Currently in South Africa research into sudden unexpected death in infancy (SUDI) is limited. The causes
of sudden infant death syndrome (SIDS) remain obscure despite full medico-legal investigations
inclusive of autopsy, scene visit and ancillary studies. Viral infections play an important role as a
multitude of respiratory viruses have been detected in autopsy specimens and are implicated in these
deaths. The specific contribution of viruses in the events preceding SIDS still warrants deciphering.
Infancy is characterised by marked vulnerability to infections due to immaturities of the immune system
that may only resolve by the age of 24 months. Routine viral screening of all SUDI cases at Tygerberg
Forensic Pathology Service (FPS) Mortuary in Cape Town focuses on only a portion of respiratory viruses
from lung and liver tissue. This review highlights important virological and immunological aspects
regarding investigations into the infectious nature of SUDI, including the lack of national standardised
guidelines for appropriate specimen collection at autopsy and subsequent laboratory analysis.