Dengue Case Definition Research Articles

The early history of dengue in Australia.

Although reports of outbreaks of dengue-like diseases in the Asia Pacific region were frequent from about 1870, the disease probably did not become endemic in Australia until about 1885. Several seminal discoveries about this disease were made in Queensland and later in Sydney. These included a refined case definition for dengue, identification of the mosquito vector, demonstration of a viraemia and its duration, quantification of the incubation time, demonstration of immunity after experimental infection and recognition that the virus could cause a fatal haemorrhagic fever, and this was more frequent in second or subsequent infections. Australian research was foundational to the modern understanding of dengue.

Region-specific improvisation on WHO case definition and environmental risk factors associated with dengue: a case-control analysis from Kerala, India.

Region-specific variations may occur in symptomatic manifestations that need to be addressed by dynamic case definitions. Environmental risk factors for dengue also vary widely across geographic settings. Our aim was to study the test positivity rate of the World Health Organization (WHO) 2009 probable dengue case definition and to suggest region-specific improvisations to it. The study also analyses the sociodemographic and environmental risk factors of dengue fever in South Kerala, India. A case-control study was conducted in South Kerala from 2017 to 2019. Dengue reverse transcription polymerase chain reaction (RT-PCR)-positive and RT-PCR-negative 'probable dengue' patients were compared to identify significant symptoms for a modified definition of dengue. A group of afebrile community controls was compared with RT-PCR-positive dengue cases to study the environmental and behavioural risk factors. Arthralgia, palmar erythema and rashes have high discriminatory power (odds ratio [OR] >3) for identifying dengue. Redness of eyes, altered consciousness, abdominal distension and chills were found to moderately discriminate (OR 2-3) dengue. The adjusted analysis showed the presence of mosquito breeding sites (indoor p=0.02, outdoor p=0.03), solid waste dumping (p<0.001) and open water drainage in the compound (p=0.007) as significant predictors. Regional modifications should be considered when using the WHO definition in endemic settings. Control of mosquito breeding at the household level is the key towards dengue prevention.

Majority of pediatric dengue virus infections in Kenya do not meet 2009 WHO criteria for dengue diagnosis.

From 1975-2009, the WHO guidelines classified symptomatic dengue virus infections as dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. In 2009 the case definition was changed to a clinical classification after concern the original criteria was challenging to apply in resource-limited settings and not inclusive of a substantial proportion of severe dengue cases. Our goal was to examine how well the current WHO definition identified new dengue cases at our febrile surveillance sites in Kenya. Between 2014 and 2019 as part of a child cohort study of febrile illness in our four clinical study sites (Ukunda, Kisumu, Msambweni, Chulaimbo) we identified 369 dengue PCR positive symptomatic cases and characterized whether they met the 2009 revised WHO diagnostic criteria for dengue with and without warning signs and severe dengue. We found 62% of our PCR-confirmed dengue cases did not meet criteria per the guidelines. Our findings also correlate with our experience that dengue disease in children in Kenya is less severe as reported in other parts of the world. Although the 2009 clinical classification has recently been criticized for being overly inclusive and non-specific, our findings suggest the 2009 WHO dengue case definition may miss more than 50% of symptomatic infections in Kenya and may require further modification to include the African experience.

Combined score based on arterial lactate, aspartate transaminase and prolonged capillary refill time is a useful diagnostic criterion for identifying severe dengue.

