Epidemiological Conditions Research Articles

Latin American and the Caribbean Code Against Cancer 1st edition: Infections and cancer

About 13% of all cancers around the world are associated with infectious agents, particularly in low-resource settings. The main infectious agents associated with cancer are Helicobacter pylori (H. pylori), that causes gastric cancer, human papillomavirus (HPV) that causes cervical, vulvar, vaginal, penile, anal, and oropharyngeal cancer, hepatitis B and C viruses that cause liver cancer, and human immunodeficiency virus (HIV), associated with cancers of the cervix, Kaposi sarcoma (KS) and non-Hodgkin´s lymphoma. In Latin America and the Caribbean (LAC), about 150,000 cancer cases are caused annually by infections. The LAC Cancer Code Against Cancer consists of a set of 17 evidence-based and individual-level cancer prevention recommendations targeted to the general population, suited to the epidemiological, socioeconomic, and cultural conditions of the region, and tailored to the availability and accessibility of health-care systems. The recommendations with respect to infection-driven malignancies include testing and treating for H. pylori in the context of specific public health programs, vaccination against HPV and Hepatitis B Virus (HBV) and detection and treatment of chronic infections with HBV, Hepatitis C virus (HCV) and HIV, in addition to the promotion of safe sex and use of condoms to prevent sexually transmitted infections (STI). Countries, policy makers, health care systems and individuals should consider the adoption of these recommendations to help reduce the incidence and mortality of infection-related cancers in LAC, to improve quality of life of individuals and reduce the costs of cancer care in the region.

Latin America and the Caribbean Code Against cancer 1st edition: Environment, occupation, and cancer

Within the framework of the Latin America and Caribbean region (LAC) Code Against Cancer 1st edition, the current work presents recommendations to reduce exposure to environmental and occupational carcinogenic agents relevant for LAC. Using the methodology established by the International Agency for Research on Cancer (IARC) in the World Code Against Cancer Framework and experience from developing the European Code Against Cancer 4th edition, a working group of LAC cancer-prevention experts reviewed the list of Group I IARC carcinogenic agents, identified prevalent environmental and occupational exposures in the region, and proposed evidence-based cancer prevention recommendations suited to the epidemiological, socioeconomic, and cultural conditions of LAC countries. Two sets of recommendations were drafted: those targeting the general public and a second set for policymakers. Outdoor and indoor air pollution, ultra-violet radiation and occupational exposures to silica dust, asbestos, benzene, diesel, and welding fumes were identified as prevalent carcinogens in LAC and as agents that could be reduced or eliminated to prevent cancers. Recommendations for additional risk factors were not included due to insufficient data of their attributable burden in LAC (sunbeds, radon, aflatoxin), or lack of a clear preventive action to be taken by the individual (arsenic in drinking water, medical radiation), or lack of evidence of carcinogenicity effect (bisphenol A, phthalates, and pesticides). A broad consensus was reached on environmental and occupational carcinogenic exposures present throughout the LAC region and on individual-level and public policy-level recommendations to reduce or eliminate these exposures. Key educational content for the dissemination of these recommendations was also developed as part of LAC Code Against Cancer 1st Edition.

Serological profile of patients suspected with non-scrub typhus rickettsioses

BackgroundRickettsial pathogens are Gram-negative, obligate intracellular bacteria. They are transmitted by arthropods and are responsible for a wide variety of disease, from minor to life-threatening, which have a global effect on human health. Limited data are available on the prevalence of rickettsial diseases from India, and the disease epidemiology is not fully described. This study aimed to diagnose non-scrub typhus rickettsioses including spotted fever and typhus group of Rickettsia in clinically suspected patients by using standard serological tests and recognition of common epidemiological conditions and clinical manifestations. MethodsDuring the study period, a total of 700 patients of all ages with acute febrile illness were enrolled. Patients were screened for rickettsial infection using IgM Enzyme-linked immunosorbent assay (ELISA) and Immunofluorescence assay (IFA) was performed to confirm the ELISA positive results. The relevant demographic, clinical, and laboratory details of patients were documented and analyzed. ResultsOf 700 samples tested, 141 (20.2%) were found to be positive for IgM antibodies against rickettsioses using ELISA and IFA. SFGR was positive in 15 (2.2%), TGR was positive in 112 (16%) and 14 (2%) samples were positive for both groups. 20 (14.2%) patients required admission to the intensive care unit (ICU), and 24 (17%) in-hospital deaths occurred. ConclusionsThe prevalence of rickettsioses in India appears to be underestimated; therefore, increased awareness and improved diagnostic testing could facilitate early detection of cases, pathogen-targeted appropriate treatment, and improved outcomes for patients. Despite the fact that Rickettsiae can be isolated or detected using molecular techniques in clinical specimens, serology still remains the most commonly used diagnostic method for rickettsioses around the world. Our study helps bridge the gap of limited data on Rickettsia in north India and could be useful for future epidemiological investigation of rickettsial diseases and outbreaks.

