We highlight opportunities, barriers, and additional considerations for wastewater surveillance for vector borne diseases.
OBJECTIVES:Population-based cohort studies on long-term sequelae post-dengue are lacking, given dengue's disproportionate burden in tropical low- and middle-income countries with limited access to diagnostic testing and follow-up. We estimated the 300-day post-acute risk of new-incident multi-systemic complications after dengue infection. METHODS:National dengue registries and healthcare-claim databases in Singapore were utilized to build a retrospective population-based adult cohort with laboratory-confirmed dengue infection (1 January 2017-30 June 2023) and a cohort of uninfected controls. Differences in baseline characteristics were adjusted using overlap weighting. Risks of new-incident complications across multiple organ systems, all-cause hospitalization, and death up to 300 days post-dengue infection were systematically contrasted against population-based controls, using competing risk regression. RESULTS:55 870 dengue-infected individuals and 3 072 309 uninfected controls were included; the majority had mild initial infection not requiring hospitalization. In the post-acute period, there was a 19.0% (adjusted hazard ratio [aHR] = 1.19 [1.13, 1.26]) increased risk of any post-acute sequelae, with a 46.0% increase in risk of cardiovascular sequelae (aHR = 1.46 [1.01, 2.10]) and 29.0% increase in risk of neuropsychiatric sequelae (aHR = 1.29 [1.14, 1.45]) in dengue-infected individuals vs. controls. There was also a 37.0% increase in the risk of autoimmune disorders (aHR = 1.37 [1.24, 1.52]), a 19% increase in the risk of endocrine disorders (aHR = 1.19 [1.12, 1.25]), a 42.0% increase in the risk of gastrointestinal sequelae (aHR = 1.42 [1.17, 1.72]), and 230.0% increase in the risk of renal sequelae (aHR = 2.30 [1.69, 3.12]). Post-acute risk of all-cause hospitalization (aHR = 1.22[1.20, 1.25]) and death (aHR = 2.08 [1.85, 2.33]) were also elevated in dengue-infected cases. The cumulative number of post-acute outcomes among dengue-infected cases increased over the 31-300 day follow-up period, vs. uninfected controls. Risks of post-acute sequelae were increased in hospitalized dengue patients, older age groups (61+ years), those with comorbidities and across DENV-2/DENV-3 predominant transmission. DISCUSSION:Increased post-acute risk of multi-organ complications, all-cause hospitalizations, and death were observed in dengue survivors, vs. uninfected population-based controls. Development of multidisciplinary care strategies to reduce chronic health loss post-dengue infection is crucial.
The associations between respiratory and cardiovascular health outcomes with air quality have been well examined. Less conclusive are the studies assessing the relationship between air quality and dengue, a mosquito-borne illness which continues to pose risk to more than half the world’s population. We examined this relationship in Singapore, a tropical city-state located in the South-East Asian region where the burden of dengue is among the highest across the globe. We analyzed the short-term associations between all laboratory-confirmed dengue reports and variations in PM2.5, PM10, CO, O3, NO2 and SO2 in Singapore from 2009 to 2019 using the Distributed Lag Non-linear Model (DLNM) framework. PM2.5 (RR90th percentile: 1.28, 95% CI 1.11,1.49), PM10 (RR90th percentile: 1.30, 95% CI 1.12, 1.51), and CO (RR90th percentile: 1.30, 95% CI 1.06, 1.61), were positively associated with dengue up to a period of 48 days with observed maximum threshold effects, while O3 and NO2 were negatively associated with dengue. There was a positive, non-linear association between ambient temperature and dengue. We observed strong evidence of ambient temperature modifying the association between particulate matter and dengue risk. Variations in the concentrations of these air pollutant types may inform short-term dengue control resource augmentation plans.
The climate of the Maritime Continent, including Singapore, is influenced by a wide range of tropical drivers including the El-Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), the Madden–Julian Oscillation (MJO), and equatorial wave activity. In Singapore, the rainfall pattern is often marked by episodes of short intense rainfall bursts, primarily driven by mesoscale convective systems, such as Sumatra squall lines. These episodes often result in local flash floods and strong wind bursts. Here we analyse 33 years of Sumatra squalls affecting Singapore and investigate the potential impact of the main modes of climate variability and atmospheric equatorial tropical waves. Highlighted results are that, on average, Sumatra squalls originate from Sumatra and the Strait of Malacca, make landfall over Singapore primarily in the morning and last about 2 h, and are more frequent from April to November. These squalls tend to be more frequent under La Niña conditions, which are associated with locally warm sea surface temperature anomalies and favourable atmospheric anomalies over the Maritime Continent region. On intraseasonal scale, the MJO may play a role in setting the westerlies and enhancing convective conditions favorable for the squalls to intensify and propagate eastward. Convectively-coupled Kelvin waves are important for the initiation and eastward propagation of the squalls over Sumatra and the Strait of Malacca, while equatorial Rossby, and mixed Rossby gravity waves influence their meridional propagation toward Singapore.
Background:Acute dengue-virus (DENV) infection, while associated with mild disease in most instances, is anecdotally associated with more severe cardiovascular complications. However, more accurate estimates of cardiac complications are required to evaluate the actual burden of dengue-associated morbidity, given significant contribution of cardiovascular events to overall morbidity and rising incidence of DENV-infection attributable to climate change. Methods:A population-based cohort of DENV-infected Singaporean adults (2017-2023) and population-based controls (without DENV-infection) was constructed using the national-dengue-registry. Overlap weights were employed to balance baseline covariates. Logistic regression was used to estimate odds of cardiovascular events in DENV-infected cases versus uninfected controls up to 30 days from T0 (notification-date in DENV-infected adults; randomly assigned in population-based controls following distribution of T0 amongst DENV-infected cases). Findings:65,207 DENV-infected cases and 1,616,865 uninfected controls were included. Higher odds of any cardiovascular event (adjusted-odds-ratio, aOR = 10.63 [95% CI = 7.56, 15.48]), major-adverse-cardiac-event (MACE) (aOR = 2.92 [95% CI = 1.81-4.88]), dysrhythmia (aOR = 18.44 [95% CI = 11.25 = 32.96]) and ischemic-heart-disease (aOR = 3.00 [95% CI = 1.83-5.15]) were observed up to 30 days post-DENV-infection, versus uninfected controls. Odds of acute cardiovascular events remained higher in both ambulatory/hospitalised DENV-infected cases, DENV-IgG-positive/negative cases, and across DENV1/2 and DENV3-predominant transmission, versus uninfected controls. However, overall excess burden (EB) of acute cardiovascular events in DENV-infected adults was modest, with <1 excess event per-100-cases except amongst those aged ≥60 years (EB = 1.25 [95% CI = 1.05-1.44]). Interpretation:Acute DENV-infection was associated with higher odds of cardiovascular events up to 30 days post-infection; though excess-burden was modest. Older adults at higher risk should be monitored for cardiac complications following acute DENV-infection. Funding:National-Medical-Research-Council, Singapore.