Taking into consideration, the variable performance of WHO's dengue case definition and the magnitude of epidemics in India, a score based on clinical and laboratory parameters is required for the early identification of severe dengue. A retrospective observational study of children (aged ≤12 y) presenting with dengue, defined as per the WHO 2009 classification and NS1 antigen/IgM ELISA positivity, was conducted at a tertiary care hospital from 2013 to 2015. Clinical laboratory parameters were compared between severe/non-severe dengue using univariate and multivariate analysis. Areas under receiver operating characteristic curves (AUROCs), sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were obtained for independent and composite markers. Of 135 dengue patients, 46 (34.1%) had non-severe dengue and 89 (65.9%) had severe dengue. Logistic regression determined prolonged capillary refill time (CRT), lactate ≥2.9 mmol/L and serum aspartate transaminase (AST) ≥135 IU/L as predictive for severe dengue. AUROCs of lactate, AST and combined score incorporating AST, lactate and prolonged CRT for identifying severity were 7.55, 7.23 and 8.5, respectively. The combined score cut-off ≥1 had 87.6% sensitivity, 65.2% specificity, 83% PPV and 73.2% NPV.The combined score cut-off ≥3 had 100% specificity and 100% PPV. However, AST >135 IU/L and lactate >2.9 mmol/L together had 97.8% specificity and 97.1% PPV for identifying severity. The presence of either 'prolonged capillary refill time with one deranged biochemical parameter' or 'both deranged biochemical parameters' is nearly 100% specific for severity of dengue.

Incidence and epidemiological features of dengue in Sabah, Malaysia.

In South East Asia, dengue epidemics have increased in size and geographical distribution in recent years. We examined the spatiotemporal distribution and epidemiological characteristics of reported dengue cases in the predominantly rural state of Sabah, in Malaysian Borneo–an area where sylvatic and urban circulation of pathogens are known to intersect. Using a public health data set of routinely notified dengue cases in Sabah between 2010 and 2016, we described demographic and entomological risk factors, both before and after a 2014 change in the clinical case definition for the disease. Annual dengue incidence rates were spatially variable over the 7-year study period from 2010–2016 (state-wide mean annual incidence of 21 cases/100,000 people; range 5-42/100,000), but were highest in rural localities in the western districts of the state (Kuala Penyu, Nabawan, Tenom and Kota Marudu). Eastern districts exhibited lower overall dengue rates, although a high proportion of severe (haemorrhagic) dengue cases (44%) were focused in Sandakan and Tawau. Dengue incidence was highest for those aged between 10 and 29 years (24/100,000), and was slightly higher for males compared to females. Available vector surveillance data indicated that during large outbreaks in 2015 and 2016 the mosquito Aedes albopictus was more prevalent in both urban and rural households (House Index of 64%) than Ae. aegypti (15%). Demographic patterns remained unchanged both before and after the dengue case definition was changed; however, in the years following the change, reported case numbers increased substantially. Overall, these findings suggest that dengue outbreaks in Sabah are increasing in both urban and rural settings. Future studies to better understand the drivers of risk in specific age groups, genders and geographic locations, and to test the potential role of Ae. albopictus in transmission, may help target dengue prevention and control efforts.

Cardiac Manifestations in Dengue Patients in a Rural Tertiary Care Centre in Coastal Kerala

Background: Dengue epidemic is a major health problem in India. Kerala has reported the highest number of dengue related deaths in the country in 2017 as per the reports of the directorate of National Vector Borne Disease Control Programme (NVBDCP). The aim of the present study is to find out the cardiac manifestations of patients admitted with dengue fever during the epidemic in 2017 in a rural tertiary care centre in coastal Kerala. Method: 341 patients who were admitted in the medicine department of a rural tertiary care Centre in Kerala with Dengue were included in the study. W.H.O case definitions were used for the diagnosis. Complete blood counts, RBS, serum creatinine and liver function tests and E.C.G were carried out in all patients. Echocardiogram and cardiac biomarkers were done when indicated. Results: Males predominated. 317 were diagnosed as dengue fever, 12 as dengue hemorrhagic fever and 12 had dengue shock syndrome. Only four patients succumbed to death. Head ache and myalgia were the common symptoms at the time of presentation. 72 patients had abnormal ECG, but all had normal ECG at the time of discharge, indicating a transient change during the episode. Conclusion: This retrospective observational study included 341 patients admitted in a rural tertiary care Centre in Kerala. Patients were diagnosed as per W.H.O. case definition for dengue. 317 were diagnosed as dengue fever, 12 as dengue hemorrhagic fever and 12 had dengue shock syndrome. Study population was predominantly males. 72 patients had abnormal ECG, but all had normal ECG at the time of discharge, indicating a transient change during the episode.

