This episode explores how fungi transition from environmental organisms to human pathogens. Drawing from Murray’s Chapter 58, it focuses on host–pathogen interaction and the central role of immunity.

Unlike many bacteria and viruses, fungi are often opportunistic pathogens. Disease frequently arises when host defences are impaired - whether through neutropenia, corticosteroid use, HIV infection, transplantation, or metabolic disorders such as diabetes.

The narrative centres on three core mechanisms of fungal pathogenesis:

* Adherence and colonisation of epithelial surfaces

* Tissue invasion via hyphal penetration

* Immune evasion and modulation, including capsule formation and altered antigen exposure

Cell-mediated immunity is critical for fungal containment. Defects in T-cell or neutrophil function markedly increase susceptibility.

Conceptually, fungal disease is relational - severity depends less on inherent virulence and more on host vulnerability. Clinically, this reinforces the importance of risk stratification in immunocompromised patients.

Key Takeaways

* Fungal disease often reflects opportunism

* Cell-mediated immunity is central to defence

* Hyphal invasion enables tissue penetration

* Capsule formation may aid immune evasion

* Immunocompromised hosts are at highest risk

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe