Distribution and genetic diversity of adeno-associated viruses in bats from coastal areas of Southeast China

Changqiang Zhu,Heng Lv,Fuqiang Ye,Bin Zhang,Chunhui Wang,Weilong Tan,Lele Ai,Ruichen Lv,Bo Li,Ting Wu,Chenxi Ding,Lu Yang,Changjun Wang,Jiahong Wu,Dan Hu

doi:10.1038/s41598-020-60721-z

Abstract

Bats are associated with several important zoonotic viruses from different families. One example includes adeno-associated viruses (AAVs), that are extensively detected in several animals, especially primates. To understand AAVs distribution and genetic diversity in the coastal areas of Southeast China, a total of 415 intestine samples were mostly collected from two provinces of southeast China, i.e., Zhejiang and Fujian province. Intestine samples from five bat species were collected for AAVs detection. The average prevalence rate for AAV detection among these samples was 18.6% (77 positives out of 415 samples) and ranged from 11.8 to 28.9% between the five bat species. This suggests that AAVs are widely distributed in diverse bat populations in southeast coastal areas of China. Based on the genome sequence of bat adeno-associated virus-CXC1(BtAAV-CXC1) from one AAV-positive sample, the genetic diversity of the detected AAVs were assessed and analyzed. Phylogenetic analysis revealed that BtAAV-CXC1 was comparatively distant to other major AAVs from mammals and non-mammals, with only a 52.9~64.7% nucleotide identity. However, they were phylogenetically closer to Rhinolophus sinicus bat adeno-associated virus (Rs-BtAAV1), with a 74.5% nt similarity. Partial analysis of the rep and cap overlapping open reading frame (ORF) sequences from bat AAV samples revealed 48 partial rep sequences and 23 partial cap sequences from positive samples shared 86.9 to 100% and 72.3 to 98.8% nucleotide identities among themselves, respectively. This suggests that the detected AAVs had a distinctly high genetic diversity. These findings led us to conclude that diverse AAVs may be widely distributed in bat populations from the southeast regions of China.

Highlights

Adeno-associated viruses (AAVs) were discovered in 1965 as a small contaminant
Among all four bat species, the virus detection rate for Rhinolophus pusillus was the highest (4 locations out of 6), followed by Myotis davidii, Rhinolophus ferrumequinum and Scotophilus kuhli. These results demonstrated that AAVs were widely distributed in diverse bat populations in southeast coastal regions of China (Table 1)
Adeno-associated viruses were detected from the majority of bats collected from the southeastern coastal regions of China

Summary

Introduction

Adeno-associated viruses (AAVs) were discovered in 1965 as a small contaminant. AAVs are a group of small single-stranded DNA (ssDNA) viruses without envelopes that belong to the parvovirus family. The genetic diversity of AAV is very high among its natural hosts. Bats have been increasingly recognized as a natural host for AAVs in recent years, in addition to the many other important zoonotic viruses, such as SARS, MERS, and Ebola virus[28,29,30,31]. With the development of molecular and sequencing technologies, numerous novel AAVs are being discovered Yan Li identified several adenoviruses and AAVs in a wide host range of bat species with remarkable genetic diversity[14]. Several novel bat-associated viruses in southeast China were annotated through metagenomic sequencing technology[36], including coronavirus, norovirus, adenovirus, bocavirus, astrovirus, circovirus, and adeno-associated viruses. Our study could enrich the understanding of bats as a pathogen library and provided new insights into the transmission of AAV from bats to humans

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