Caveats on COVID-19 herd immunity threshold: the Spain case

After a year of living with the COVID-19 pandemic and its associated consequences, hope looms on the horizon thanks to vaccines. The question is what percentage of the population needs to be immune to reach herd immunity, that is to avoid future outbreaks. The answer depends on the basic reproductive number, R0, a key epidemiological parameter measuring the transmission capacity of a disease. In addition to the virus itself, R0 also depends on the characteristics of the population and their environment. Additionally, the estimate of R0 depends on the methodology used, the accuracy of data and the generation time distribution. This study aims to reflect on the difficulties surrounding R0 estimation, and provides Spain with a threshold for herd immunity, for which we considered the different combinations of all the factors that affect the R0 of the Spanish population. Estimates of R0 range from 1.39 to 3.10 for the ancestral SARS-CoV-2 variant, with the largest differences produced by the method chosen to estimate R0. With these values, the herd immunity threshold (HIT) ranges from 28.1 to 67.7%, which would have made 70% a realistic upper bound for Spain. However, the imposition of the delta variant (B.1.617.2 lineage) in late summer 2021 may have expanded the range of R0 to 4.02–8.96 and pushed the upper bound of the HIT to 90%.This work was supported by the University of Alicante [COVID-19 2020-41.30.6P.0016 to CB] and the Montgó-Dénia Research Station (Agreement Ajuntament de Dénia-O.A. Parques Nacionales, Ministry of the Environment—Generalitat Valenciana -Conselleria de Agricultura, Desarrollo Rural, Emergencia Climática y Transición Ecológica, Spain, Spain) [2020-41.30.6O.00.01 to CB]

Retrospective methodology to estimate daily infections from deaths (REMEDID) in COVID-19: the Spain case study

The number of new daily infections is one of the main parameters to understand the dynamics of an epidemic. During the COVID-19 pandemic in 2020, however, such information has been underestimated. Here, we propose a retrospective methodology to estimate daily infections from daily deaths, because those are usually more accurately documented. Given the incubation period, the time from illness onset to death, and the case fatality ratio, the date of death can be estimated from the date of infection. We apply this idea conversely to estimate infections from deaths. This methodology is applied to Spain and its 19 administrative regions. Our results showed that probable daily infections during the first wave were between 35 and 42 times more than those officially documented on 14 March, when the national government decreed a national lockdown and 9 times more than those documented by the updated version of the official data. The national lockdown had a strong effect on the growth rate of virus transmission, which began to decrease immediately. Finally, the first inferred infection in Spain is about 43 days before the official data were available during the first wave. The current official data show delays of 15–30 days in the first infection relative to the inferred infections in 63% of the regions. In summary, we propose a methodology that allows reinterpretation of official daily infections, improving data accuracy in infection magnitude and dates because it assimilates valuable information from the National Seroprevalence Studies.The funding was provided by Universidad de Alicante (COVID-19 2020-41.30.6P.0016) and also by Ajuntament de Dénia - Montgó-Dénia Research Station (2020-41.30.6O.00.01)

MEDUSAPP: App móvil de ciencia ciudadana para geolocalizamiento cuantitativo de avistamientos de medusas y registro de picaduras con fines educativos, científicos y médicos

MedusApp es una aplicación que: 1) Permite a los usuarios (ciencia ciudadana) geolocalizar medusas, identificando la especie y su abundancia; 2) Tiene información de fichas sobre cada especie de medusa, para poder identificarla; 3) Se muestra la información relacionada con la toxicidad de su picadura, así como recomendaciones de primeros auxilios; 4) Se pueden enviar imágenes de las picaduras para ser evaluadas por un servicio médico especializado, a efectos científicos (no pretende interferir en la praxis médica).Proyecto LIFE CUBOMED (www.cubomed.eu) (LIFE08 NATES 0064 CUBOMED). Estación Científica Montgó-Dénia

An embedding method for the analysis of tiny statoliths: preliminary results for the Mediterranean box jellyfish Carybdea marsupialis

5th International Jellyfish Bloom Symposium, 30 May to 3 June 2016, Barcelona.-- 1 page, 3 figuresStatoliths are inorganic crystals located on the rhopalia of jellyfish that serve as gravity sensors. Morphological and geochemical analysis of these rhopalia are considered useful means of understanding their taxonomy and ecology. Cubozoan statoliths are made of calcium sulfate hemihydrate (bassanite) and tend to disintegrate rapidly once removed from the rhopalium and preserved (e.g. frozen or preserved in 4% buffered formaldehyde). Moreover, the small size of the statoliths of some species, such as Carybdea marsupialis (~40μm juveniles, ~400μm adults), makes them even more difficult to work with. The aim of this study is to provide a method which enables us to slice the statolith with micrometer precision, making their study and characterization possible, focusing on C. marsupialis from Malta and Spain. Although the literature includes some references to epoxy resin embedding procedures for statoliths of other species, none of these papers indicate the component proportions in the embedding medium or other specific requirements. Steps: 1) dehydration in ethanol; 2) infiltration with several ratios of propylene oxide and Embed 812 embedding medium; 3) transfer to a mold filled with Embed 812 embedding medium 100%; 4) curation at 60ºC in an oven for 48h; 5) sectioning in a microtome (~4μm precision); 6) the embedded sample was polished using 0.25 μm diamond-dispersion powder. Different techniques can then be used to characterize the statolith section, including whole analysis, mapping, compositional profiles and punctual data. Scanning electron microscopy, X-ray photoelectron and raman spectroscopies and micro-X ray diffraction were successfully appliedPeer Reviewe

