34
3.1 Introduction
3.1.1 Human Fungal Diseases
A number of diseases that impact human are caused by fungal infections, affecting
over one billion people worldwide (Brown et al. 2012; Guinea et al. 2010; Marr
et al. 2002). Like other microbiota, fungi also classified as helpful and harmful to
human. In the case of harmful fungi, they invade the human body and adopt to the
environment; they can be challenging to kill since the grow inside the body and
reinfect the host again. Fungal diseases affect seriously the lifetime of human, but
they are curable with antifungal drugs and different treatments invented in recent
times (Denning 2006; Nascimento et al. 2003; Arikan et al. 1999). Most of the fungal infections are harmless; in some cases fungal infections lead to life-threatening
problems that attack the blood, lungs, and other major human organs. Fungal pathogens are known to exist in the host system mainly based on the immune efficiency
of the host. Importantly patients with immunosuppression such as those with
impaired immune system (due to HIV, cancer, or undergoing treatments like chemotherapy) are at an increased risk of fungal infections (Denning 1998; Denning and
Stevens 1990; Washburn et al. 1988). Invasive aspergillosis is a severe and aggressive fungal disease that arises in severely immunocompromised hosts (Denning
1998). Aspergillus (Denning 2017), Candida (Morrissey et al. 1996), Pneumocystis
jirovecii (Carmona and Limper 2011), Cryptococcus species (Nyhus et al. 1997),
Histoplasma capsulatum (Timmerman and woods 1999), and mucormycetes (Jamed
William et al. 2006) are the most significant fungal pathogens responsible for the
majority of fungal diseases. Candida albicans is responsible for mucosal disease
(Moyes and Naglik 2011), Aspergillus fumigatus for the majority of the allergic
fungal diseases (Latge 2001), and Trichophyton spp., particularly T. rubrum, for
skin infections (Achterman and White 2013; White et al. 2014). Dermatophytosis is
a type of fungal disease caused by dermatophytes, wherein keratinophilic fungi
affect keratinized tissues of the body like the hair, nails, and skin (Carrillo-Munoz
et al. 2007; Walsh and Groll 1996; Ghannoum 2009).
3.1.2 Aspergillosis
Aspergillosis is a universal and invasive infection affecting the human respiratory
system which is caused by inhaling spores of the mold Aspergillus, existing in the
environment (Vonberg and Gastmeier 2006). Diseases caused by Aspergillus are
commonly called aspergillosis. In 1842 the very first case of human Aspergillus
infection was reported, and it was aspergilloma (Cawley 1947). Two different noninvasive types of Aspergillus disease exists, viz., aspergilloma and allergic
S. Jayapalan et al.
3.1 Introduction
3.1.1 Human Fungal Diseases
A number of diseases that impact human are caused by fungal infections, affecting
over one billion people worldwide (Brown et al. 2012; Guinea et al. 2010; Marr
et al. 2002). Like other microbiota, fungi also classified as helpful and harmful to
human. In the case of harmful fungi, they invade the human body and adopt to the
environment; they can be challenging to kill since the grow inside the body and
reinfect the host again. Fungal diseases affect seriously the lifetime of human, but
they are curable with antifungal drugs and different treatments invented in recent
times (Denning 2006; Nascimento et al. 2003; Arikan et al. 1999). Most of the fungal infections are harmless; in some cases fungal infections lead to life-threatening
problems that attack the blood, lungs, and other major human organs. Fungal pathogens are known to exist in the host system mainly based on the immune efficiency
of the host. Importantly patients with immunosuppression such as those with
impaired immune system (due to HIV, cancer, or undergoing treatments like chemotherapy) are at an increased risk of fungal infections (Denning 1998; Denning and
Stevens 1990; Washburn et al. 1988). Invasive aspergillosis is a severe and aggressive fungal disease that arises in severely immunocompromised hosts (Denning
1998). Aspergillus (Denning 2017), Candida (Morrissey et al. 1996), Pneumocystis
jirovecii (Carmona and Limper 2011), Cryptococcus species (Nyhus et al. 1997),
Histoplasma capsulatum (Timmerman and woods 1999), and mucormycetes (Jamed
William et al. 2006) are the most significant fungal pathogens responsible for the
majority of fungal diseases. Candida albicans is responsible for mucosal disease
(Moyes and Naglik 2011), Aspergillus fumigatus for the majority of the allergic
fungal diseases (Latge 2001), and Trichophyton spp., particularly T. rubrum, for
skin infections (Achterman and White 2013; White et al. 2014). Dermatophytosis is
a type of fungal disease caused by dermatophytes, wherein keratinophilic fungi
affect keratinized tissues of the body like the hair, nails, and skin (Carrillo-Munoz
et al. 2007; Walsh and Groll 1996; Ghannoum 2009).
3.1.2 Aspergillosis
Aspergillosis is a universal and invasive infection affecting the human respiratory
system which is caused by inhaling spores of the mold Aspergillus, existing in the
environment (Vonberg and Gastmeier 2006). Diseases caused by Aspergillus are
commonly called aspergillosis. In 1842 the very first case of human Aspergillus
infection was reported, and it was aspergilloma (Cawley 1947). Two different noninvasive types of Aspergillus disease exists, viz., aspergilloma and allergic
S. Jayapalan et al.