First report of pathogenic Leptospira spp. in Tadarida brasiliensis bats (family Molossidae) and Eptesicus furinalis (family Vespertilionidae) of Argentina. New host species in this country?

Leptospirosis is an endemic disease caused by Leptospira spp., a bacterium that affects animals and humans. In recent years, the number of reports of leptospirosis in wild animals has increased, which highlights the need to study the infectious agents in these animals. In this study, a duplex PCR for the detection of leptospiral DNA was performed on 50 kidney samples from bats, and a MAT (Microscopic Agglutination Test) for serological detection of anti-leptospiral antibodies was applied to 47 serum samples from bats from different regions of Buenos Aires Province, Argentina. DNA was extracted using Chelex-100 and duplex PCR was performed by targeting the detection of genes secY and flaB, of pathogenic Leptospira spp. Of the 50 kidney samples, 3 were positive for Eumops sp. and Tadarida brasiliensis by duplex PCR. Of the 47 serum samples, 12 were positive for different serovars: Leptospira interrogans serovars Icterohaemorrhagiae, Cynopteri and Bataviae, and Leptospira borgpetersenii serovar Ballum. This is the first report of the detection of pathogenic leptospires by serology in bats belonging to the T. brasiliensis and Eptesicus furinalis species in Argentina. In addition, this is the first report of the detection of pathogenic leptospiral DNA by PCR in T. brasiliensis species. The detection of Leptospira spp. in these wild animals shows that they may play an important role as wildlife reservoirs of leptospires.

[A comparative study of commercial ELISAs for antibody detection in the diagnostic investigation of Neospora caninum-associated abortion in dairy cattle herds in Uruguay]. / Comparación de ELISAs comerciales para la detección de anticuerpos en la investigación diagnóstica del aborto asociado a Neospora caninum en rodeos lecheros de Uruguay.

Bovine abortion causes considerable economic losses to the livestock industry worldwide and is of concern for public health and food safety, given that many abortigenic infectious agents of cattle are zoonotic. Despite its importance, the etiological diagnosis of abortion in cattle is challenging both for veterinary practitioners and laboratory technicians, partly due to the difficulty in recovering aborted fetuses under extensive field conditions for pathological and microbiological diagnostic investigation, and in the early identification of aborted dams. Neospora caninum is a cosmopolitan protozoon identified as one of the main abortigenic agents in cattle worldwide. In this study we propose a comparative seroepidemiological approach for the diagnosis of abortion by N. caninum in dairy cattle. Samples from 12 to 93 cows/heifers with and without recent history of abortion (cases and controls) in four commercial dairy farms were tested. The ratio of controls to cases tested varied from 1:1 to 4.6:1. All samples (n=230) were analyzed by three commercial ELISA kits for the detection of anti-N. caninum antibodies. In all four dairy farms, the proportion of seropositive cows and/or heifers per kit was significantly higher in the cases than in the controls (Odds Ratios=5.13 to 36, p=0.0002 to 0.0485). The agreement among the three kits varied from weak to strong (Cohens kappa coefficients=0.58 to 0.83). We conclude that, despite the imperfect agreement between these kits, all of them allowed to arrive at similar conclusions regarding the statistical association between N. caninum seropositivity and abortion, thus representing a useful tool for the diagnostic approach at the population level under field conditions.

[Bartonella henselae: Serological evidence in pediatric patients with clinical suspicion of cat scratch disease]. / Bartonella henselae: evidencia serológica en pacientes pediátricos con sospecha clínica de enfermedad por arañazo de gato.

Cat scratch disease (CSD) is caused by Bartonella henselae, which mainly affects children. The cat is the reservoir. The laboratory diagnosis is based on the detection of antibodies by the Indirect Immunofluorescence (IFI) assay. The objective of this study was to analyze the serological evidence of B. henselae infection in pediatric patients that met the clinical/epidemiological criteria for suspected CSD. We studied 92 patients, who were categorized into four serological groups: 1) IgG (+)/IgM(+), 31,5% (n=29); 2) IgG (-)/IgM(+), 10,9% (n=10); 3) IgG (+)/IgM(-), 9,8% (n=9); 4) IgG (-)/IgM(-), 47,8% (n=44). These findings aim to promote future works for investigating the seroprevalence of Bartonella spp. in Argentina, which will allow us to know the importance of this zoonosis in our population and to evaluate new cut-off points of the technique.

