Fungal infections are either opportunistic or endemic ubiquitous fungi that exist freely in the environment cause endemic fungal infections. On the other hand, opportunistic fungal infections only cause disease when the immune system degrades . Opportunistic fungi are commensal with the host and a very low intrinsic virulence to cause until the immunity is altered. Some of these include: Candida species, Aspergillus species, pneumocystic jirovecii and Cyptococcus neoformans. These disseminate diseases such as: oral candidiasis (oral thrush), genito-urinary disease and ocular or sinus infections which may spread to involve the Central Nervous system . Opportunistic fungal infections are mainly immunocompromised individuals such as: those with HIV, extensive surgery, haematological disorders, and those who have corticosteroids, cytotoxic and suppressive chemotherapy. As a result, their neutrophils drop to abnormal counts, a conditioning know as neutropenia. This state predisposes these patients to many opportunistic fungal infections such as: candidiasis, aspergillosis, cryptococcosis and pneumocystis among others .
Candidiasis is a common fungal infection in immunocompromised individuals caused by Candida albicans- a normal oral flora in the genitourinary tract, gastrointestinal tract and on the skin. It form bio films on any surface and cause both mucosal and systemic infections in immunocompromised hosts disseminated as: oral thrush, vulvovaginitis, endocarditis among others . Although Candida albicans still remains the major cause of nosocomial infections, other non albicans candida species such as: Candida glabrata, Candida tropicalis and Candida parapsilosis are increasingly becoming common. According to Pfaller et al., 2007, Candida glabrata was the second most cause of invasive infections in the USA while the ARTEMIS Global Antifungal Surveillance Program revealed that Candida albicans was the major cause of fungal infections followed by Candida glabrata, Candida tropicalis, and Candida parapsilosis respectively. The major predisposing factors to candidiasis are: T-Lymphocyte deficit, renal dysfunction, HIV infection, cancer, treatment with immunosuppressive drugs and organ transplantation.
According to Levy et al., 2009, HIV infection lowers the CD4+ and CD8+ T cells of the host leading to decreased levels of phagocytic and cytotoxic cell which are vital cells in anti-fungal immunity.
As a result, Candida albicans uses its yeast-hyphal switch to penetrate into deep epithelial walls and endothelia human tissues to cause disease. In addition, Candida albicans possesses cAMP dependant pathways such as Efg1  transcription factor that controls and regulates its morphogenesis and secretes putative virulent factors such as phospholipase A,B and C which are hydrolytic enzymes and proteinases that destroy many host factors, speed up the yeast's host adherence and penetration [19, 20].