In a breakthrough that will help scientists track coronavirus variants in wild and domestic animals, researchers report that they can now detect exposure to the SARS-CoV-2 virus in even what species of animal. Most coronavirus antibody tests require special chemical reagents to detect host antibody responses against the virus in each species tested, which hinders research across species.
The virus that causes COVID-19 in humans also affects a variety of animals, said University of Illinois Urbana-Champaign pathobiology professor and virologist Ying Fang, who led the new research. So far, the virus has been found in cats, dogs, mice, deer, monkeys and various farm and zoo animals. The virus also mutates in these hosts, which can lead to new variants that are harmful to their—and human—health.
“More sensitive and specific diagnostic reagents and assays are urgently needed for the rapid identification and implementation of strategies for the prevention and control of infection in animals,” the researchers wrote in the journal mSpherewhere their findings are reported.
The new coronavirus test targets antibodies against a protein, called the N-protein, embedded in the virus’s nucleocapsid – a structure made up of proteins and nucleic acids contained within the a virus membrane. The N-protein makes a better target than the membrane-bound viral proteins commonly used in tests for antibody responses, Fang said.
“The N-protein is more abundant and it is more conserved than the proteins used in most tests,” he said. This means the protein structure is more consistent across species, making it a good target for all-species antibody testing.
The team used an N-protein-based blocking ELISA protocol for their test. This method involves coating an ELISA plate with N-protein, then adding a sample of the serum of any animal being tested. When the animal is infected with the coronavirus, its serum contains anti-N-protein antibodies, which bind to the N-protein-coated plate.
The scientists then washed the plate and added a second biotin-tagged monoclonal antibody targeting the N-protein. If the animal is positive for the coronavirus infection, its antibodies will prevent the secondary antibodies from binding to the N-protein. If the animal has not been infected, the monoclonal antibodies will stick to the coated plate and produce a color signal when specific chemicals are added to the plate.
The researchers validated their test using samples from different animals with known SARS-CoV-2 infection status, finding that the tests had more than 97% sensitivity and 98% specific. Further tests on domestic cats showed that the assay detected infection within seven days of exposure to the virus.
The development of accurate cross-species coronavirus tests provides a useful tool for field monitoring of SARS-CoV-2 in animal populations, helping scientists to identify potential new animal reservoirs to prevent future disease outbreaks, Fang said.
Ying Fang et al, Development of monoclonal antibody-based blocking ELISA for detection of exposure to SARS-CoV-2 in animals, mSphere (2023). DOI: 10.1128/msphere.00067-23 , journals.asm.org/doi/10.1128/msphere.00067-23
Awarded by the University of Illinois at Urbana-Champaign
Citation: Team develops all-species coronavirus test (2023, July 6) retrieved 6 July 2023 from https://phys.org/news/2023-07-team-all-species-coronavirus.html
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