Demographic and epidemiological characteristics of Ukrainian refugees in an Italian Local Health Authority.

The Russian invasion of Ukraine caused millions of Ukrainian refugees to flee to other nations. To provide the most appropriate assistance, host nations necessitate up-to-date information regarding Ukrainian refugee's demographic and epidemiological conditions. We aim to investigate the demographic composition, the COVID-19 vaccinations performed, specialist care provided and the prevalence of non-communicable diseases (NCDs) in refugees assisted by an Italian Local Health Authority (LHA). We conducted a retrospective cross-sectional analysis from March to June 2022, analyzing the demographic and epidemiological status of Ukrainians. Statistical analyses were carried out to assess possible associations between NCDs distribution, age and gender. LHA Roma 1 assisted 9349 Ukrainian refugees. Of these, 2784 (29.8%) were males and 6565 (70.2%) were females, with a median age of 25 years. Two thousand four hundred and eighty-five Ukrainian refugees were vaccinated against COVID-19. Among them, 401 (16.1%) had at least one NCD. The most frequent groups of diseases were related to the circulatory system (50.6%), the endocrine system (24.9%), and mental and behavioral disorders (6.5%). Refugees need healthcare services targeted mainly towards minors and females. It is essential to analyze and monitor the demographic and epidemiological conditions to provide evidence about patient management and the best care integrated into the health service of host countries.

Interdisciplinarity between Medicine and Veterinary Medicine in urban rabies control actions

Medicine and veterinary medicine are health knowledge areas that work together in various spheres of their competencies, including the prevention and treatment of urban rabies. The objective of this study was to relate medicine and veterinary medicine within the epidemiological scope of urban rabies, particularly in Brazil, highlighting the importance of interdisciplinarity between the two health professions. It is noted from the bibliography that the association of a veterinarian with an infectious disease specialist in epidemiological actions causes a drastic decrease in the transmissibility of the rabies virus. Therefore, the association of these two areas is of great importance for planning strategies in epidemiological surveillance to achieve rapid responses to changes in infectious conditions. Thus, we can consider that for proper epidemiological surveillance of the urban cycle of rabies, the comprehensiveness and interdisciplinarity of medical and veterinary fields become necessary, as considerable reductions in epidemiological conditions are observed in strategies and actions that encompass both areas of health.

Role of children’s polyclinic in primary prevention of diseases

Objective. To carry out a single-stage descriptive study of realizing preventive direction in the work of a childrens polyclinic in modern conditions. A modern trend of Russian medicine is its preventive direction. As a result of great modifications of the primary medico-social care during the recent years, there were formed structural departments dealing with the status of childrens health, medico-social problems, provision of sanitary and epidemiological conditions of child-care facilities in childrens polyclinics. Materials and methods. Using the example of a standard childrens polyclinic of the second level, the results of work of structural departments of childrens polyclinic involved in preventive work with child population are presented. Results. Realization of preventive directions in the work of pediatric and consultative-diagnostic departments and organization of medical care permitted to increase the share of preventive visits in 2022 to 47%, to ensure covering with preventive examinations up to 98-100%, vaccination 97% of the contingent. The level of sickness rate among infants under one year decreased by 25%. The department of medico-social care individually follows up children and their parents in difficult conditions of life. At the Center of Health, six types of screening investigations, individual recommendations regarding the formation of behavioral stereotypes for maintaining health are provided in childrens polyclinic. Conclusions. Organization of the structure and functional of modern childrens polyclinic provide an effective prevention of diseases and create optimal conditions for formation of childrens health, their physical and intellectual abilities, prevention of infectious and noninfectious diseases.