Outbreak of Dengue Virus Type 2 - American Samoa, November 2016-October 2018.

The U.S. territory of American Samoa has experienced recent outbreaks of illnesses caused by viruses transmitted by Aedes species mosquitoes, including dengue, chikungunya, and Zika virus. In November 2016, a traveler from the Solomon Islands tested positive for infection with dengue virus type 2 (DENV-2). Additional dengue cases were identified in the subsequent weeks through passive and active surveillance. Suspected dengue cases were tested locally with a dengue rapid diagnostic test (RDT) for DENV nonstructural protein 1 (NS1). Specimens from RDT-positive cases and patients meeting the dengue case definition were tested by real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) at Hawaii State Laboratories. During November 2016-October 2018, a total of 3,240 patients were tested for evidence of DENV infection (118 by RDT-NS1 alone, 1,089 by real-time RT-PCR alone, and 2,033 by both methods), 1,081 (33.4%) of whom tested positive for dengue (19.5 per 1,000 population). All 941 real-time RT-PCR-positive specimens were positive for DENV-2. The monthly number of laboratory-confirmed cases peaked at 120 during December 2017. Among laboratory-confirmed dengue cases, 380 (35.2%) patients were hospitalized; one patient, who was transferred to American Samoa for care late in his illness, died. The public health response to this outbreak included disposal of solid waste to remove mosquito breeding sites, indoor residual spraying of pesticides in schools, reinforcement of dengue patient management education, and public education on mosquito avoidance and seeking medical care for symptoms of dengue.

Comparison of morbidity and mortality between serologically positive and serologically negative dengue cases

Background: Dengue is most common arboviral disease caused by 4 types of dengue viruses. In most of the hospitals laboratory diagnosis is made by dengue serology using Rapid Immunochromatographic Test for NS1Ag, IgM and IgG antibodies. We found more morbidity and mortality in suspected dengue cases whose serology was negative for dengue.Methods: Children with clinical features suggestive for case definition for dengue, who belonged to group C of World Health organisation (WHO) guidelines for dengue fever (severe dengue), were included. They were categorised into dengue positive and dengue negative groups. The clinical features and complications of the disease between the two groups were compared.Results: 98 cases (77.8%) were serologically positive for dengue and 28 (22.2%) were negative. 39% of the patients with dengue negative serology developed hypotensive shock in comparison to 18% of dengue positive cases, mortality in serology negative cases (21%) was significantly higher than positive cases (8%).Conclusions: We could not find the reasons for more morbidity and mortality in seronegative dengue group, we stress up on improving the sensitivity and specificity of rapid diagnostic tests. More caution need to be taken for serology negative dengue cases. Epidemiological studies directed to find circulation of other viruses which causes dengue like symptoms should be made.

Serological, molecular and clinical correlates of dengue from a tertiary care centre in Chennai, India

