Comparison between the traditional (1997) and revised (2009) WHO classifications of dengue disease: a retrospective study of 30 670 patients

Improving dengue diagnosis and case confirmation in children by combining rapid diagnostic tests, clinical, and laboratory variables

Background

Dengue is the most widely distributed arboviral disease in tropical and subtropical countries. Most suspected cases are diagnosed according to the clinical criteria, and early diagnosis is difficult. Moreover, in underdeveloped countries, several factors continue to challenge the diagnosis and surveillance of dengue cases. This study aimed to design a diagnostic algorithm using rapid diagnostic tests (RDTs), ELISA tests, and clinical and hematological variables to confirm dengue cases in febrile patients in Colombia.

Methods

Altogether, 505 samples were collected. Serum samples were evaluated by RDTs (IgM and IgG antibodies and NS1 antigen), capture IgM and IgG ELISAs, and endpoint hemi-nested RT-PCR assay (qualitative). We statistically analyzed the performance of individual tests to determine the most useful ones to confirm dengue cases accurately.

Results

Individual results for IgM, IgG, and NS1 RDTs yielded lower sensitivity and specificity values than the reference standard. High sensitivity and specificity were obtained after combining IgM and NS1 ELISA results (96.3% and 96.4%) and NS1 RDT plus IgM ELISA results (90.3% and 96.2%), respectively. Adjusted odds ratios (aORs) were calculated for clinical variables and laboratory tests to differentiate dengue from other febrile illnesses (OFI). This approach showed that myalgia, abdominal tenderness, and platelet count were identified with higher sensitivity to confirm dengue cases. IgM RDT and NS1 RDT differentiated dengue cases from OFI. A positive IgM RDT or a positive NS1 RDT combined with specific signs or symptoms confirmed 81.6% of dengue cases. A combination of clinical findings and a positive NS1 RDT or positive ELISA IgM confirmed 90.6% of the cases.

Conclusion

Our findings showed that clinical diagnoses in pediatric population alone cannot confirm true dengue cases and needs to be complemented by laboratory diagnostic tests. We also demonstrate the usefulness of combining clinical criteria with RDTs, suggesting that their implementation with the IgM ELISA test improves dengue case confirmation.

Epidemiology, biology, pathogenesis, clinical manifestations, and diagnosis of dengue virus infection, and its trend in Ethiopia: a comprehensive literature review

Dengue fever is a dengue virus infection, emerging rapidly and posing public health threat worldwide, primarily in tropical and subtropical countries. Nearly half of the world's population is now at risk of contracting the dengue virus, including new countries with no previous history-like Ethiopia. However, little is known about the epidemiology and impact of the disease in different countries. This is especially true in countries, where cases have recently begun to be reported. This review aims to summarize epidemiology, biology, pathogenesis, clinical manifestations, and diagnosis of dengue virus infection and its trend in Ethiopia. It may help countries, where dengue fever is not yet on the public health list-like Ethiopia to alert healthcare workers to consider the disease for diagnosis and treatment. The review retrieved and incorporated 139 published and organizational reports showing approximately 390 million new infections. About 100 million of these infections develop the clinical features of dengue, and thousands of people die annually from severe dengue fever in 129 countries. It is caused by being bitten by a dengue virus-infected female mosquito, primarily Aedes aegypti and, lesser, Ae. albopictus. Dengue virus is a member of the Flavivirus genus of the Flaviviridae family and has four independent but antigen-related single-stranded positive-sense RNA virus serotypes. The infection is usually asymptomatic but causes illnesses ranging from mild febrile illness to fatal dengue hemorrhagic fever or shock syndrome. Diagnosis can be by detecting the virus genome using nucleic acids amplification tests or testing NS1 antigen and/or anti-dengue antibodies from serum, plasma, circulating blood cells, or other tissues. Dengue cases and outbreaks have increased in recent decades, with a significant public health impact. Ethiopia has had nearly annual outbreaks since 2013, devastating an already fragmented health system and economy. Standardization of medication, population-level screening for early diagnosis and prompt treatment, and minimization of mosquito bites reduce overall infection and mortality rates.

A cross-sectional survey to evaluate prescribers' knowledge and understanding of safety messages following Dengvaxia® product information update

Purpose

We evaluated the effectiveness of additional risk minimisation measures (aRMMs; i.e., educational materials) distributed to prescribers to ensure that only individuals with evidence of prior dengue infection (PDI, i.e., dengue seropositive) would be vaccinated with the tetravalent dengue vaccine (CYD‐TDV; Dengvaxia®).

Methods

A survey was conducted in 2020 among 300 CYD‐TDV prescribers in Brazil and Thailand to ascertain three success criteria: prescribers' awareness of the materials (receiving and reading them); knowledge of the key messages; and whether their self‐reported behaviour regarding practice‐related scenarios was aligned with the updated guidance.

