As of November 2020, the coronavirus pandemic is here to stay. The SARS-CoV-2 virus has had a devastating impact on public health and the economy. Recent months have also brought the news that pets too can get infected with the virus.
The USDA tracks the number of COVID-19 positive animals in the US and has so far recorded over 30 cat cases and over 20 dog cases. In addition, there is published scientific evidence demonstrating that infected cats have the capacity to spread the virus to other cats. That being said, there is absolutely no evidence of cats (or other pets) ever spreading the disease to humans.
The pandemic has so far been characterized by a severe undersupply of accurate RT-PCR (Real-Time Polymerase Chain Reaction) COVID-19 tests for human use. This has led to under-testing and long result waiting times. Shortage of supplies for human tests is one of the reasons why routine testing of companion animals is not currently recommended by the USDA. There are now high-quality veterinarian-administered RT-PCR COVID-19 tests available specifically for animal use. However, these tests rely on the same reagents used in human COVID-19 RT-PCR tests, meaning that they do little to reduce the pressure on the core reagent supply chain. Earlier this year, there were reported shortages and back-orders of some of those key reagents, such as RNA extraction kits. In addition, from our own internal observations at Basepaws, TaqMan-based RT-PCR reagents (the most commonly used reagents for COVID-19 RT-PCR based testing) saw a significant price increase and buccal/nasopharyngeal swab collection kits designed for RNA preservation were in extremely short supply.
At Basepaws, we are all personally invested in the health and well-being of every cat. Since cats are among the most susceptible animals to COVID-19, we decided to tackle the challenge of developing a versatile PCR-based COVID-19 test with minimal impact on the already strained reagent supply chain for COVID-19 testing. The availability of such a test would be important for improving our understanding of the spread and impact of the SARS-CoV-2 virus on cats. There were three main criteria that we wanted to meet in our test development:
- Use a sample collection kit not specifically designed for RNA storage and avoid using commercial RNA isolation kits
- Use a PCR method different to the gold standard TaqMan method
- Develop and validate a fast and accurate test that can be used for cats and, potentially, other animals
We succeeded in developing a test that is comprised of two different workflows. These can be used together or separately, depending on the available reagents and lab setup. The method can, in principle, be used to test both humans and animals (although more validation is needed for human testing). After discussing our method with the Center for Veterinary Medicine (CVM) at the Food and Drug Administration (FDA), we were invited to participate in an inter-lab comparison study for COVID-19 testing. While participating labs cannot publicly share results from this study, you can read about our internal results, conclusions and experimental rationale below. If you have ever wondered how does one begin to develop a COVID-19 diagnostic test, please read on.