Citizen science effectively monitors biogeographical and phenological patterns of jellyfish

Jellyfish encounters are set to rise as human activity in the marine environment increases. Although jellyfish pose a threat to human health and the economy, there is limited understanding of their population dynamics. To mitigate the impact of jellyfish and gather information on their biogeographical patterns, we created MedusApp, a citizen science tool for collecting data on jellyfish sightings in the Spanish Mediterranean. From 2018 to 2021, the most commonly sighted species were Pelagia noctiluca, Rhizostoma pulmo, Cotylorhiza tuberculata, and Rhizostoma luteum. Sightings increased for all species, but the Jellyfish Intensity (JI) index showed no significant rise in overall abundance. The JI revealed the inter-annual fluctuations in R. pulmo's nature and more a larger purporting of weight on total JI from C. tuberculata while P. noctiluca decreased. The seasonality of the four species remained stable, providing a basis for time-effective management strategies. MedusApp has further provided new evidence that R. luteum is expanding its range northward in the Western Mediterranean and becoming a commonly observed species. The information collected through MedusApp can be used to improve jellyfish management measures, such as monitoring, control, and alert systems, to reduce conflicts with humans and the environment.This work was supported by the project GVA-THINKINAZUL/2021 ″A comprehensive marine observatory in the coast of Oliva-Dénia-Jávea for the conservation of biodiversity, observation of global change and promotion of the blue economy (OBSERMAR-CV)." to CB, supported by the MCIN with the funding from European Union NextGenerationEU (PRTR-C17.I1) and by Generalitat Valenciana. Part of this research has been conducted at the Marine Laboratory UA-Dénia (Agreement Ajuntament de Dénia-Conselleria de Agricultura, Desarrollo Rural, Emergencia Climática y Transición Ecológica, Generalitat Valenciana, Spain) https://web.ua.es/en/marlabdenia/presentation.html [2020-41.30.6O.00.01 to CB]

Remediación de sedimentos marinos anóxicos

El objetivo de este trabajo fue el desarrollo de una novedosa técnica de remediación de sedimentos marinos anóxicos a partir de la inyección de agua de mar saturada en oxígeno. El estudio se llevó a escala laboratorio, muestreando sedimento procedente de la playa de la Marineta Casiana (Dénia, Alicante), en una superficie de 20 m2 a 5 metros de la orilla. Se establecieron dos tratamientos: inyección de agua de mar saturada en oxígeno a 20 cm de profundidad desde la superficie del sedimento, durante 68 días, y con una frecuencia de inyección de 180:60 minutos (reposo:inyección), y un control sin tratar que reproducía las condiciones de campo. Los resultados muestran que la inyección de agua de mar saturada en oxígeno fue efectiva como método de remediación de los sedimentos fangosos en estudio, observándose una pérdida gradual del olor fétido, de la textura plástica y de la coloración oscura del sustrato, como consecuencia de la degradación de más del 80% de la materia orgánica acumulada y por la oxidación de los compuestos de azufre reducidos generados bajo esas condiciones de anaerobiosis.El presente trabajo se ha realizado con la financiación de la Universidad de Alicante (Prueba de Concepto, BOUA 5/6/2015) y ROUTE PONT SL

Remediación de sedimentos marinos anóxicos

El objetivo de este trabajo fue el desarrollo de una novedosa técnica de remediación de sedimentos marinos anóxicos a partir de la inyección de agua de mar saturada en oxígeno. El estudio se llevó a escala laboratorio, muestreando sedimento procedente de la playa de la Marineta Casiana (Dénia, Alicante), en una superficie de 20 m2 a 5 metros de la orilla. Se establecieron dos tratamientos: inyección de agua de mar saturada en oxígeno a 20 cm de profundidad desde la superficie del sedimento, durante 68 días, y con una frecuencia de inyección de 180:60 minutos (reposo:inyección), y un control sin tratar que reproducía las condiciones de campo. Los resultados muestran que la inyección de agua de mar saturada en oxígeno fue efectiva como método de remediación de los sedimentos fangosos en estudio, observándose una pérdida gradual del olor fétido, de la textura plástica y de la coloración oscura del sustrato, como consecuencia de la degradación de más del 80% de la materia orgánica acumulada y por la oxidación de los compuestos de azufre reducidos generados bajo esas condiciones de anaerobiosis.El presente trabajo se ha realizado con la financiación de la Universidad de Alicante (Prueba de Concepto, BOUA 5/6/2015) y ROUTE PONT SL

