Geographically and Temporally Weighted Regression in Assessing Dengue Fever Spread Factors in Yunnan Border Regions

Objective This study employs the Geographically and Temporally Weighted Regression(GTWR)model to assess the impact of meteorological elements and imported cases on dengue fever outbreaks,emphasizing the spatial-temporal variability of these factors in border regions.Methods We conducted a descriptive analysis of dengue fever’s temporal-spatial distribution in Yunnan border areas.Utilizing annual data from 2013 to 2019,with each county in the Yunnan border serving as a spatial unit,we constructed a GTWR model to investigate the determinants of dengue fever and their spatio-temporal heterogeneity in this region.Results The GTWR model,proving more effective than Ordinary Least Squares(OLS)analysis,identified significant spatial and temporal heterogeneity in factors influencing dengue fever’s spread along the Yunnan border.Notably,the GTWR model revealed a substantial variation in the relationship between indigenous dengue fever incidence,meteorological variables,and imported cases across different counties.Conclusion In the Yunnan border areas,local dengue incidence is affected by temperature,humidity,precipitation,wind speed,and imported cases,with these factors’influence exhibiting notable spatial and temporal variation.

Climate-driven dengue fever outbreaks in Nepal:Trends,challenges,and strategies

Dengue fever(DF)has become a major public health concern in Nepal,with increasing outbreaks in recent years.Transmitted by Aedes mosquitoes,this climate-sensitive viral disease presents a significant challenge for healthcare providers and policymakers.Since 2004,Nepal has experienced a sharp increase in DF cases,peaking in 2022 with 54784 cases and 88 deaths.The surge,driven mainly by serotypes 1,2,and 3,is exacerbated by climate change,which prolongs mosquito breeding seasons due to warmer temperatures and increased rainfall.This trend has even impacted previously unaffected hilly regions.Effective dengue control strategies must focus on climate change adaptation,strengthening healthcare system reinforcement,raising public awareness,and enhancing vector control measures.Government initiatives,like the national dengue control program,play a critical role,but research and community engagement are also vital for prevention and early detection.Integrating climate resilience into public health efforts is essential to reducing the dengue burden in Nepal.

The Impacts of Mosquito Density and Meteorological Factors on Dengue Fever Epidemics in Guangzhou, China, 2006-2014: a Time-series Analysis

Objective To explore the associations between the monthly number of dengue fever（DF） cases and possible risk factors in Guangzhou, a subtropical city of China. Methods The monthly number of DF cases, Breteau Index （BI）, and meteorological measures during 2006-2014 recorded in Guangzhou, China, were assessed. A negative binomial regression model was used to evaluate the relationships between BI, meteorological factors, and the monthly number of DF cases. Results A total of 39,697 DF cases were detected in Guangzhou during the study period. DF incidence presented an obvious seasonal pattern, with most cases occurring from June to November. The current month＇s BI, average temperature （Tare）, previous month＇s minimum temperature （Train）, and Tare were positively associated with DF incidence. A threshold of 18.25℃ was found in the relationship between the current month＇s Tmin and DF incidence. Conclusion Mosquito density, Tove, and Tmin play a critical role in DF transmission in Guangzhou. These findings could be useful in the development of a DF early warning system and assist in effective control and prevention strategies in the DF epidemic.

Dengue Fever Epidemiological Status and Relationship with Meteorological Variables in Guangzhou, Southern China, 2007-2012

Ecological methodology plus negative binomial regression were used to identify dengue fever （DF） epidemiological status and its relationship with meteorological variables. From 2007 to 2012, annual incidence rate of DF in Guangzhou was 0.33, 0.11, 0.15, 0.64, 0.45, and 1.34 （per 100 000） respectively, showing an increasing trend. Each 1℃ rise of temperature corresponded to an increase of 10.23% （95% CI 7.68% to 12.83%） in the monthly number of DF cases, whereas l hPa rise of atmospheric pressure corresponded to a decrease in the number of cases by 5.14% （95% CI： 7.10%-3.14%）. Likewise, each one meter per second rise in wind velocity led to an increase by 43.80% or 107.53%, and one percent rise of relative humidity led to an increase by 2.04% or 2.19%.

