Seroprevalence of dengue in Trinidad using rapid test kits: a cord blood survey

Evaluation of the Diagnostic Accuracy of a New Biosensors-Based Rapid Diagnostic Test for the Point-Of-Care Diagnosis of Previous and Recent Dengue Infections in Malaysia

Dengue is a major threat to public health globally. While point-of-care diagnosis of acute/recent dengue is available to reduce its mortality, a lack of rapid and accurate testing for the detection of previous dengue remains a hurdle in expanding dengue seroepidemiological surveys to inform its prevention, especially vaccination, to reduce dengue morbidity. This study evaluated ViroTrack Dengue Serostate, a biosensors-based semi-quantitative anti-dengue IgG (immunoglobulin G) immuno-magnetic agglutination assay for the diagnosis of previous and recent dengue in a single test. Blood samples were obtained from 484 healthy participants recruited randomly from two communities in Petaling district, Selangor, Malaysia. The reference tests were Panbio Dengue IgG indirect and capture enzyme-linked immunosorbent assays, in-house hemagglutination inhibition assay, and focus reduction neutralization test. Dengue Serostate had a sensitivity and specificity of 91.1% (95%CI 87.8-93.8) and 91.1% (95%CI 83.8-95.8) for the diagnosis of previous dengue, and 90.2% (95%CI 76.9-97.3) and 93.2% (95%CI 90.5-95.4) for the diagnosis of recent dengue, respectively. Its positive predictive value of 97.5% (95%CI 95.3-98.8) would prevent most dengue-naïve individuals from being vaccinated. ViroTrack Dengue Serostate's good point-of-care diagnostic accuracy can ease the conduct of dengue serosurveys to inform dengue vaccination strategy and facilitate pre-vaccination screening to ensure safety.

Current challenges and implications for dengue, chikungunya and Zika seroprevalence studies worldwide: A scoping review

BACKGROUND

Arboviral infections are a public health concern and an escalating problem worldwide. Estimating the burden of these diseases represents a major challenge that is complicated by the large number of unapparent infections, especially those of dengue fever. Serological surveys are thus required to identify the distribution of these diseases and measure their impact. Therefore, we undertook a scoping review of the literature to describe and summarize epidemiological practices, findings and insights related to seroprevalence studies of dengue, chikungunya and Zika virus, which have rapidly expanded across the globe in recent years.

METHODOLOGY/PRINCIPAL FINDINGS

Relevant studies were retrieved through a literature search of MEDLINE, WHOLIS, Lilacs, SciELO and Scopus (2000 to 2018). In total, 1389 publications were identified. Studies addressing the seroprevalence of dengue, chikungunya and/or Zika written in English or French and meeting the inclusion and exclusion criteria were included. In total, 147 studies were included, from which 185 data points were retrieved, as some studies used several different samples. Most of the studies were exclusively conducted on dengue (66.5%), but 16% were exclusively conducted on chikungunya, and 7 were exclusively conducted on Zika; the remainder were conducted on multiple arboviruses. A wide range of designs were applied, but most studies were conducted in the general population (39%) and in households (41%). Although several assays were used, enzyme-linked immunosorbent assays (ELISAs) were the predominant test used (77%). The temporal distribution of chikungunya studies followed the virus during its rapid expansion since 2004. The results revealed heterogeneity of arboviruses seroprevalence between continents and within a given country for dengue, chikungunya and Zika viruses, ranging from 0 to 100%, 76% and 73% respectively.

CONCLUSIONS/SIGNIFICANCE

Serological surveys provide the most direct measurement for defining the immunity landscape for infectious diseases, but the methodology remains difficult to implement. Overall, dengue, chikungunya and Zika serosurveys followed the expansion of these arboviruses, but there remain gaps in their geographic distribution. This review addresses the challenges for researchers regarding study design biases. Moreover, the development of reliable, rapid and affordable diagnosis tools represents a significant issue concerning the ability of seroprevalence surveys to differentiate infections when multiple viruses co-circulate.

