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Fulltext The Role of Serotype Interactions and Seasonality in Dengue Model Selection and Control: Insights from a Pattern Matching Approach

Ten Bosch QA, Singh BK, Hassan MR, Chadee DD, Michael E

PLoS Negl Trop Dis, 2016 05;10(5):e0004680.
PMID: 27159023 DOI: 10.1371/journal.pntd.0004680

The epidemiology of dengue fever is characterized by highly seasonal, multi-annual fluctuations, and the irregular circulation of its four serotypes. It is believed that this behaviour arises from the interplay between environmental drivers and serotype interactions. The exact mechanism, however, is uncertain. Constraining mathematical models to patterns characteristic to dengue epidemiology offers a means for detecting such mechanisms. Here, we used a pattern-oriented modelling (POM) strategy to fit and assess a range of dengue models, driven by combinations of temporary cross protective-immunity, cross-enhancement, and seasonal forcing, on their ability to capture the main characteristics of dengue dynamics. We show that all proposed models reproduce the observed dengue patterns across some part of the parameter space. Which model best supports the dengue dynamics is determined by the level of seasonal forcing. Further, when tertiary and quaternary infections are allowed, the inclusion of temporary cross-immunity alone is strongly supported, but the addition of cross-enhancement markedly reduces the parameter range at which dengue dynamics are produced, irrespective of the strength of seasonal forcing. The implication of these structural uncertainties on predicted vulnerability to control is also discussed. With ever expanding spread of dengue, greater understanding of dengue dynamics and control efforts (e.g. a near-future vaccine introduction) has become critically important. This study highlights the capacity of multi-level pattern-matching modelling approaches to offer an analytic tool for deeper insights into dengue epidemiology and control.

Matched MeSH terms: Dengue/immunology
Fulltext The association between obesity and dengue severity among pediatric patients: A systematic review and meta-analysis

Zulkipli MS, Dahlui M, Jamil N, Peramalah D, Wai HVC, Bulgiba A, et al.

PLoS Negl Trop Dis, 2018 02;12(2):e0006263.
PMID: 29415036 DOI: 10.1371/journal.pntd.0006263

BACKGROUND: Severe dengue infection often has unpredictable clinical progressions and outcomes. Obesity may play a role in the deterioration of dengue infection due to stronger body immune responses. Several studies found that obese dengue patients have a more severe presentation with a poorer prognosis. However, the association was inconclusive due to the variation in the results of earlier studies. Therefore, we conducted a systematic review and meta-analysis to explore the relationship between obesity and dengue severity.
METHODS: We performed a systematic search of relevant studies on Ovid (MEDLINE), EMBASE, the Cochrane Library, Web of Science, Scopus and grey literature databases. At least two authors independently conducted the literature search, selecting eligible studies, and extracting data. Meta-analysis using random-effects model was conducted to compute the pooled odds ratio with 95% confidence intervals (CI).
FINDINGS: We obtained a total of 13,333 articles from the searches. For the final analysis, we included a total of fifteen studies among pediatric patients. Three cohort studies, two case-control studies, and one cross-sectional study found an association between obesity and dengue severity. In contrast, six cohort studies and three case-control studies found no significant relationship between obesity and dengue severity. Our meta-analysis revealed that there was 38 percent higher odds (Odds Ratio = 1.38; 95% CI:1.10, 1.73) of developing severe dengue infection among obese children compared to non-obese children. We found no heterogeneity found between studies. The differences in obesity classification, study quality, and study design do not modify the association between obesity and dengue severity.
CONCLUSION: This review found that obesity is a risk factor for dengue severity among children. The result highlights and improves our understanding that obesity might influence the severity of dengue infection.

Matched MeSH terms: Severe Dengue/immunology
The distribution of antibodies to Japanese Encephalitis, dengue, and yellow fever viruses in five rural communities in Malaya

SMITH CE

Trans R Soc Trop Med Hyg, 1958 May;52(3):237-52.
PMID: 13556868
Matched MeSH terms: Dengue/immunology*
The influence of antibody levels in dengue diagnosis by polymerase chain reaction

Chan SY, Kautner IM, Lam SK

J Virol Methods, 1994 Oct;49(3):315-22.
PMID: 7868649

The potential of RT-PCR to rapidly diagnose dengue infections from both acute and convalescent phase patients' sera was evaluated. The RNA extraction method involved binding of the viral RNA to silica particles in the presence of high concentration of guanidine thiocyanate. The protocol that was established was sensitive enough to detect 40 plaque forming units per 100 microliter of serum and results could be obtained within one day. Results from this study indicate that clinical samples should be collected in the early acute phase of illness when anti-dengue antibodies were undetectable or of low titres to ensure a more reliable diagnosis.

Matched MeSH terms: Dengue/immunology*
The use of two-dimension electrophoresis to identify serum biomarkers from patients with dengue haemorrhagic fever

Thayan R, Huat TL, See LL, Tan CP, Khairullah NS, Yusof R, et al.

Trans R Soc Trop Med Hyg, 2009 Apr;103(4):413-9.
PMID: 19203772 DOI: 10.1016/j.trstmh.2008.12.018

Dengue infection is a major public health problem affecting millions of people living in tropical countries. With no suitable vaccines and specific antiviral drugs, treatment for dengue is usually symptomatic and supportive. Early diagnosis and recognition of severe disease is therefore crucial for better management of the patient. Two-dimension electrophoresis was used to identify disease-associated proteins that can be used for diagnosis and as drug targets for treatment. Two markers, identified by mass spectrometry analysis as alpha1-antitrypsin and NS1 proteins were found to be upregulated in dengue fever (DF; n=10) and dengue haemorrhagic fever (DHF; n=10) patients compared with healthy individuals (n=8). Both alpha1-antitrypsin and NS1 proteins were overexpressed two-fold in DHF patients compared with DF patients. Our study suggests that alpha1-antitrypsin and NS1 protein could be used as biomarkers as early indicators of DHF risk among patients with suspected dengue infection.

Matched MeSH terms: Severe Dengue/immunology
[Hemorrhagic dengue fever after trip to Malaysia]

Hafner C, Koellner K, Vogt T, Landthaler M, Szeimies RM

Hautarzt, 2006 Aug;57(8):705-7.
PMID: 16283129

A 39-year-old patient developed a disseminated rash with scattered petechiae, fever, malaise and arthralgia after a trip to Malaysia. The patient displayed increasing dengue IgG titers and borderline dengue IgM titers. Dengue fever with a hemorrhagic course is a rare condition in adult patients. Patients who have previously had dengue fever and retained non-neutralizing heterotypic antibodies are more likely to develop this complication via the phenomenon of antibody-dependent enhancement.

Matched MeSH terms: Severe Dengue/immunology