Follow-up of surgically treated patients with cystic echinococcosis: can novel recombinant antigens compete with imaging? Analysis of a patient cohort.

OBJECTIVE: To compare the performance of two novel recombinant antigens (EgP29, 2B2t) with imaging in a well-defined cohort of surgically treated cystic echinococcosis (CE) patients to determine whether serology reflects surgical cure as defined by imaging. METHODS: From a cohort of 223 CE-confirmed patients of a national clinical center for echinococcosis, 36 surgically treated patients were eligible for analysis. Sera were tested by enzyme-linked immunosorbent assay (ELISA) for specific IgG and IgG4 antibodies against the EgP29 and 2B2t antigens. We used a hierarchical linear regression model to examine the course of antibody levels over time for each patient. A meta-analysis of the patient-specific estimates of the time to negativity was performed using the metan command in Stata. RESULTS: The range of positive serological results at the beginning of post-surgical monitoring was 34-60%: 2B2t 51%, 2B2t-IgG4 34%, EgP29 60% and EgP29-IgG4 40%. The pooled estimates of time to seronegativity were as follows: 2B2t-ELISA 3.92 (3.24, 4.61) years; 2B2t-IgG4-ELISA 4.60 (3.91, 5.29) years; EgP29-ELISA 3.94 (3.50, 4.39) years; EgP29-IgG4-ELISA 2.55 (1.93, 3.18) years. CONCLUSION: After surgical treatment, antibodies to the recombinant antigens 2B2t and EgP29 become negative in the majority of CE-confirmed, surgically cured patients. The major drawback is the fact that only around half of the CE-confirmed, surgically treated patients were at all responsive to the test antigens, so they are of limited benefit for documenting primary cure. Equally, these antigens do not appear to be sensitive to recurrences.

Rapid diagnosis in serology. / Diagnóstico rápido en serología.

Serological diagnosis of acute phase infections implies the detection of IgM specific response, an effective marker of primary infection, but with less clinical significance in reactivations or reinfections. The aim of this article is to provide an updated view of the rapid diagnosis in serology by detecting the IgM isotype and reviewing its applications and limitations. Point-of-care (PoC) tests are analyzed. PoC tests are used in geographical areas where traditional tests are not available, as well as in other circumstances where their use brings the diagnosis directly to the target population. Likewise, their use reduces the response time between taking the sample and the diagnosis, making it easier to make clinical decisions. PoC assays have proven cost-effective, especially in preventing vertical transmission of syphilis and HIV infection.

[Serological detection of Brucella suis, influenza virus and Aujeszky's disease virus in backyard and small swine holders in Argentina]. / Detección serológica de Brucella suis, virus de influenza y virus de la enfermedad de Aujeszky en criaderos porcinos familiares de menos de 100 madres en Argentina.

Farmers raising less than 100 sows represent more than 99% of swine producers in Argentina, although little is known about their sanitary status and productive characteristics in the country. Sanitary and productive information was obtained. Furthermore, samples for serological studies were taken to detect antibodies against Brucella suis (Bs), Aujeszky's disease virus (AV) and influenza virus (IV) in 68 backyard and small producers with less than 100 sows located in the north, central and south regions of Argentina. Antibodies against H1 pandemic were detected in 80% of the farms while 11%, 11.7% and 6.0% of the producers were positive to influenza H3 cluster 2, AV and Bs, respectively. None of the producers was aware of the risk factors concerning the transmission of diseases from pigs to humans. A percentage of 47% of them buy pigs for breeding from other farmers and markets. With regard to biosecurity measures, only 16% of the farms had perimeter fences. The results of this study demonstrate that productive characterization and disease surveys are important to improve productivity and to reduce the risk of disease transmission among animals and humans. The study of sanitary status and risk factors is necessary for better control and eradication of diseases in backyard or small producers. More representative studies at country level should be carried out to detect the pathogensthat circulate and, with this knowledge, to implement prevention and control measures.

