Sorologia baseada em ELISA e nanotecnologia para detecção da infecção em cães e gatos pelo SARS-CoV-2

Abstract

The knowledge about the seroepidemiological situation of SARS-CoV-2 in dogs and cats in Brazil is still limited. This situation occurs, in part, due to the lack of commercially available serological methods for analyzing these animals. Thus, we aimed to develop two indirect immunoenzymatic assays based on the N and S-RBD antigens of SARS-CoV-2 to detect IgG against the virus in the sera of dogs and cats. Serum samples were obtained from 308 cats and 260 dogs from September 2021 to August 2022 in Belo Horizonte, Minas Gerais. The origin of the animal (household with COVID-19 owners, Veterinary Hospital, Districtal Park), gender (male, female), age (< 1 year, 1-3 years, 3-6 years and > 6 years), as well as positivity for feline retroviruses were evaluated as possible risk factors for seropositivity for SARS-CoV-2. At the same time, a new Point of Care serological diagnostic method based on nanotechnology was also developed to detect antibodies against the N protein of SARS-CoV-2 in the serum of cats (Portable Biodiagnosis Platform - PPB). The overall occurrence of IgG antibodies against SARS-CoV-2 in cats was 16.88% (52/308) and 5% (13/260) in dogs. No association was found between seropositivity for SARS-CoV-2 and origin, sex or age for both species and retroviruses (FIV& FeLV) in cats. The chance of occurrence of SARS-CoV-2 was 3.85 times higher in cats than in dogs. No seropositive animals in the ELISA showed clinical signs suggestive of COVID-19. A higher occurrence of seropositive animals was detected by ELISA-RBD compared to ELISA-N. ELISA-N and PPB-N showed substantial differences in the detection of seropositive animals. In light of the natural exposure of dogs and cats to SARS-CoV-2, the ELISAs developed here showed potential to be used in the epidemiological monitoring of the virus in these species.