Objective: This study aimed to improve dengue fever predictions in Singapore using a machine learning model that incorporates meteorological data, addressing the current methodological limitations by examining the intricate relationships between weather changes and dengue transmission. Method: Using weekly dengue case and meteorological data from 2012 to 2022, the data was preprocessed and analyzed using various machine learning algorithms, including General Linear Model (GLM), Support Vector Machine (SVM), Gradient Boosting Machine (GBM), Decision Tree (DT), Random Forest (RF), and eXtreme Gradient Boosting (XGBoost) algorithms. Performance metrics such as Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and R-squared (R2) were employed. Results: From 2012 to 2022, there was a total of 164,333 cases of dengue fever. Singapore witnessed a fluctuating number of dengue cases, peaking notably in 2020 and revealing a strong seasonality between March and July. An analysis of meteorological data points highlighted connections between certain climate variables and dengue fever outbreaks. The correlation analyses suggested significant associations between dengue cases and specific weather factors such as solar radiation, solar energy, and UV index. For disease predictions, the XGBoost model showed the best performance with an MAE = 89.12, RMSE = 156.07, and R2 = 0.83, identifying time as the primary factor, while 19 key predictors showed non-linear associations with dengue transmission. This underscores the significant role of environmental conditions, including cloud cover and rainfall, in dengue propagation. Conclusion: In the last decade, meteorological factors have significantly influenced dengue transmission in Singapore. This research, using the XGBoost model, highlights the key predictors like time and cloud cover in understanding dengue’s complex dynamics. By employing advanced algorithms, our study offers insights into dengue predictive models and the importance of careful model selection. These results can inform public health strategies, aiming to improve dengue control in Singapore and comparable regions.
Blastocystis hominis (Bh) is zoonotic parasitic pathogen with a high prevalent globally, causing opportunistic infections and diarrhea disease. Human immunodeficiency virus (HIV) infection disrupts the immune system by depleting CD4+ T lymphocyte (CD4+ T) cell counts, thereby increasing Bh infection risk among persons living with HIV (PLWH). However, the precise association between Bh infection risk and HIV-related biological markers and treatment processes remains poorly understood. Hence, the purpose of the study was to explore the association between Bh infection risk and CD4+ T cell counts, HIV viral load (VL), and duration of interruption in antiviral therapy among PLWH.A large-scale multi-center cross-sectional study was conducted in China from June 2020 to December 2022. The genetic presence of Bh in fecal samples was detected by real-time fluorescence quantitative polymerase chain reaction, the CD4+ T cell counts in venous blood was measured using flowcytometry, and the HIV VL in serum was quantified using fluorescence-based instruments. Restricted cubic spline (RCS) was applied to assess the non-linear association between Bh infection risk and CD4+ T cell counts, HIV VL, and duration of interruption in highly active antiretroviral therapy (HARRT).A total of 1245 PLWH were enrolled in the study, the average age of PLWH was 43 years [interquartile range (IQR): 33, 52], with 452 (36.3%) being female, 50.4% (n = 628) had no immunosuppression (CD4+ T cell counts > 500 cells/μl), and 78.1% (n = 972) achieved full virological suppression (HIV VL < 50 copies/ml). Approximately 10.5% (n = 131) of PLWH had interruption. The prevalence of Bh was found to be 4.9% [95% confidence interval (CI): 3.8-6.4%] among PLWH. Significant nonlinear associations were observed between the Bh infection risk and CD4+ T cell counts (Pfor nonlinearity < 0.001, L-shaped), HIV VL (Pfor nonlinearity < 0.001, inverted U-shaped), and duration of interruption in HARRT (Pfor nonlinearity < 0.001, inverted U-shaped).The study revealed that VL was a better predictor of Bh infection than CD4+ T cell counts. It is crucial to consider the simultaneous surveillance of HIV VL and CD4+ T cell counts in PLWH in the regions with high level of socioeconomic development. The integrated approach can offer more comprehensive and accurate understanding in the aspects of Bh infection and other opportunistic infections, the efficacy of therapeutic drugs, and the assessment of preventive and control strategies.