Cysticercosis and epilepsy in rural Tanzania: a community-based case-control and imaging study.

OBJECTIVE: To assess the contribution of neurocysticercosis (NCC) to the burden of epilepsy in a rural Tanzanian population. METHODS: We identified adult people with epilepsy (PWE) in a door-to-door study in an established demographic surveillance site. PWE and community controls were tested for antibodies to Taenia solium, the causative agent of NCC, and all PWE were offered a computed tomography (CT) head scan. Data on household occupancy and sanitation, pig-keeping and pork consumption were collected from PWE and controls and associations with epilepsy were assessed using chi-square or Fisher's exact tests. RESULTS: Six of 218 PWE had antibodies to T. solium (2.8%; 95% CI 0.6-4.9), compared to none of 174 controls (Fisher's exact test, P = 0.04). Lesions compatible with NCC were seen in eight of 200 CT scans (4.0%; 95% CI 1.3-6.7). A total of 176 PWE had both investigations of whom two had positive serology along with NCC-compatible lesions on CT (1.1%; 95% 0.3-4.0). No associations between epilepsy and any risk factors for NCC were identified. CONCLUSIONS: Neurocysticercosis is present in this population but at a lower prevalence than elsewhere in Tanzania and sub-Saharan Africa. Insights from low-prevalence areas may inform public health interventions designed to reduce the burden of preventable epilepsy.

Prevalence of hepatitis C virus in mothers and their children in Malawi.

OBJECTIVES: Hepatitis C virus (HCV) prevalence is poorly mapped in the East African region; with the advent of novel HCV therapies, better epidemiological data are required to target the infection. We sought to estimate HCV prevalence in healthy Malawian mothers and assess mother-to-child transmission (MTCT); context is provided by reviewing previously published HCV prevalence data from the region. METHODS: Using ELISA screening and confirmatory blot, serological testing of 418 healthy Malawian mothers for HCV was performed. To examine MTCT, the children of any positive women were also tested for HCV; all children had malignant disease unrelated to hepatocellular carcinoma. We compared our results to published literature on HCV prevalence in Malawi and its neighbouring countries. RESULTS: Three of 418 women were HCV reactive by ELISA; two were confirmed positive by immunoblot (0.5%). One child of an HCV-infected mother was HCV seropositive. The literature review revealed HCV prevalence ranging from 0 to 7.2% in the region, being highest in Tanzania and specifically for cohorts of inpatients and HIV-co-infected people. The overall estimated prevalence of HCV in Malawi was 1.0% (95%CI 0.7-1.4) when all studies were included (including this one), but lower in healthy cohorts alone at 0.3% (95%CI 0.1-1.2). CONCLUSIONS: This is the first study using confirmatory tests to examine HCV prevalence in healthy Malawian mothers; the prevalence was low. Future studies need to address the source of infection in healthy women.

Serological diagnosis of canine visceral leishmaniasis in Brazil: systematic review and meta-analysis.

