Slump in Hospital Admissions for Stroke, a Fact of an Uncertain Nature That Requires Explanation.

(1) Background: The impact of the health crisis caused by coronavirus disease 2019 (COVID-19) has provoked collateral effects in the attention to pathologies with time-dependent treatments such as strokes. We compare the healthcare activity of two stroke units in the same periods of 2019 and 2020, with an emphasis on what happened during the state of alarm (SA). (2) Materials and methods. Hospitals in the region implemented contingency plans to contain the pandemic; in this planning, the stroke units were not limited in their operational capacity. The SA was declared on 15 March and remained in place for 10 weeks. For the analysis, the data were grouped by consecutive calendar weeks. (3) Results. When the SA was declared the number of calls to the emergency telephone went from 1225 to 3908 calls per week (318% increase). However, the activation of the stroke code went from 6.6 to 5.0 (p = 0.04) and the activity in both stroke units decreased. The largest drop in hospitalizations was for transient ischemic attacks (TIAs) with 35.7% less, 28 vs. 18, (p = 0.05). Reperfusion therapies fell by 37.5%; Poisson regression model 0.64; (95% confidence interval (CI), 0.43-0.95). The overall activity of the telestroke suffered a reduction of 28.9%. We also observed an increase in hospital mortality. (4) Conclusion. The excessive duration of the pandemic precludes any hope of resolving this public health crisis in the short or medium term. Further studies should be conducted to better understand the multifactorial nature of this dramatic decline in stroke admissions and its negative impact.

Mask-associated 'de novo' headache in healthcare workers during the COVID-19 pandemic.

OBJECTIVES: The pandemic caused by the new coronavirus (COVID-19) has changed care activities of health professionals. We analysed the possible association between the appearance of 'de novo' headache according to the type of mask used, the related factors and the impact of the cephalalgia on health professionals. METHODS: Cross-sectional study in a tertiary hospital in Extremadura, Spain. We provided an online questionnaire to healthcare workers during the period of maximum incidence of COVID-19 in our setting. RESULTS: The subjects are n=306, 244 women (79.7%), with an average age of 43 years (range 23-65). Of the total, 129 (42.2%) were physicians, 112 (36.6%) nurses and 65 (21.2%) other health workers. 208 (79.7%) used surgical masks and 53 (20.3%) used filter masks. Of all those surveyed, 158 (51.6%) presented 'de novo' headache. The occurrence of a headache was independently associated with the use of a filter mask, OR 2.14 (95% CI 1.07 to 4.32); being a nurse, OR 2.09 (95% CI 1.18 to 3.72) or another health worker, OR 6.94 (95% CI 3.01 to 16.04); or having a history of asthma, OR 0.29 (95% CI 0.09 to 0.89). According to the type of mask used, there were differences in headache intensity, and the impact of a headache in the subjects who used a filter mask was worse in all the aspects evaluated. CONCLUSION: The appearance of 'de novo' headache is associated with the use of filter masks and is more frequent in certain healthcare workers, causing a greater occupational, family, personal and social impact.

Monitoring Anti-NS1 Antibodies in West Nile Virus-Infected and Vaccinated Horses.

West Nile virus (WNV) is a zoonotic arboviral pathogen affecting humans, birds, and horses. Vaccines are available for veterinary use, which efficiently prevent the infection in horses. Most common diagnostic tools rely on the identification of the agent (RT-PCR, virus isolation), or on the detection of antibodies (IgM and IgG) recognizing structural proteins of the virus or neutralizing virus infection in cell cultures (virus-neutralization tests). The recent emergence of WNV in different parts of the world has resulted in an increase in the vaccination of horses in many countries. Methods for differentiation between infected and vaccinated animals ("DIVA" assays) would be useful for surveillance and control purposes but are still not available. A usual approach in this regard is the use of antibodies to nonstructural proteins as markers of nonvaccinated, infected animals, and the nonstructural NS1 protein of WNV has been proposed as a candidate for such a marker. The aim of this study was to test the hypothesis that NS1 can be a useful antigen in DIVA assays for differentiating WNV vaccinated and infected horses in field conditions. For that, we examined serum samples from either vaccinated and infected horses both from experimental infections/vaccinations (under controlled conditions) and from the field, exposed to natural infection or vaccinated in response to a risk of infection. The overall conclusion of the study is that NS1 antigen can effectively differentiate WNV infected from vaccinated horses in experimental (controlled) conditions, but this differentiation might be difficult depending on the conditions prevailing in the field.

A monoclonal antibody to DIII E protein allowing the differentiation of West Nile virus from other flaviviruses by a lateral flow assay.