Dengue disease is caused by dengue viruses 1-4 and has been ranked by the World Health Organisation (WHO) as the fastest spreading vector-borne viral disease. Dengue is often underreported and misdiagnosed due to a wide spectrum of clinical manifestations. Diagnosis of dengue is based on clinical case definitions and laboratory methods. Newer case definitions of dengue have been formulated by clinical studies in order to improve case detection. Owing to its epidemic potential, mortality and morbidity, there is a need for a rapid and accurate diagnostic assay for dengue in order to help the clinician in the early detection of cases and to prevent disease progression. A duplex real time PCR targeting the 3'UTR region for rapid and simultaneous detection of all dengue viruses serotypes (1-4) was standardized based on published literature. About 150 patients with acute undifferentiated febrile illness classified based on the 2009 WHO dengue case definition were tested using the duplex real time dengue PCR. Sequencing based PCR was performed on selected PCR positive samples for partial nucleotide sequence of the CprM gene and a phylogenetic tree was constructed. Statistical analysis was done using the MedCalc software. Out of the 126 patients classified as dengue disease positive, according to the 2009 WHO dengue case definition, 54% had "probable dengue", 43% had "dengue with warning signs" and 3% had "severe dengue". The performance of the duplex real time PCR was assessed among the various clinical groups of dengue and it was found that in the "dengue with warning signs group" PCR had a positive predictive value of 85.29% (range - 68.94%to95.05%) when compared with dengue NS1 ELISA. The average time for PCR positivity was found to be four days from the onset of illness. The cycling threshold values obtained from real time PCR were used as a semi quantitative measure of viremia. Accordingly, there was a relatively low CT value among the "warning signs dengue group" when compared to the "probable dengue group". The use of the duplex PCR is suggested in the early diagnosis of dengue, especially in the 'warning signs' group of patients as they showed a higher positivity rate. Also, the use of the resultant CT value as a semi-quantitative measure of viremia will assist the clinician in early diagnosis and prevention of disease development.

Clinical evaluation of dengue and identification of risk factors for severe disease: protocol for a multicentre study in 8 countries.

BackgroundThe burden of dengue continues to increase globally, with an estimated 100 million clinically apparent infections occurring each year. Although most dengue infections are asymptomatic, patients can present with a wide spectrum of clinical symptoms ranging from mild febrile illness through to severe manifestations of bleeding, organ impairment, and hypovolaemic shock due to a systemic vascular leak syndrome. Clinical diagnosis of dengue and identification of which patients are likely to develop severe disease remain challenging. This study aims to improve diagnosis and clinical management through approaches designed a) to differentiate between dengue and other common febrile illness within 72 h of fever onset, and b) among patients with dengue to identify markers that are predictive of the likelihood of evolving to a more severe disease course.Method/DesignThis is a prospective multi-centre observational study aiming to enrol 7–8000 participants aged ≥ 5 years presenting with a febrile illness consistent with dengue to outpatient health facilities in 8 countries across Asia and Latin America. Patients presenting within 72 h of fever onset who do not exhibit signs of severe disease are eligible for the study. A broad range of clinical and laboratory parameters are assessed daily for up to 6 days during the acute illness, and also at a follow up visit 1 week later.DiscussionData from this large cohort of patients, enrolled early with undifferentiated fever, will be used to develop a practical diagnostic algorithm and a robust clinical case definition for dengue. Additionally, among patients with confirmed dengue we aim to identify simple clinical and laboratory parameters associated with progression to a more severe disease course. We will also investigate early virological and serological correlates of severe disease, and examine genetic associations in this large heterogeneous cohort. In addition the results will be used to assess the new World Health Organization classification scheme for dengue in practice, and to update the guidelines for “Integrated Management of Childhood Illness” used in dengue-endemic countries.Trial registrationNCT01550016. Registration Date: March 7, 2012

Epidemiology of Dengue Among Children Aged < 18 Months-Puerto Rico, 1999-2011.

Dengue, a mosquito-borne viral illness caused by dengue virus types (DENV)-1 to DENV-4, is endemic in Puerto Rico. Severe dengue usually occurs in individuals previously infected with DENV or among infants born to previously infected mothers. To describe clinical features of dengue in infants, we retrospectively characterized dengue patients aged < 18 months reported to the Passive Dengue Surveillance System (PDSS) during 1999–2011. To determine frequency of signs, symptoms, and disease severity, case report forms and medical records were evaluated for patients who tested positive for dengue by reverse transcriptase polymerase chain reaction or anti-DENV immunoglobulin Menzyme-linked immunosorbent assay. Of 4,178 reported patients aged < 18 months, 813 (19%) were laboratory positive. Of these, most had fever (92%), rash (53%), bleeding manifestations (52%), and thrombocytopenia (52%). Medical records were available for 145 (31%) of 472 hospitalized patients, of which 40% had dengue, 23% had dengue with warning signs, and 33% had severe dengue. Mean age of patients with severe dengue was 8 months. Anti-DENV immunoglobulin G (IgG) titers were not statistically different in patients with (50%) and without (59%) severe dengue. In this study, one-third of DENV-infected infants met the severe dengue case definition. The role of maternal anti-DENV IgG in development of severe disease warrants further study in prospective cohorts of mother-infant pairs.