OBJECTIVE: To evaluate the quality and accuracy of serological diagnosis of canine visceral leishmaniasis in the Americas. METHODS: A systematic review found original studies in the databases MEDLINE, EMBASE and LILACS up to November 2012 and in complementary sources up to February 2013. Studies were evaluated in accordance with QUADAS 2 and STARD parameters and recommended in accordance with GRADE parameters. Meta-analysis was carried out with Meta-DiSc software, using the random-effect model. RESULTS: Two hundred and eighty-four studies were identified, of which 25 met the inclusion criteria, comprising the final synthesis. All but one was conducted in Brazil, and only two were judged to be of good quality. 15 studies involving immuno-enzymatic tests with crude antigens (cELISA), 11 studies on indirect immunofluorescence tests (IFAT) and three on the immunochromatographic dual-path platform (DPP) test were meta-analysed. The combined results for sensitivity and specificity were cELISA: 0.89 (CI 95% 0.87-0.91) and 0.87 (CI 95% 0.86-0.88); IFAT: 0.88 (CI 95% 0.85-0.91) and 0.63 (CI 95% 0.61-0.65); and DPP: 0.83 (CI 95% 0.78-0.88) and 0.73 (CI 95% 0.70-0.75). CONCLUSION: Enzyme-linked immunosorbent assay with crude antigens and DPP tests have moderate accuracy for the diagnosis of canine visceral leishmaniasis, and the quality of the design, implementation and analysis of validation studies on diagnostic tests for this disease urgently require improvement. The recommendation for use of the evaluated tests is based on evidence that is scarce and restricted to Brazil.

[Serological diagnosis of congenital infections and algorithms to improve diagnostic efficacy]. / Diagnóstico serológico de las infecciones congénitas y algoritmos para mejorar la eficacia diagnóstica.

Congenital infection is those transmitted by the mother to the fetus before delivery. It can occur transplacentally or by direct contact with the pathogen during birth or in the immediate postnatal period. Congenital infection can be due to viruses (rubella, cytomegalovirus, herpes simplex, varicella-zoster, hepatitis B and C virus, human inunodeficiencia, erythrovirus B19) as bacteria (Treponema pallidum) and parasites (Toxoplasma gondii and Trypanosoma cruzi). Serological diagnosis of congenital infection is based on both the knowledge of infectious serology in the mother, including the systematic serological screening and diagnostic aspects of the determination of IgM and confirmatory methods, IgG avidity tests, establishment of antibody profiles, and in the diagnosis the neonate. Serological diagnosis of congenital infection in the newborn is mainly based on the detection of specific IgM usually by immunoenzymatic assays or immunochemiluminescence techniques. In some instances it is important to perform the serological follow up of the newborn to confirm the congenital infection.

[Standardization of Dot-ELISA for detection of anti-Trypanosoma cruzi antibodies, compared to ELISA and Western blot]. / Estandarización de la técnica Dot-ELISA para la detección de anticuerpos anti-Trypanosoma cruzi y su comparación con ELISA y Western blot.

INTRODUCTION: Chagas disease is considered endemic of Latin America. Because of migration of people from this region to non-endemic areas, such as the United States, Canada and Europe, it has become a major health problem. There are parasitology and serology tests for its diagnosis, but only the latter are useful during the chronic phase. Most of these tests require expensive equipment, which make them also inaccessible for laboratories in endemic areas. In the present work we standardize Dot-ELISA as a diagnostic test for Trypanosoma cruzi infection, since it is an easy, inexpensive and an accessible test. METHODS: A total of 360 samples were tested: 96 sera from Chagas patients and 153 from healthy people; 40 blood samples spots collected and eluted from filter paper were also tested, as well as 71 serum samples of patients with non-related infections. Sensitivity, specificity and kappa index of Dot-ELISA test were calculated, in order to determine a correlation value of this technique compared to ELISA and Western blot that are already being used for diagnosis. RESULTS: Dot-ELISA obtained 97% sensitivity and 89% specificity, since it showed cross-reaction mainly with Leishmania spp., and a kappa index of 0,79. CONCLUSIONS: Dot-ELISA results correlate well with other tests that are already being used for diagnosis of Chagas disease. As it is easy and inexpensive, it may be useful as an additional diagnostic test or for field studies.

[Infection by human cytomegalovirus]. / Infección por citomegalovirus humano.

Prevalence of human cytomegalovirus infection is very high worldwide. Following primary infection, the virus remains latent, being able to cause recurrences either by reinfection with a new strain or by reactivation of the replication of the latent virus. The most severe disease is seen in congenital infection and in immunosuppressed patients, in whom the virus act as an opportunistic pathogen. Serological techniques are the methods of choice in primary infection and to determine the immune status against CMV in organ donor and receptor. Although well-standardized studies are lacking, the recent commercial availability of methods that measure cellular immune response are promising to predict the risk of CMV disease in immunosuppressed individuals. Molecular assays, that have gradually been substituting viral culture and/or antigen detection, are the most widely used methods for the diagnosis and control of CMV infection.

