Detection of Recombinant Type of Human Adenovirus C Composed of Types 89 and 5 in Aichi Prefecture, Japan (2016-2019).

Recombinant human adenoviruses (HAdVs) have been identified in many countries, including Japan. Herein, we report a recombinant HAdV-C type detected in feces with gastroenteritis infection or throat swabs with upper respiratory tract inflammation in six children in Aichi Prefecture. This type may have been prevalent in the area. Between April 2014 and March 2019, we attempted to detect HAdVs in 9,483 specimens (feces, urine, and throat and conjunctival swabs) collected from patients with suspected viral infection. A total of 220 HAdV-C isolates were obtained and serotyped using a neutralization test (NT). Of these, 62 HAdV-C strains (HAdV-C1: 15, -C2: 19, -C5: 22, and -C6: 6) were genotyped by sequencing for the three regions, penton base, hexon, and fiber regions, respectively. All 62 strains were grouped into the same genotype as the serotype for the hexon and fiber regions. In contrast, phylogenetic analysis showed that 6 of the 22 strains with serotype HAdV-C5 were grouped into HAdV-C89 for the penton base region. This type was detected as a recombinant HAdV causing severe acute respiratory infection in China between 2017 and 2021 and has been persistently detected in the transnational Aichi Prefecture over the same period.