Heilsa - COVID-19 verkætlan
Finnast meira og minni sjúkuelvandi SARS-CoV-2 variantar í Føroyum?
Debes Hammershaimb Christiansen
Heilsufrøðiliga Starvsstovan og Landssjúkrahúsið
Bjarni á Steig, Marnar Fríðheim Kristiansen, Sanna á Borg, Bodil H. Heimustovu, Tróndur Høgnason Mohr, Lars Fodgaard Møller, Hannes Gislason, Marin Strøm, Maria Skaalum Petersen og Guðrið Andorsdóttir, Shahin Gaini
Stuðul úr Granskingargrunninum:
The World Health Organization (WHO) declared the coronavirus disease 2019 (COVID-19) as a global pandemic in mid-March 2020 and, so far, the global deaths have surpassed 120.000 individuals. The Faroese authorities were ready to test for the causative virus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in mid-February. The first case of SARS-CoV-2 infection was documented in the Faroe Islands on March 3rd, 2020 in a returning traveller from France. Following the second case the same week measures for containment and mitigation were established with closing of all educational facilities, day care aimed at slowing virus transmission. Subsequently, COVID-19 has been diagnosed among returning travellers and from people they have been in contact with. The first week a stringent policy was applied for testing of potential cases of COVID-19 following the guidelines from the WHO1. By March 12th testing was expanded and conducted on clinical indication as well as a less stringent case definition. Now, 5509 tests have been performed among the ~52.000 inhabitants (10.5%) in the Faroes of which 184 (3%) have been tested SARSCoV-2 positive2. Because of the high number of tests, the Faroese authorities seems to have identified and isolated most of the SARS-CoV-2 cases. This is reflected in the positive cases where the incidence peaked with 9.5% SARS-CoV-2 positives on March 16th. The following three weeks incidence declined to ~2% and no positive cases have been found since April 6th, 2020. Of the 184 positive cases, many have been defined as primary cases ¬i.e. cases returning from Europe and Iceland. The remaining cases are mostly secondary cases i.e. infected in the Faroe Islands and linked epidemiologically to the primary cases. Clinical observations from the Faroes, when mapping the contagion, revealed that some patients set off long, aggressive chains of contagion while others did not. This is intriguing and may indicate that different more or less aggressive strains of SARS-CoV-2 are co-circulating in the Faroes, a hypothesis supported by preliminary studies3,4. As the number of infected patients increases a major concern is that the SARS-CoV-2 will accumulate more mutations and more aggressive strain might emerge. With a large test capacity in the Faroe Islands with FFVA performing the testing and allocation of resources, the Faroe Islands presently have the highest COVID-19 test performance relative to the population size. This puts us at a favourable position to carry out efficient SARS-CoV-2 and COVID-19 related research. MAIN OBJECTIVES: To get a better understanding of how the SARS-CoV-2 transmits, spreads and evolves and whether different virulent SARS-CoV-2 strains are co-circulating in the Faroe Islands, we suggest a genetic characterization and molecular phylogenetic analysis of the Faroese SARS-CoV-2 isolates. These results will be linked to the throughout epidemiological characterization that has been done on all the SARS-CoV-2 infected cases in the Faroe Islands. Continuous genetic characterization of SARSCoV-2 will provide critical information on virus pathogenicity and help inform epidemiological investigations during future COVID-19 outbreaks. METHODS For the RNA sequencing, we will conduct genetic and molecular phylogenetic analysis of the Faroese SARS-CoV-2 isolates with a two-step sequencing strategy: 1. Cell entry of coronaviruses depends on binding of the viral spike protein to the cellular receptor ACE25. The spike protein has been demonstrated to determine tissue trophism and pathogenicity6. Thus, we will initially sequence the entire 3819 open reading frame of the spike (S) protein from all the SARS-CoV-2 cases in the Faroes. 2. Based on the epidemiological data and the sequencing of the Spike protein we will perform a full genome sequencing of approximately 50 selected Faroese SARS-CoV-2 isolates. We will use in-house developed multiplex PCR enrichment and Illumina sequencing virus genomes directly from clinical samples adapted from Quick et al.7. This method has been used for genome sequencing of the infectious salmon anemia virus (ISAV) and piscine myocarditis virus (PMCV) two important viruses in the salmon aquaculture.