We have already written a column regarding the rapid increase in the number of cases of mucormycosis associated with COVID-19, particularly in India.
The visceral mycosis rarely affects individuals with no major illness; it usually develops in patients with systemic immunodeficiency (including decreased resistance to microorganisms). For example, after the organ transplants or the bone marrow transplants, patients usually receive immunosuppressive agents to prevent graft rejection. Decreased number of white blood cells from any cause may impair systemic immunity. With the advancement of medical treatment, various intractable diseases have become treatable; however, some agents such as immunosuppressive or molecular-targeted agents to treat those diseases could create different risks, including infectious diseases.
On the other hand, severe viral infection in an apparently healthy individual can be associated with the development of visceral mycosis. Influenza Associated Pulmonary Aspergillosis (IAPA), severe influenza virus infection followed by pulmonary aspergillosis, is a previously well-known disease.
Aspergillus is one of the primary fungi that often infect viscera, in particular, the lung. This pathogen is alarming because it frequently causes infection in immunosuppressive individuals such as transplant patients. Recently, many cases of COVID-19 Associated Pulmonary Aspergillosis (CAPA) have been reported. IAPA has already reported worldwide in the 1970s and is the object of much discussion again due to the issue of CAPA (Costantini C, et al. Vaccines 2020 and over 70 articles). IAPA and CAPA resemble each other in many respects, but some differences have recently been reported. Based upon the emerging new coronavirus variants and in anticipation of post-pandemic era, we need to continue further investigations.
The mechanisms of Aspergillus infection in patients with severe viral infections such as COVID-19 or influenza have not been thoroughly understood. The virus infection might cause severe damages to the bronchial epithelium that plays a role in the barrier mechanism of the human lungs. Then Aspergillus could invade the lungs.
Emerging novel viral infectious diseases are expected in the near future again. MMRC is conducting research projects and the clinical practice of mycoses in collaboration with domestic and overseas research and medical institutions.
(August 17, 2021)