WHO Dengue Case Classification 2009 and its usefulness in practice: an expert consensus in the Americas

Introduction:In 2009, the new World Health Organization (WHO) dengue case classification – dengue/severe dengue (D/SD) – was introduced, replacing the 1997 WHO dengue case classification: dengue fever/dengue haemorrhagic fever/dengue shock syndrome (DF/DHF/DSS).Methods:A 2-day expert consensus meeting in La Habana/Cuba aimed to (1) share the experiences from Pan American Health Organization (PAHO) member states when applying D/SD, (2) present national and local data using D/SD, and (3) agree with the presented evidence on a list of recommendations for or against the use of D/SD for PAHO, and also globally.Results:Eight key questions were discussed, concluding: (1) D/SD is useful describing disease progression because it considers the dynamic nature of the disease, (2) D/SD helps defining dengue cases correctly for clinical studies, because it defines more precisely disease severity and allows evaluating dynamically the progression of cases, (3) D/SD describes correctly all clinical forms of severe dengue. Further standards need to be developed regionally, especially related to severe organ involvement, (4) D/SD allows for pathophysiological research identifying – in a sequential manner – the clinical manifestations of dengue related to pathophysiological events, (5) the warning signs help identifying early cases at risk of shock (children and adults), pathophysiology of the warning signs deserves further studies, (6) D/SD helps treating individual dengue cases and also the reorganization of health-care services for outbreak management, (7) D/SD helps diagnosing dengue, in presumptive diagnosis and follow-up of the disease, because of its high sensitivity and high negative predictive value (NPV), and (8) there is currently no update of the International Disease Classification10 (ICD10) to include the new classification of dengue (D/SD); therefore, there are not enough experiences of epidemiological reporting. Once D/SD has been implemented in epidemiological surveillance, D/SD allows to (1) identify severity of dengue cases in real time, for any decision-making on actions, (2) measure and compare morbidity and mortality in countries, and also globally, and (3) trigger contingency plans early, not only based on the number of reported cases but also on the reported severity of cases.Conclusion:The expert panel recommends to (1) update ICD10, (2) include D/SD in country epidemiological reports, and (3) implement studies improving sensitivity/specificity of the dengue case definition.

Dengue fever or West Nile virus outbreak? Yemen 2013

Background: Multiple dengue outbreaks reported fromYemensince 2002. In March 2013, a suspected dengue outbreak was reported from Hadramoat. However, atypical neurological signs were reported for first time that may favor the diagnosis of West Nile Virus (WNV).FETP residents investigated the outbreak to confirm etiology and make recommendations to control and prevent similar outbreaks in the future. Methods & Materials: WHO case definitions for dengue and WNV were used. Data collected from the suspected cases on a predesigned form. Forty-two Blood specimens were collected and tested for dengue and WNV IgM. Results: During 8March to 6 July 2013, 352 (97%) of suspected cases met dengue case definition and 10 (3%) met WNV case definition. Male to female ratio was 2:1with a case fatality of 2%. Overall incidence rate was 3/1000 but highest (6.4/1000) among 10-19 years age group. Most reported symptoms among dengue cases were fever (100%), headache (99%), myalgia (98%). joint pain (96%) while among WNV cases fever (100%), headache (100%), photophobia (95%), nick rigidity (50%), and coma (50%)were reported. Out of 42 specimens tested for IgM4 (9%) were positive for dengue, 2 (5%) for WNV and 4 for both. Conclusion: Although the meningoencephalitis picture favors the diagnosis WNV, WNV has not been reported previously fromYemen. As cross reactivity may occur, PCR confirmation is still needed. The risk of introduction of WNV toYementhrough open borders and trade remains high. Beside strengthen surveillance system, multi-sectorial coordination and increased community awareness is crucial to prevent infection and transmission.

