Influence of geographic, knowledge and behavioral factors on Opisthorchis viverrini infection in the Northeast of Thailand

Objective:To determine the influence of geographic,knowledge and behavioral factors on Opisthorchis(O.)viverrini infection in the Northeast of Thailand.Methods:This cross-sectional study was conducted by using four datasets of years 2016 and 2017.Generalized linear mixed model was employed to analyze association between geographic,knowledge and behavioral factors and O.viverrini infection.Results:Totally there were 1885 participants.The prevalence of O.viverrini infection was 10.03%.Geographic factors that showed statistically significant association with O.viverrini infection in the Northeast region were featured by at least a dam and reservoir(Adj.OR=4.21,95%CI:2.49-7.13,P<0.001),at least a weir(Adj.OR=1.74,95%CI:1.09-2.77,P=0.020),>50 dogs and cats per village(Adj.OR=3.40,95%CI:2.17-5.31,P<0.001),and rice fields covered>50%of its areas(Adj.OR=1.91,95%CI:1.04-4.01,P=0.036),as well as low to moderate levels of knowledge(Adj.OR=1.60,95%CI:1.32 to 1.94,P<0.001),consumed raw fish(Adj.OR=1.90,95%CI:1.02 to 3.52,P=0.040)and consumed processed raw fish(Adj.OR=3.03,95%CI:2.20 to 4.18,P<0.001).Other significant covariates were gender and age of the respondents.Conclusions:O.viverrini infection still remains a public health problem of the Northeast of Thailand.Geographic and demographic factors,knowledge,and consumption behaviors of raw fish products are significantly associated with O.viverrini infection.

Glycoproteomics analysis of plasma proteins associated with Opisthorchis viverrini infection-induced cholangiocarcinoma in hamster model

Objective: To apply lectin affinity chromatography and glycoproteomics-based LC-MS/MS to preliminarily investigate the possible potential plasma biomarkers of Opisthorchis viverrini(OV)-associated CCA in OV/dimethylnitrosamine(DMN)-induced CCA hamster model. Methods: Nine Syrian hamsters were divided into 3 groups as follows(n=3 each): normal(healthy control group); OV group; and OV/DMN group(CCA group). Pooled plasma samples collected from animals in each group at the 6th month post-infection with OV metacercarae were subjected to glycoproteomics analysis. Glycoproteins in the pooled sample from each group were initially isolated by concanavilin A(Con A)-based affinity chromatography. The expression of glycoproteins isolated by both enrichment methods were determined using LCMS/MS. Results: Among the 24 Con A-binding glycoproteins isolated, two proteins, N-myc downstream regulated gene 1(NDRG1) and fetuin-B(FETUB) were found up-regulated only in the samples from the OV and control groups, but not in the OV/DMN(CCA) groups. On the other hand, one protein, i.e., NSFL1 cofactor p47 isoform x3(NSFL1C) was found only in the samples from OV/DMN(CCA) and control groups, but not in the OV group. The remaining 21 proteins were upregulated in the samples from all groups. Conclusions: NDRG1, FETUB and NSFL1 C glycoproteins isolated by Con A-based affinity chromatography could be potential biomarkers for CCA. Plasma samples with negative for NDRG1 and FETUB proteins but positive for NSFL1 C are likely to be OV-associated CCA. Nevertheless, this conclusion remains to be confirmed whether this battery test can discriminate OV-associated CCA from other risk factors.

Effects of albendazole,artesunate,praziquantel and miltefosine,on Opisthorchis viverrini cercariae and mature metacercariae

