| 31. |
- Liu, Ying, et al.
(författare)
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What is the reproductive number of yellow fever?
- 2020
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Ingår i: Journal of Travel Medicine. - : Oxford University Press. - 1195-1982 .- 1708-8305. ; 27:7
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Tidskriftsartikel (refereegranskat)abstract
- Teaser Our review found the average reproductive number R-0 for yellow fever to be 4.81 with a median of 4.21.
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| 32. |
- Liyanage, Prasad, et al.
(författare)
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Assessing the associations between Aedes larval indices and dengue risk in Kalutara district, Sri Lanka : a hierarchical time series analysis from 2010 to 2019
- 2022
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Ingår i: Parasites & Vectors. - : BioMed Central. - 1756-3305. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Dengue is a major public health problem in Sri Lanka. Aedes vector surveillance and monitoring of larval indices are routine, long-established public health practices in the country. However, the association between Aedes larval indices and dengue incidence is poorly understood. It is crucial to evaluate lagged effects and threshold values of Aedes larval indices to set pragmatic targets for sustainable vector control interventions.METHODS: Monthly Aedes larval indices and dengue cases in all 10 Medical Officer of Health (MOH) divisions in Kalutara district were obtained from 2010 to 2019. Using a novel statistical approach, a distributed lag non-linear model and a two-staged hierarchical meta-analysis, we estimated the overall non-linear and delayed effects of the Premise Index (PI), Breteau Index (BI) and Container Index (CI) on dengue incidence in Kalutara district. A set of MOH division-specific variables were evaluated within the same meta-analytical framework to determine their moderator effects on dengue risk. Using generalized additive models, we assessed the utility of Aedes larval indices in predicting dengue incidence.RESULTS: We found that all three larval indices were associated with dengue risk at a lag of 1 to 2 months. The relationship between PI and dengue was homogeneous across MOH divisions, whereas that with BI and CI was heterogeneous. The threshold values of BI, PI and CI associated with dengue risk were 2, 15 and 45, respectively. All three indices showed a low to moderate accuracy in predicting dengue risk in Kalutara district.CONCLUSIONS: This study showed the potential of vector surveillance information in Kalutara district in developing a threshold-based, location-specific early warning system with a lead time of 2 months. The estimated thresholds are nonetheless time-bound and may not be universally applicable. Whenever longitudinal vector surveillance data areavailable, the methodological framework we propose here can be used to estimate location-specific Aedes larval index thresholds in any other dengue-endemic setting.
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| 33. |
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| 34. |
- Liyanage, Prasad, et al.
(författare)
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Effect of El Niño–Southern Oscillation and local weather on Aedes dvector activity from 2010 to 2018 in Kalutara district, Sri Lanka: a two-stage hierarchical analysis
- 2022
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Ingår i: The Lancet Planetary Health. - : Elsevier. - 2542-5196. ; 6:7, s. e577-e585
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dengue, transmitted by Aedes mosquitoes, is a major public health problem in Sri Lanka. Weather affects the abundance, feeding patterns, and longevity of Aedes vectors and hence the risk of dengue transmission. We aimed to quantify the effect of weather variability on dengue vector indices in ten Medical Officer of Health (MOH) divisions in Kalutara, Sri Lanka.Methods: Monthly weather variables (rainfall, temperature, and Oceanic Niño Index [ONI]) and Aedes larval indices in each division in Kalutara were obtained from 2010 to 2018. Using a distributed lag non-linear model and a two-stage hierarchical analysis, we estimated and compared division-level and overall relationships between weather and premise index, Breteau index, and container index.Findings: From Jan 1, 2010, to Dec 31, 2018, three El Niño events (2010, 2015–16, and 2018) occurred. Increasing monthly cumulative rainfall higher than 200 mm at a lag of 0 months, mean temperatures higher than 31·5°C at a lag of 1–2 months, and El Niño conditions (ie, ONI >0·5) at a lag of 6 months were associated with an increased relative risk of premise index and Breteau index. Container index was found to be less sensitive to temperature and ONI, and rainfall. The associations of rainfall and temperature were rather homogeneous across divisions.Interpretation: Both temperature and ONI have the potential to serve as predictors of vector activity at a lead time of 1–6 months, while the amount of rainfall could indicate the magnitude of vector prevalence in the same month. This information, along with knowledge of the distribution of breeding sites, is useful for spatial risk prediction and implementation of effective Aedes control interventions. Funding: None.
