Retrospective Seroepidemiology study of dengue virus infection in Taiwan

A scoping literature review of global dengue age-stratified seroprevalence data: estimating dengue force of infection in endemic countries

BACKGROUND

Dengue poses a significant burden worldwide, and a more comprehensive understanding of the heterogeneity in the intensity of dengue transmission within endemic countries is necessary to evaluate the potential impact of public health interventions.

METHODS

This scoping literature review aimed to update a previous study of dengue transmission intensity by collating global age-stratified dengue seroprevalence data published in the Medline, Embase and Web of Science databases from 2014 to 2023. These data were then utilised to calibrate catalytic models and estimate the force of infection (FOI), which is the yearly per-capita risk of infection for a typical susceptible individual.

FINDINGS

We found a total of 66 new publications containing 219 age-stratified seroprevalence datasets across 30 endemic countries. Together with the previously available average FOI estimates, there are now more than 250 dengue average FOI estimates obtained from seroprevalence studies from across the world.

INTERPRETATION

The results show large heterogeneities in average dengue FOI both across and within countries. These new estimates can be used to inform ongoing modelling efforts to improve our understanding of the drivers of the heterogeneity in dengue transmission globally, which in turn can help inform the optimal implementation of public health interventions.

FUNDING

UK Medical Research Council, Wellcome Trust, Community Jameel, Drugs for Neglected Disease initiative (DNDi) funded by the French Development Agency, Médecins Sans Frontières International; Swiss Agency for Development and Cooperation and UK aid.

Evolving Spectrum of Dengue: A Two-Year Experience From a Tertiary Care Hospital in Pakistan

OBJECTIVE

This study focused on examining the clinical manifestations, disease severity, and outcomes among cases of dengue fever (DF) confirmed through serological testing. The study specifically targeted individuals admitted to a tertiary care hospital in Islamabad, Pakistan.

METHODOLOGY

This prospective observational study at the Pakistan Institute of Medical Sciences, Islamabad, Pakistan, tracked 1,003 patients from admission to discharge or death between August 2022 and November 2023. Patients were monitored, and admission criteria were established based on the identification of warning signs. The data collection process encompassed gathering demographic information, documenting clinical symptoms, and utilizing a severity classification system for the disease. Outcome measures comprised the duration of critical illness, length of hospital stay, overall outcomes (discharge or mortality), and the assessment of complications. The collected data were analyzed using IBM Statistical Package for the Social Sciences (SPSS) software version 22.0 (IBM Corp., Armonk, NY).

RESULTS

Baseline characteristics revealed a male predominance (67.8%), with an average age of 35.77 years, and common comorbidities such as hypertension (9.3%) and diabetes mellitus (7.3%). Dengue fever was most prevalent among patients whose blood group was B+ (15.0%). Nonstructural protein 1 (NS1) was positive in 73.4% of the cases. Fever was the predominant complaint in 98.0% of instances. Common bleeding manifestations included epistaxis, gum bleeding, and hematemesis. About 52.20% of cases were observed to have severe thrombocytopenia at admission. Hospital-related aspects demonstrated a mean stay of 3.35 days, a critical phase lasting 1.68 days, and rare complications like expanded dengue syndrome (2.2%). Encouragingly, 98.9% of patients were discharged, 0.4% were shifted, and 0.7% succumbed to the disease.

CONCLUSION

This study comprehensively analyzes the demographic and clinical aspects of DF, emphasizing a male predominance and the fact that fever was the most common presenting complaint. The duration of hospitalization revealed a brief mean stay, a short critical phase, and low complication rates, with a high discharge rate suggesting positive outcomes.