1202-P: Comparison of the Clinical Characteristics, Glycemic Control, and Pregnancy Outcomes between Wave I and III of COVID-19 Pandemic in Women with Gestational Diabetes Mellitus—A Reference Center Report

Background: The medical care for gestational diabetes mellitus (GDM) during the COVID-19 pandemic was influenced by changing epidemiological conditions and governmental regulations. Aim To compare the clinical data of GDM women between wave I and III of COVID-19 pandemic. Materials and methods: We performed retrospective analysis of the medical records from the GDM clinic of the University Hospital in Krakow, and compared the periods of March-May 2020 and March-May 2021, corresponding to wave I and III, respectively. Results: GDM women during wave I (N=118) as compared to wave III (N=116) were older (33.0±4.7 vs 32.1±4.8 years; p=0.03), booked later (21.8±8.4 vs 20.3±8.5 weeks; p=0.08) and had the last visit earlier (35.5±2.0 vs. 35.7±3.2 weeks; p<0.01). The pregnancy weight gain were similar (8.9±5.6 vs 8.4±5.6 kg; p=NS). Telemedicine consultations were used more frequently during wave I (36% vs 18% of all visits; p<0.01) while insulin therapy less often (64.7% vs. 80.2%; p<0.01). The mean fasting self-control glucose did not differ (4.8±0.3 vs 4.8±0.3 mmol/l; p=0.25) but a worse postprandial glycemia during wave I was reported (6.6±0.9 vs. 6.3±0.6 mmol/l; p<0.01). Pregnancy outcome data were available from 77 and 73 pregnancies, respectively. The groups were similar for the delivery time (38.2±1.4 vs. 38.1±1.6 weeks), cesarean sections (58.4% vs. 61.3%), APGAR score (9.7±1.0 vs. 9.7±1.0 pts) and birth weight (3306.6±460.6 g vs 3243.9±500.2) (p=NS for all), slightly higher length occurred for Wave I (54.3±2.6 cm vs. 53.3±2.6; p=0.02). Conclusions: We identified differences in many areas between GDM women booking either during wave I or III of COVID-19 pandemic, however, the pregnancy outcomes were mostly similar. Disclosure M.Wilk: None. M.Kania: None. M.Malecki: Advisory Panel; Abbott Diabetes, Novo Nordisk, Lilly, Sanofi, Dexcom, Inc., Bayer Inc., Research Support; Medtronic, Speaker's Bureau; AstraZeneca, AlfaSigma, Merck & Co., Inc., BIOTON S.A., Servier Laboratories, KRKA.

Epidemic Management via Imperfect Testing: A Multi-criterial Perspective

Diagnostic testing may represent a key component in response to an ongoing epidemic, especially if coupled with containment measures, such as mandatory self-isolation, aimed to prevent infectious individuals from furthering onward transmission while allowing non-infected individuals to go about their lives. However, by its own nature as an imperfect binary classifier, testing can produce false negative or false positive results. Both types of misclassification are problematic: while the former may exacerbate the spread of disease, the latter may result in unnecessary isolation mandates and socioeconomic burden. As clearly shown by the COVID-19 pandemic, achieving adequate protection for both people and society is a crucial, yet highly challenging task that needs to be addressed in managing large-scale epidemic transmission. To explore the trade-offs imposed by diagnostic testing and mandatory isolation as tools for epidemic containment, here we present an extension of the classical Susceptible-Infected-Recovered model that accounts for an additional stratification of the population based on the results of diagnostic testing. We show that, under suitable epidemiological conditions, a careful assessment of testing and isolation protocols can contribute to epidemic containment, even in the presence of false negative/positive results. Also, using a multi-criterial framework, we identify simple, yet Pareto-efficient testing and isolation scenarios that can minimize case count, isolation time, or seek a trade-off solution for these often contrasting epidemic management objectives.

