adam
BANNED
Jonathan Latham, PhD
and
Allison Wilson, PhD
We agree that ordinary rates of evolution would not allow RaTG13 to evolve into SARS-CoV-2 but we also believe that conditions inside the lungs of the miners were far from ordinary. Five major factors specific to the hospitalised miners favoured a very high rate of evolution inside them.
i) When viruses infect new species they typically undergo a period of very rapid evolution because the selection pressure on the invading pathogen is high. The phenomenon of rapid evolution in new hosts is well attested among corona- and other viruses (Makino et al., 1986; Baric et al., 1997; Dudas and Rambaut 2016; Forni et al., 2017).
ii) Judging by their clinical symptoms such as the CT scans, all the miner’s infections were primarily of the lungs. This localisation likely occurred initially because the miners were exerting themselves and therefore inhaling the disturbed bat guano deeply. As miners, they may already have had damaged lung tissues (patient 3 had suspected pneumoconiosis) and/or particulate matter was present that irritated the tissues and may have facilitated initial viral entry.
In contrast, standard coronavirus infections are confined to the throat and upper respiratory tract. They do not normally reach the lungs (Perlman and Netland, 2009). Lungs are far larger tissues by weight (kilos vs grammes) than the upper respiratory tract. There was therefore likely a much larger quantity of virus inside the miners than would be the case in an ordinary coronavirus infection.
Evolutionary change is in large part a function of the population size. The lungs of the miners, we suggest, supported a very high viral load leading to proportionately rapid viral evolution.
Furthermore, according to the Master’s thesis, the immune systems of the miners were compromised and remained so even for those discharged. This weakness on the part of the miners may also have encouraged evolution of the virus.
iii) The length of infection experienced by the miners (especially patients 2, 3 and 4) far exceeded that of an ordinary coronavirus infection. From first becoming too sick to work in the mine, patient 2 survived 57 days until he died. Patient 3 survived 120 days after stopping work. Patient 4 survived 117 days and then was discharged as cured. Each had been exposed in the mine for 14 days prior to the onset of severe symptoms; thus each presumably had nascent infections for some time before calling in sick (See Table 2 of the thesis).
In contrast, in ordinary coronavirus infections the viral infection is cleared within about ten to fourteen days after being acquired (Tay et al., 2020). Thus, unlike most sufferers from coronavirus infection, the hospitalised miners had very long-term bouts of disease characterised by a continuous high load of virus. In the cases of patients 3 and 4 their illnesses lasted over 4 months.
iv) Coronaviruses are well known to recombine at very high rates: 10% of all progeny in a cell can be recombinants (Makino et al., 1986; Banner and Lai, 1991; Dudas and Rambaut, 2016). In normal virus evolution the mutation rate and the selection pressure are the main foci of attention. But in the case of a coronavirus adapting to a new host where many mutations distributed all over the genome are required to fully adapt to the new host, the recombination rate is likely to be highly influential in determining the overall speed of adaptation by the virus population (Baric et al., 1997).
Inside the miners a large tissue was simultaneously infected by a population of poorly-adapted viruses, with each therefore under pressure to adapt. Even if the starting population of virus lacked any diversity, many individual viruses would have acquired mutations independently but only recombination would have allowed these mutations to unite in the same genome. To recombine, viruses must be present in the same cell. In such a situation the particularities of lung tissues become potentially important because the existence of airways (bronchial tubes, etc.) allows partially-adapted viruses from independent viral populations to travel to distal parts of the lung (or even the other lung) and encounter other such partially-adapted viruses and populations. This movement around the lungs would likely have resulted in what amounted to a passaging effect without the need for a researcher to infect new tissues. Indeed, in the Master’s thesis the observation is several times made that areas of the lungs of a specific patient would appear to heal even while other parts of the lungs would become infected.
v) There were also a number of unusual things about the bat coronaviruses in the mine. They were abnormally abundant but also there were many different kinds, often causing co-infections of the bats (Ge et al., 2016). Viral co-infections are often more infectious or more pathogenic (Latham and Wilson, 2007).
As the WIV researchers remarked about the bats in the mine:
“we observed a high rate of co-infection with two coronavirus species and interspecies infection with the same coronavirus species within or across bat families. These phenomena may be owing to the diversity and high density of bat populations in the same cave, facilitating coronavirus intra- and interspecies transmissions, which may result in recombination and acceleration of coronavirus evolution.” (Ge et al., 2016).
