Surveillance of SARS-CoV-2 virus circulation using Acute Respiratory Infections sentinel system of Catalonia (PIDIRAC) during the 2019-2020 season: A retrospective observational study.

BACKGROUND: In the context of COVID-19 pandemic in Catalonia (Spain), the present study analyses respiratory samples collected by the primary care network using Acute Respiratory Infections Sentinel Surveillance System (PIDIRAC) during the 2019-2020 season to complement the pandemic surveillance system in place to detect SARS-CoV-2. The aim of the study is to describe whether SARS-CoV-2 was circulating before the first confirmed case was detected in Catalonia, on February 25th, 2020. METHODS: The study sample was made up of all samples collected by the PIDIRAC primary care network as part of the Influenza and Acute Respiratory Infections (ARI) surveillance system activities. The study on respiratory virus included coronavirus using multiple RT-PCR assays. All positive samples for human coronavirus were subsequently typed for HKU1, OC43, NL63, 229E. Every respiratory sample was frozen at-80°C and retrospectively studied for SARS-CoV-2 detection. A descriptive study was performed, analysing significant differences among variables related to SARS-CoV- 2 cases comparing with rest of coronaviruses cases through a bivariate study with Chi-squared test and statistical significance at 95%. RESULTS: Between October 2019 and April 2020, 878 respiratory samples from patients with acute respiratory infection or influenza syndrome obtained by PIDIRAC were analysed. 51.9% tested positive for influenza virus, 48.1% for other respiratory viruses. SARS-CoV-2 was present in 6 samples. The first positive SARS-CoV-2 case had symptom onset on 2 March 2020. These 6 cases were 3 men and 3 women, aged between 25 and 50 years old. 67% had risk factors, none had previous travel history nor presented viral coinfection. All of them recovered favourably. CONCLUSION: Sentinel Surveillance PIDIRAC enhances global epidemiological surveillance by allowing confirmation of viral circulation and describes the epidemiology of generalized community respiratory viruses' transmission in Catalonia. The system can provide an alert signal when identification of a virus is not achieved in order to take adequate preparedness measures.

Detection of Rickettsia massiliae/Bar29 and Rickettsia conorii in red foxes (Vulpes vulpes) and their Rhipicephalus sanguineus complex ticks.

To determine the prevalence of exposure to Rickettsia massiliae/Bar29 and Rickettsia conorii in wild red foxes, we collected blood samples and ticks from 135 foxes shot in different game reserve areas in Catalonia. To detect SFG rickettsia in Rhipicephalus sanguineus complex ticks collected from the foxes, we used real-time polymerase chain reaction (PCR) to screen for ompA gene and a tick-borne bacteria flow chip technique based on multiplex PCR. Serum samples were positive for antibodies against spotted fever group (SFG) rickettsiae in 68 (50.3%). Molecular techniques identified R. massiliae in 107 ticks, R. aeschlimannii in 3 ticks, and R. slovaca in one tick; no R. conorii was identified in any of the ticks analyzed. We conclude that red foxes can carry ticks with SFG rickettsia.