Results

The aRMMs were not generally effective as <80% of prescribers in both countries met two of the three predefined success criteria. In Brazil, 98.7% were aware of the aRMMs whereas in Thailand this criterion was fulfilled by 74.0%. Almost all prescribers knew that CYD‐TDV was recommended only in individuals with PDI (98.7% and 96.7% in Brazil and Thailand, respectively). In Brazil, where vaccination was restricted to those with a documented history of PDI, 11.3% considered that confirmation should be done through a blood test. More than 75% in both countries considered additional signs of dengue, as early warning signs, and not only those regarded as such by the 2009 WHO guidelines.

Conclusions

These results do not support that the aRMMs were effective as the predefined success criteria were not met. The use of reliable rapid diagnosis tests together with the revised prescribing information and educational materials will facilitate the implementation and compliance with pre‐vaccination screening for CYD‐TDV eligibility.

Evaluating the validity of dengue clinical-epidemiological criteria for diagnosis in patients residing in a Brazilian endemic area

BACKGROUND

We evaluated the validity of clinical diagnosis compared with laboratory diagnosis of dengue in a retrospective sample of patients in São José do Rio Preto, Brazil.

METHODS

Our sample included 148 299 clinically (56.3%) or laboratory-diagnosed (43.7%) dengue cases. We compared the sensitivity, specificity, positive and negative predictive value (PPV and NPV) of dengue patients' demographic and clinical characteristics with laboratory-based diagnosis. We used logistic regressions to estimate the correlation between clinical and laboratory diagnosis of dengue and a full set of dengue signs and symptoms.

RESULTS

We found substantial variability in sensitivity and specificity of signs and symptoms ranging from 0.8-81.1 and 21.5-99.6, respectively. Thrombocytopenia exhibited the highest PPV (92.0) and lowest NPV (42.2) and was the only symptom showing agreement with laboratory-confirmed dengue (φ = 0.38). The presence of exanthema and thrombocytopenia led to a greater likelihood of concordant clinical and laboratory diagnoses (exanthema: OR: 4.23; 95% CI: 2.09 to 8.57; thrombocytopenia: OR: 4.02; 95% CI: 1.32 to 12.27).

CONCLUSIONS

We found substantial variation in sensitivity, specificity, PPV and NPV of dengue signs and symptoms. For accuracy, clinical and laboratory diagnosis of dengue should be performed concurrently. When laboratory tests are not available, we suggest focusing on the clinical manifestations most associated with dengue.

Untapped Potential: A Qualitative Study of a Hospital-Based Dengue Surveillance System

The incidence and geographical distribution of dengue fever has increased in recent decades. The actual disease burden is unknown owing to frequent underreporting and misclassification of cases. A well-functioning system for diagnosing, treating, and reporting cases is of prime importance as disease statistics is the foundation for decisions aiming to control the disease. This study aimed to explore the hospital-based disease surveillance system in Yogyakarta, a dengue-endemic region on Java, Indonesia. Semi-structured interviews were performed with 16 informants from four hospitals, including five general practitioners, three internists, four pediatricians, and four administrative staff working with administration relating to dengue diagnostics and reporting. Data were analyzed using content analysis. A theme arose from the analysis “Dengue surveillance stands and falls by the rigor of the health system.” The theme, and underlying categories and subcategories, describes a surveillance system that in the best-case scenario works well and is likely to produce reliable dengue case data. However, there is a lack of synchronization between regulations and guidelines in different hospitals and some friction between regulatory bodies and the care provider. Knowledge among the staff appears to vary, and many clinical and financial decisions are made rather arbitrarily, which ultimately might lead to unequal health service delivery. In conclusion, the dengue surveillance system under study could improve further, particularly by ensuring that all regulations and recommended procedures are standardized and that all staff are given the best opportunity to stay updated on dengue-related matters, clinical as well as regulatory, on a regular basis.

Severe dengue and liver involvement: an overview and review of the literature

Introduction: Two billion population are at risk of dengue fever and by 2080, over six billion population will be at risk. Hepatitis is common in dengue and the liver is invariably involved in severe cases. We conducted a literature review using the PubMed database on articles covering a broad range of issues related to dengue and hepatitis.Areas covered: This article overviews available literature on changes in the definition of severe dengue, pathogenesis of liver involvement in dengue, clinical manifestations, and predictors of mortality in severe dengue with liver involvement, impact of viral hepatitis co-infections and hepatotoxic drugs, and hemophagocytic lymphohistiocytosis.Expert commentary: Hepatitis is commonly seen in dengue however the degree of elevation of transaminases did not correlate well with severity of illness in observational studies, except in the elderly. The underlying pathogenesis of liver injury is still being elucidated and further studies are required to fully understand the cellular pathways. Acute or chronic viral hepatitis does not appear to affect dengue outcomes. Commonly used medications such as paracetamol and statins may influence dengue outcomes.

