Molecular phylogeny of a novel human adenovirus type 8 strain causing a prolonged, multi-state keratoconjunctivitis epidemic in Germany

Abstract

The German infectious disease surveillance system revealed an increase of epidemic keratoconjunctivitis (EKC) from an average of 320 cases/year (2001 to 2010) up to 2146 and 1986 cases in 2012 and 2013, respectively. From November 2011 until December 2013 (epidemic period) 85% of typed isolates were human adenovirus type 8 (HAdV-D8), whereas only low level circulation (19%) of HAdV-D8 was observed outside the epidemic period. In order to investigate whether a novel monophyletic HAdV-D8 strain prevailed during the epidemic period, complete genomic sequences of 23 HAdV-D8 isolates were generated by deep sequencing and analyzed phylogenetically. For comparison, eight HAdV-D8 isolates from outside the epidemic period were sequenced. HAdV-D8 isolates of the epidemic period had a very high sequence identity of at least 99.9% and formed a monophyletic cluster with two subclusters. A single outlier was closely related to HAdV-D8 strains isolated prior to the epidemic period. Circulation of the epidemic strain was detected as early as 2010 but not after the epidemic period in 2014. In conclusion, molecular phylogeny of complete genomic sequences proved a monophyletic HAdV-D8 epidemic. However, co-circulation of other HAdV types as well as better reporting may have contributed to the huge increase of reported cases.

<p>Epidemiology of Human Adenoviruses: A 20-Year Retrospective Observational Study in Hospitalized Patients in Bern, Switzerland</p>

“…25 Our finding is also consistent with other studies that showed HAdV8 to be a major culprit of adenovirus-associated conjunctivitis. 9,26,27 In addition, the predominance of HAdV species C genotypes, particularly HAdV1 and HAdV2, found among young children is also supported by other studies. 28 As young children have developing immune system, they may be more prone to infections.…”

Molecular typing of conjunctivitis‐causing adenoviruses in Hanoi, Vietnam from 2017 to 2019 and complete genome analysis of the most prevalent type (HAdV‐8)

“…The HAdV‐8 strains were also the major cause of many conjunctivitis outbreaks in different populations around the world such as in Tunisia, 39 China, 40 South Korea, 41 Brazil, 42 India, 39 and Germany 34 . Detailed sequence comparisons among HAdV‐8 in Vietnam (VN2017) with 60 other HAdV‐8 genomes isolated from various parts of the world (Figure 3) revealed that the genome of VN2017 had high nucleotide sequence homology with HAdV‐8 genomes in the International cluster including HAdV‐8 from Japan (99.80%), Saudi Arabia (99.80%), Germany (99.78%), and United States (99.79%).…”

Molecular typing and whole genome next generation sequencing of human adenovirus 8 strains recovered from four 2012 outbreaks of keratoconjunctivitis in New York State

“…HAdV‐D8 is the most frequently reported type among confirmed cases of EKC . It was first isolated in the United States in 1955, during an outbreak of conjunctivitis in a shipyard .…”

“…13 HAdV-D8 is the most frequently reported type among confirmed cases of EKC. [14][15][16] It was first isolated in the United States in 1955, during an outbreak of conjunctivitis in a shipyard. 17 The isolated strain was designated as the prototype and named Trim (AB448767).…”