Did wildlife trafficking cause the largest epidemy of this century?

Coronavirus origin?

In less than two months, over 60,000 people were confirmed to be infected with the new strain of coronavirus, making it the biggest disease outbreak of this century. As they are thought to be the epicenter of this epidemy, China’s shady “wet markets” are in everyone’s lips. However, many are unaware of their terrifying impact on wildlife and why they were labelled “ground 0”.

Table I – Pandemics of the 21st century, ranked by number of people infected. Pandemics are diseases that start from a single source and that spread across the globe. As you can see, despite the fear surrounding the new coronavirus, this outbreak has one of the lowest fatality rates. All the diseases named in the table are zoonotic.

Since the beginning of the century, several diseases have brought havoc into our world and killed thousands of people. Most of them were transmitted to humans by animals – experts call them zoonotic diseases. In fact, about 60% of all infectious diseases affecting humans are zoonotic. And the new coronavirus is one of them. This virus belongs to the family of Coronaviridae, which comprise many viruses with potential to severely affect the respiratory and gastrointestinal tracts in humans. But, how did it all start? Well, coronaviruses have been identified in countless wild and domestic animals, including mice, rats, chickens, turkeys, swine, cattle, rabbits, horses, cats, bats and pangolins. And the first patients infected with this new virus were visitors of the so called “wet market” in Wuhan – a place where a wide variety of wildlife is sold for…human consumption. Hence, from an early stage, this market has been treated as the most likely epicenter of the outbreak. Recent research supports this theory. According to Peng Zhou and his team, the genome of the new virus is 96% identical to a coronavirus found in bats, making these animals the most likely primary source – as was the case with previous coronavirus epidemies, namely SARS and MERS. Although it is still not clear how this virus made its way into the human population, its genome is 99% similar to the coronavirus found in pangolins, which suggests this animal might be the missing link. Due to this alarming situation, the Chinese Government has announced a nationwide temporary ban on the trade of wild animals, which has been described as the toughest restrictions ever enforced on this “sector”. But, non-governmental agencies, media and regular people all around the world are not convinced yet and they pressure for far-reaching policy changes. Despite of these concerns being triggered due to a worldwide public health crisis, unregulated “wet markets” also pose a significant threat to wildlife conservation. Why? In these markets, you can fairly easily buy a delicious giant salamander (Andrias davidianus) or a tasty Chinese pangolin (Manis pentadactyla) for your dinner, which are both critically endangered of extinction. But, let me further illustrate the magnitude of the problem. Within two decades, it is estimated that about 1.5 million Chinese Pangolins were harvested and sold for meat in China. Today, only around 50,000 animals are left in the wild.

(1) A giant salamander (Andrias davidianus) in an aquarium. Photo by J. Patrick Fischer (CC BY-SA 3.0 license). (2) A Temminck’s pangolin (Smutsia temminckii), which is very similar in appearance to the Chinese panogolin. Photo by David Brossard (CY BY 2.0 license).

So far, the recent coronavirus outbreak demonstrated that illegal wildlife trade not only provides disease transmission mechanisms that can lead to human epidemic diseases, but that can also negatively affect international trade, people livelihoods, and the health of our dear wildlife. But this phenomenon is not exclusive to China. Wildlife trafficking is present all around the globe. Although is almost impossible to quantify the illegal trade worldwide due to its immense magnitude, there are some estimates. About 40,000 primates, 4 million birds, 640,000 reptiles, and 350 million tropical fish are thought to be traded each year. As these numbers only account for live animals, unfortunately the real trade figures will be much higher. As biodiversity continues to decline at unprecedented rates, this horrific and often overlooked reality demands more efficient actions to be taken by competent authorities. Regardless, only public health emergencies seem to trigger colossal advances in this regard. So, one might wonder how many outbreaks away we are from efficiently addressing wildlife trafficking.

A short coronavirus tale for those who have been absent from the planet for the last 2 months

Somewhere between December 2019 and January 2020, a novel coronavirus outbreak emerged in China. The location as well as timing of the outbreak made the situation worse. The “ground 0 wet market” was only a block away from one of Wuhan’s major train stations and the spike in cases started just before Chinese New Year, which is considered the biggest annual migration of humans in the planet. This outbreak forced the world’s second most powerful economy to cancel all New Year celebrations as well as to lock down Wuhan – a city of 11 million people. Regardless, besides engulfing every region of mainland China, this new strain found its way to other 27 countries and earned the status of global public health emergency. The end. Or is it?  

References:
(1) CDC – Centre for Disease Control (2020). Coronavirus Disease 2019 (COVID-19) Situation Summary. Retrieved on February 14, 2020, from https://www.cdc.gov/coronavirus/2019-nCoV/summary.html
(2) CDC – Centre for Disease Control (No date). 2014-2016 Ebola Outbreak in West Africa. Retrieved February 14, 2020, from https://www.cdc.gov/vhf/ebola/history/2014-2016-outbreak/index.html
(3) Challender, D., Wu, S., Kaspal, P., Khatiwada, A., Ghose, A., Ching-Min Su, N. & Laxmi Suwal, T. (2019). Manis pentadactyla. The IUCN Red List of Threatened Species. doi:10.2305/IUCN.UK.2019-3.RLTS.T12764A123585318.en
(4) Gang, L., Baorong, G. & Ermi, Z. (2004). Andrias davidianus. The IUCN Red List of Threatened Species. doi:10.2305/IUCN.UK.2004.RLTS.T1272A3375181.en
(5) Karesh, W. B., Cook, R. A., Bennett, E. L. & Newcomb, J. (2005). Wildlife Trade and Global Disease (6) Emergence. Emerging Infectious Diseases, 11(7), 1000–1002. doi:10.3201/eid1107.050194
(6) NHS – Nation Health System (No date). MERS: Middle East Respiratory Syndrome. Retrieved February 14, 2020, from https://www.nhs.uk/conditions/middle-east-respiratory-syndrome-mers/
(7) NHS – Nation Health System (No date). SARS: Severe Acute Respiratory Syndrome. Retrieved February 14, 2020, from https://www.nhs.uk/conditions/sars/
(8) World Health Organization (2009). Weekly Epidemiological Record. Retrieved February 14, 2020, from http://www.who.int/wer
(9) XINHUANET (2020). Pangolins a potential intermediate host of novel coronavirus: study. Retrieved on February 14, 2020, from http://www.xinhuanet.com/english/2020-02/07/c_138763566.htm
(10) Zhou, P., Yang, X-L., Wang, X-G., Hu, B., Zhang, L., Zhang, W., Si, H-R., Zhu, Y., Li, Bei, Huang, C-L. et al. (2020) Discovery of a novel coronavirus associated with the recent pneumonia outbreak in humans and its potential bat origin. doi:10.1101/2020.01.22.914952

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