Re-emergent Human Adenovirus Genome Type 7d Caused an Acute Respiratory Disease Outbreak in Southern China After a Twenty-one Year Absence

Abstract

Human adenoviruses (HAdVs) are highly contagious pathogens causing acute respiratory disease (ARD), among other illnesses. Of the ARD genotypes, HAdV-7 presents with more severe morbidity and higher mortality than the others. We report the isolation and identification of a genome type HAdV-7d (DG01_2011) from a recent outbreak in Southern China. Genome sequencing, phylogenetic analysis, and restriction endonuclease analysis (REA) comparisons with past pathogens indicate HAdV-7d has re-emerged in Southern China after an absence of twenty-one years. Recombination analysis reveals this genome differs from the 1950s-era prototype and vaccine strains by a lateral gene transfer, substituting the coding region for the L1 52/55 kDa DNA packaging protein from HAdV-16. DG01_2011 descends from both a strain circulating in Southwestern China (2010) and a strain from Shaanxi causing a fatality and outbreak (Northwestern China; 2009). Due to the higher morbidity and mortality rates associated with HAdV-7, the surveillance, identification, and characterization of these strains in population-dense China by REA and/or whole genome sequencing are strongly indicated. With these accurate identifications of specific HAdV types and an epidemiological database of regional HAdV pathogens, along with the HAdV genome stability noted across time and space, the development, availability, and deployment of appropriate vaccines are needed.

Severe Infections with Human Adenovirus 7d in 2 Adults in Family, Illinois, USA, 2014

“…Our molecular typing findings suggest that genome type 7d might be circulating in the United States as a recently introduced newly emerging variant probably imported from Southeast Asia where increased incidence of severe HAdV7-associated respiratory disease has been reported ( 11 , 12 , 14 ). The 2 patients in this study had not traveled outside the United States and had not had contact with persons who recently traveled to Asia.…”

“…A comparison between these profiles (Figure 3, panel A) and the corresponding in silico−generated profiles for HAdV7 genomic sequences available from GenBank (accession nos. KC440171 [Figure 3, panel B], JF800905, JX625134, KC857700, and KJ019880−KJ019888), and phylogenetic analysis of hexon and fiber gene sequences performed by using MEGA version 6.0 software ( 10 ) (Figure 3, panels C, D) showed a close relationship of the strain from Illinois with strains described in association with cases of severe pneumonia recently reported in difference provinces in China ( 11 ) and in Taiwan ( 12 ). …”

“…This issue merits further investigation. Severe respiratory disease has been reported in association with various genomic variants of HAdV7 ( 1 , 11 , 15 ), which suggests that the severity of HAdV-associated disease might also be attributable to population or individual host differences in susceptibility. Although patient 1 did not have an unusual medical history, patient 2 had concurrent conditions that might have contributed to severity of disease.…”

Fatal Community-acquired Pneumonia in Children Caused by Re-emergent Human Adenovirus 7d Associated with Higher Severity of Illness and Fatality Rate

“…Human adenoviruses (HAdVs) are highly contagious pathogens and associated with a broad spectrum of human diseases, such as acute respiratory disease (ARD), including bronchopneumonia, community-acquired pneumonia (CAP) and upper respiratory tract infection1234. The infections in immunocompetent individuals are usually mild and self-limiting, but more and more severe and even fatal cases in children and immunocompetent adults caused by emergent and re-emergent HAdV types have been reported135678910.…”

“…The infections in immunocompetent individuals are usually mild and self-limiting, but more and more severe and even fatal cases in children and immunocompetent adults caused by emergent and re-emergent HAdV types have been reported135678910.…”