Risk Factors for Fatality among Confirmed Adult Dengue Inpatients in Singapore: A Matched Case-Control Study

ObjectivesTo identify demographic, clinical and laboratory risk factors for death due to dengue fever in adult patients in Singapore.MethodsMulti-center retrospective study of hospitalized adult patients with confirmed dengue fever in Singapore between 1 January 2004 and 31 December 2008. Non-fatal controls were selected by matching age and year of infection with fatal cases. World Health Organization 1997, 2009 criteria were applied to define dengue hemorrhagic fever (DHF), warning signs and severe dengue. Statistical significance was assessed by conditional logistic regression modeling.ResultsSignificantly more fatal cases than matched controls had pre-existing co-morbid conditions, and presented with abdominal pain/tenderness. Median pulse rates were significantly higher while myalgia was significantly less frequent in cases. . Fatal cases also had higher leucocyte counts, platelet counts, serum sodium, potassium, urea, creatine and bilirubin levels on admission compared to controls. There was no statistical significant difference between the prevalence of DHF and hematocrit level among cases and controls. Multivariate analysis showed myalgia and leucocyte count at presentation were independent predictors of fatality (adjusted odds ratios 0.09 and 2.94 respectively). None of the controls was admitted to intensive care unit (ICU) or given blood transfusion, while 71.4% and 28.6% of fatal cases received ICU admission and blood transfusion.ConclusionsAbsence of myalgia and leucocytosis on admission were independently associated with fatality in our matched case-control study. Fatalities were also commonly associated with co-morbidities and clinicians should be alarmed if dengue patients fulfilled severe dengue case definition on admission.

Evaluation of the Diagnostic Utility of the Traditional and Revised WHO Dengue Case Definitions

Dengue, a mosquito-borne viral illness, is a major public health problem worldwide, and its incidence continues to increase. In 2009, the World Health Organization published guidelines that included a revision of the dengue case definition. Compared to the traditional definition, the revised case definition relies more on signs than on symptoms, making it more applicable to young children. We evaluated the diagnostic utility of both case definitions in two studies of pediatric dengue in Managua, Nicaragua. In a community-based cohort study, we included data from 3,407 suspected dengue cases, of which 476 were laboratory-confirmed. In the second study, we collected information from 1,160 participants recruited at the national pediatric reference hospital (723 laboratory-confirmed). In the cohort study, the traditional definition had 89.3% sensitivity and 43.1% specificity, while the revised definition yielded similar sensitivity (86.6%) and higher specificity (55.2%, p<0.001). In the hospital study, the traditional case definition yielded 96.7% sensitivity and 22.0% specificity, whereas the revised case definition had higher sensitivity (99.3%, p<0.001) but lower specificity (8.5%, p<0.001). We then evaluated the performance of two diagnostic models based on the signs/symptoms included in each definition by analyzing the effect of increasing numbers of signs/symptoms on the sensitivity and specificity of case capture. Receiver operating characteristic analysis showed a slightly better performance for the revised model in both studies. Interestingly, despite containing less symptoms that cannot be readily expressed by children aged less than 4 years, the revised definition did not perform better in this age group. Overall, our results indicate that both case definitions have similar capacity to diagnose dengue. Owing to their high sensitivity and low specificity, they should be primarily used for screening purposes. However, in a primary care setting, neither of the case definitions performed well as a screening test in younger children.

