RESUMO
In April 2019, a suspect cluster of enterovirus cases was reported in a neonatology department in Guangdong, China, resulting in five deaths. We aimed to investigate the pathogen profiles in fatal cases, the circulation and transmission pattern of the viruses by combining metatranscriptomic, phylogenetic, and epidemiological analyses. Metatranscriptomic sequencing was used to characterize the enteroviruses. Clinical and environmental surveillance in the local population was performed to understand the prevalence and genetic diversity of the viruses in the local population. The possible source(s), evolution, transmission, and recombination of the viruses were investigated by incorporating genomes from the current outbreak, from local retrospective surveillance, and from public databases. Metatranscriptomic analysis identified Echovirus 11 (E11) in three fatal cases. Seroprevalence of neutralization antibody to E11 was 35 to 44 per cent in 3-15 age groups of general population, and the viruses were associated with various clinical symptoms. From the viral phylogeny, nosocomial transmissions were identified and all E11 2019 outbreak strains were closely related with E11 strains circulating in local population 2017-19. Frequent recombination occurred among the 2019 Guangdong E11 outbreak strains and various genotypes in enterovirus B species. This study provides an example of combining advanced genetic technology and epidemiological surveillance in pathogen diagnosis, source(s), and transmission tracing during an infectious disease outbreak. The result highlights the hidden E11 circulation and the risk of viral transmission and infection in the young age population in China. Frequent recombination between Guangdong-like strains and other enterovirus genotypes also implies the prevalence of these emerging E11 strains.
RESUMO
Human metapneumovirus (hMPV), first identified in 2001, is a major viral respiratory pathogen that worldwide reported. Fundamental questions concerning the dynamics of viral evolution and transmission at both regional and global scales remain unanswered. In this study, we obtained 32 G gene and 51 F gene sequences of hMPV in Guangzhou, China in 2013-2017. Temporal and spatial phylogenetic analyses were undertaken by incorporating publicly available hMPV G gene (978) and F gene (767) sequences. The phylogenetic results show different global distribution patterns of hMPV before 1990, 1990-2005, and 2006-2017. A sharply increasing hMPV positive rate (11%) was detected in Guangzhou 2017, mainly caused by the B1 lineage of hMPV. A close phylogenetic relation was observed between hMPV strains from China and Japan, suggesting frequent hMPV transmissions between these regions. These results provide new insights into hMPV evolution, transmission, and spatial distribution and highlight Asia as a new epicenter for viral transmission and novel variant seeding after the year 2005. Conducting molecular surveillance of hMPV in Asian countries is critical for understanding the global circulation of hMPV and future vaccine design.
