ABSTRACT
Seven human coronaviruses have been identified so far: four seasonal coronaviruses (HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1) and three novel coronaviruses (SARS-CoV, MERS-CoV, SARS-CoV-2). While seasonal coronaviruses cause only mild symptoms, novel coronaviruses cause severe and potentially fatal infections. All known coronaviruses originated in animals. Bats are considered as an origin for the majority of coronaviruses capable of infecting humans;however, rodents are proposed as natural hosts for HCoV-OC43 and HCoV-HKU1. Different animal species could serve as intermediate hosts including alpacas (HCoV-229E), livestock (HCoV-OC43), civet cats (SARS-CoV), camels (MERS-CoV), and pangolins (SARS-CoV-2). In Croatia, SARS-CoV-2 was detected in humans, pet animals, wildlife, and the environment. The COVID-19 pandemic has highlighted the role of the 'One Health' approach in the surveillance of zoonotic diseases.Copyright © 2022, University Hospital of Infectious Diseases. All rights reserved.
ABSTRACT
The first cases of human disease from COVID-19 were recorded in December 2019 in China, from where it spread rapidly around the world. COVID-19, the third emerging coronavirus infection in humans, is caused by the new SARS-CoV-2 virus, which can cause a severe acute respiratory syndrome in some infected individuals. Previous research has revealed the possible animal origin of SARS-CoV-2, with bats considered as natural reservoirs and pangolins as intermediate hosts. To better understand COVID-19 and more successfully control the spread, domestic and wild animals have been infected in experimental conditions. On the other hand, in some species, infections have been recorded in field conditions. Natural infections have been reported in dogs, cats, tigers, lions, and minks, who have been in contact with SARS-CoV-2 positive humans. The reverse transmission of the pathogen, from infected animals to humans, has only been recorded on intensive mink farms. To better understand the pathogenesis of this disease's causative agent, drugs and vaccine trials, some experimental infections were performed on animal models, of which ferrets, rhesus macaques, and hamsters proved to be the most suitable. This article aimed to consolidate known data on the potential origin of SARS-CoV-2, its transmission to humans, infections in animals, and their significance in the epidemiology of COVID-19.
ABSTRACT
The most important use of serology in the COVID-19 diagnostics is for determination of the extent of disease in the population. However, immunoassays could represent an additional diagnostic method, especially in patients with exposure history and clinical symptoms compatible with COVID-19 who failed to be confirmed by RT-PCR. We analyzed the preliminary results of six serology tests for the diagnosis of SARS-CoV-2. Three point-of-care lateral flow chromatographic immunoassays (POC): ACRO, AMP and ENCODE and three enzyme immunoassays (ELISA): DiaPro, Vircell and Euroimmun were used. A total of 15 serum samples from COVID-19 patients and 15 serum samples from asymptomatic persons were tested. Time of sampling for COVID-19 patients was 4 – 10 days (N=4), 11 – 19 days (N=6) and 20 – 34 days (N=5) after disease onset. Initially reactive results were confirmed using a virus neutralization test (VNT). In COVID-19 patients (N=15), IgM/IgA positive detection rates were 9/60.0% (ACRO), 11/73.3% (AMP, ENCODE, Euroimmun), 12/80.0% (DiaPro) and 13/86.6% (Vircell). Overall IgG detection rates were 10//66.6% (AMP, Euroimmun) and 11/73.3% (other tests). According to the sampling time, positive detection rates were as follows: a) days 4 – 10: 1/25.0% and 2/50.0% (IgM/IgA and IgG);b) days 11 –19: 4/66.6%-6/100% (IgM/IgA), 4/66.6% and 5/83.3% (IgG);c) days 20 – 34: 4/80.0% and 5/100% (IgM/IgA), 5/100% (IgG). One asymptomatic participant tested IgM/IgA positive using ACRO, DiaPro and Vircell was confirmed seropositive using a VNT. In a group of asymptomatic persons detected seronegative using a VNT (N=14), IgM/IgA negative detection rates were 12/85.7% (ACRO), 13/92.8% (DiaPro, Vircell) and 14/100% (AMP, ENCODE, Euroimmun). IgG negative detection rates were 13/92.8% (ACRO) and 14/100% (other tests). ELISA tests showed a higher overall IgM/IgA sensitivity compared to POC tests in patients with COVID-19, while the IgG sensitivity was similar in both POC and ELISA.