Common viral illnesses in intensive care: presentation, diagnosis, and management

Early references to viral illnesses are found in ancient Egyptian texts with stone tablet depictions of patients suffering from poliomyelitis. Despite this, early experimentation into viral infections, led by Jenner, did not begin until 1798 with later contributions from Pasteur in the early 1880s. Viruses as a distinct biological entity, however, were not discovered until 1892 when Ivanovsky identified non-bacterial pathogens affecting tobacco plants. Subsequent work by Beijerink, Loeffler, and Frosch in 1898 distinguished the tobacco mosaic disease and footand-mouth disease agents from pathogenic bacteria and recorded their ‘obligate parasite’ nature. The first recorded human illness to be confirmed of viral origin was yellow fever in 1901, a discovery made by Reed et al. Since then, large numbers of viral pathogens have been identified. This review does not attempt to be exhaustive but deals with some of the more common viral illnesses that can necessitate ICU admission. Despite this, there remain notable exclusions including arboviruses (including those which cause viral haemorrhagic fever), zoonotic viruses (including rabies), and the hepatitis viruses, which could in themselves constitute a review article. In cases where rare viruses are the cause for ICU admission and where the patient is immunocompromised, early involvement from a medical virologist or medical microbiologist is required.