Bat wild virus -very close match to SARS-Cov2-19

[jim mcnamara]

TL;DR

...findings therefore indicate that bat-borne SARS-CoV-2-like viruses, [which are] potentially infectious for humans. circulate in Rhinolophus spp. in the Indochinese peninsula.

Paper, accepted during editing into researchsquare.com, part of nature.com.
https://www.researchsquare.com/article/rs-871965/v1

Two species of bats in Laos had Corona viruses very close to the SARS-Cov2-19 virus. Closer than any other virus found. They infect human cells via ACE2, in culture.
Short version: we are a lot closer to finding the ultimate source of COVID.

[abstract]
The animal reservoir of SARS-CoV-2 is unknown despite reports of various SARS-CoV-2-related viruses in Asian Rhinolophus bats, including the closest virus from R. affinis, RaTG13. Several studies have suggested the involvement of pangolin coronaviruses in SARS-CoV-2 emergence. SARS-CoV-2 presents a mosaic genome, to which different progenitors contribute. The spike sequence determines the binding affinity and accessibility of its receptor-binding domain (RBD) to the cellular angiotensin-converting enzyme 2 (ACE2) receptor and is responsible for host range. SARS-CoV-2 progenitor bat viruses genetically close to SARS-CoV-2 and able to enter human cells through a human ACE2 pathway have not yet been identified, though they would be key in understanding the origin of the epidemics. Here we show that such viruses indeed circulate in cave bats living in the limestone karstic terrain in North Laos, within the Indochinese peninsula. We found that the RBDs of these viruses differ from that of SARS-CoV-2 by only one or two residues, bind as efficiently to the hACE2 protein as the SARS-CoV-2 Wuhan strain isolated in early human cases, and mediate hACE2-dependent entry into human cells, which is inhibited by antibodies neutralizing SARS-CoV-2. None of these bat viruses harbors a furin cleavage site in the spike. Our findings therefore indicate that bat-borne SARS-CoV-2-like viruses potentially infectious for humans circulate in Rhinolophus spp. in the Indochinese peninsula.
[/abstract]

 

[Astronuc]

I just read that headline from different media.

Scientists have found three viruses in bats in Laos that are more similar to SARS-CoV-2 than any known viruses. Researchers say that parts of their genetic code bolster claims that the virus behind COVID-19 has a natural origin — but their discovery also raises fears that there are numerous coronaviruses with the potential to infect people.

https://www.nature.com/articles/d41586-021-02596-2

The northern border of Laos abutts the southern border of Yunnan province, China, and Myanmar and Northern Thailand share the western border of Laos. I would expect the bats can be found throughout the region depending on the food availability.

https://www.virology.ws/2021/09/23/sars-cov-2-related-viruses-from-bats-in-laos/

The genome of a virus called RaTG13, from Rhinolophus affinis bats in China, is the closest to SARS-CoV-2 (although infectious RaTG13 has never been isolated). However the spike receptor binding domain (RBD) encoded in this genome has low sequence similarity with that of SARS-CoV-2 and its affinity for ACE2 is very limited. RaTG13 is clearly not the proximal ancestor of SARS-CoV-2.

Sampling of 645 bats from limestone caves in Northern Laos (see map) yielded three Sarbecovirus genomes, called BANAL-52, -103, and -236, with high sequence similarity to SARS-CoV-2 and RaTG13. These three viral genomes were obtained from three different Rhinolophus species. Of the 17 amino acids that interact with the receptor binding domain of ACE2, 16 are conserved between SARS-CoV-2 and BANAL-52 or -103, and 15/17 conserved with BANAL-236. In contrast, only 11/17 RBD amino acids are conserved among SARS-CoV-2 and RaTG13. In other words, the RBD encoded in these BANAL genomes are closer to SARS-CoV-2 than that of any other known bat virus.

 

[jim mcnamara]

It is a karst region just like central Florida with caves but not underwater everywhere.
https://researchonline.jcu.edu.au/3429/

Bats prefer caves to nest and sleep. So that region has lots of bat species.