Emergence of Invasive Fungal Infection: Diagnosis and Treatment in Humans

Abstract

Fungi are a versatile group of saprophytic microorganisms that have evolved a mechanism to survive in their hosts. Infections caused by fungi are called opportunistic, as they cause no disease or mild symptoms in infected healthy individuals, but which can be fatal, life–threatening, and invasive in nature in immunocompromised individuals. In invasive fungal infections, fungi invade the deep tissues and establish themselves, where they cause prolonged illness. They pose an important health problem worldwide and are the main reason for the high rates of morbidity and mortality among immunocompromised individuals and other individuals at high risk of invasive fungal infections. Candida spp., Aspergillus spp., Cryptococcus spp., and Pneumocystis spp. are the most common species responsible for invasive fungal infections. An invasive fungal infection kills about one and half million people every year. The use of antineoplastic, immunosuppressive agents, broad-spectrum antibiotics, and antifungal agents increases the chance of invasive fungal infections. Irrespective of the large amount of recent effort being made, the treatment of invasive fungal infections is very challenging, and due to limited research in this field, the diagnosis of invasive fungal infections is also a hurdle. The objective and focus of this chapter are the invasive fungal infections in humans, diagnostic methods, and future implications of treatment of these infections, which need more research in the field to facilitate the development of better diagnostic tests, therapies, and preventive vaccines as well.