Coronavirus disease 2019 (COVID-19) is the most recent world-wide spread health burden, which reached the status of Pandemic on 11th of March 2020, has over 800’000 registered cases of infected people, and over 40’000 deaths at the time of writing of this article [1]. Unfortunately, there is abundant misinterpreted information and even apparent lies being circulated in social media and even regular media. Here, we would like to clarify some misconceptions circulating around, debunk some of the myths around the virus, and outline the scientific facts regarding the origin of the SARS-CoV-2, the causative agent of COVID-19.

The first cases of people with a pneumonia disease caused by a previously unidentified virus were reported in Wuhan, a city in the Hubei Province in China on December 30th 2019 [2]. Many cases were linked to the seafood market from that city, as some of the first patients were either sellers or deliverymen working there [3]. That information, together with a video showed in Western media, recorded 3 years earlier by a Chinese celebrity Wang Mengyun eating a bat in Palau, led to a popular belief that Chinese people eating bats are responsible for this current outbreak [4]. Another circulating opinion claimed that the Bill Gates foundation was responsible for creating the SARS-CoV-2 virus and its release to infect the world’s population [5]. These claims were clearly based on conspiracy and malignant intentions and only help to increase fear and confusion in the population.

The most important problem here is to understand why we are in this situation and, additionally, how it all started. Viruses infecting humans are very often of zoonotic origin, which means that they are transmitted from animals to humans [6]. This was the case, for example, with severe acute respiratory syndrome (SARS) epidemic which started in November 2002. It was not until 2017 when a group of researchers found a bat cave in Yunnan province in China with horseshoe bats that were infected by coronavirus strains. These strains had a very high level of similarity to the SARS-CoV one, which was responsible for the SARS epidemic from 2002 [7]. Many of these viruses were capable of binding to the SARS-CoV binding receptor in humans called ACE2 (Angiotensin-converting enzyme 2).

One of the first reports about the origin of SARS-CoV-2 comes from the 3rd of February 2020, where it was presented that this new virus holds 79.6% genome similarity to the SARS-CoV virus [3]. In the same publication, it was also shown that the virus has 96.2% genome similarity to BatCoV RaTG13 virus collected in 2013 – on a separate sample collection than the previously mentioned one related to SARS pandemic – in Yunnan from the bat Rhinolophus affinis, and presented as the closest relative to the new human infecting virus. Unfortunately, 96.2% similarity does not grant that SARS-CoV-2 evolved from this bat infecting virus. Furthermore, BatCoV RaTG13 was not collected from any animal sample coming from Wuhan during the period of the outbreak.

Moreover, research published just 2 weeks later stated that the receptor-binding domain (RBD) which is responsible for the interaction with receptor ACE2 in humans has only 89.2% amino-acid similarity with the virus infecting humans [2]. In the same publication, another animal, the Malayan pangolin (Manis javanica), is shown as a more likely carrier of the virus that infected humans. Even though it was shown that the highest genome similarity from viruses obtained from these animals reached only 92.4%, the RBD showed 97.4% similarity in amino-acid sequence. Given that pangolins are the most illegally trafficked mammals, they are more likely to be present in the wild-animal food market and be the potential source of the human infecting SARS-CoV-2 virus.

Indeed, it showed that bats could potentially be the primary hosts of the virus and, most probably, bats passed it to another mammal, as just 2 days later another research pointed to pangolins as a potential source of the SARS-CoV-2 virus [8]. Even though their final conclusion is that the pangolin-CoV-2020 virus found in sick pangolins is of further relation to the human SARS-CoV-2 than the bat BatCoV RaTG13, they still speculate another intermediate host carrier of the virus.

On the 20th of February 2020, two other publications were released. They compared genomes of viruses extracted from sick pangolins to the virus found in humans [9, 10]. Unfortunately, even though samples were extracted from a much closer time point to the human SARS-CoV-2 virus outbreak, the conclusion remained the same. These results show that further investigation is required to look for animals infected with SARS-CoV-2.

Consequently, on the 11th of March 2020, a new study was introduced on a preprint server for biological studies (bioRxiv) showing a novel coronavirus extracted from 227 bats from Yunnan Province [11]. This time, samples came from a time period between May and October 2019. These bats were of 20 different species with the majority (21.2%) belonging to Rhinolophus malayanus (Malayan horseshoe bat). One of the extracted viruses, named RmYN02, showed 93.3% genome similarity to the human infecting SARS-CoV-2. Even though it is a higher value than presented for virus extracted from pangolins, RBD interacting with human receptors showed only 62.4% amino-acid similarity, which is lower than 97.4% from the pangolin extracted virus.