Frequency, Duration and Intensity of Dengue Fever Epidemic Risk in Townships in Pearl River Delta and Yunnan in China, 2013

Dengue fever （DF）, one of the neglected tropical diseases also known as breakbone fever, is a mosquito-borne disease common in the tropics and subtropics. Dengue fever is transmitted primarily by A.aegypti, resulting in infection with any of four distinct but closely related virus serotypes. The majority of infected people experience a self-limiting clinical course. A small proportion of cases develop into life-threatening Dengue Hemorrhagic Fever or Dengue Shock Syndrome.

Modeling and predicting dengue fever cases in key regions of the Philippines using remote sensing data

Objective: To correlate climatic and environmental factors such as land surface temperature, rainfall, humidity and normalized difference vegetation index with the incidence of dengue to develop prediction models for the Philippines using remote-sensing data.Methods: Timeseries analysis was performed using dengue cases in four regions of the Philippines and monthly climatic variables extracted from Global Satellite Mapping of Precipitation for rainfall, and MODIS for the land surface temperature and normalized difference vegetation index from 2008-2015.Consistent dataset during the period of study was utilized in Autoregressive Integrated Moving Average models to predict dengue incidence in the four regions being studied.Results: The best-fitting models were selected to characterize the relationship between dengue incidence and climate variables.The predicted cases of dengue for January to December 2015 period fitted well with the actual dengue cases of the same timeframe.It also showed significantly good linear regression with a square of correlation of 0.869 5 for the four regions combined.Conclusion: Climatic and environmental variables are positively associated with dengue incidence and suit best as predictor factors using Autoregressive Integrated Moving Average models.This finding could be a meaningful tool in developing an early warning model based on weather forecasts to deliver effective public health prevention and mitigation programs.

Assessment of Biochemical and Antioxidative Status in Patients Suffering from Dengue Fever

Summary：A multi-centred study was designed to collect dengue epidemiologic data from government and registered private hospitals/clinics and maintained archive of frozen specimens in bio-bank to be used for future dengue epidemic control program, and assess the epidemiology of dengue fever（DF） by evaluating biochemical and oxidative status of patients. ELISA Ig M antibodies test was done to confirm DF. From August 2010 to December 2011, 101 confirmed blood samples of DF patients referred to pathology lab of Jinnah Hospital Lahore were subjected to the epidemiologic assessment by evaluating the biochemical and physiological indices and alterations of circulating antioxidants. Clinical features of DF patients and effect of fever on blood components and serum proteins of liver were recorded. The hospital stay in DF, dengue hemorrhagic fever（DHF） and dengue shock syndrome（DSS） showed significant difference. Significant increases in serum alanine amino transferase（ALT）（P=0.000）, aspartate amino transferase（AST）（P=0.000）, alkaline phosphatase（ALP）（P=0.000）, malondialdehyde（MDA） along with significant decreases in total protein（TP）（P=0.000）, reduced glutathione（GSH）（P=0.000）, superoxide dismutase（SOD）, catalase（CAT）（P=0.000）, and sialic acid contents（P=0.016） were observed. A positive correlation existed between bound sialic acid levels, liver enzymes and circulating antioxidants（r=0.656, P=0.016）. In the present study, alterations of circulating antioxidants in DF suggest that DF might be a metabolic response to an acute, self-limiting tropical viral infection, and a consequence of the viral inflammatory process.

Community social capital on fighting dengue fever in suburban Surabaya, Indonesia: A qualitative study

Purpose:Dengue hemorraghic fever(DHF)is a communicable disease that is difficult to manage,espe-cially in tropical countries.Social capital is believed to be able to improve the ability of entire com-munities to work together to solve a collective health problem.This study aimed to describe the existing social capital in a community and how it was used to fight DHF.Methods:Qualitative descriptive methods were used,and in-depth interviews were conducted with 13 participants.This study was conducted in the Sawahan sub-district,Surabaya,Indonesia,an endemic area that combats DHF every year.Findings:Results showed that social capital as a community feature provides the main cornerstone of collective action.The creation of social groups,intersectoral collaboration,mutual assistance in cleaning,and voluntary work were visible forms of social capital in the prevention and control of DHF.Support from strong leaders also had significant implications.Conclusions:This study showed that social capital was an important feature,which,if managed,used and accessed properly,would be able to provide ideas for solving community problems.