Objective:To explore larvicidal effects of anthelmintic drugs on Opisthorchis viverrini(O.viverrini) for alternative approach to interrupting its cycle for developing a field-based control program.Methods:The larvicidal activities of albendazole(A1),artesunate(Ar),praziquantel(Pzq) and miltefosine(Mf) on O.viverrini cercariae and mature metacercariae were investigated.Lethal concentrations(LC_(50) and LC_(95)) of these drugs were determined.Mature metacercariae previously exposed to various concentrations of the drugs were administered to hamsters.Worms were harvested 30 d post infection and worm recovery rates calculated.Al,Ar,Pzq and Mf produced morphological degeneration and induced shedding tails of cercariae after 24 h exposure.Results:The LC_(50) and LC_(95) of Al,Ar,Pzq and Mf on cercariae were 0.720 and 1.139,0.350 and 0.861,0.017 and 0.693,and 0.530 and 1.134 ppm,respectively.LC_(50) and LC_(95) of Ar on mature metacercariae were 303.643 and 446.237 ppm and of Mf were 289.711 and 631.781 ppm,respectively but no lethal effect in Pzq-and Al-treated groups(up to 1 ppt).No worms were found in hamsters administered Pzq-treated metacercariae.The adult worms from Al-treated metacercariae were significantly bigger in size compared to the control group(P<0.05).Fecundity and body width were greater in adults from Mf-treated metacercariae compared to the control group(P<0.05).Conclusions:The larvicidal effects of these drugs were high efficacy to O.viverrini cercariae but lesser efficacy to metacercariae.It should be further studied with the eventual aim of developing a field-based control program.

Bithynia siamensis goniomphalos,the first intermediate host of Opisthorchis viverrini in Thailand

Opisthorchiasis caused by Opistorchis viverrini(O.viverrini) remains as medically important problem in Thailand especially in the north-eastern part.Infection with this parasite can lead to cholangiocarcinoma improvement.The highest prevalence of O.viverrini infection has been found in the Northeast Thailand and is associated with the high incidence rate of cholangiocarcinoma.To complete the life cycle of 0.viverrini,the freshwater snails namely Bithynia funiculata,Bithynia siamensu siamensis and Bithynia siamensis goniomphalos(B.s.goniomphalos) are required to serve as the first intermediate host.Within these snails group,B.s.goniomphalos is distributed concisely in northeast Thailand and acts as the majority snail that transmitted the opisthorchiasis in this region.This study described the information of B.s.goniomphalos which research are needed for understanding the biology,distribution,transmission and factors influencing on the infection of the snail vector of this carcinogenic parasite.

Effects of physicochemical factors on development and survival of Opisthorchis viverrini uterine eggs

Objective: To investigate the maturity development of miracidia in uterine eggs from four portions of the Opisthorchis viverrini uterus and environmental factors possibly affected in maturation and infectivity of distal part uterine eggs.Methods: Uteri of adult worms were divided into 4 equal parts.Development of eggs was determined under light microscope.Only embryonated eggs were used to evaluate the effects of physicochemical factors: temperature, salinity, acidity, ultraviolet A, B, C.Infection success was evaluated by feeding treated eggs to intermediate host snails and determining by using a PCR approach.Results: Eggs obtained from the uterus closest to the ovary(regions 1 and 2) failed to develop in vitro.Eggs from region 4 of the uterus(close to the genital pore) were used to study effects of physicochemical factors.The highest survival and infection success was in groups of eggs kept at 30 ℃(95.20%).The calculated period of loss infection success(LI_(50) and LI_(95)) on miracidia in distal uterine eggs by exposure to UV-A, UV-B and UV-C were 73 and 1 523 d; 8 and 20 d; 1 and 2 d, respectively.Lethal concentrations(LC_(50) and LC_(95)) of salinity, HCl and NaOH on miracidia in distal uterine eggs were 45.43 and 120.09 ppt, 0.01 and 0.25 M; 0.01 and 0.11 M, respectively, after 24 h exposure.Conclusions: Opisthorchis viverrini eggs display a high tolerance to environmental conditions, especially after snail host eating for infection.