Candida auris screening practices at healthcare facilities in the United States: A survey of the Emerging Infections Network

Background:Candida auris, an emerging fungal pathogen, is frequently drug resistant and spreads rapidly in healthcare facilities. Screening to identify patients colonized with C. auris can prevent further spread by prompting aggressive infection prevention and control measures. The CDC recommends C. auris screening based on local epidemiological conditions, patient characteristics, and facility-level risk factors; such screening might help facilities in higher burden areas to mitigate transmission and those in lower-burden areas to detect new introductions before spread begins. To describe US screening practices and challenges, we surveyed a network of infection disease practitioners, comparing responses by local C. auris case burdens. Methods: In August 2022, we emailed a survey about C. auris screening practices to ~3,000 members of the IDSA Emerging Infection Network. We describe survey results, stratifying findings by whether the healthcare facility was in a region where C. auris is frequently identified (tier 3 facility) or not frequently identified (tier 2 facility), based on CDC assessment using existing multidrug-resistant organism containment guidance (https://www.cdc.gov/hai/containment/guidelines.html). Results: We received 253 responses (tier 3 facilities: 119, tier 2 facilities: 134); overall, 37% performed screening. Tier 3 facilities more frequently performed screening than tier 2 facilities (59% vs 17%). Among facilities that performed screening, tier 3 facilities, compared with tier 2 facilities, more frequently screened patients on admission (84% vs 55%) and used an in-house laboratory for testing (68% vs 29%), most often with culture-based methods. Tier 2 facilities more frequently screened patients already admitted in the facility (eg, in response to cases or as part of point-prevalence surveys) compared with tier 3 facilities (59% vs 49%). Among facilities performing screening, 72% had identified ≥1 case in the previous year (tier 3 facilities, 85%; tier 2 facilities, 33%). Barriers to screening included limited laboratory capacity, long testing turnaround times, and the perception that screening was not useful. Conclusions: Most facilities surveyed did not perform C. auris screening. However, most facilities that performed screening, including those in regions of higher and lower C. auris burden, detected cases during the previous year. Admission screening, which might help detect new introductions before spread begins, was uncommon in facilities in lower-burden areas. Improving ease of C. auris screening through access to in-house laboratory testing with rapid turnaround times might increase the adoption of C. auris screening by facilities, thereby increasing detection and preventing spread.Disclosures: None

The 2023 AAAS Annual Meeting: Some Communication-Related Highlights—And Challenges

Selection pressures from the COVID-19 pandemic and its aftermath have caused much in society, including conferences, to evolve. For example, for 2021 and 2022, the American Association for the Advancement of Science (AAAS) moved its annual meeting online. For 2023, with epidemiologic conditions improving, AAAS chose a hybrid model for its annual meeting, themed “Science for Humanity” and held March 2–5 in Washington, DC. Sessions were to be available simultaneously in person and online. As usual, I was coordinating Science Editor coverage of the AAAS meeting. Several current or former graduate students and I were each to cover a session, and I was to compile the reports into an article. As secretary of an AAAS section, I was attending the meeting in person. The others planning to provide session reports had arranged to attend online. Soon into the meeting, I began receiving messages from the graduate students, stating that their assigned sessions were now being listed as available only in person. AAAS then posted a message1 saying that because of technical issues, the rest of the virtual portion of the meeting was being suspended. AAAS said it was striving to record the sessions and make them available. Later, however, it announced that recordings suitable to share could not be recovered. Having committed to Science Editor coverage, I revamped my schedule to attend more of the communication-related sessions, and I have written the report. Some team members who had planned to cover sessions served as reviewers of a draft. Highlights of […]

Performance reporting in the healthcare sector: evidence from Italian healthcare organisations

PurposeThe present research aims to understand the performance disclosure levels provided by Italian healthcare organisations (HCOs). The authors conducted this study to assess the transparency of HCOs' performance reporting processes by examining the amount and the type of information disclosed in Annual Performance Reports (APRs).Design/methodology/approachThe present study uses a qualitative research methodology based on manual content analysis. The APRs of a sample of 171 Italian public HCOs were analysed.FindingsResults evidence that the APRs provide a sufficient level of disclosure of performance information, putting high attention on the epidemiological conditions; however, the APRs do not present a strong information function for stakeholders' decision-making purposes. The Italian HCOs APRs are not easily understandable because the APRs are not very concise and present information mainly in discursive terms with limited graphic support.Originality/valueTo the best of the authors' knowledge, this is the first research investigating both the extent and type of performance information reported by Italian HCOs in the APRs, considering the particular contextual conditions caused by the most significant challenge the healthcare (HC) sector has faced in recent years: the epidemiological crisis of the coronavirus disease 2019 (COVID-19). The study also explores whether APRs are currently used by HCOs as a merely regulatory requirement or as an information tool for accountability and decision-making purposes.

