Published on 23 December 2024

Coronaviruses cause respiratory and enteric viral infections and zoonoses

IVI coronavirus research is conducted in a biosafety level 3 laboratory. Researchers wear full-body protective suits that also cover the head. Virus work is carried out with extreme care using a biological safety cabinet.

The IVI is conducting research into respiratory and enteric coronavirus (CoV) infections in humans and animals. Our aim is to better understand the interactions between the virus and the host organism, in order to decipher the mechanisms of pathogenesis and thus develop strategies for the prevention and control of CoV infections.

IVI coronavirus research is conducted in a biosafety level 3 laboratory. Researchers wear full-body protective suits that also cover the head. Virus work is carried out with extreme care using a biological safety cabinet.

Coronaviruses are RNA viruses that were first described almost a century ago. They are genetically very variable and capable of infecting many species of animal as well as humans. They therefore pose a high risk of causing zoonoses and reverse zoonoses (diseases transmitted from animals to humans and vice versa).

The best-known of these are the highly pathogenic coronaviruses that cause severe clinical symptoms in humans, such as SARS-CoV (Severe Acute Respiratory Syndrome Coronavirus), MERS-CoV (Middle East Respiratory Syndrome Coronavirus) and SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). However, there are also many coronaviruses in veterinary medicine. These infect a variety of animals, including pigs, cattle, cats, dogs, rodents and birds. Coronaviruses in animals mainly infect the respiratory and intestinal tracts, causing not only respiratory symptoms, but also clinical symptoms such as diarrhoea, peritonitis, hepatitis and encephalomyelitis.

Examples of coronaviruses in animals:

Chickens: infectious bronchitis virus (IBV)
Cattle: bovine coronavirus (BCoV)
Cats: feline coronavirus (FCoV), feline infectious peritonitis virus (FIPV)
Pigs: porcine epidemic diarrhoea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine respiratory coronavirus (PRCoV)

• Why is this important?

  Coronaviruses pose a risk and a threat, not just to humans but also to many species of animal. They can cause zoonoses, which makes their prevention and control even more difficult, with animals acting as reservoirs or intermediate hosts. Coronavirus research is essential in order to develop effective control and prevention measures, as vaccines or treatment options are not yet available for every disease caused by coronaviruses. They can also cause significant economic damage.

• What does the IVI do?

  One of our long-term goals is to study the replication of coronaviruses. To do this, we use reverse genetic systems to analyse the mechanisms and enzymes that influence coronavirus gene expression at the molecular level. The reverse genetic system has proven to be fast, robust and versatile, and recombinant viruses of the main CoV strains are available in the laboratory. We have been able to identify and characterise the mechanisms of translational regulation of CoV gene expression. In addition, we have studied the enzymatic activities encoded by the CoV replicase gene and analysed the replication, transcription and packaging of coronaviruses using recombinant CoVs, replicon RNAs, defective minigenomes and virus-like particles. In order to study the virus-host interactions of respiratory viruses, we have established primary epithelial cultures of the respiratory tract that grow under «air-liquid interface» conditions. This culture system is now available for several species (humans, camelids, bats) and allows us to characterise certain virus-host interactions (e.g. innate immune evasion) and zoonotic transmission of CoVs in an environment resembling the authentic primary target tissue of CoV infection.

  • Research into coronaviruses in animals and coronaviruses with high zoonotic potential (such as MERS-CoV and SARS-CoV-2). We are also working to develop vaccines against several coronaviruses.
  • Functional characterisation of emerging SARS-CoV-2 variants.
  • Identification and evaluation of antiviral substances and inhibitors.
  • We are testing potential antiviral substances for the treatment of feline infectious peritonitis (FIP), a coronavirus disease in cats.
  • Together with the Centre for Emerging Viral Diseases of the University of Geneva, we are the reference laboratory for SARS-CoV-2 variants in the WHO Corona Virus Network CoViNet. This is the first WHO reference laboratory network for SARS-CoV-2 and consists of 20 laboratories worldwide. It supports WHO in the characterisation of new SARS-CoV-2 variants, helping to create the basis for assessing health risks.

• Main findings

  • Support during the pandemic: Thanks to its extensive experience with coronaviruses, the IVI was able to step in quickly as a key partner in research projects and in advising various authorities.
  • First clone of SARS-CoV-2 produced at the IVI: The entire viral genome was cloned in yeast. This experimental tool is being used by many laboratories worldwide.
  • SARS-CoV-2 and MERS-CoV: Prospects for development of a live attenuated vaccine in the form of a nasal spray.
  • Development of treatment options for feline infectious peritonitis (FIP) in cats: Testing of potential antiviral substances.
  • PEDV: Development of a vaccine in collaboration with the FSVO and industry partners.
  • Functional characterisation of new SARS-CoV-2 variants: Communication with WHO and publication of studies on SARS-CoV-2 spike D614G and the Alpha, Beta, Delta and Omicron-BA.1 variants.
  • Development and characterisation of antiviral substances: For the treatment of COVID-19.

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