PLEASE READ
Jonathan Latham, PhD and Allison Wilson, PhD
LINK below FOR THE REST
[/s][/s]
and
Allison Wilson, PhD
We agree that ordinary rates of evolution would not allow RaTG13 to evolve into SARS-CoV-2 but we also believe that conditions inside the lungs of the miners were far from ordinary. Five major factors specific to the hospitalised miners favoured a very high rate of evolution inside them.
i) When viruses infect new species they typically undergo a period of very rapid evolution because the selection pressure on the invading pathogen is high. The phenomenon of rapid evolution in new hosts is well attested among corona- and other viruses (Makino et al., 1986; Baric et al., 1997; Dudas and Rambaut 2016; Forni et al., 2017).
ii) Judging by their clinical symptoms such as the CT scans, all the miner’s infections were primarily of the lungs. This localisation likely occurred initially because the miners were exerting themselves and therefore inhaling the disturbed bat guano deeply. As miners, they may already have had damaged lung tissues (patient 3 had suspected pneumoconiosis) and/or particulate matter was present that irritated the tissues and may have facilitated initial viral entry.
In contrast, standard coronavirus infections are confined to the throat and upper respiratory tract. They do not normally reach the lungs (Perlman and Netland, 2009). Lungs are far larger tissues by weight (kilos vs grammes) than the upper respiratory tract. There was therefore likely a much larger quantity of virus inside the miners than would be the case in an ordinary coronavirus infection.
Evolutionary change is in large part a function of the population size. The lungs of the miners, we suggest, supported a very high viral load leading to proportionately rapid viral evolution.
Furthermore, according to the Master’s thesis, the immune systems of the miners were compromised and remained so even for those discharged. This weakness on the part of the miners may also have encouraged evolution of the virus.
iii) The length of infection experienced by the miners (especially patients 2, 3 and 4) far exceeded that of an ordinary coronavirus infection. From first becoming too sick to work in the mine, patient 2 survived 57 days until he died. Patient 3 survived 120 days after stopping work. Patient 4 survived 117 days and then was discharged as cured. Each had been exposed in the mine for 14 days prior to the onset of severe symptoms; thus each presumably had nascent infections for some time before calling in sick (See Table 2 of the thesis).
In contrast, in ordinary coronavirus infections the viral infection is cleared within about ten to fourteen days after being acquired (Tay et al., 2020). Thus, unlike most sufferers from coronavirus infection, the hospitalised miners had very long-term bouts of disease characterised by a continuous high load of virus. In the cases of patients 3 and 4 their illnesses lasted over 4 months.
iv) Coronaviruses are well known to recombine at very high rates: 10% of all progeny in a cell can be recombinants (Makino et al., 1986; Banner and Lai, 1991; Dudas and Rambaut, 2016). In normal virus evolution the mutation rate and the selection pressure are the main foci of attention. But in the case of a coronavirus adapting to a new host where many mutations distributed all over the genome are required to fully adapt to the new host, the recombination rate is likely to be highly influential in determining the overall speed of adaptation by the virus population (Baric et al., 1997).
Inside the miners a large tissue was simultaneously infected by a population of poorly-adapted viruses, with each therefore under pressure to adapt. Even if the starting population of virus lacked any diversity, many individual viruses would have acquired mutations independently but only recombination would have allowed these mutations to unite in the same genome. To recombine, viruses must be present in the same cell. In such a situation the particularities of lung tissues become potentially important because the existence of airways (bronchial tubes, etc.) allows partially-adapted viruses from independent viral populations to travel to distal parts of the lung (or even the other lung) and encounter other such partially-adapted viruses and populations. This movement around the lungs would likely have resulted in what amounted to a passaging effect without the need for a researcher to infect new tissues. Indeed, in the Master’s thesis the observation is several times made that areas of the lungs of a specific patient would appear to heal even while other parts of the lungs would become infected.
v) There were also a number of unusual things about the bat coronaviruses in the mine. They were abnormally abundant but also there were many different kinds, often causing co-infections of the bats (Ge et al., 2016). Viral co-infections are often more infectious or more pathogenic (Latham and Wilson, 2007).
As the WIV researchers remarked about the bats in the mine:
“we observed a high rate of co-infection with two coronavirus species and interspecies infection with the same coronavirus species within or across bat families. These phenomena may be owing to the diversity and high density of bat populations in the same cave, facilitating coronavirus intra- and interspecies transmissions, which may result in recombination and acceleration of coronavirus evolution.” (Ge et al., 2016).
PLEASE READ
Jonathan Latham, PhD and Allison Wilson, PhD
LINK below FOR THE REST
A Proposed Origin for SARS-CoV-2 and the COVID-19 Pandemic - Independent Science News | Food, Health and Agriculture Bioscience News
We propose that SARS-CoV-2, the cause of the COVID-19 pandemic, likely derives from a disease outbreak in a mine in Yunnan province, China, in 2012.
www.independentsciencenews.org
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