Carybdea marsupialis, the box-jellyfish of the Mediterranean

Un documental de LIFE CUBOMED "Desarrollo y demostración de métodos de erradicación y control de una especie invasora, Carybdea marsupialis (Cubozoa) en el Mediterráneo español"Documental de carácter científico y educativo sobre la especie de cubomedusa Carybdea marsupialis. Resume los principales hallazgos del proyecto LIFE+08 NAT ES0064 CUBOMED (www.cubomed.eu). Aborda aspectos de su biología, ecología, modelos poblacionales y análisis de los factores ambientales que hacen que en algunas localizaciones esta especie aumente significativamente sus poblaciones. También se aborda la problemática de las picaduras de medusas en general y de esta especie en particular, cabe mencionar que es la primera causa de atención en puestos de socorro en las playas del Mediterráneo español, con más del 72% de las atenciones.Comisión Europea, programa LIFE (LIFE+NAT ES08 0064 CUBOMED). Ministerio de Medio Ambiente, Medio Rural y Marino, Conselleria de Medio Ambiente de la Generalitat Valenciana, Fundación Biodiversidad

Beach lifeguard intervention data as a tool for detecting jellyfish population trends and jellyfish sting >hot spots>

5th International Jellyfish Bloom Symposium, 30 May to 3 June 2016, Barcelona.-- 1 page, 4 figuresDespite their ecological and socio-economic impact, on tourism, fisheries and aquaculture, for instance, quantitative data on jellyfish abundance in coastal areas is scarce. As part of the LIFE Cubomed project, we explored the usefulness of data on beach lifeguard interventions as a tool for monitoring seasonal trends and spatial distribution of coastal jellyfish.Lifeguard services in the Spanish Mediterranean cover almost all beaches during the tourist season and attend around 200,000 non-severe injuries each year. Jellyfish stings account for around 65% of these interventions. We developed a Sting Index (SI) to determine the seasonal trend of jellyfish stings at different spatial scales and consider it a good indicator of jellyfish abundance. The number of stings is standardized by the sum of injuries (wounds, dislocation, bruising, bone fracture, fainting and sunburn), which are proportional to the amount of people on the beach. We calculated the average SI over 4 years (2010-2013) at some 400 lifeguard stations along the Spanish Mediterranean. SI values ranged between 1.8 and 2.7 and showed no significant trends during this period. This could reflect stable population levels in the area. However, the SI did allow us to detect “hot spots”, where the rate of stings was up to 10 times the average, and we were able to correlate these areas to the presence of certain jellyfish species. This kind of information can be obtained from places where records are kept on jellyfish stings and can help to obtain data on jellyfish at a larger geographical scalePeer Reviewe

Identification of the first COVID-19 infections in the US using a retrospective analysis (REMEDID)

Accurate detection of early COVID-19 cases is crucial to reduce infections and deaths, however, it remains a challenge. Here, we used the results from a seroprevalence study in 50 US states to apply our Retrospective Methodology to Estimate Daily Infections from Deaths (REMEDID) with the aim of analyzing the initial spread of SARS-CoV-2 infections across the US. Our analysis revealed that the virus likely entered the country through California on December 28, 2019, which corresponds to 16 days prior to the officially recognized entry date established by the Centers of Disease Control and Prevention. Furthermore, the REMEDID algorithm provides evidence that SARS-CoV-2 entered, on average, a month earlier than previously reflected in official data for each US state. Collectively, our mathematical modeling provides more accurate estimates of the initial COVID-19 cases in the US, and has the ability to be extrapolated to other countries and used to retrospectively track the progress of the pandemic. The use of approaches such as REMEDID are highly recommended to better understand the early stages of an outbreak, which will enable health authorities to improve mitigation and preventive measures in the future.This work was supported by the University of Alicante [COVID-19 2020-41.30.6P.0016 to CB] and the Montó-Dénia Research Station (Agreement Ajuntament de Dénia-O.A. Parques Nacionales-Generalitat Valenciana) [2020-41.30.6O.00.01 to CB]. Cesar de la Fuente-Nunez holds a Presidential Professorship at the University of Pennsylvania, is a recipient of the Langer Prize by the AIChE Foundation and acknowledges funding from the Institute for Diabetes, Obesity, and Metabolism, the Penn Mental Health AIDS Research Center of the University of Pennsylvania, the Nemirovsky Prize, the Dean's Innovation Fund from the Perelman School of Medicine at the University of Pennsylvania, the National Institute of General Medical Sciences of the National Institutes of Health under award number R35GM138201, and the Defense Threat Reduction Agency (DTRA; HDTRA11810041 and HDTRA1-21-1-0014)