medications act either by damaging the cell wall of fungi or inhibiting the formation of compounds necessary for formation of cell walls or damaging the nuclear proteins of the fungus. Some examples of anti-fungal medications include Amphotericin-B, Clotimazole, Griesofulvrin etc.
Antibiotics are useless against the fungal infections. Hence use of antibiotics in case of fungal infections will not only increase chance of side effects of the anti-biotics but also increase the chances of risk of formation of resistance in bacteria against anti biotics.