To understand the distribution of Angiostrongylus cantonensis foci in Guangdong Province for making surveillance program.Survey sites were chosen by strata sampling according to different geographic locations. Totally 22 survey sites were selected in four regions: East Guangdong, West Guangdong, North Guangdong and the Pearl River Delta. One or two administrative villages in each site were randomly selected for the investigation. Pomacea canaliculata and Achatina fulica collected from fields and other species of freshwater or terrestrial snails obtained in the restaurants and wet markets were examined for the third stage larvae by tissue grinding or lung examination. Rats were captured in the fields, and their hearts and lungs were dissected for adult worms. Rat feces were also collected for the detection of first stage larvae by water precipitation.Large number of P. canaliculata was found in all sites. A. fulica was found in most surveyed sites. Totally 2929 P. canaliculata and 1354 A. fulica were collected with a larva infection rate of 5.9% (172/2929) and 16.5% (223/1354), respectively (P<0.01). The average prevalence among the regions was different (P<0.01) with the highest prevalence in Pearl River Delta (15.6%, 152/975), especially in Dongguan City of the Delta (34.7%, 78/225). 114 Cipangopaludina sp. and 252 Bellamya sp. were bought from wet markets of 9. sites. Larvae were found only in Bellamya snails from Luoding and Kaiping cities with an infection rate of 1.4% (1/70) and 3.3% (3/91), respectively. Totally 491 rats were captured in 9 sites including Rattus norvegicus, R. flavipectus, Suncus murinus, Mus musculus, Bandicota indica, R. losea and R. rattus, with an average infection rate of 11.4% (56/491). Adult worms were found in R. norvegicus, R. flavipectus and B. indica with a prevalence of 19.8% (52/263), 2.5% (3/118) and 10.0% (1/10), respectively. Thirty-four rodent fecal samples were collected in 7 sites and examined with a larva positive rate of 44.1% (15/34).Foci of Angiostrongylus cantonensis are widely distributed in Guangdong Province as natural infection has been found in its intermediate and definitive hosts.
OBJECTIVE To study the susceptibility of Pomacea canaliculata of different developmental stages to Angiostrongylus cantonensis infection.P. canaliculata snails breeding at laboratory were divided into four rank (I-IV) according to the weight, and infected with the first stage larvae of A. cantonensis from Fujian Province. Their mortality, infection rate, worm burden, and the size, development and distribution of larvae in snails were examined.Snails at different developmental stages were readily infected with A. cantonensis. The infection rate was between 76% and 100%, with no significant difference among the groups (P>0.05). Snails at earlier developmental stage showed higher mortality. The heaviest worm burden and the largest number of snails harboring more than 100 larvae were found in snails of rank III. In general the larvae in snails showed a synchronous development in the groups. Sizes of the third stage larvae in snails of various ranks were homogeneous. The period before the third stage larva emergence and the time for a peak percentage of the larvae exhibited no significant difference among the four ranks. The larvae widely distributed in various parts of snails, with more in the lung and foot, and larvae from snails of different ranks could all infect rats successfully.P. canaliculata of the four ranks can all be infected by the first stage larvae of A. cantonensis. Rank III snails may be better for studying the relationship between P. canaliculata and A. cantonensis. The potential role of young snails in angiostrongyliasis transmission should be recognized.
Abstract Aim To determine the genetic diversity of invasive snails ( Pomacea spp.) that are implicated in crop damage, environmental degradation and human disease, and to determine their distribution pattern in a large part of eastern Asia. Location People's Republic of China (P.R. China). Methods We collected Pomacea snails in a national survey using a grid sampling approach. Overall, 544 snails from 54 sites were used for the present investigation. The mitochondrial cox1 gene was amplified and sequenced from all the snails. We determined and classified the haplotypes using network analyses and mapped them within P.R. China. Haplotypes from this study, together with sequences available from GenBank, were used to reveal the global distribution of Pomacea canaliculata and P. insularum . Results We obtained 521 cox1 sequences and identified 24 unique haplotypes. Six haplotypes were commonly found in P.R. China. Two species, P. canaliculata and P. insularum , and one cryptic group were observed. The distribution of the 24 haplotypes across P.R. China shows a mosaic pattern. Globally, only six of 112 haplotypes of P. canaliculata , P. insularum , P. dolioides , P. lineata and P. paludosa are shared between introduced and native snail populations. We found 16 haplotype clusters, five of which occur in mainland P.R. China. Three of the five clusters could be traced back to South America. The remaining two clusters were unique to P.R. China. Main conclusions Phylogenetic analyses indicate that P. canaliculata , P. insularum and two cryptic groups, discovered by the present and previous studies, coexist in the mainland of P.R. China. The mosaic distribution and the high diversity found in the collection sites suggests multiple and secondary introductions. The findings indicate the importance of preventing further intentional introductions and call for appraisal of the risk posed by these snails in vulnerable areas. Discrimination of the ecological impacts of the different species or genotypes will help to develop setting‐specific management strategies.
