Nuclear-derived tools supplied to countries worldwide by the IAEA in partnership with the Food and Agriculture Organization of the United Nations (FAO) play a critical role in researching, detecting, diagnosing and characterizing zoonotic diseases such as COVID-19. They are also important to understand and track changes in a virus. In recent discoveries in the Netherlands and Denmark, COVID-19 infections have been, for the first time, recorded to transmit from humans to mink and back to humans, showing that the virus quickly adapts to new hosts. Understanding such mutations is vital in the development of an effective vaccine against the virus causing COVID-19 and other similar viruses.
The IAEA and FAO have established a platform that promotes and facilitates the access to DNA sequencing technology to laboratories worldwide to enable in-depth understanding of locally circulating or introduced pathogens. To date, the IAEA has over 3000 submissions by counterpart laboratories and 24 publications using the DNA sequencing service of various viruses, including coronaviruses, in peer reviewed journals.
“The recent discovery in Danish mink farms highlights the need for constant monitoring and surveillance at the animal-human interface and the necessity for scientists and laboratories around the world to have available appropriate diagnostic and surveillance tools to be applied for early and rapid detection and characterization of pathogens, monitoring their evolution and mining new pathogens as soon as they evolve and emerge,” said Gerrit Viljoen, Head of the Animal Production and Health Section of the Joint FAO/IAEA Programme for Nuclear Techniques in Food and Agriculture.
Real time RT-PCR is the most accurate method to detect the COVID-19 virus. TheI IAEA, in partnership with FAO, has been helping countries use this technique to detect zoonotic diseases for decades. (Photo: D. Calma/IAEA)
The family of coronaviruses has four genera – Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Delatacoronavirus – and accounts for 10 to 30 per cent of the agents responsible for a range of diseases, starting from common cold to much more serious diseases. COVID-19 is a novel coronavirus that had not been previously identified and is not the same as the coronaviruses that commonly circulate among humans causing the common cold.
The emergence of Severe Acute Respiratory Syndrome (SARS-CoV-1), caused by the Betacoronavirus in humans in China in 2002 was considered to have an animal origin (most likely from bats and transmitted through civets – cat-like mammals – to humans). Once the virus jumped from the animal host to humans, the predominant transmission was human-to-human. From 2002 to 2003, SARS-CoV-1 spread through 26 countries, causing approximately 8000 infections and 800 deaths, according to WHO.
About a decade later in 2012, another Betacoronavirus infection in humans – Middle East Respiratory Syndrome (MERS-CoV) – was identified in Saudi Arabia, introduced through camels or possibly other animals. The disease has affected 27 countries, according to WHO, with 2519 cases and 866 deaths, by the end of January 2020.
The emergence of the SARS-CoV-2 strain causing COVID-19 was reported in China at the end of 2019. WHO’s latest report tallies 53.2 million cases with more than 1.3 million deaths worldwide.
Read more about the IAEA's work in transboundary animal and zoonotic diseases.
“The problem is that we do not, yet, know how the virus is being modified in mink,” Viljoen said. “Right now, despite the genetic changes crossed by the transmission to and from mink, the virus strain has only become slightly less sensitive to human neutralizing antibodies, but this could change. If the virus changes its structure while adapting to multiple hosts, it can become highly pathogenic and more fatal to people once it comes back to humans.” This could pose a risk to the efficacy of future vaccines.
Since June 2020, 214 human cases of COVID-19 have been identified in Denmark with virus variants associated with farmed mink, according to the World Health Organization (WHO). Similar infections were reported from mink farms in Spain, Sweden, Italy and the Netherlands. The virus identified in Denmark had a combination of genetic mutations that had not previously been observed. It is not clear at this point whether this new strain is more dangerous for humans, but the virus has shown decreased sensitivity to antibodies able to neutralize virus infectivity.
Mink are the first animal species identified that can be infected by people and vice versa – but they may not be the only ones. The IAEA, which has already assisted over 120 countries by transferring knowledge and equipment to detect the virus that causes COVID-19, has for decades been supporting veterinary laboratories in developing countries in serological and molecular detection techniques, as well as in the genetic sequencing and characterization of viruses, including coronaviruses in both animals and people (see Coronaviruses in the 21st century).
Nuclear-derived tools, such as RT-PCR, are being utilized in the situation surrounding mink and the farmers tending to mink in Denmark.
ZODIAC (Zoonotic Disease Integrated Action), a new IAEA initiative aimed at preventing and controlling future outbreaks of diseases that spread from animals to humans, will expand and upgrade the VETLAB network, through which veterinary labs exchange information, share best practices and support each other. It will help national laboratories in monitoring, surveillance, early detection and control of animal and zoonotic diseases, such as COVID-19, Ebola, avian influenza and Zika. Zoonotic diseases kill around 2.7 million people every year.