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| 35. |
- Liyanage, Prasad, et al.
(författare)
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Evaluation of intensified dengue control measures with interrupted time series analysis in the Panadura Medical Officer of Health division in Sri Lanka : a case study and cost-effectiveness analysis
- 2019
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Ingår i: The Lancet Planetary Health. - : Elsevier. - 2542-5196. ; 3:5, s. e211-e218
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dengue has become a major public health problem in Sri Lanka with a considerable economic burden. As a response, in June, 2014, the Ministry of Health initiated a proactive vector control programme in partnership with military and police forces, known as the Civil-Military Cooperation (CIMIC) programme, that was targeted at high-risk Medical Officer of Health (MOH) divisions in the country. Evaluating the effectiveness and cost-effectiveness of population-level interventions is essential to guide public health planning and resource allocation decisions, particularly in resource-limited health-care settings.Methods: Using an interrupted time series design with a non-linear extension, we evaluated the impact of vector control interventions from June 22, 2014, to Dec 29, 2016, in Panadura, a high-risk MOH division in Western Province, Sri Lanka. We used dengue notification and larval survey data to estimate the reduction in Breteau index and dengue incidence before and after the intervention using two separate models, adjusting for time-varying confounding variables (ie, rainfall, temperature, and the Oceanic Niño Index). We also assessed the cost and cost-effectiveness of the CIMIC programme from the perspective of the National Dengue Control Unit under the scenarios of different levels of hospitalisation of dengue cases (low [25%], medium [50%], and high [75%]) in terms of cost per disability-adjusted life-year averted (DALY).Findings: Vector control interventions had a significant impact on combined Breteau index (relative risk reduction 0·43, 95% CI 0·26 to 0·70) and on dengue incidence (0·43, 0·28 to 0·67), the latter becoming prominent 2 months after the intervention onset. The mean number of averted dengue cases was estimated at 2192 (95% CI 1741 to 2643), and the total cost of the CIMIC programme at 2016 US$271 615. Personnel costs accounted for about 89% of the total cost. In the base-case scenario of moderate level of hospitalisation, the CIMIC programme was cost-saving with a probability of 70% under both the lowest ($453) and highest ($1686) cost-effectiveness thresholds, resulting in a net saving of $20 247 (95% CI −57 266 to 97 790) and averting 176 DALYs (133 to 226), leading to a cost of −$98 (−497 to 395) per DALY averted. This was also the case for the scenario with high hospitalisation levels (cost per DALY averted −$512, 95% CI −872 to −115) but with a higher probability of 99%. In the scenario with low hospitalisation levels (cost per DALY averted $690, 143 to 1379), although the CIMIC programme was cost-ineffective at the lowest threshold with a probability of 77%, it was cost-effective at the highest threshold with a probability of 99%.Interpretation: This study suggests that communities affected by dengue can benefit from investments in vector control if interventions are implemented rigorously and coordinated well across sectors. By doing so, it is possible to reduce the disease and economic burden of dengue in endemic settings.Funding: None.
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| 36. |
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| 37. |
- Liyanage, Prasad, et al.