Primary Dengue Infection in Patients Requiring Hospitalization During an Outbreak in a Low Incidence Mexican Region

Background: Dengue manifestations can range from subclinical to fatal. The study of factors that influence dengue's clinical severity can provide information to potentially limit or predict severe cases. Secondary infection (SI) with a different dengue serotype has been recognized as an important determinant of severity. However, severe dengue (SD) manifestations, including shock, can happen during primary infection (PI) too and the mechanisms involved are less understood. To characterize the severe manifestations associated to PI, we distinguished between primary and secondary dengue cases in hospitalized patients from a region of low and recent dengue incidence in central Mexico. This region can serve as a model for dengue's behavior as it spreads to new areas worldwide. Methods: Dengue-specific immunoglobulin M (IgM) and IgG concentrations were measured in the serum of 78 hospitalized patients with dengue hemorrhagic fever, and their ratios were used to discriminate between PI and SI, as recommended by World Health Organization. Clinical and laboratory manifestations were compared between PI and SI. Results and Conclusions: PI was detected in 23% of hospitalized dengue cases, a proportion similar to that reported in high-incidence regions in Mexico. PI was more frequent in 16- to 40-year-olds, and was absent in patients older than 60 years. Only dengue with warning signs and SD were present in the studied population of hospitalized patients, and case frequency decreased with clinical severity both in PI and SI groups. No significant differences in demographics, laboratory tests, or symptoms were found between PI and SI, which illustrates that cases requiring hospitalization during outbreaks can be severe, even if they are PI. This information can help plan for sanitary contingencies in places where dengue is recently emergent and numerous PI cases are expected. The mechanisms involved in PI clinical severity need to be studied further.

Warning signs and severe dengue in end stage renal disease dialysis patients

BACKGROUND/PURPOSE

The 2009 WHO guideline established warning signs (WS) to predict severe dengue (SD). However, their positive predictive value has been found to be low in the general adult population, but they might be higher in a different population. This study investigated the association between WS and SD in end stage renal disease (ESRD) patients on maintenance dialysis in Taiwan where both diseases are prevalent.

METHODS

This study enrolled ESRD dialysis patients with dengue in 2015. Demographic, laboratory data, symptoms/signs and complication of dengue were retrospectively collected from medical records at our hospital.

RESULTS

Of 49 ESRD patients with dengue, 44 patients were receiving hemodialysis and 5 peritoneal dialysis. Older patients (>65 years old) tended to have the WS(56% vs 16.7%, P = 0.007). The rate of hospitalization, intensive care unit admission and in-hospital mortality was 79.6%, 22.5%, and 8.2%, respectively. Eighteen patients (36.7%) presented WS and eighteen patients (36.7%) developed to SD, including ten with plasma leakage, twelve with hemorrhage, and six with organ failure. Patients with WS were seven times more likely to develop SD than those without (OR: 7.06; 95%CI: 1.34-37.21). WS was associated with plasma leakage (OR: 12.36; 95% CI: 1.56-97.74) and severe hemorrhage (OR: 5.1; 95% CI: 1.03-25.18), but not organ failure.

CONCLUSIONS

Prevalence of SD is high in ESRD dialysis patients. The presence of WSs in this group was highly correlated with SD. Thus, more attention should be paid to treating ESRD patients with dengue fever if they present WSs.

Yellow fever (YF) vaccination does not increase dengue severity: A retrospective study based on 11,448 dengue notifications in a YF and dengue endemic region

BACKGROUND

We study the association between prior yellow fever immunization and clinical outcomes of dengue infections in individuals of varying sexes and ages. Serological interactions between dengue virus and other flaviviruses could drive antibody dependent enhancement, which is associated with disease severity in dengue infections. This effect may influence disease severity in individuals subsequently affected by related flaviviruses, such as dengue. We compare the severity of dengue episodes between patients vaccinated and non-vaccinated against yellow fever.

METHODS

We evaluated the severity of 11,448 lab-confirmed dengue cases reported in São José do Rio Preto, Brazil, in 7370 YF vaccinated patients compared to 4043 unvaccinated patients. We regressed dengue severity against YF vaccine status and a number of demographic, clinical, and laboratory variables as controls. We also evaluated the association between YF vaccination status and the clinical and laboratory symptoms of dengue patients.

RESULTS

We did not find any evidence of increased risk for severe dengue in patients vaccinated against YF (odds ratio = 1.00; 95% confidence interval = 0.87-1.14). Most of the variables analyzed did not have a statistically significant association with YF vaccination status.

CONCLUSIONS

We found no evidence that YF vaccination in dengue-endemic areas increases the risk of severe dengue fever.