Identification of Risk Areas of Dengue Transmission in Culiacan, Mexico

Dengue is a public health problem in more than 100 countries around the world and in virtually the entire region of the Americas, including Mexico. Mosquitoes of the genus Aedes aegypti transmit dengue; its reproduction requires certain geographical, epidemiological, demographic and socioeconomic conditions. Detailed information on socioeconomic, epidemiological and entomological data is available, but detailed meteorological information is not. The objective of this study was to identify the areas of risk of dengue transmission for each month of the year based on environmental, social, entomological and epidemiological information from 2010 to 2020, in Culiacan, Mexico. LST, NDVI and NDMI were calculated from Landsat 8 satellite images with remote sensing techniques. Additional variables were human population density and overcrowding; mosquito egg density from positive ovitraps; and probable cases of dengue. A descriptive analysis of the study variables and a multiple linear regression analysis were performed to determine the significant variables. In addition, a multicriteria spatial analysis was applied through the AHP technique to identify areas at risk of dengue transmission. The results revealed that the variables NDVI, NDMI and overcrowding were not significant; however, the LST, population density, egg density per positive ovitrap and probable cases were. The highest population in the transmission risk areas was in November, and the highest transmission area was identified in October. In conclusion, it was possible to identify which of the study variables were significant; in addition, monthly maps of risk areas of dengue transmission for Culiacan were obtained. Each geographical area had its own characteristics that influenced, in one way or another, the incidence of dengue, highlighting that the strategies for control of dengue must be specific to each region.

Socioeconomic disparities in the reopening of schools during the pandemic in Chile

The COVID-19 pandemic produced the most significant disruption in education in history. More than 190 countries suspended in-person instruction, affecting an estimated 1.6 billion students. The reopening of schools has been unequal. Schools in more affluent areas reopened sooner than poorer ones, exacerbating preexisting inequalities. There is limited research about the reopening processes in Latin America, where schools were closed for extended periods. Using a rich administrative dataset, we investigate the gaps in the resumption of in-person instruction in Chilean schools across socioeconomic groups in the fall of 2021. Schools with lower socioeconomic status were significantly less likely to offer in-person instruction. Disparities in reopening decisions were associated with administrative factors rather than economic or local epidemiological conditions.

Prevalence and Risk Factors Associated with Theileria annulata Infection in Two Bovine Portuguese Autochthonous Breeds.

Tropical Bovine Theileriosis is an important tick-borne disease. This study aims to assess the occurrence of Theileria annulata infection in two indigenous Portuguese cattle breeds. A total of 843 blood samples collected from animals of Alentejana (n = 420) and Mertolenga (n = 423) breeds were analyzed. The detection of Theileria annulata was determined by amplification of a fragment of the merozoite-pyroplasm surface antigen gene with 319 base pairs (bp). The prevalence found (10.8%) is lower than that reported in previous studies (21.3%). A statistically significant difference was found for positivity between breeds (p < 0.05). There is also a higher probability of older animals being positive compared to younger ones (p < 0.05). The region where Mertolenga animals are located is shown to have a significant impact on positivity (p < 0.05). Thus, the development of sustainable T. annulata control strategies and their implementation, adapted to the epidemiological conditions of higher risk, will be extremely important.