[Endemic and epidemic bovine neosporosis: description of two events in beef cattle]. / Neosporosis epidémica y endémica: descripción de dos eventos en bovinos para cría.

The aim of this study was to describe two events in which Neospora caninum was involved in bovine abortions in beef cattle. In the first event, 11 abortions in 57 heifers were recorded in 45 days. One aborted heifer was 5 times more likely to be seropositive than a non-aborted heifer (OR=4.9; IC 1.2-19.9) (p<0.05). In the second event, no association between serological results and abortions were observed (OR=0,69; 0,06-7,31) (p>0.05). Neither antibodies nor isolation of other pathogens were achieved in any case. On the contrary, antibodies and pathognomonic histopathological lesions were observed in the four fetuses from both cases. Interestingly, the findings in the first event suggest the epidemic behavior of the disease. In contrast, in the second event it appears that few abortions were due to N. caninum, suggesting the presence of endemic neosporosis.

Screening for tropical and imported infections in migrant kidney transplant candidates from the kidney transplant access consultation.

BACKGROUND AND OBJECTIVE: Kidney transplantation (KT) should be postponed in those people with active bacterial, fungal, viral and parasitic processes, since these must be treated and resolved previously. The objective of this study is to present the screening circuit implemented by the Nephrology clinic and describe the prevalence of tropical and imported infections in KT candidates born or coming from endemic areas. MATERIALS AND METHODS: Descriptive cross-sectional study, carried out in 2021. Sociodemographic and clinical variables, serological data of general infections and specific tests of tropical infectious diseases were collected. A descriptive analysis of the data was carried out. RESULTS: 67 TR candidates from Latin America (32.8%), North Africa (22.4%), Sub-Saharan Africa (14.9%) and Asia (29.9%) were included. 68.7% were men and the mean age was 48.9 ±â€¯13.5 years. After the general and specific studies, 42 (62.7%) patients were referred to the Infectious Diseases Service to complete this study or indicate treatment. 35.8% of the patients had eosinophilia, and in one case parasites were detected in feces at the time of the study. Serology for strongyloidiasis was positive in 18 (26.9%) cases, while positive serology for other tropical infections was hardly detected. 34.3% of patients had latent tuberculosis infection. CONCLUSIONS: The prevalence of tropical and imported infections in migrant candidates for RT was low, except for strongyloidiasis and latent tuberculosis infection. Its detection and treatment are essential to avoid serious complications in post-TR. To this end, the implementation of an interdisciplinary screening program from the KT access consultation is feasible, necessary and useful.

Lyme borreliosis in pediatric population: Clinical, diagnostic and therapeutic features.

INTRODUCTION: Lyme borreliosis (LB) in the paediatric population is an understudied entity with certain peculiarities. The objective of this study is to describe the characteristics of paediatric patients with LB, and their diagnostic and therapeutic processes. METHODS: Descriptive and retrospective study in patients up to 14 years old with suspected or confirmed LB between 2015 and 2021. RESULTS: A total of 21 patients were studied: 18 with confirmed LB (50% women; median age 6.4 years old) and 3 false positive of the serology. Clinical features in the 18 patients with LB were: neurological (3, neck stiffness; 6, facial nerve palsy), dermatological (6, erythema migratory), articular (1), and non-specific manifestations (5). Serological diagnosis was confirmatory in 83.3% of cases. A total of 94.4% patients received antimicrobial treatment (median duration, 21 days). All recovered with resolution of symptoms. CONCLUSIONS: LB diagnosis is difficult in the paediatric population and presents clinical and therapeutic peculiarities, with favourable prognosis.

Associations of diagnostic findings with disease activity in primary SjÓ§gren's syndrome: a cluster analysis.