Re-examination of the risk of dementia after dengue virus infection: A population-based cohort study

Dengue infection can affect the central nervous system and cause various neurological complications. Previous studies also suggest dengue was associated with a significantly increased long-term risk of dementia. A population-based cohort study was conducted using national health databases in Taiwan and included 37,928 laboratory-confirmed dengue patients aged ≥ 45 years between 2002 and 2015, along with 151,712 matched nondengue individuals. Subdistribution hazard regression models showed a slightly increased risk of Alzheimer's disease, and unspecified dementia, non-vascular dementia, and overall dementia in dengue patients than the nondengue group, adjusted for age, sex, area of residence, urbanization level, income, comorbidities, and all-cause clinical visits within one year before the index date. After considering multiple comparisons using Bonferroni correction, only overall dementia and non-vascular dementia remained statistically significant (adjusted SHR 1.13, 95% CI 1.05-1.21, p = 0.0009; E-value 1.51, 95% CI 1.28-NA). Sensitivity analyses in which dementia cases occurring in the first three or five years after the index dates were excluded revealed no association between dengue and dementia. In conclusion, this study found dengue patients had a slightly increased risk of non-vascular dementia and total dementia than those without dengue. However, the small corresponding E-values and sensitivity analyses suggest the association between dengue and dementia may not be causal.

Reinvestigation of the risk of stroke after dengue virus infection: A population-based cohort study

BACKGROUND

Dengue virus (DENV) infection is the most prevalent mosquito-borne viral disease. Stroke is a severe manifestation of dengue. However, few large-scale studies have investigated post-dengue risk of stroke.

METHODS

This population-based cohort study included 57,934 newly diagnosed, laboratory-confirmed dengue patients in Taiwan from 2002 to 2015; patients were matched to nondengue individuals by age, sex, and area of residence at a ratio of 1:4 (n = 231,736). We used subdistribution hazard regression to evaluate short-term (≤ 30 days), medium-term (31-365 days), and long-term (1-3 years) risk of stroke after DENV infection. The robustness of the results to unmeasured confounding was assessed with E-values.

RESULTS

DENV infection was associated with a significantly increased risk of overall stroke (aSHR 4.51; 95% CI: 3.23-6.32; P < 0.0001; E-value = 8.49), hemorrhagic stroke (aSHR 4.13; 95% CI: 2.20-7.76; P < 0.0001; E-value =7.73), and ischemic stroke (aSHR 3.80; 95% CI: 2.37-6.11; P < 0.0001; E-value = 7.06) within 30 days. Stratified analysis by age showed that the aSHRs for overall stroke, hemorrhagic stroke, and ischemic stroke were larger among dengue patients aged ≥ 65 during the first 30 days. The 30-day risks of overall stroke, hemorrhagic stroke, and ischemic stroke among elderly dengue patients were 6.71, 1.29, and 3.49 per 1000, respectively. No increased risk was observed after 30 days.

CONCLUSION

DENV infection was associated with a significant short-term increased risk of stroke. Clinical practitioners should remain alert to patients with stroke-associated symptoms during epidemic seasons, especially elderly patients.

Risks of Acute Cholecystitis, Acute Pancreatitis, and Acute Appendicitis in Patients with Dengue Fever: A Population-Based Cohort Study in Taiwan

INTRODUCTION

Although cases of acute cholecystitis, acute pancreatitis, and acute appendicitis following dengue virus infections have been documented, very few large-scale studies have investigated the postdengue risk of these acute abdominal conditions.

METHODS

This retrospective population-based cohort study included all patients with laboratory-confirmed dengue from 2002 to 2015 in Taiwan and 1:4 nondengue individuals matched by age, sex, area of residence, and symptom onset time. Multivariate Cox proportional hazards regression models were used to investigate the short-term (≤ 30 days), medium-term (31-365 days), and long-term (> 1 year) risks of acute cholecystitis, pancreatitis, and appendicitis after dengue infection, adjusted for age, sex, area of residence, urbanization level, monthly income level, and comorbidities. Bonferroni correction was used for multiple testing; E-values were used to assess the robustness of the results to unmeasured confounding.

RESULTS

This study included 65,694 individuals with dengue and 262,776 individuals without dengue. Patients with dengue had a significantly increased risk of acute cholecystitis (adjusted hazard ratio (aHR) 60.21; 95% CI 29.11-124.54; P < 0.0001, E-value = 119.92) and acute pancreatitis (aHR 17.13; 95% CI 7.66-38.29; P < 0.0001, E-value = 33.75) within the first 30 days postinfection compared to those without dengue, but this increased risk was not present after that. The incidence rates of acute cholecystitis and pancreatitis in the first 30 days were 18.79 and 5.27 per 10,000, respectively. No increased risk of acute appendicitis was observed among patients with acute dengue infection.