Cost of diabetes and its complications: results from a STEPS survey in Punjab, India

BackgroundDiabetes mellitus is an obtrusive universal health emergency in developed and developing countries, including India. With the exponential rise of epidemiological conditions, the costs of treating and managing diabetes are on an upsurge. This study aimed to estimate the cost of diabetes and determine the determinants of the total cost among diabetic patients.MethodsThis cross-sectional study was executed in the northern state of Punjab, India. It involves the multi-stage area sampling technique and data was collected through a self-structured questionnaire adapted following the “WHO STEPS Surveillance” manual. Mann–Whitney U and Kruskal–Wallis tests were performed to compare the cost differences in socio-demographic variables. Lastly, multiple linear regression was conducted to determine and evaluate the association of the dependent variable with numerous influential determinants.ResultsThe urban respondents' average direct and indirect costs are higher than rural respondents. Age manifests very eccentric results; the highest mean direct outpatient care expenditure of ₹52,104 was incurred by the respondents below 20 years of age. Gender, complications, income, history of diabetes and work status were statistically significant determinants of the total cost. Study reports a rapid increase in the median annual direct and indirect cost from ₹15,460 and ₹3572 in 1999 to ₹34,100 and ₹4200 in 2021.ConclusionsThe present study highlights that the economic jeopardy of diabetes can be managed by educating people about diabetes and its associated risk factors. The economic burden of diabetes could be restrained by formulating new health policies and promoting the use of generic medicines. The result of the study directs that expenditure on outpatient care is to be reimbursed under the ‘Ayushman Bharat-Sarbat Sehat Bima Yojana’.

Lyme Neuroborreliosis-Significant Local Variations in Incidence within a Highly Endemic Region in Sweden.

The aim of this study was to perform a detailed epidemiological overview of Lyme neuroborreliosis (LNB) 2008-2021 in a highly Lyme borreliosis-endemic area in Sweden using a geographic information system (GIS). Diagnosis of LNB was based on clinical symptoms and analysis of cerebrospinal fluid (CSF) according to European guidelines. From laboratory databases and medical records, we detected all patients with CSF pleocytosis and intrathecal anti-Borrelia antibody production and listed clinical features. The distribution of LNB cases within Kalmar County, Sweden was investigated using GIS. In total, 272 cases of definite LNB were confirmed with an average yearly incidence of 7.8/100,000. Significant differences in incidence were noted between children 0-17 years (16/100,000) and adults 18+ years (5.8/100,000) (p < 0.001), between rural (16/100,000) and urban areas (5.8/100,000) (p < 0.001) and between selected municipalities (p < 0.001). Distinct clinical differences in presentation of LNB were also noted between children and adults. Thus, the incidence of LNB varies significantly locally and in relation to age, and clinical presentation shows differences between children and adults. Surveillance of LNB and knowledge of local epidemiological conditions may facilitate preventive measures.

The Role of Socioeconomic Status in the Development of Arterial Hypertension in HIV-Infected Population

Development of a more advanced model for the formation of unfavorable epidemiological conditions in relation to the therapeutic continuum in the HIV-infected population, also to study and evaluate, along with behavioral risk factors, such factors as characteristics of family status, living conditions, social and educational status against the background of HIV infection

Modeling COVID-19 infection dynamics and mitigation strategies for in-person K-6 instruction.

U.S. school closures due to the coronavirus disease 2019 (COVID-19) pandemic led to extended periods of remote learning and social and economic impact on families. Uncertainty about virus dynamics made it difficult for school districts to develop mitigation plans that all stakeholders consider to be safe. We developed an agent-based model of infection dynamics and preventive mitigation designed as a conceptual tool to give school districts basic insights into their options, and to provide optimal flexibility and computational ease as COVID-19 science rapidly evolved early in the pandemic. Elements included distancing, health behaviors, surveillance and symptomatic testing, daily symptom and exposure screening, quarantine policies, and vaccination. Model elements were designed to be updated as the pandemic and scientific knowledge evolve. An online interface enables school districts and their implementation partners to explore the effects of interventions on outcomes of interest to states and localities, under a variety of plausible epidemiological and policy assumptions. The model shows infection dynamics that school districts should consider. For example, under default assumptions, secondary infection rates and school attendance are substantially affected by surveillance testing protocols, vaccination rates, class sizes, and effectiveness of safety education. Our model helps policymakers consider how mitigation options and the dynamics of school infection risks affect outcomes of interest. The model was designed in a period of considerable uncertainty and rapidly evolving science. It had practical use early in the pandemic to surface dynamics for school districts and to enable manipulation of parameters as well as rapid update in response to changes in epidemiological conditions and scientific information about COVID-19 transmission dynamics, testing and vaccination resources, and reliability of mitigation strategies.

