Adenovirus infections

Adenoviruses are endemic, primarily causing respiratory and ocular (pharyngoconjunctival fever) symptoms and gastroenteritis in infants and children. They also cause epidemic keratoconjunctivitis, pneumonia in military recruits and severe, life-threatening infections in transplant recipients. The hardy non-enveloped virus resists environmental degradation and is transmitted by aerosolized droplets, fomites and faecal-oral spread. Outbreaks occur in medical, day care, military and other facilities where people live in close proximity. Diagnosis is predominantly by nucleic acid amplification technology. Molecular species identification and typing are not used in routine clinical practice, but are important for investigating outbreaks and as research tools. Most infections are subclinical or self-limiting when symptomatic, but adenoviruses cause significant morbidity and mortality, especially in paediatric haemopoietic stem cell transplant (HSCT) recipients. No effective treatment is available. Routine viral load surveillance of high-risk HSCT patients is advocated, with high or increasing levels of viraemia prompting, where possible, a reduction in immunosuppression as first-line management. The antiviral agent cidofovir, is active against adenoviruses in vitro, but is not licensed for this indication. Pre-emptive therapy with cidofovir may reduce plasma viral loads, but whether it reduces mortality is less certain. It remains to be seen whether brincidofovir, the oral pro-drug of cidofovir, currently under development, will be effective in pre-empting severe or fatal disease.