(författare)
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The impact of COVID-19 lockdown on dengue transmission in Sri Lanka : A natural experiment for understanding the influence of human mobility
- 2021
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Ingår i: PLoS Neglected Tropical Diseases. - : Public Library of Science. - 1935-2727 .- 1935-2735. ; 15:6
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Dengue is one of the major public health problems in Sri Lanka. Its outbreak pattern depends on a multitude of drivers, including human mobility. Here we evaluate the impact of COVID-19 related mobility restriction (lockdown) on the risk of dengue in Sri Lanka.METHODOLOGY: Two-stage hierarchical models were fitted using an interrupted time-series design based on the notified dengue cases, January 2015 to July 2020. In the first stage model, the district level impact was estimated using quasi-Poisson regression models while accounting for temporal trends. Estimates were pooled at zonal and national levels in the second stage model using meta-analysis. The influence of the extended period of school closure on dengue in children in the western province was compared to adults.FINDINGS: Statistically significant and homogeneous reduction of dengue risk was observed at all levels during the lockdown. Overall an 88% reduction in risk (RR 0.12; 95% CI from 0.08 to 0.17) was observed at the national level. The highest impact was observed among children aged less than 19 years showing a 92% reduction (RR 0.8; 95% CI from 0.03 to 0.25). We observed higher impact in the dry zone having 91% reduction (RR 0.09; 95% CI from 0.05 to 0.15) compared to wet zone showing 83% reduction (RR 0.17; 95% CI from 0.09 to 0.30). There was no indication that the overall health-seeking behaviour for dengue had a substantial influence on these estimates.SIGNIFICANCE: This study offers a broad understanding of the change in risk of dengue during the COVID-19 pandemic and associated mobility restrictions in Sri Lanka. The analysis using the mobility restrictions as a natural experiment suggests mobility patterns to be a very important driver of dengue transmission.
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| 38. |
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| 39. |
- Ompad, Danielle C., et al.
(författare)
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The effectiveness of malaria camps as part of the Durgama Anchalare Malaria Nirakaran (DAMaN) program in Odisha, India: study protocol for a cluster-assigned quasi-experimental study
- 2021
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Ingår i: Global Health Action. - : Informa UK Limited. - 1654-9716 .- 1654-9880. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The Indian state of Odisha has a longstanding battle with forest malaria. Many remote and rural villages have poor access to health care, a problem that is exacerbated during the rainy season when malaria transmission is at its peak. Approximately 62% of the rural population consists of tribal groups who are among the communities most negatively impacted by malaria. To address the persistently high rates of malaria in these remote regions, the Odisha State Malaria Control Program introduced ‘malaria camps’ in 2017 where teams of health workers visit villages to educate the population, enhance vector control methods, and perform village-wide screening and treatment. Malaria rates declined statewide, particularly in forested areas, following the introduction of the malaria camps, but the impact of the intervention is yet to be externally evaluated. This study protocol describes a cluster-assigned quasi-experimental stepped-wedge study with a pretest-posttest control group design that evaluates if malaria camps reduce the prevalence of malaria, compared to control villages which receive the usual malaria control interventions (e.g. IRS, ITNs), as detected by PCR.
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| 40. |
- Phyo Myint, Ei Ei, et al.
(författare)
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Discovery of Carcinogenic Liver Fluke Metacercariae in Second Intermediate Hosts and Surveillance on Fish-Borne Trematode Metacercariae Infections in Mekong Region of Myanmar
- 2020
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 17:11
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Tidskriftsartikel (refereegranskat)abstract
- Countries of lower Mekong regions are highly alarmed by the spread of fish-borne trematode infections, i.e., small liver flukes and minute intestinal flukes especially in Thailand, Lao People’s Democratic Republic (Lao PDR), Vietnam, Cambodia and Myanmar. Moreover; the incidence of cholangiocarcinoma has also been increasing in the endemic area of liver fluke infections. Only a few reports have been published concerning the fish-borne trematodes infections in the central region of Myanmar. However; there is still a lack of information regarding the status of trematodes infections in second intermediate hosts in the Mekong region of Myanmar. Therefore, we conducted surveillance on the distribution of trematode metacercariae in small cyprinoid fishes collected from the Mekong region of Myanmar. A total of 689 fishes (12 different species of cyprinoid fishes) have been collected and examined by pepsin digestion methods. We discovered four species of fish-borne trematode metacercariae infections, i.e., carcinogenic liver fluke, Opisthorchis viverrini; minute intestinal flukes, Haplorchis taichui; Haplorchis pumilio and Haplorchoides sp. in Tachileik, the Mekong Region of Myanmar. The outcome of this study could be a useful index for the fish-borne zoonotic trematode epidemiology in the Mekong area. Besides, the results of our study contribute to filling the gap of information necessary for the control and prevention of fish-borne trematode zoonotic infections in the Mekong region.
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