Type A influenza: postmortem virus isolations from different organs in human lethal cases

Area of Science:

• Virology
• Pathology
• Neurology

Background:

• Influenza is a significant cause of mortality worldwide.
• The systemic spread and organ involvement of influenza viruses are not fully understood.
• Previous studies have primarily focused on respiratory manifestations.

Purpose of the Study:

• To investigate the presence and distribution of influenza viruses in various organs of patients who died from influenza.
• To determine the correlation between viral detection and histopathological findings.
• To assess the extent of systemic viral dissemination in lethal influenza cases.

Main Methods:

• Virological examination of trachea, lung, liver, spleen, pancreas, and brain from 77 deceased patients.
• Histopathological analysis of affected tissues.
• Isolation and characterization of influenza A virus strains.
• Immunofluorescence staining to detect influenza antigen in brain tissue.

Main Results:

• Type A influenza viruses were isolated from 12 out of 77 lethal cases.
• Viral presence was detected in organs beyond the respiratory tract in 10 of these cases.
• The brain was the most frequently affected non-respiratory organ.
• Influenza antigen was confirmed in brain tissue via immunofluorescence.

Conclusions:

• Influenza A virus can disseminate systemically, reaching organs such as the brain in fatal cases.
• Detection of influenza virus in non-respiratory organs highlights the potential for widespread organ involvement.
• These findings underscore the importance of considering systemic influenza infection in post-mortem investigations.