Ophthalmic complications related to dengue fever: a case report

Two patients aged of 30 and 22(female in cases 1,and male in case 2) both complained of unilateral blurring of vision and scotoma within a week of being diagnosed with dengue fever.No other abnormal findings were found in their anterior segment.Retinal examination revealed blurring of the optic disc margin and several white spots in the posterior in both cases.Optical coherence tomography(OCT)imagery revealed that the white spots were only located in the retinal outer layers.Macular cystic foveolitis were also found in case 1 and diffused macular edema in case 2.In case 1,visual and retinal recovery were seen to resolve spontaneously.In case 2,patient had complete visual recovery two months after onset of the disease after being treated with steroids but central scotomata has continued to persist.

Liver Damage during Dengue Fever in Ouagadougou

Dengue fever is widespread in all tropical and subtropical areas of the world and is the main public health problem posed by arboviroses. In Burkina Faso, an outbreak of dengue serotype “DENV-2”, which is responsible for severe forms of dengue, has been reported. In this study, we will discuss liver damage during this disease. The aim of this study was to describe the sociodemographic, diagnostic, therapeutic and evolutionary aspects of dengue patients with hepatic cytolysis. Patients and Methods: This was a prospective cross-sectional study of dengue disease in 2 facilities in the city of Ouagadougou. The study was spread over a period of 3 months from August to November 2019. The study population consisted of all patients hospitalised for dengue with a positive AgNS1 and/or IgM rapid diagnostic test (RDT) and presenting signs of liver damage. Results: During our study period we recruited 134 patients with dengue fever of which 93 or 69.4% had at least one elevated transaminase. The sex ratio was 1.90 and the average age was 35 years. Symptoms of liver damage were rare with right hypochondrial pain in 4.30% of cases and jaundice in 1.07% of cases. Dengue haemorrhagic fever was found in 5 patients. IgG was negative in 77.42%. The majority of patients (44% or 47.31%) had at least one transaminase value elevated to the upper limit of normal (ULN);and a minority, 14 patients or 15.06%, had transaminases above 10 ULN. A small proportion of patients had hepatocellular failure 26.92% with a lowered prothrombin level. Ninety-four per cent (94.62%) of the patients received analgesics. Level 1 analgesic (paracetamol) was the most widely administered, particularly in 76 patients (86.36%). More than half of the patients (57.14%) had a length of stay of less than or equal to 3 days and the outcome was favourable in 91.40%. Conclusion: Dengue virus causes alterations in the liver parenchyma. The degree of liver damage is variable. As clinical symptoms are almost non-existent, the measurement of transaminases remains important.

Transient polycythemia during diabetic ketoacidosis triggered by dengue fever in a middle-aged woman

Either dengue fever or diabetic ketoacidosis can cause the high hemoglobin concentration due to intravascular volume loss.When both entities were found together as in our case,the hemoglobin concentration could access the strikingly high level until either of them could not contribute it.She was a Thai woman with 46 years of age presenting with fever,fatigue and severe sore throat for a few days.The physical examination showed she had mild dyspnea and oral thrush,the temperature was 36.4 degree Celsius,and her pulse rate was 102/min.Her blood tests showed:Hb 18.3 g%,WBC 9,850/mm^(3),atypical lymphocyte 10%,platelet 16,000/mm^(3),MCV 89.2 fl,Dengue NS1 antigen-positive,dengue IgG-positive,IgM-weakly positive,KOH preparation of curd from buccal mucosa-positive for budding yeasts and pseudo-hyphae,blood sugar 442 mg%,triglyceride 578 mg%,Na 122.8 mEq/L,K 6.28 mEq/L,Cl 90.6 mEq/L,CO_(2)9.2 mEq/L,blood ketone 53.6 mmol/L,lactate 4.5 mmol/L,pH 7.257,pCO_(2)27.4 mmHg,HCO_(3)11.9 mmo/L,BUN 22.9 mg%,creatinine 0.64 mg%,AST 375 U/L,ALT 224 U/L,alkaline phosphatase 151 U/L.She was diagnosed as having diabetes with diabetic ketoacidosis,dengue fever and polycythemia.She was immediately treated with intravenous fluid therapy to correct the metabolic acidosis,electrolyte imbalance and dehydration,insulin for hyperglycemia,clotrimazole for oral thrush and platelet transfusion.Her high hemoglobin level was dramatically lowered until became normal within one day of therapy whereas she also recovered from DKA although the platelet was progressively lowered every day.It suggested that transient polycythemia was solely contributed by DKA that was triggered by dengue fever hence DKA from dengue fever should be added in the list of unusual causes of transient polycythemia.