Thinking beyond Opisthorchis viverrini for risk of cholangiocarcinoma in the lower Mekong region:a systematic review and meta-analysis

Background:Cholangiocarcinoma(CCA)is a fatal bile duct cancer associated with infection by the liver fluke,Opisthorchis viverrini,in the lower Mekong region.Numerous public health interventions have focused on reducing exposure to O.viverrini,but incidence of CCA in the region remains high.While this may indicate the inefficacy of public health interventions due to complex social and cultural factors,it may further indicate other risk factors or interactions with the parasite are important in pathogenesis of CCA.This systematic review aims to provide a comprehensive analysis of described risk factors for CCA in addition to O.viverrini to guide future integrative interventions.Main body:We searched five international and seven Thai research databases to identify studies relevant to risk factors for CCA in the lower Mekong region.Selected studies were assessed for risk of bias and quality in terms of study design,population,CCA diagnostic methods,and statistical methods.The final 18 included studies reported numerous risk factors which were grouped into behaviors,socioeconomics,diet,genetics,gender,immune response,other infections,and treatment for O.viverrini.Seventeen risk factors were reported by two or more studies and were assessed with random effects models during meta-analysis.This meta-analysis indicates that the combination of alcohol and smoking(OR=11.1,95%CI:5.63-21.92,P<0.0001)is most significantly associated with increased risk for CCA and is an even greater risk factor than O.viverrini exposure.This analysis also suggests that family history of cancer,consumption of raw cyprinoid fish,consumption of high nitrate foods,and praziquantel treatment are associated with significantly increased risk.These risk factors may have complex relationships with the host,parasite,or pathogenesis of CCA,and many of these risk factors were found to interact with each other in one or more studies.Conclusions:Our findings suggest that a complex variety of risk factors in addition to O.viverrini infection should be addressed in future public health interventions to reduce CCA in affected regions.In particular,smoking and alcohol use,dietary patterns,and socioeconomic factors should be considered when developing intervention programs to reduce CCA.

Transmission of Opisthorchis viverrini,Schistosoma mekongi and soil-transmitted helminthes on the Mekong Islands,Southern Lao PDR

Background:Prevalence of Opisthorchis viverrini,Schistosoma mekongi and soil-transmitted helminths(STH)remains high in Lao People’s Democratic Republic(Lao PDR),despite control efforts including mass-drug administration,education and communication campaigns.New approaches are required to advance helminth control.Methods:An ecohealth study was conducted on two Mekong islands in Southern Laos.Demographic and behavioural data were collected by questionnaire.Human and animal reservoir stools were examined.Bithynia spp.and Neotricula aperta snails were examined using shedding.Fresh water fish were examined using digestion technique.Multivariate random-effects analysis was used to find risk factors associated with helminth infections.Results:Human infection rates with O.viverrini,hookworm,S.mekongi,Trichuris trichiura,Ascaris lumbricoides and Taenia spp.were 60.7%,44.1%,22.2%,4.1%,0.6%and 0.1%,respectively.Heavy intensity infections were 4.2%,3.6%and 1.8%for O.viverrini,S.mekongi and hookworm,respectively.O.viverrini and S.mekongi infection rates among dogs and cats were 25.0%and 14.7%,respectively.Of the cats tested,53.1%were infected with O.viverrini.Prevalence of O.viverrini and S.mekongi in snails was 0.3%and 0.01%,respectively.Overall prevalence of O.viverrini infection in fresh water fish was 26.9%,with the highest infection rates occurring in Hampala dispa(87.1%),Cyclocheilichthys apogon(85.7%)and Puntius brevis(40.0%).Illiteracy and lower socioeconomic status increased the risk of O.viverrini infection,while those aged 10-16 years and possessing latrines at home were less likely to be infected.Household dogs and cats that consumed raw fish were significantly and positively associated with O.viverrini infection of the household members.For S.mekongi,children under 9 years old were exposed significantly to this infection,compared to older age groups.Conclusions:There is a pressing need to design and implement an integrated helminth control intervention on the Mekong Islands in southern Lao PDR.Given the highly dynamic transmission of O.viverrini,S.mekongi,STH and extended multiparasitism,annual mass-drug administration is warranted along with environmental modifications,health education and improved access to clean water and adequate sanitation to consolidate morbidity control and move towards elimination.Trail registration number:Our findings presented here are from a cross-sectional study,therefore,it has not been registered.