West Nile Virus (WNV) belongs to the Flaviviridae family, genus Flavivirus, which includes other emerging arthropod-borne viruses (arboviruses) pathogenic for animals and/or humans. West Nile Virus is a genetically diverse RNA virus with at least 7 different recognized lineages. Following its recent introduction and subsequent expansion to the Americas, WNV is currently one of the most widely spread arboviruses in the world having recently re-emerged in the Mediterranean basin, Central and Eastern Europe. Laboratory tests are essential to confirm WNV infection and monoclonal antibodies represent useful tools for the development of diagnostic assays. A monoclonal antibody, 1D11, recognizing an epitope in the domain III of the envelope glycoprotein of WNV, was selected for this study. Its suitability to detect a range of WNV variants representative of its whole genetic range, and to differentiate it from other flaviviruses and arboviruses, was assessed by means of an immunochromatographic assay in an LFA format. A panel of cell culture supernatants infected with 9 different WNV isolates representing a wide range of genetic lineages, and 16 non-WNV arboviruses, including flaviviruses closely related to WNV, were tested. The mAb correctly detected all WNV strains, and did not react with any of the non-WNV arboviruses.

Diagnostic aptitude of West Nile virus-like particles expressed in insect cells.

West Nile virus is a globally spread zoonotic arbovirus. The laboratory diagnosis of WNV infection relies on virus identification by RT-PCR or on specific antibody detection by serological tests, such as ELISA or virus-neutralization. These methods usually require a preparation of the whole virus as antigen, entailing biosafety issues and therefore requiring BSL-3 facilities. For this reason, recombinant antigenic structures enabling effective antibody recognition comparable to that of the native virions, would be advantageous as diagnostic reagents. WNV virions are enveloped spherical particles made up of 3 structural proteins (C, capsid; M, membrane and E, envelope) enclosing the viral RNA. This study describes the co-expression of these 3 proteins yielding non-infectious virus-like particles (VLPs) and the results of the initial assessment of these VLPs, used instead of the whole virus, that were shown to perform correctly in two different ELISAs for WNV diagnosis.

Absence of protection from West Nile virus disease and adverse effects in red legged partridges after non-structural NS1 protein administration.

The red-legged partridge (Alectoris rufa) is a competent host for West Nile virus (WNV) replication and highly susceptible to WNV disease. With the aim to assess in this species whether the inoculation of non-structural protein NS1 from WNV elicits a protective immune response against WNV infection, groups of partridges were inoculated with recombinant NS1 (NS1 group) or an unrelated recombinant protein (mock group), and challenged with infectious WNV. A third group received no inoculation prior to challenge (challenge group). The NS1 group failed to elicit detectable antibodies to NS1 while in the mock group a specific antibody response was observed. Moreover, no protection against WNV disease was observed in the NS1 group, but rather, it showed significantly higher viral RNA load and delayed neutralizing antibody response, and suffered a more severe clinical disease, which resulted in higher mortality. This adverse effect has not been observed before and warrants further investigations.

Comparison of two commercial enzyme-linked immunosorbent assays for the diagnosis of Porcine reproductive and respiratory syndrome virus infection.

Early diagnosis of Porcine reproductive and respiratory syndrome virus (PRRSV) is critically important for control of the disease. Two new commercially available enzyme-linked immunosorbent assays (ELISAs) based on different methodologies have been developed. In the present report, the 2 ELISAs were compared using blood samples from experimentally and naturally infected pigs. One of the 2 ELISAs was shown to be more sensitive than the other. The higher sensitivity of one of the ELISAs could pose a problem in PRRS diagnosis in endemic farms, because it can detect maternally derived antibodies for a longer time, overlapping with the detection of antibodies developed after PRRSV infection. However, the ELISA with higher sensitivity could be suitable for early detection of PRRSV antibodies in individual pigs, especially in PRRS-free herds.

Development and evaluation of a new epitope-blocking ELISA for universal detection of antibodies to West Nile virus.

West Nile virus (WNV) is an emerging zoonotic pathogen with a wide range of hosts, including birds, horses and humans. The development and evaluation of the performance of a new enzyme-linked immunosorbent assay (ELISA) are described for rapid detection of WNV-specific antibodies in samples originating from an extensive range of vertebrates susceptible to WNV infection. The assay uses a monoclonal antibody (MAb) which binds whole virus particles and neutralizes infection in vitro by recognizing a neutralizing epitope within the envelope (E) glycoprotein of the virus. This MAb, labelled with horseradish peroxidase, was used to compete with WNV-specific serum antibodies for virus-binding in vitro. The epitope-blocking ELISA was optimized in a manner that enabled its validation with a number of experimental and field sera, from a wide range of wild bird species, and susceptible mammals. The new ELISA exhibited high specificity (79.5-96.5%) and sensitivity (100%), using the virus-neutralization test as reference standard. It also required a much lower volume of sample (10 µl per analysis) compared to other ELISAs available commercially. This new method may be helpful for diagnosis and disease surveillance, particularly when testing samples from small birds, which are available in limited amounts.