Seroprevalencia en una zona de hiperendemia por dengue, en Barranquilla, Colombia

Objetivo: Estimar seroprevalencia de anticuerpos IgG e IgM para dengue y factores asociados. Método: estudio transversal, mediante la aplicación de encuesta y estimación serológica para IgG e IgM para dengue en mayores de 15 años con representabilidad por localidad y sexo. 478 sujetos encuestados en la ciudad de Barranquilla Colombia Análisis estadístico, mediante el programa SPSS®, versión 22. Se estimó la sero-prevalencia para el análisis univariado y el análisis bivariado mediante la odds ratio de proporciones con una p<0,05. Resultados: la seroprevalencia para IgG fue 88,2% (IC 95% =85,2-91,1) y para IgM de 11,8% (IC 95%= 8,80-14,75). Se encon- tró asociación estadística en edades de 30 a 49 y 50-69 años (OR=7,09 [2,6-19,3] y OR= 8,93 [2,9-27,0] respectivamente), pertenecer al régimen de salud subsidiado (OR=2,56[1,18-5,53]) y ocupación hogar (OR= 3,38[1,31-8,67]. Conclusiones: la alta seroprevalencia para IgG es explicada por la circulación de los cuatro serotipos en el país, los brotes epidémicos cada dos a tres años y los comportamientos y prácticas desfavorables relacionadas con el manejo de agua. Se requiere cambios de conducta frente al manejo de factores predisponen- tes, la atención oportuna de sintomáticos y vigilancia activa comunitaria e institucional ante casos sospechosos.

Epidemiological Characteristics of Dengue Disease in Latin America and in the Caribbean: A Systematic Review of the Literature

Dengue, an important mosquito-borne virus transmitted mainly by Aedes aegypti, is a major public health issue in Latin America and the Caribbean. National epidemiological surveillance systems, usually based on passive detection of symptomatic cases, while underestimating the true burden of dengue disease, can provide valuable insight into disease trends and excess reporting and potential outbreaks. We carried out a systematic review of the literature to characterize the recent epidemiology of dengue disease in Latin America and the English-speaking and Hispanic Caribbean Islands. We identified 530 articles, 60 of which met criteria for inclusion. In general, dengue seropositivity across the region was high and increased with age. All four virus serotypes were reported to circulate in the region. These observations varied considerably between and within countries and over time, potentially due to climatic factors (temperature, rainfall, and relative humidity) and their effect on mosquito densities and differences in socioeconomic factors. This review provides important insight into the major epidemiological characteristics of dengue in distinct regions of Latin America and the Caribbean, allowing gaps in current knowledge and future research needs to be identified.

Dengue seroprevalence in the French West Indies: a prospective study in adult blood donors

Using an anti-dengue immunoglobulin G (IgG) indirect enzyme-linked immunosorbent assay, seroprevalence was determined among 783 adult blood donors in the French Caribbean islands of Guadeloupe and Martinique in 2011. Overall, 93.5% [91.5; 95.1] samples were positive for dengue antibodies, 90.7% (350 of 386) in Martinique and 96.2% (382 of 397) in Guadeloupe. Only 30% of these adults recalled having had dengue disease before. Serotype-specific neutralization assays applied to a subset of IgG-positive samples indicated that a majority (77 of 96; 80%) reacted to the four serotypes. These seroprevalence findings are the first reported for Guadeloupe and Martinique and are consistent with the dengue epidemiology in these territories.

Epidemiological Trend and Clinical Observations among Children and Adults with Dengue in Barbados

OBJECTIVE

To describe the epidemiological characteristics and the clinical manifestations of the confirmed dengue cases over a ten-year period in Barbados, one of the English-speaking Caribbean countries.

METHODS

All the cases of confirmed dengue from 2000 to 2009 were retrospectively studied. Long-term trends in incidence rate, demographic characteristics such as age, gender and seasonal distribution; clinical manifestations, immunological characteristics, need for hospitalization and mortality were studied.