CONCLUSION

This study was the first large epidemiological study to show a significantly increased risk of acute cholecystitis and pancreatitis among patients with dengue during the acute phase of dengue infection, while no such association was observed for acute appendicitis. Early identification of acute cholecystitis and pancreatitis in patients with dengue is crucial for preventing fatal complications.

Re-examination of the risk of autoimmune diseases after dengue virus infection: A population-based cohort study

Previous studies suggested that dengue was associated with an increased risk of several autoimmune diseases. However, this association still needs to be explored due to the limitations of these studies. A population-based cohort study was conducted using national health databases in Taiwan and included 63,814 newly diagnosed, laboratory-confirmed dengue patients between 2002 and 2015 and 1:4 controls (n = 255,256) matched by age, sex, area of residence and symptom onset time. Multivariate Cox proportional hazard regression models were used to investigate the risk of autoimmune diseases after dengue infection. Dengue patients had a slightly higher risk of overall autoimmune diseases than non-dengue controls (aHR 1.16; P = 0.0002). Stratified analyses by specific autoimmune diseases showed that only autoimmune encephalomyelitis remained statistically significant after Bonferroni correction for multiple testing (aHR 2.72; P < 0.0001). Sixteen (0.025%) dengue patients and no (0%) controls developed autoimmune encephalomyelitis in the first month of follow-up (HR >9999, P < 0.0001), but the risk between groups was not significantly different thereafter. Contrary to previous studies, our findings showed that dengue was associated with an increased short-term risk of a rare complication, autoimmune encephalomyelitis, but not associated with other autoimmune diseases.

Estimating Dengue Transmission Intensity in China Using Catalytic Models Based on Serological Data

In recent decades, the global incidence of dengue has risen sharply, with more than 75% of infected people showing mild or no symptoms. Since the year 2000, dengue in China has spread quickly. At this stage, there is an urgent need to fully understand its transmission intensity and spread in China. Serological data provide reliable evidence for symptomatic and recessive infections. Through a literature search, we included 23 studies that collected age-specific serological dengue data released from 1980 to 2021 in China. Fitting four catalytic models to these data, we distinguished the transmission mechanisms by deviation information criterion and estimated force of infection and basic reproduction number (R₀), important parameters for quantifying transmission intensity. We found that transmission intensity varies over age in most of the study populations, and attenuation of antibody protection is identified in some study populations; the R₀ of dengue in China is between 1.04-2.33. Due to the scarceness of the data, the temporal trend cannot be identified, but data shows that transmission intensity weakened from coastal to inland areas and from southern to northern areas in China if assuming it remained temporally steady during the study period. The results should be useful for the effective control of dengue in China.

Dengue Meteorological Determinants during Epidemic and Non-Epidemic Periods in Taiwan

The identification of the key factors influencing dengue occurrence is critical for a successful response to the outbreak. It was interesting to consider possible differences in meteorological factors affecting dengue incidence during epidemic and non-epidemic periods. In this study, the overall correlation between weekly dengue incidence rates and meteorological variables were conducted in southern Taiwan (Tainan and Kaohsiung cities) from 2007 to 2017. The lagged-time Poisson regression analysis based on generalized estimating equation (GEE) was also performed. This study found that the best-fitting Poisson models with the smallest QICu values to characterize the relationships between dengue fever cases and meteorological factors in Tainan (QICu = −8.49 × 10−3) and Kaohsiung (−3116.30) for epidemic periods, respectively. During dengue epidemics, the maximum temperature with 2-month lag (β = 0.8400, p < 0.001) and minimum temperature with 5-month lag (0.3832, p < 0.001). During non-epidemic periods, the minimum temperature with 3-month lag (0.1737, p < 0.001) and mean temperature with 2-month lag (2.6743, p < 0.001) had a positive effect on dengue incidence in Tainan and Kaohsiung, respectively.