Fighting COVID-19 in animals and humans

Several countries have reported that the coronavirus SARS-CoV-2 can also infect animals, primarily felines and mustelids. The risk this poses to public health is currently considered negligible. The driving force behind the COVID-19 pandemic is, after all, transmission between humans. However, once this transmission has been sufficiently reduced, a virus reservoir in animals could pose a considerable threat. Therefore, the Ministry of Agriculture, Nature and Food Quality has commissioned an extensive study on COVID-19 in domestic pets.

The research project

Various research groups, united within the Netherlands Centre for One Health, are collaborating on an interdisciplinary research project called “Fighting COVID-19 in animals and humans, a one health approach”. The project is coordinated by the Utrecht University Faculty of Veterinary Sciences.

Establishing whether SARS-CoV-2 can continue to circulate between humans and animals if the transmission between humans has been dampened is the most important.
Arjan Stegeman – Project leader Utrecht University

The research results will serve as a scientific basis for the strategy developed by policymakers and stakeholders such as vets and animal owners on how to deal with animals during this pandemic. 

Six partial studies

The research project is subdivided into six partial studies.

1. SARS-CoV-2 in dogs and cats in Dutch households

Incidents, where owners tested positive for COVID-19 transmitted the disease to their dog or cat, have been reported. Therefore, studies will be conducted on the presence of antibodies for the virus in dogs and cats, both in households tested positive for COVID-19 and in households tested negative. This study is led by Utrecht University.

2. SARS-CoV-2 in different animal populations

Incidental cases of SARS-CoV-2 in pets and results from previous studies raise questions on the role of animals during the pandemic.  Particularly in our densely populated country, with many pets, animals could form a reservoir for the virus and thus instigate a revival of COVID-19 in humans. This is why we study the prevention of SARS-CoV-2 in various animal populations. This study is led by Utrecht University.

3. Disease development and transmission in cats

Several studies show that cats are sensitive to the SARS-CoV-2 virus. Since humans and cats cohabit closely, it is important to discern whether the virus can be transmitted between cats, and between humans and cats. This study is led by Professor Wim van der Poel of Wageningen University & Research.

What does this research encompass?

In this study, scientists investigate the susceptibility of cats and how the transmission between cats takes place. If the results show that cats can effectively infect each other, additional measures to get (and keep) the COVID-19 pandemic under control may be required. The efficacy of such measures will be studied in collaboration with the researchers involved in partial study 5 ‘Modelling transmission between cats and humans’.

Moreover, the researchers investigate the clinical symptoms and production of antibodies after infection. There are indications that some antibodies even contribute to the pathology. This study will provide more insight into this effect. The results of this study will serve as a basis for vaccine research.

4. Genetic research on SARS-CoV-2 in humans and animals

A characteristic of RNA viruses, such as SARS-CoV-2, is that they mutate easily: the continuous alterations in the genetic material results in genetic diversity. Mapping the genetic diversity of a virus is a key aspect of source investigation. The Erasmus Medical Centre leads this study.

5. Modelling transmission between cats and humans

Thanks to measures such as social distancing, frequent hand-washing and staying indoors with mild symptoms, the pandemic can be controlled. However, if research shows that cats have a role in transmitting SARS-CoV-2 between households, additional measures may be required. Mathematical models contribute significantly to this research. Professor Mart de Jong of Wageningen University & Research leads this investigation.

What does this research encompass?

Models allow us to study how to respond to the risk of infection from animals to humans
Mart de Jong - Wageningen University & Research

In this partial study, scientists investigate to what degree the transmission of SARS-CoV-2 between households is contingent on the interventions already in place (social distancing, hand hygiene etc.) and the presence or lack thereof of cats. If cats contribute to the transmission of SARS-CoV-2 between households, the R0 may increase to above 1 in areas with many cats, which allows the virus to continue circulating. Scientists use mathematical models to gain more insight into this process.

Mart de Jong leads the study: ‘The question that needs answering is to what degree the infection risk of humans becomes more dependent on infections in animals, cats in particular. An additional question is how we handle this risk. We use models to investigate these questions.’

What are mathematical models used for?

Researchers increasingly use mathematical models in determining measures against potential infectious diseases such as COVID-19. These models contribute to structuring the available interdisciplinary knowledge, finding epidemiological links and revealing information gaps as well as comparing expected results of possible mitigating measures against infectious diseases. Mathematical models thus contribute significantly to substantiating the policies in combatting infectious diseases.

6. Sharing research results

The research results will serve as a scientific basis for the strategy developed by policymakers and stakeholders such as veterinarians and animal owners on how to deal with animals during this pandemic.  Adequate communication on the research results is essential. Scientific publications and media presentations are gathered on the website of Utrecht University.