Fatal pneumonia cases caused by human adenovirus 55 in immunocompetent adults

Background: Adenovirus is a frequent cause of mild self-limiting upper respiratory tract infection, gastroenteritis, and conjunctivitis. Severe or fatal infection mostly occurs in newborn, elderly or immunocompromised persons. Methods: Fatal adenovirus pneumonia in three immunocompetent adults was identified. The clinical data and virological findings were reported from patients. Additional review of recently recorded fatal patients with adenovirus infection was carried out. Results: The patients presented with sudden onset respiratory distress that progressed rapidly to respiratory failure and death. Human adenovirus (HAdV)-55 was detected in both nasopharyngeal aspirates and serum samples in all three cases, and moreover detected in lung, liver, and kidney in one case. In another case, remarkably elevated aspartate aminotransferase, alanine transaminase, and lactate dehydrogenase were identified. Three HAdV-55 strains were isolated and genome sequencing revealed a high similarity with other strains from mild infection. Conclusions: Fatal infection with HAdv-55 might occur in otherwise healthy adults. Diagnosis of adenovirus infection should be considered in patients with severe pneumonia yielding negative bacterial culture and presenting no response to antibiotic therapy.