Fish sharing as a risk factor for Opisthorchis viverrini infection:evidence from two villages in north-eastern Thailand

Background:Foodborne trematodiasis(FBT)is a significant global health problem,with the liver flukes Opisthorchis viverrini,O.felineus,and Clonorchis sinensis contributing to half of the global burden of FBT.North-eastern Thailand where O.viverrini is endemic and un-cooked fish dishes remain an integral part of the food culture has the highest reported incidence of opisthorchiasis,including associated cholangiocarcinoma.Both food sharing and eating practices are potentially important factors in FTB,suggesting an important role for the social ecology of disease transmission in these rural communities.Methods:Two rural Thai-Lao villages that were part of a 12-village project in Northeastern Thailand were selected for detailed investigation of O.viverrini infection risk associated with sharing of raw fish dishes among households.The project included screening individuals for infection and cholangiocarcinoma,a household questionnaire,and offering treatment options for positive individuals.Social network mapping was used to construct raw fish dish-sharing networks and create a proxy variable capturing variability in the degree of food sharing(DFS),measured as the number of different households with which each household shared fish dishes.Measures of associations between DFS,O.viverrini infection,the frequency of raw fish consumption,and the number of raw fish dishes consumed were generated using binary logistic regression,proportional odds ordinal logistic regression,and Poisson regression.Results:The results showed that the probability that a household has members infected with O.viverrini increased by~7%(P<0.01)for each additional household included in its network.Moreover,the frequency and number of types of raw fish dishes consumed increased significantly as the DFS increased.Of the two villages,that with the highest infection prevalence(48%versus 34.6%)had significantly higher social connectivity overall(P<0.001).Conclusions:Our findings suggest that the social ecology of human settlements may be key to understanding the transmission dynamics of some FBT.In the case of O.viverrini in Thai-Lao communities,for which food sharing is a traditional practice supporting social cohesion,food sharing network mapping should be incorporated into community-based interventions.These should encourage fish dish preparation methods that minimize infection risk by targeting households with high DFS values.

Repeated praziquantel treatment and Opisthorchis viverrini infection:a population-based cross-sectional study in northeast Thailand

Background:Opisthorchis viverrini infection is highly prevalent in northeast Thailand.This liver fluke is classified as a carcinogen due to its causal links with cholangiocarcinoma(CCA)development.Although treatment with praziquantel(PZQ)effectively cures O.viverrini infection,the prevalence remains high due to the traditional consumption of raw fish.Therefore,re-infection is common in the endemic community,leading to severe hepatobiliary morbidities including the fatal CCA.In this study,we evaluate the association between the frequency of previous PZQ treatment and current O.viverrini infections among Thai adults living in the endemic area of northeast Thailand.Methods:This study includes all participants who were screened for O.viverrini infection in the Cholangiocarcinoma Screening and Care Program(CASCAP),northeast Thailand.History of PZQ treatment was recorded using a health questionnaire.O.viverrini infections were diagnosed using urine antigen detection.Associations between PZQ and O.viverrini were determined by adjusted odds ratio(aOR)and 95%confidence interval(CI)using multiple logistic regression.Results:Among participants,27.7%had previously been treated once with PZQ,8.2%twice,2.8%three times,and 3.5%more than three times.Current O.viverrini prevalence was 17%(n=524).Compared with participants who never used PZQ,the aOR for infection among those who used the drug once was 1.09(95%CI:0.88-1.37),twice was 1.19(95%CI:0.85-1.68),three times was 1.28(95%C/:0.74-2.21),and more than three times was 1.86(95%C/:1.18-2.93;P=0.007).Conclusions:The population with a frequent history of PZQ use and still continued raw fish consumption showed high levels of repeated reinfection with O.viverrini.They were infected,treated and re-infected repeatedly.These findings suggest that certain participants continue raw fish consumption even after previous infection.This is a particular problem in highly endemic areas for O.viverrni and increases the risk of CCA.

