Estudo soroepidemiológico da infecção pelo sars-cov-2 em cães de abrigos e tutores de Feira de Santana, BA

Abstract

SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), responsible for the COVID-19 syndrome (Coronavirus Infectious Disease 2019), was identified and described in December 2019, when a group of patients with pneumonia of unknown viral origin started being admitted to hospitals in Wuhan, Hubei province in China. The detection of this pathogen in numerous animal species, such as ferrets, tigers, lions, monkeys, rabbits, hamsters and, in particular, dogs and cats, raises the concern of researchers that they are possible zoonotic sources of the virus. When analyzing the scenario of the relationship between man and domesticated animals, the concern due to SARS-CoV-2 is that this etiological agent has genomic characteristics that allow interspecies transmission and adaptation to conditions in a new host; The aim of this study was to detect the presence of SARS-CoV-2 and anti-SARS-CoV-2 antibodies in shelters and house-hold dogs. A cross-sectional study was carried out on dogs from tutors who agreed to participate in the project and from institutions that shelter animals, such as shelters run by Non-Governmental Organizations (NGOs), the Zoonoses Control Center - CCZ and temporary homes. Blood, oropharyngeal (or nasopharyngeal) and rectal secretions were collected from each animal in a single moment. The collections were made in the shelters where the animals were kept, and the epidemiological questionnaire was answered by the person in charge of the animal or the shelter. Samples were collected from 111 dogs for the study, resulting in 222 swabs. All samples were negative by RT-qPCR and showed the same pattern as the negative control. 89 dog samples were tested using the magnetic ELISA, in which 18 animals (20.22%; 95%CI: 12.45 - 30.07) had IgG antibodies to the SARS-CoV-2 N protein and none of the evaluated animals reacted to the Spike protein.66 blood samples were evaluated, all without major variations compared to the blood count reference values, however we did not verify active infection and, therefore, how these variables behave against the virus in this case. During the execution of the project, 428 samples of oral and rectal swabs were collected from 214 felines, among which 149 sera were collected. Regarding the molecular detection of these animals, as well as dogs, the presence of viral RNA was not detected in any of the swab samples. To perform the ELISA using magnetic spheres, as well as canines, we used 51 serum samples from a pre-pandemic period (2014). We notice that the pre-pandemic samples had higher optical density values, for the most part, than the samples collected during the pandemic. It was impossible to draw a cutoff point for the reaction by analyzing the ROC curve with the results obtained. Therefore, these results demonstrate that research in the area of molecular surveillance and serological studies with animals are extremely important to understand the extent of infection with other coronaviruses, what are the roles of these animals in viral epidemiology and how their immune response evolve.