Seroreactive Profiling of Filoviruses in Chinese Bats Reveals Extensive Infection of Diverse Viruses

Abstract

Southern China is a hot spot of emerging infectious diseases, in which diverse species of bats dwell, a large group of flying mammals considered natural reservoirs for zoonotic viruses. Recently, divergent filoviruses (FiVs) have been identified in bats within this region, which pose a potential risk to public health, but the true infection situation in bats remains largely unclear. Here, 689 archived bat serum samples were analyzed by enzyme-linked immunosorbent assay (ELISA), Western blotting, and neutralization assay to investigate the seroprevalence and cross-reactivity of four divergent FiVs and two other viruses (rabies virus and Tuhoko pararubulavirus 1) of different families within the order Mononegavirales. Results showed no cross-antigenicity between FiVs and other mononegaviruses but different cross-reactivity among the FiVs themselves. The total FiV seroreactive rate was 36.3% (250/689), with infection by the indigenous Chinese FiV DH04 or an antigenically related one being the most widely and the most highly prevalent. Further viral metagenomic analysis of fruit bat tissues also identified the gene sequence of a novel FiV. These results indicate the likely prevalence of other so far unidentified FiVs within the Chinese bat population, with frugivorous Rousettus leschenaultii and Eonycteris spelaea bats and insectivorous Myotis horsfieldii and Miniopterus schreibersii bats being their major reservoirs. IMPORTANCE Bats are natural hosts of many FiVs, from which diverse FiVs were serologically or virologically detected in Africa, Europe, and East Asia. Recently, very divergent FiVs were identified in the Chinese bat population, but their antigenic relationship with other known FiVs remains unknown. Here, we conducted serological characterization and investigation of Chinese indigenous FiVs and prototypes of other viruses in bats. Results indicated that Chinese indigenous FiVs are antigenically distant to other FiVs, and infection of novel or multiple FiVs occurred in Chinese bats, with FiV DH04 or an antigenically related one being the most widely and the most highly prevalent. Additionally, besides Rousettus leschenaultii and Eonycteris spelaea bats, the insectivorous Myotis horsfieldii and M. schreibersii bats are highly preferential hosts of FiVs. Seroreactive and viral metagenomic results indicated that more as yet unknown bat-borne FiVs circulate in Southern China, and to uncover them further, investigation and timely surveillance is needed.

Bat-borne virus diversity, spillover and emergence

“…The identification of viruses related to Ebola virus in various bat species, including the novel Bombali virus, has provided additional support for bats as reservoirs for Ebola viruses and, even though there are no reports of filovirus haemorrhagic fever in China, filoviruses have also been identified in Rousettus spp. bats in China 139 . Thus, further research is needed to confirm host species range and the potential for human infection 25 .…”

De-heterogeneity of the eukaryotic viral reference database (EVRD) improves the accuracy and efficiency of viromic analysis

“…Compared to the results revealed using reads, 22 viral families were lost including Filoviridae that has proved to be present in samples (38). The annotation using EVRD-nt excluded the false positives of Caliciviridae, Reoviridae and Herpesviridae in certain datasets, indicating an improvement of accuracy at the contig level.…”

“…First, reasonable bioinformatic pipelines should be implemented for different purposes. Annotation using reads provides richer information than using contigs, especially for ultra-low abundant viruses (38, 42), hence could be considered in viral disease diagnosis. But sequence completeness is a priority in viral ecology, thus assembly is preferentially performed before annotation (26).…”

Epidemiological Aspects, Control and Prophylaxis of the Rabies Virus: A Literature Review

“…In the studies by ZHANG et al (2020), in which when performing the profile of Filovirus seroreactive in Chinese bats, an extensive infection of several viruses was evidenced. Furthermore, it is worth noting that southern China is the origin of several emerging infectious diseases, with bats being the main natural reservoirs of these zoonoses.…”