Polymorphism of genes encoding drug-metabolizing and inflammation-related enzymes for susceptibility to cholangiocarcinoma in Thailand

BACKGROUND Cholangiocarcinoma(CCA)is an intractable cancer,and its incidence in north eastern Thailand is the highest worldwide.Infection with the liver fluke Opisthorchis viverrini(OV)has been associated with CCA risk.However,animal experiments have suggested that OV alone does not induce CCA,but its combination with a chemical carcinogen like nitrosamine can cause experimentally induced CCA in hamsters.Therefore,in humans,other environmental and genetic factors may also be involved.AIM To examine relations between risk for CCA and genetic polymorphisms in carcinogenmetabolizing and inflammation-related genes.METHODS This hospital-based case-control study enrolled 95 case-control pairs matched by age(±5 years)and sex.We examined relations between risk for CCA and genetic polymorphisms in carcinogenmetabolizing and inflammation-related genes,serum anti-OV,alcohol consumption,and smoking.Polymorphisms of CYP2E1,IL-6(-174 and-634),IL-10(-819),and NF-κB(-94)and their cooccurrence with polymorphisms in the drug-metabolizing enzyme gene GSTT1 or GSTM1 were also analyzed.RESULTS Although CCA risk was not significantly associated with any single polymorphism,persons with the GSTT1 wild-type and CYP2E1 c1/c2+c2/c2 genotype had an increased risk(OR=3.33,95%CI:1.23-9.00)as compared with persons having the GSTT1 wild-type and CYP2E1 c1/c1 wild genotype.The presence of anti-OV in serum was associated with a 7-to 11-fold increased risk,and smoking level was related to an OR of 1.5-1.8 in multivariable analyses adjusted for each of the seven genetic polymorphisms.CONCLUSION In addition to infection with OV,gene-gene interactions may be considered as one of the risk factors for CCA development.

Annexin A1: A new immunohistological marker of cholangiocarcinoma

AIM: To evaluate a new immunohistological marker, annexin A1 (ANXA1), in cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC). METHODS: Expression of ANXA1 protein was investigated in liver tissues from patients with CCA and HCC by immunohistochemistry. Its expression on differences stages of tumor development was investigated in hamster CCA tissues induced by Opisthorchis viverrini and N -nitrosodimethylamine. Moreover, mRNA expression of ANXA1 was assessed in CCA cell lines by quantitative real-time polymerase chain reaction and silencing of ANXA1 gene expression using small interfering RNA. RESULTS: In human CCA tissue arrays, immunohistochemical analysis revealed that the positive expression of ANXA1 was 94.1% (64/68 cases) consisting of a high expression (66.2%, 45/68 cases) and a low expression (33.8%, 23/68 cases). However, expression of ANXA1 protein was negative in all histologic patterns for HCC (46/46 cases) and healthy individuals (6/6 cases). In hamster with opisthorchiasis-associated CCA, the expression of ANXA1 was observed in the cytoplasm of inflammatory cells, bile duct epithelia and tumor cells. Grading scores of ANXA1 expression were significantly increased with tumor progression. In addition, mRNA expression of ANXA1 significantly increased in all of the various CCA cell lines tested compared to an immortalized human cholangiocyte cell line (MMNK1). Suppressing the ANXA1 gene significantly reduced the matrix metalloproteinase (MMP) 2 and MMP9, and transforming growth factor-β genes, but increased nuclear factor-kB gene expression. CONCLUSION: ANXA1 is highly expressed in CCA, but low in HCC, suggesting it may serve as a new immunohistochemical marker of CCA. ANXA1 may play a role in opisthorchiasis-associated cholangiocarcinogenesis.