Dengue fever may mislead the surgeons when it presents as an acute abdomen

Objective: To review the management experience of a consecutive series of patients presenting as acute surgical abdomen whom were ultimately diagnosed to have DF(Dengue fever)/ DHF(Dengue heamorrhagic fever),Methods: Clinical data of all cases of apparent acute abdomen(AA) which were later confirmed as having DF/DHF reviewed by two surgical units from December 2012 to December 2013 were analyzed,Initially confirmed patients with DF/DHF who developed abdominal symptoms were not considered,Results: Out of the seventeen cases(7 males,age range 10-71 years) presented with fever and AA; appendicitis,cholecystitis,pancreatitis and non-specific peritonitis were suspected initially in 8,5,1 and 3 cases,respectively,Neutropenia or thrombocytopenia signifying DF/DHF occurred only in 11 patients at first evaluation thus six remained as surgical candidates beyond 24 h,One patient underwent appendicectomy with a prolonged hospital stay,DF was confirmed by serology in all patients,latest by fourth day of admission,One required blood product transfusion,4 needed critical care treatment and there was 1 death,Conclusions: DF/DHF misleads the clinicians when it presents as AA,Initial heamatological and ultrasonographic findings may be equivocal creating a diagnostic and management dilemma,Vigilant clinical suspicion and early dengue serological assessment is advisable in equivocal cases of AAs with fever in dengue endemic areas,to confirm/exclude the infection in order to avoid unnecessary surgical morbidity in the presence of DF.

Outbreak of Dengue Fever in Central China,2013

In 2013,the first dengue fever（DF） outbreak in central China was reported in the central of Henan province,northern temperate regions,although they have been sequentially recorded in Southern China.106 suspected DF cases were reported and 73 patients were confirmed dengue virus type 3（DEN-3） infections.62/392（15.8%） local health persons showed DEN antibodies positive.To this day Henan is the northernmost province in China which has been reported about outbreak of DF and what is important is that it warns us the endemic range of DF has been expanded geographically in China.

Dengue fever leading to acute dengue hemorrhagic leukoencephalitis:A case report

Rationale:Dengue fever is a prevalent tropical infectious disease that has a broad panorama of presentations from mild febrile illness to life-threatening manifestations in the form of dengue hemorrhagic fever and dengue shock syndrome.Patient’s concerns:A 20-year-old male presented with a 2-day history of fever,multiple episodes of vomiting,and altered sensorium.Diagnosis:Dengue fever leading to acute hemorrhagic leukoencephalitis.Interventions:Multiple transfusions of single donor platelets,intravenous methylprednisolone,intravenous immunoglobulin,anti-seizure prophylaxis,and broad-spectrum antibiotics.Outcomes:Repeat brain magnetic resonance imaging showed resolution of lesions.The patient was subsequently discharged from the hospital in a healthy state.Lessons:This report helps us to gain a better understanding of the patient’s presentation,which will help to improve the timely recognition and prevention of this rare devastating presentation.