RESULTS

There were 3413 confirmed cases of dengue including 778 (22.8%) children and 2635 (77.2%) adults. The mean annual incidence rate of dengue was 1.36/1000 population. The median age of the persons with confirmed dengue was 27 years. The largest number of cases was seen in the 11 to 16-year age group. Hospitalization was required in 13.1% of dengue cases; 72.5% and 84% of all dengue were secondary infections among the children and adults, respectively. Dengue haemorrhagic fever accounted for 2.2% and 6% of all confirmed dengue among children and adults, respectively. The overall case fatality rate in this study was 0.35%.

CONCLUSIONS

Dengue is a significant health problem primarily in adolescents and young adults. It is characterized by less severe cases and lower mortality rate.

Biosensors and rapid diagnostic tests on the frontier between analytical and clinical chemistry for biomolecular diagnosis of dengue disease: a review

The past decades have witnessed enormous technological improvements towards the development of simple, cost-effective and accurate rapid diagnostic tests for detection and identification of infectious pathogens. Among them is dengue virus, the etiologic agent of the mosquito-borne dengue disease, one of the most important emerging infectious pathologies of nowadays. Dengue fever may cause potentially deadly hemorrhagic symptoms and is endemic in the tropical and sub-tropical world, being also a serious threat to temperate countries in the developed world. Effective diagnostics for dengue should be able to discriminate among the four antigenically related dengue serotypes and fulfill the requirements for successful decentralized (point-of-care) testing in the harsh environmental conditions found in most tropical regions. The accurate identification of circulating serotypes is crucial for the successful implementation of vector control programs based on reliable epidemiological predictions. This paper briefly summarizes the limitations of the main conventional techniques for biomolecular diagnosis of dengue disease and critically reviews some of the most relevant biosensors and rapid diagnostic tests developed, implemented and reported so far for point-of-care testing of dengue infections. The invaluable contributions of microfluidics and nanotechnology encompass the whole paper, while evaluation concerns of rapid diagnostic tests and foreseen technological improvements in this field are also overviewed for the diagnosis of dengue and other infectious and tropical diseases as well.

Dengue cases and Aedes aegypti indices in Trinidad, West Indies

This study was conducted to determine whether any relationships exist between Aedes aegypti indices, dengue seroprevalence and dengue transmission in County Victoria, Trinidad, West Indies. The cardinal points surveillance method was used to evaluate 50 suspected dengue fever (DF) cases. Thirty-three (33) confirmed DF cases were fully investigated within 48h of clinical diagnosis. Using retrospective data collected during the previous year (2003-2004) and study data, key premises and key containers were determined. Ninety-two percent of the houses were considered key premises, and 66% (22/33) of the houses with dengue positive cases harboured Ae. aegypti immature stages. These results showed that significantly (P<0.001) more adults (1050 vs 493) and immatures were collected during dengue case investigations than during routine inspection and treatment cycles. In addition, when the DF diagnosis was made the pupae per person rates increased from 0.65 to 1.35 with significantly (P<0.001) larger numbers of Ae. aegypti females emerging daily, increasing from 221 to 472.5. That is, the mosquito density required for DF transmission may be high for Trinidad given the high seroprevalence rates (94% among pregnant women). These results suggest that dengue transmission occurs, not at a fixed entomologic figure/quantity but rather at a variable level based on numerous factors including seroprevalence, mosquito density and climate. These findings have implications for effective programs: by combining cardinal points and the key premises approaches; vector control programs can now target the most productive containers in key premises thus reducing dengue transmission levels.

Serological versus PCR methods for the detection of tick-borne encephalitis virus infections in humans

Tick-borne encephalitis (TBE) virus is the most important flaviviral etiological agent affecting the CNS in Europe and Asia, where it has a significant impact on public health. Current laboratory diagnosis is based mainly on the detection of specific IgM and IgG antibodies in serum and cerebrospinal fluid by serological methods. However, recent developments in PCR methods could reveal that molecular diagnostics may play a more important role than previously described, especially for the early differential diagnosis of TBE. This review considers the recent developments in TBE diagnostics. The advantages and disadvantages of both serological and molecular methods are presented. Moreover, the results of quality control assessment studies for serological and PCR diagnosis of TBE infections are discussed, showing the need for some laboratories to improve their test systems with regards to sensitivity and specificity. Both diagnostic techniques will continue to be valuable approaches in clinical diagnosis and TBE research.