Genetic and environmental determinants of risk for cholangiocarcinoma in Thailand

Cholangiocarcinoma(CCA) is a difficult cancer to diagnose in the early stage and to treat by curative resec-tion. The incidence of CCA in the northeast of Thailand is the highest in the world. To make progress in detecting a high risk group and in the prevention and detection of CCA, we have been analyzing the risk factors for CCA. Although liver fluke infection is known to be a risk factor, there are patients who are not infected with the liver fluke and not all people infected with the liver fluke will suffer from the disease. Therefore, it is of the utmost importance to analyze the risk factors and the mechanism to prevent the disease and also to detect the disease in its early stage to save patients' lives. Through collaboration among Thai and Japanese researchers, we analyzed the genetic and environmental determinants of risks for CCA. Also, we have been trying to develop methods to detect the disease in a non-invasive way. Without repeating findings reported in various reviews on CCA, we will first discuss the environmental and genetic determinants of the risks for CCA. Second, we will discuss the properties of CCA, including the etiological agents and the mechanism of cholangiocarcinogenesis, and finally, we will discuss future approaches to prevent and cure CCA from the standpoint of evidence-based medicine. We will discuss these points by including the data from our laboratories. We would like to emphasize the importance of the genetic data, especially whole genome approaches, to understand the properties of CCA, to find a high risk population for CCA and to develop effective preventative methods to stop the carcinogenic steps toward CCA in the near future. In addition, it is of the upmost importance to develop a non-invasive, specific and sensitive method to detect CCA in its early stage for the application of modern medical approaches to help patients with CCA.

Cancer and Infectious Causes

Various kinds of organisms, including viruses, bacteria, trematodes and fungi are known carcinogens that cause cancer. Infectious identification related to cancer may lead to better treatment for both the prevention and targeting of cancer therapy. Although nearly 20% of all cancers are caused by an infection of a microbe, the amount of evidence and information regarding the mechanisms associated with oncogenesis varies dramatically from one organism to the next. This review cannot be exhaustive because we are not aware of all infections worldwide in addition to their potential mechanisms for oncogenesis. More research is required for all of the species mentioned in this review.

Accuracy of a new rapid diagnostic test for urinary antigen detection and assessment of drug treatment in opisthorchiasis

Background Screening for opisthorchiasis,a parasitic worm infection affecting many millions of people in Southeast Asia,has traditionally relied on faecal egg examination such as the formalin-ethyl acetate concentration technique(FECT)and Kato-Katz method.Although the urinary enzyme-linked immunosorbent assay(ELISA)has been used more recently,we developed a urinary antigen-based rapid diagnostic test(RDT)to simplify diagnosis and as a point-of-care testing(POCT)and field applications for surveillance and control of opisthorchiasis.Methods A urinaryOpisthorchis viverrini(OV)-RDT was developed using immunochromatographic methodology with a specific monoclonal antibody against OV.The diagnostic performance of the urinary OV-RDT was compared to that of quantitative faecal FECT and urinary antigen ELISA(n=493).Cross-reactivities of urinary OV-RDT with other helminthiases coexisted withO.viverrini were determined(n=96).A field trial in the application of urinary OV-RDT was compared with urinary antigen ELISA at baseline screening and assessment of drug treatment outcomes in opisthorchiasis(n=1629).The McNemar chi-square,Kruskal-Wallis and Cohen’s kappa coefficient(κ-value)tests were used for statistical analyses.Results Urinary OV-RDT had sensitivity of 94.2%and specificity of 93.2%,compared to faecal FECT.Urinary OV-RDT had high diagnostic agreement(Kappa=0.842-0.874,P<0.001)and quantitative correlation with urinary antigen ELISA(Kruskal-Wallis tests=316.2,P<0.0001)and faecal FECT(Kruskal-Wallis tests=362.3,P<0.0001).The positive rates by OV-RDT,ELISA and FECT were 48.9%,52.5%and 49.3%,respectively.Cross-reactions of urinary OV-RDT with other helminthiases were few(2%).Field trials of urinary OV-RDT yielded comparable prevalence ofO.viverrini between urinary OV-RDT(53.2%)and urinary antigen ELISA(54.0%).OV screening showed high diagnostic agreement(kappa>0.8,P<0.0001)between urinary OV-RDT and urinary antigen ELISA.The cure rates of opisthorchiasis at 1 month post-praziquantel treatment determined by urinary OV-RDT(86.6%)and urinary antigen ELISA(80.5%)were similar(P>0.05).Conclusions The urinary OV-RDT test has high potential as a new tool for screening and evaluating treatment outcomes in opisthorchiasis.The ease of sample collection and simplicity of urinary OV-RDT may facilitate mass screening,control and elimination of opisthorchiasis,thereby contributing to a reduction in the disease burden in Southeast Asia.