Pituitary apoplexy secondary to dengue fever-induced-thrombocytopenia:A case report and review of literature

Rationale:Pituitary apoplexy(PA)is a rare endocrine emergency that requires prompt diagnosis and management.Dengue fever-induced-thrombocytopenia may rarely predispose to PA.Patient’s Concern:A 58-year-old male patient having known pituitary macroadenoma presented to the emergency department with fever,a sudden onset severe headache,and altered sensorium.Diagnosis:Pituitary apoplexy caused by dengue fever-induced-thrombocytopenia.Interventions:Conservative management with fluids,mannitol,dexamethasone and symptomatic treatment.Outcomes:The patient responded well to the treatment and was discharged uneventfully.Lessons:Although dengue hemorrhagic fever is a rare cause of pituitary apoplexy,it should be considered if a patient presents with headache and altered sensorium,and prompt initiation of treatment is crucial to prevent fatality and neuro-ophthalmic deficits.

Dengue fever outbreaks in Eritrea,2005-2015 A case for strengthening surveillance,control and reporting

Background:The geographic distribution and burden of dengue is increasing globally.This study aims to evaluate dengue outbreaks and to substantiate the need for strengthened surveillance,reporting and control in Eritrea.Methods:Data from two cross-sectional dengue epidemic investigations in 2005 and 2010 were analyzed.Samples were tested for dengue virus-specific IgM and IgG antibodies using capture enzyme-linked immunosorbent assays.Dengue vectors’breeding attributes were characterized and epidemic risk indices determined.National routine surveillance weekly reports from 2005 to the second quarter of 2015 were analyzed for spatiotemporal trends.Results:Dengue outbreaks increased in Eritrea from 2005 to 2015 with clinical presentation varying markedly among patients.The house and container indices for Aedes aegypti were 40 and 39.6%respectively,with containers having A.aeqypti varying significantly(P<0.04).Serum from 33.3%(n=15)and 88%(n=26)of clinical dengue cases in Aroget sub-Zoba(district)of Gash Barka Zoba(region)contained anti-DENV IgM antibody in 2005 and 2006,respectively.The national surveillance data from 2005 to 2015 indicate an overall spatiotemporal increase of dengue fever.Conclusions:The increase in dengue outbreaks has been confirmed in Eritrea and necessitates strengthening of surveillance and health worker and laboratory capacity,as well as targeted vector control interventions.

Dengue hemorrhagic fever with rectus sheath hematoma:A case report

Rationale:Acute pain is a medical emergency that requires prompt abdominal evaluation and management.Dengue,a mosquito-borne arboviral infection,can lead to complications such as acute abdominal pain.Patient concerns:A 72-year-old hypertensive female presented with high-grade intermittent fever with chills and rigors for four days.She was diagnosed with dengue fever(NS1Ag-reactive)the day before admission.A contrast-enhanced computed tomography of the abdomen showed a hematoma along the rectus sheath which was managed conservatively as per surgical opinion.Diagnosis:Dengue hemorrhagic fever with rectus sheath hematoma.Interventions:Blood transfusion and fluid therapy.Outcomes:Ten days after discharge,the patient reproted no pain in the right iliac fossa and the size of the hematoma was significantly reduced.Lessons:Although it is rarely seen as a cause of acute abdomen,complaints of adnominal pain should never be ignored in critical or convalescent phase of dengue fever.Radiological investigations should be promptly conducted as hematoma is often difficult to be diagnosed clinically.Delay in diagnosis of rectus sheath hematoma can be fatal.