Dogma in Classifying Dengue Disease

In his recent perspective entitled Dengue: the Syndromic Basis to Pathogenesis Research, Inutility of the 2009 WHO Case Definition, Halstead expresses concern that adoption of the 2009 World Health Organization (WHO) classification scheme will compromise the “analytic clarity needed to understand mechanisms underlying dengue pathophysiology, pathogenesis, treatment, and therapeutics.”1 Leaving aside the important issue of how best to resolve the long running and convoluted debate on dengue case definitions and classification, two important misconceptions need to be addressed.

Ongoing outbreak of dengue serotype-3 in Solomon Islands, January to May 2013

In January 2013, clinicians in Honiara, Solomon Islands noted several patients presenting with dengue-like illness. Serum from three cases tested positive for dengue by rapid diagnostic test. Subsequent increases in cases were reported, and the outbreak was confirmed as being dengue serotype-3 by further laboratory tests. This report describes the ongoing outbreak investigation, findings and response. Enhanced dengue surveillance was implemented in the capital, Honiara, and in the provinces. This included training health staff on dengue case definitions, data collection and reporting. Vector surveillance was also conducted. From 3 January to 15 May 2013, 5254 cases of suspected dengue were reported (101.8 per 10 000 population), including 401 hospitalizations and six deaths. The median age of cases was 20 years (range zero to 90), and 86% were reported from Honiara. Both Aedes aegyti and Aedes albopictus were identified in Honiara. Outbreak response measures included clinical training seminars, vector control activities, implementation of diagnostic and case management protocols and a public communication campaign. This was the first large dengue outbreak documented in Solomon Islands. Factors that may have contributed to this outbreak include a largely susceptible population, the presence of a highly efficient dengue vector in Honiara, a high-density human population with numerous breeding sites and favourable weather conditions for mosquito proliferation. Although the number of cases has plateaued since 1 April, continued enhanced nationwide surveillance and response activities are necessary.

Evaluation of the 2009 WHO Dengue Case Classification in an Indonesian Pediatric Cohort

The classification of dengue virus-infected patients continues to be a challenge to researchers and clinicians in the field. The accuracy of the 1997 World Health Organization (WHO) dengue case definition has been debated for a decade, because the definition was very stringent, for instance, several researchers showed that apparently severe cases were misclassified as not severe. Therefore the WHO issued revised guidelines in 2009. Here, we retrospectively compared the performance of the WHO case definition of 2009 with the WHO case definition of 1997 in a detailed documented pediatric cohort from Indonesia. Intensive treatment intervention was used as an indicator of severity of disease. In line with our expectations, the 2009 WHO case classification proved to be significantly more specific, albeit less sensitive than the WHO case classification of 1997. We conclude that the revised classification is promising both from research and clinical perspectives, but validation of the classification criteria still needs to be addressed.

O4-3.3 Accuracy of clinical and laboratory signs for dengue diagnosis

BackgroundIn many endemic regions, serological tests for dengue are unavailable and diagnosis relies solely on clinical signs and basic laboratory workup.ObjectiveTo identify clinical signs and basic haematological laboratory results potentially...

Evaluation of the NS1 Rapid Test and the WHO Dengue Classification Schemes for Use as Bedside Diagnosis of Acute Dengue Fever in Adults

Because healthcare facilities in many dengue endemic countries lack laboratory support, early dengue diagnosis must rely on either clinical recognition or a bedside diagnostic test. We evaluated the sensitivity and specificity of the 1997 and 2009 World Health Organization (WHO) dengue classification schemes and the NS1 strip test in acute sera from 154 virologically confirmed dengue patients and 200 patients with other febrile illnesses. Both WHO classification schemes had high sensitivity but lacked specificity. The NS1 strip test had high specificity, but its sensitivity was significantly lower in secondary compared with primary dengue infections. Differences in viral serotypes did not affect the performance of any of the three diagnostic approaches. Taken collectively, our findings indicate that the 1997 WHO dengue case definition can be used to exclude dengue, and the NS1 strip test can be used to confirm dengue infection, although the latter should be interpreted with caution in regions where secondary dengue infection is prevalent.