OBJECTIVE: The diagnosis of primary SjÓ§gren's syndrome still relies upon a constellation of clinical, laboratory, imaging, and pathological findings. We aimed to evaluate the relation of the disease activity with the results of diagnostic tests for primary SjÓ§gren's syndrome. METHODS: A principal component with cluster analysis was performed to classify 69 patients with primary SjÓ§gren's syndrome based on the results of diagnostic evaluations. RESULTS: Anti-SSA autoantibody was the most represented feature on the principal components. The anti-SSA and ultrasound score were positively correlated (p=0.001). We identified two distinct clusters of low or high disease activity (p<0.001). Except for disease duration and serum beta2-microglobulin, the clusters were significantly different in salivary flow (p= 0.004), ultrasound findings (p<0.001), IgG (p= 0.001), and salivary beta2-microglobulin (p= 0.048). Also, positive findings were significantly different between the clusters in rheumatoid factor, antinuclear antibody, anti-SSA, and anti-SSB (all p≤0.013). CONCLUSION: Patients with higher syndrome activity were best recognized with serological and ultrasound assessments. However, patients with lower syndrome activity had a longer disease duration, higher stimulated salivary flow rate, and a positive biopsy of minor salivary glands (56%).

Evaluation of five immunoassays and one lateral flow immunochromatography for anti-SARS-CoV-2 antibodies detection.

INTRODUCTION: In order to deal with the current pandemic caused by the novel SARS-CoV-2 coronavirus several serological immunoassays have been recently developed with the objective of being used as a complementary diagnostic tool and to support the RT-PCR technique currently considered the "gold-standard" method. However, these new assays need to be evaluated and validated. The purpose of this study was to assess the performance of five immunoassays (two ELISA and three CLIA assays) and one rapid immunochromatographic test for the detection of anti-SARS-CoV-2 antibodies. METHODS: Five semiquantitative immunoassays (MENARINI®, PALEX®, VIRCLIA®, ROCHE® and SIEMENS®) and one lateral flow rapid test (WONDFO®) were performed. A total of 124 samples were studied. Case serum samples (n=78) were obtained from COVID-19 patients confirmed by real-time RT-PCR/epidemiological-clinical-radiological criteria, and control non-SARS-CoV-2 samples (n=46) belonged to healthy healthcare workers involved in a seroprevalence study. RESULTS: Overall, the tests showed sensitivities around 70-90% and specificities greater than 95%, including the immunochromatographic test. In addition, we observed very good agreements among them, being better for the detection of IgG than for IgM antibodies (Cohen's kappa index of 0.95 for VIRCLIA® IgG with ROCHE®), as well as good diagnostic power of the tests as determined by the ROC curves. CONCLUSIONS: This study demonstrates the proper performance of the different immunoassays in order to be applied in the clinical practice as support in the diagnostic approach and in the development of vaccines and seroepidemiological studies of COVID-19.

Pericardial and myocardial involvement after SARS-CoV-2 infection: a cross-sectional descriptive study in healthcare workers.

INTRODUCTION AND OBJECTIVES: The cardiac sequelae of SARS-CoV-2 infection are still poorly documented. We conducted a cross-sectional study in healthcare workers to report evidence of pericardial and myocardial involvement after SARS-CoV-2 infection. METHODS: We studied 139 healthcare workers with confirmed past SARS-CoV-2 infection. Participants underwent clinical assessment, electrocardiography, and laboratory tests, including immune cell profiling and cardiac magnetic resonance (CMR). Clinically suspected pericarditis was diagnosed when classic criteria were present and clinically suspected myocarditis was based on the combination of at least 2 CMR criteria. RESULTS: Median age was 52 (41-57) years, 71.9% were women, and 16.5% were previously hospitalized for COVID-19 pneumonia. On examination (10.4 [9.3-11.0] weeks after infection-like symptoms), participants showed hemodynamic stability. Chest pain, dyspnea or palpitations were present in 41.7% participants, electrocardiographic abnormalities in 49.6%, NT-proBNP elevation in 7.9%, troponin in 0.7%, and CMR abnormalities in 60.4%. A total of 30.9% participants met criteria for either pericarditis and/or myocarditis: isolated pericarditis was diagnosed in 5.8%, myopericarditis in 7.9%, and isolated myocarditis in 17.3%. Most participants (73.2%) showed altered immune cell counts in blood, particularly decreased eosinophil (27.3%; P<.001) and increased cytotoxic T cell numbers (17.3%; P <.001). Clinically suspected pericarditis was associated (P <.005) with particularly elevated cytotoxic T cells and decreased eosinophil counts, while participants diagnosed with clinically suspected myopericarditis or myocarditis had lower (P <.05) neutrophil counts, natural killer-cells, and plasma cells. CONCLUSIONS: Pericardial and myocardial involvement with clinical stability are frequent after SARS-CoV-2 infection and are associated with specific immune cell profiles.

