Outbreak of severe acute respiratory infections caused by recombinant human adenovirus type B 7/3 in hospitalized infants from a nursery in Dakar, April 2024

Objectives

Acute respiratory infections are among the leading cause of mortality in children under 5 years of age worldwide, with most of these deaths due to bronchiolitis and pneumonia. We investigated and analyzed a pediatric outbreak of acute respiratory infections that resulted in the hospitalization of four infants in a nursery in Dakar in late April 2024.

Methods

Nasopharyngeal specimens were collected from infants and tested for a panel of respiratory pathogens by multiplex real-time reverse transcription–polymerase chain reaction. Subsequently, the positive samples underwent next-generation sequencing for molecular analysis.

Results

Human adenovirus (HAdV) was the principal etiologic agent detected in hospitalized infants with pneumonia and nearly half (46.7%; seven of 15) of the suspected cases identified during the investigation at the nursery. All the HAdV isolates were classified as being of subgroup B1. Molecular characterization revealed that infants attending the nursery were infected with a recombinant HAdV strain containing an adenovirus serotype 7 penton and serotype 3 hexon and fiber proteins.

Conclusions

Our findings reinforce previous evidence that recombination leads to the emergence of new adenovirus strains with epidemic and lethal potential. These results emphasize the need to strengthen surveillance in inpatient settings across the country.