Characterizing a large outbreak of dengue fever in Guangdong Province, China

Background:Dengue cases have been reported each year for the past 25 years in Guangdong Province,China with a recorded historical peak in 2014.This study aims to describe the epidemiological characteristics of this large outbreak in order to better understand its epidemic factors and to inform control strategies.Methods:Data for clinically diagnosed and laboratory-confirmed dengue fever cases in 2014 were extracted from the China Notifiable Infectious Disease Reporting System.We analyzed the incidence and characteristics of imported and indigenous cases in terms of population,temporal and spatial distributions.Results:A total of 45224 dengue fever cases and 6 deaths were notified in Guangdong Province in 2014,with an incidence of 47.3 per 100000 people.The elderly(65+years)represented 11.7%of total indigenous cases with the highest incidence(72.3 per 100000).Household workers and the unemployed accounted for 23.1%of indigenous cases.The majority of indigenous cases occurred in the 37th to 44th week of 2014(September and October)and almost all(20 of 21)prefecture-level cities in Guangdong were affected.Compared to the non-Pearl River Delta Region,the Pearl River Delta Region accounted for the majority of dengue cases and reported cases earlier in 2014.Dengue virus serotypes 1(DENV-1),2(DENV-2)and 3(DENV-3)were detected and DENV-1 was predominant(88.4%).Conclusions:Dengue fever is a serious public health problem and is emerging as a continuous threat in Guangdong Province.There is an urgent need to enhance dengue surveillance and control,especially for the high-risk populations in high-risk areas.

Epidemiological characteristics and temporal-spatial analysis of overseas imported dengue fever cases in outbreak provinces of China, 2005–2019

Background Overseas imported dengue fever is an important factor in local outbreaks of this disease in the mainland of China.To better prevent and control such local outbreaks,the epidemiological characteristics and temporal-spatial distribution of overseas imported dengue fever cases in provincial-level administrative divisions(PLADs)where dengue fever is outbreak in the mainland of China were explored.Methods Using the Chinese National Notifiable Infectious Disease Reporting Information System(CNNDS),we identified overseas imported dengue fever cases in dengue fever outbreak areas in the mainland of China from 2005 to 2019 to draw the epidemic curve and population characteristic distribution of overseas imported cases in each PLAD.Based on spatial autocorrelation analysis of ArcGIS 10.5 and temporal-spatial scanning analysis of SaTScan 9.5,we analyzed the temporal-spatial distribution of overseas imported dengue fever in dengue fever outbreak areas in the mainland of China.Results A total of 11,407 imported cases,mainly from Southeast Asia,were recorded from 2005 to 2019 in these 13 PLADs.Of which 62.1%were imported into Yunnan and Guangdong Provinces.Among the imported cases,there were more males than females,mainly from the 21–50 age group.The hot spots were concentrated in parts of Yunnan,Guangdong and Fujian Provinces.We found the cluster of infected areas were expanding northward.Conclusions Based on the analysis of overseas imported dengue cases in 13 PLADs of the mainland of China from 2005 to 2019,we obtained the epidemiological characteristics and spatial distribution of imported dengue cases.Border controls need to pay attention to key population sectors,such as 21–50 years old men and education of key populations on dengue prevention.There is a need to improve the awareness of the prevention and control of imported cases in border areas.At the same time,northern regions cannot relax their vigilance.

Phylogenetic Analysis of the Dengue Virus Strains Causing the 2019 Dengue Fever Outbreak in Hainan,China

Dengue virus is an arthropod-borne pathogen that is transmitted to humans primarily by Aedes spp.mosquitos,causing the acute infectious disease,dengue fever(DF).Until 2019,no dengue outbreak had been reported in Hainan Province for over 20 years.However,in early September of 2019,an increasing number of infected cases appeared and the DF outbreak lasted for over one month in Haikou City,Hainan Province.In our study,we collected 97 plasma samples from DF patients at three hospitals,as well as 1585 mosquito larvae samples from puddles in different areas of Haikou.There were 49(50.5%)plasma samples found to be strongly positive and 9(9.3%)plasma samples were weakly positive against the NS1 antigen.We discovered DENV both in the patient's plasma samples and mosquito larvae samples,and isolated the virus from C6/36 cells inoculated with the acute phase serum of patients.Phylogenetic analysis revealed that the new strains were the most closely related to the epidemic strain in the southern regions of China,belonging to lineageⅣ,genotypeⅠ,DENV-1.Compared to the seven closest strains from neighboring countries and provinces,a total of 18 amino acid mutations occurred in the coding sequences(CDS)of the new isolated strain,DENV1 HMU-HKU-2.Our data shows that dengue virus is re-emerged in Hainan,and pose new threats for public health.Thus regular molecular epidemiological surveillance is necessary for control and prevention of DENV transmission.