Performance estimation of two in-house ELISA assays for COVID-19 surveillance through the combined detection of anti-SARS-CoV-2 IgA, IgM, and IgG immunoglobulin isotypes.

The main objective of this study was to estimate the performance, under local epidemiological conditions, of two in-house ELISA assays for the combined detection of anti-SARS-CoV-2 IgA, IgM, and IgG immunoglobulins. A total of 94 serum samples were used for the assessment, where 44 corresponded to sera collected before the pandemic (free of SARS-CoV-2 antibodies), and 50 sera were collected from confirmed COVID-19 patients admitted to the main public hospital in the city of Valdivia, southern Chile. The Nucleocapsid (Np) and the receptor-binding domain (RBD) proteins were separately used as antigens (Np and RBD ELISA, respectively) to assess their diagnostic performance. A receiver operating characteristic (ROC) analysis was performed to estimate the optical density (OD) cut-off that maximized the sensitivity (Se) and specificity (Sp) of the ELISA assays. Np ELISA had a mean Se of 94% (95% CI = 83.5-98.8%) and a mean Sp of 100% (95% CI = 92.0-100%), with an OD 450 nm positive cut-off value of 0.88. On the other hand, RBD ELISA presented a mean Se of 96% (95% CI = 86.3-99.5%) and a mean Sp of 90% (95% CI = 78.3-97.5%), with an OD 450 nm positive cut off value of 0.996. Non-significant differences were observed between the Se distributions of Np and RBD ELISAs, but the latter presented a significant lower Sp than Np ELISA. In parallel, collected sera were also analyzed using a commercial lateral flow chromatographic immunoassay (LFCI), to compare the performance of the in-house ELISA assays against a commercial test. The LFCI had a mean sensitivity of 94% (95% CI = 87.4-100%) and a mean specificity of 100% (95% CI = 100-100%). When compared to Np ELISA, non-significant differences were observed on the performance distributions. Conversely, RBD ELISA had a significant lower Sp than the LFCI. Although, Np ELISA presented a similar performance to the commercial test, this was 2.5 times cheaper than the LFCI assay (labor cost not considered). Thus, the in-house Np ELISA could be a suitable alternative tool, in resource limited environments, for the surveillance of SARS-CoV-2 infection, supporting further epidemiological studies.

Antibody cross-reactivity and evidence of susceptibility to emerging Flaviviruses in the dengue-endemic Brazilian Amazon

ObjectivesSeveral Flaviviruses can co-circulate. Pre-existing immunity to one virus can modulate the response to a heterologous virus; however, the serological cross-reaction between these emerging viruses in dengue virus (DENV)-endemic regions are poorly understood. MethodsA cross-sectional study was performed among the residents of Manaus city in the state of Amazonas, Brazil. The serological response was assessed by hemagglutination inhibition assay (HIA), enzyme-linked immunosorbent assay, and neutralization assay. ResultsA total of 74.52% of the participants were immunoglobulin G-positive (310/416), as estimated by lateral flow tests. Overall, 93.7% of the participants were seropositive (419/447) for at least one DENV serotype, and the DENV seropositivity ranged between 84.8% and 91.0%, as determined by HIA. About 93% had antiyellow fever virus 17D-reactive antibodies, whereas 80.5% reacted to wild-type yellow fever virus. Zika virus (ZIKV) had the lowest seropositivity percentage (52.6%) compared with other Flaviviruses. Individuals who were DENV-positive with high antibody titers by HIA or envelope protein domain III enzyme-linked immunosorbent assay reacted strongly with ZIKV, whereas individuals with low anti-DENV antibody titers reacted poorly toward ZIKV. Live virus neutralization assay with ZIKV confirmed that dengue serogroup and ZIKV-spondweni serogroup are far apart; hence, individuals who are DENV-positive do not cross-neutralize ZIKV efficiently. ConclusionTaken together, we observed a high prevalence of DENV in the Manaus-Amazon region and a varying degree of cross-reactivity against emerging and endemic Flaviviruses. Epidemiological and exposure conditions in Manaus make its population susceptible to emerging and endemic arboviruses.