How much of a public health threat is the emerging novel rabies virus? （3）

　　 Foreword: Nine internationally renowned rabies experts from 5 countries, including the United Kingdom, South Africa, France, Germany, and the United States, jointly published a review paper on the newly emerging new rabies virus (Lisha virus) in the professional magazine Viruses.

The new rabies virus is basically hosted by bats. Since the global pandemic of the new crown virus, the study of pathogens in bats around the world has entered a new stage, and further advanced the in-depth study of bat rabies virus. This article is a summary of the results of this research, introduces the possible threat to public health posed by the emerging novel Lisha virus, and makes recommendations for future research directions.

This blog will continue to translate the main content of this article.

Table of Contents:

summary

1. Preface

2. The growing diversity of Lisa virus

3. Are miniopterus bats a source of genetically diverse Lisa virus?

4. Bat Lisa virus found in Lleida, France

5. West Caucasian bat virus found in Italy

6. Matlo bat Lisa virus in the Republic of South Africa

7. Bat host association analysis

8. Availability of bat Lisa virus vaccine

9. The emerging Lisa virus

10. Conclusion

bibliography

2. Growing diversity of Lisa virus (1)

Lisa viruses are classified as family Rhabdoviridae of order Mononegavirales. Within the Lyssavirus genus, The International Committee on Taxonomy of Viruses (ICTV) has identified 17 different Species of Lisa virus. According to the genome sequence, they are classified as independent species, including: Aravan lyssavirus (ARAV); Australian bat lyssavirus (ABLV); Bokeloh bat lyssavirus (BBLV); Duvenhage lyssavirus (DUVV); European bat 1 lyssavirus (EBLV-1); European bat Lisa virus type 2 (European bat 1 lyssavirus, EBLV-2); Gannoruwa bat lyssavirus (GBLV); Ikoma lyssavirus (IKOV); Irkut lyssavirus (IRKV); Kujad lisha virus (Khujand lyssavirus, KHUV); Lagos bat lyssavirus (LBV); Lleida bat lyssavirus (LLEBV); Mokola Lisa virus (Mokola lyssavirus, MOKV); Rabies lyssavirus (RABV, the most common classic rabies virus); Shimoni bat lyssavirus (SHIBV); Taiwan bat lyssavirus (TWBLV); West Caucasian bat lyssavirus (WCBV).

Another new type of Lisa virus, Kotalahti bat lyssavirus (KBLV), was detected in a Myotis brandtii in Finland. There is also a potential new type of Lisa virus, tentatively named Matlo bat lyssavirus (MBLV), whose two sequences have been reported but remain tentative until fully identified. In addition to being classified by species, these viruses can be classified as different genetic lineages (phylogroups) using nucleoprotein genes, phylogenetic and antigenic data, depending on genetics.

Through systematic topological analysis, at least two genetic lineages can be identified (Figure 1). The phylogenetic tree of genetic lineage I is divided into two main branches, one of which includes palearctic and indo-Malay regions species (ARAV, BBLV, EBLV-2, KBLV, ABLV, GBLV and KHUV); The other branch consists of EBLV-1, DUVV, IRKV, and TWBLV. Lineage II consists of African Lisa virus: LBV, MOKVm, and SHIBV. The most genetically differentiated Lisa viruses are tentatively classified as genetic lineage III, which are then subdivided into two branches to collect viruses isolated from Europe to Africa, including WCBV-MBLV and IKOV-LLEBV, respectively.

In terms of sequence similarity, the mean nucleotide sequence similarity of the viral glycoprotein gene of genetic lineage II was the highest, at 71.5%, and the average nucleotide sequence similarity of viruses of genetic lineage I was 70.3%. The nucleotide sequence similarity of viruses initially classified as genetic lineage III averaged 58.2%, indicating that there were large differences between these viruses. The mean similarity of viral nucleotide sequences in genetic lineage III was lower, with mean similarities of 54.1% and 54.5% compared to viruses of lineage I and lineage II, respectively.

Similar to evolutionary and genetic data, antigen analysis has identified several antigen groupings that are comparable to genetic lineages (Figure 1). The degree of differentiation in these genetic lineages is a predictable degree of cross-protection that existing rabies vaccines based on RABV (the most common classical rabies virus) may provide. Although immune responses to vaccines vary from individual to individual, it is generally accepted that conservative virus neutralizing antibody (VNA) levels equal to or greater than 0.5 international units (IU/mL) are positively correlated with seroconversion after RABV vaccination. In addition to RABV, approved rabies vaccines appear to provide protective immunity to large extent against both Lisa viruses of lineage I, with the lowest immune protection against IRKV. In conclusion, the level of VNA required for protection against non-RABV Lisa virus is currently unclear.

bibliography:

Fooks, A.R.; Shipley, R.; Markotter, W.; Tordo, N.; Freuling,C.M.; Müller, T.; McElhinney, L.M.; Banyard, A.C.; Rupprecht, C.E.Renewed Public Health Threat fromEmerging Lyssaviruses.Viruses2021,13(9), 1769; https://doi.org/10.3390/v13091769 - 04 Sep 2021