It has not yet been conclusively clarified whether the pandemic took its course in a market in Wuhan, China. It is more likely that the virus could spread from bats to humans via another animal.
According to new data modeling, the first cases of Sars-CoV-2 in humans are likely to have occurred in China between around the beginning of October and mid-November 2019. This is confirmed by an analysis presented in the journal “PLOS Pathogens”.
According to the bill, a date around November 17 is likely, the researchers report. The virus is likely to have spread much faster in the world than known after the first evidence.
In early December 2019 in Wuhan
The first officially confirmed infections with the novel pathogen were recorded in the central Chinese metropolis of Wuhan at the beginning of December 2019.
However, experts have long assumed that the virus had already circulated in humans before that. This suspicion was also expressed by the World Health Organization (WHO) investigation team, which searched China for the origin of the virus in January and February.
Extinction model used from nature conservation
The scientists led by David Roberts from the UK University of Kent calculated the most likely time span for the pathogen to pass from animals to humans using the data for the first confirmed cases in China and abroad. They used a mathematical model with which predictions about the extinction of species are made in the nature conservation area.
Accordingly, the virus is likely to have spread worldwide as early as January. According to the scientists’ calculations, the first infections outside of China could have occurred in Japan around January 3. According to their calculations, the first case in Europe in Spain would have been around January 12, the first in the USA around January 16.
Data availability affects results
The scientists point out, however, that their conclusions are “only as good as the data that were used”. Factors such as the quality of the first available detection methods in the individual countries are therefore likely to have influenced the results. In addition, many infections are asymptomatic – or with rather mild cold symptoms, with which people often did not see a doctor, especially at the beginning of the pandemic, and therefore were not tested.
How exactly Sars-CoV-2 passed on to humans is still unclear. A large number of experts worldwide assume that the virus was transmitted from bats to humans via an as yet unknown intermediate host – such as raccoon dogs in fur farms. In US politics in particular, however, accidental or deliberate occurrence in the laboratory is repeatedly brought up – much to the annoyance of China.
It is uncertain whether the actual course of events can still be clarified – experts have noted several times that no analyzes have been made known from China. It is unclear whether data is kept under lock and key or simply does not exist. (SDA)