Evaluation of five immunoassays and one lateral flow immunochromatography for anti-SARS-CoV-2 antibodies detection.

INTRODUCTION: In order to deal with the current pandemic caused by the novel SARS-CoV-2 coronavirus several serological immunoassays have been recently developed with the objective of being used as a complementary diagnostic tool and to support the RT-PCR technique currently considered the "gold-standard" method. However, these new assays need to be evaluated and validated. The purpose of this study was to assess the performance of five immunoassays (two ELISA and three CLIA assays) and one rapid immunochromatographic test for the detection of anti-SARS-CoV-2 antibodies. METHODS: Five semiquantitative immunoassays (MENARINI®, PALEX®, VIRCLIA®, ROCHE® and SIEMENS®) and one lateral flow rapid test (WONDFO®) were performed. A total of 124 samples were studied. Case serum samples (n=78) were obtained from COVID-19 patients confirmed by real-time RT-PCR/epidemiological-clinical-radiological criteria, and control non-SARS-CoV-2 samples (n=46) belonged to healthy healthcare workers involved in a seroprevalence study. RESULTS: Overall, the tests showed sensitivities around 70-90% and specificities greater than 95%, including the immunochromatographic test. In addition, we observed very good agreements among them, being better for the detection of IgG than for IgM antibodies (Cohen's kappa index of 0.95 for VIRCLIA® IgG with ROCHE®), as well as good diagnostic power of the tests as determined by the ROC curves. CONCLUSIONS: This study demonstrates the proper performance of the different immunoassays in order to be applied in the clinical practice as support in the diagnostic approach and in the development of vaccines and seroepidemiological studies of COVID-19.

[Strategy for planning and execution of a large-scale SARS-CoV-2 seroprevalence study on teaching hospital workers during a pandemic situation]. / Estrategia de planificación y ejecución de un estudio a gran escala de seroprevalencia de SARS-CoV-2 en trabajadores de un hospital universitario durante una situación de pandemia.

OBJECTIVE: To describe the planning and execution process of a massive seroprevalence study for SARS-CoV-2 in professionals of the Hospital Universitario Fundación Alcorcón (HUFA) (Spain). METHODS: A description is presented of the plan designed and developed at the HUFA for the execution of the extraction of the samples for serology from all the professionals who worked in the hospital between 14 and 29 April 2020. A descriptive analysis of the participation of the professionals in the study is carried out. Extraction areas, health personnel, and execution times were planned. A total of 2326 extractions were assigned to health personnel, the remaining extractions were assigned to workers from external companies. RESULTS: A total of 2641 workers (90.5%) out of 2918 candidates participated in the study. The professional category most analysed was nursing with 28.3% (n = 590). The percentage of compliance with schedule planning was 28.6%. Up to a maximum of 298 daily extractions were planned. The busiest day was the 4th day of the study with 399 extractions. CONCLUSIONS: The organising of such a large study, with a 100% coverage of those who worked in the hospital, and with such a great response from the workers involved, has led to obtaining results of high reliability in the seroprevalence study carried out. Although the percentage of participation was very high, the level of compliance with the planning was low.