Background Several angiostrongyliasis outbreaks have been reported in recent years but the disease continues to be neglected in public health circles. We describe an outbreak in Dali, southwest China in order to highlight some key problems for the control of this helminth infection. Methodology/Principal Findings All available medical records of suspected angiostrongyliasis patients visiting hospitals in Dali in the period 1 October 2007–31 March 2008 were reviewed, and tentative diagnoses of varying strengths were reached according to given sets of criteria. Snails collected from local markets, restaurants and natural habitats were also screened for the presence of Angiostrongylus cantonensis. A total of 33 patients met criteria for infection, and 11 among them were classified as clinically confirmed. An additional eight patients were identified through a surveillance system put in operation in response to the outbreak. The epidemic lasted for 8 months with its peak in February 2008. Of the 33 patients, 97.0% complained of severe headache. 84.8% patients had high eosinophil cell counts either in the peripheral blood or in cerebrospinal fluid (CSF). Three-quarters of the patients were treated with a combination of albendazole and corticosteroids, resulting in significantly improved overall conditions. Twenty-two patients reported the consumption of raw or undercooked snails prior to the onset of the symptoms, and approximately 1.0% of the Pomacea canaliculata snails on sale were found to be infected with A. cantonensis. The snails were also found in certain habitats around Dali but no parasites were detected in these populations. Conclusions/Significance The import and sale of infected P. canaliculata is the likely trigger for this angiostrongyliasis outbreak. Awareness of angiostrongyliasis must be raised, and standardized diagnosis and treatment are needed in order to provide clinicians with a guide to address this disease. Health education campaigns could limit the risk, and a hospital-based surveillance system should be established in order to detect future outbreaks.
Abstract Back ground : Schistosomiasis, caused by Schistosoma mekongi , remains public health concern on islands in the Khong district, Champasack province, Southern Lao PDR. Other helminth infections, including Opisthorchis viverrini , hookworm, and Trichuris trichiura , are also prevalent on these islands. This study aimed to assess the impact of an Eco-health/One-health intervention package combined with mass drug administration (MDA) on these helminth infections. Methods We conducted a community intervention using a stepped-wedge trial approach on two endemic islands (Donsom and Donkhone) of the Kong district, Champasack province, Lao PDR, between April 2012 and March 2013. After the baseline (T0), the eco-health/one-health intervention package was implemented on Donsom (intervention) and Donkhone island (control). An assessment was conducted in 2014 (T1), one year after the completion of intervention implementation, to assess the short-term impact of the Eco-health/One-health intervention package on helminth infections and compare intervention and control islands. Later in 2015, the Eco-health/One-health intervention package was implemented on control island (Donkhone). After the implementation of intervention, the parasitological assessments were conducted annually in humans in 2015 (T2), in 2016 (T3) and in 2017 (T4), and in dogs in 2017 (T4) to evaluate the long-term impact of the intervention on helminth infections. Results Results showed that the Eco-health/One-health intervention package significantly reduced the infection with S. mekongi by 9.0% compared to the use of mass drug administration alone (control island). Additionally, this intervention package significantly reduced O. viverrini infection by 20.3% and hookworm by 17.9%. Annual parasitological assessments between 2012 and 2017 showed that the eco-health/one-health intervention package, coupled with MDA, steadily reduced the prevalence of S. mekongi on the intervention island from 29.1–1.8% and on the control island from 28.4–3.1%, respectively. Conclusion The study findings suggest that the Eco-health/One-health intervention significantly contributes to the prevalence reduction of S. mekongi and helminth co-infections, particularly hookworm and T. trichiura . Therefore, implementing the Eco-health/One-health intervention in schistosomiasis-endemic areas could accelerate the achievement of national goals for transmission interruption by 2025 and elimination by 2030.
Abstract Oncomelania hupensis is the unique intermediate host of Schistosoma japonicum , which plays a key role in the transmission of human blood fluke Schistosoma . The complete mitochondrial (mt) genome of O. hupensis has been characterized; however, the phylogenetic performance of mt protein‐coding genes (PCGs) of the snail remain unclear. In this study, 11 whole mt genomes of snails collected from four different ecological settings in China and the Philippines were sequenced. The mt genome sizes ranged from 15 183 to 15 216 bp, with the G + C contents from 32.4% to 33.4%. A total of 15 251 characters were generated from the multiple sequence alignment. Of 2711 (17.8%) polymorphic sites, 56.22% (1524) were parsimony sites. The mt genomes' phylogenetic trees were reconstructed using minimum evolution, neighbor joining, maximum likelihood, maximum parsimony, and Bayesian tree estimate methods, and two main distinct clades were identified: (i) the isolate from mountainous regions; (ii) the remaining isolate which included three inner branches. All phylogenetic trees of the 13 PCGs were generated by running 1000 bootstrap replicates and compared with the complete mtDNA tree, the classification accuracy ranging from 21.23% to 87.87%, the topological distance of phylogenetic trees between PCGs ranging from 5 to 14. Therefore, the performance of PCGs can be divided into good condition ( COI , ND2 , ND5 , and ND3 ), medium ( COII , ATP6 , ND1 , ND6 , Cytb , ND4 , and COIII ), poor ( ATP8 and ND4L ). This study represents the first analysis of mt genome diversity of the O. hupensis snail and phylogenetic performance of mt PCGs. It presents clear evidence that the snail populations can be separated into four landscape genetic populations in mainland China based on whole mt genomes. The identification of the phylogenetic performance of PCGs provides new insight into the intensive genetic diversity study using mtDNA markers for the snail.
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