6 - Role of co-infections in modulating disease severities and clinical phenotypes

Abstract

Humans are continually being affected by infectious diseases, which are often believed to be caused by a single pathogen. Although, in the real-world context, co-infections—where several microbial pathogens infect humans simultaneously, are more common. The co-infecting microorganisms may either aggravate or conciliate the disease severity. In spite of co-infection, infection with one pathogen disrupts the normal human microbiota, causing dysbiosis. Since the microbiome is undeniably linked to life quality and longevity, this may lead to serious disease conditions if they are present in their proliferative or active state i.e., called transcriptionally active microbes (TAMs). Understanding the multiple TAMs, in various infectious diseases can open up fresh perspectives on microbial-based infections and therapeutics. However, while the important role of the human microbiome has been established by independent research studies, including in the recent COVID-19 pandemic, little emphasis has been dedicated to examining the simultaneous co-presence and dynamics of these pathogens in disease manifestation. This chapter aims to provide a holistic view of how the co-infecting TAMs modulate the disease trajectory.