Association between helminth infections and diabetes mellitus in adults from the Lao People’s Democratic Republic:a crosssectional study

Background:As a result of epidemiological transition,the health systems of low-and middle-income countries are increasingly faced with a dual disease burden of infectious diseases and emerging non-communicable diseases.Little is known about the mutual influence of these two disease groups.The aim of this study was to investigate the cooccurrence of helminth infections and diabetes mellitus in adults in Lao People’s Democratic Republic(Lao PDR).Methods:We conducted a cross-sectional study among 1600 randomly selected adults aged 35 and older from four different socio-economical and ecological provinces.Information on socio-demographics,risk factors and health conditions was obtained from personal interviews.Clinical assessments including anthropometry(height,weight,waist and hip circumference)and blood pressure measurements were also conducted.Diabetes was classified based on selfreported diagnoses and a point-of-care glycated haemoglobin(HbA1c)test from finger prick blood samples.Stool samples for helminth diagnosis were examined with formalin-ether concentration technique for intestinal parasitic infections.The independent associations of helminth infections with diabetic status and HbA1c were assessed using multiple regression analyses.Results:The prevalence of pre-diabetes and diabetes was 37.3%and 22.8%,respectively.Fifty-six percent of diabetic cases were undiagnosed and 85%of diagnosed diabetic cases had poor glycemic control.Participants from rural areas and from southern parts of the country had higher infection rates,with Opisthorchis viverrini,being the most common helminth infection(30.5%).We found a positive association between Taenia spp.infections and HbA1c(β=0.117;95%CI:0.042-0.200)and diabetes mellitus risk(OR=2.98;95%CI:1.10-8.05).No other helminth species was associated with glycated hemoglobin.Conclusions:Hyperglycaemia and diabetic rates in Lao PDR are alarmingly high,but consistent with other high rates in the region.Given the high rates of under-diagnosis and poorly-controlled glycaemia in diabetes mellitus patients,routine diabetes screening and treatment is essential for the local healthcare system.Large longitudinal cohorts integrating biomarkers are warranted in the search of causal diabetes mellitus risk factors in the region.Common intestinal helminth infections,including O.viverrini,are unlikely to explain the high diabetes mellitus rates observed.

Cross-reaction of POC-CCA urine test for detection of Schistosoma mekongi in Lao PDR: a cross-sectional study

Background:The point-of-care circulating cathodic antigen(POC-CCA)test is increasingly used as a rapid diagnostic method for Schistosoma mansoni infection.The test has good sensitivity,although false positive results have been reported among pregnant women and patients with urine infections and hematuria.We validated the POC-CCA test's ability to diagnose Schistosoma mekongi infection in Lao People's Democratic Republic(Lao PDR),where S.mekongi is endemic.Of particular interest was the test's specificity and possible cross-reactivity with other helminth infections.Methods:We conducted a cross-sectional study of children and adults in the provinces of Champasack(Schistosoma mekongi and Opisthorchis viverrini endemic),Savannakhet(O.viverrini endemic)and Luang Prabang(soil-transmitted helminths endemic)between October 2018 and April 2019.POC-CCA and urine dipstick tests were administered to all study participants,while an additional pregnancy test was offered to women.Two stool samples were collected from participants and examined with a Kato-Katz test(two smears per stool).Logistic regression was used to associate potential confounding factors(predictors)with POC-CCA test results(outcome).Results:In S.mekongi-endemic Champasack,11.5%(n=366)and 0.5%(n=2)of study participants had positive POC-CCA and Kato-Katz test results,respectively.Only one of the two Kato-Katz positive patients was also POC-CCA positive.In Champasack and Luang Prabang,where S.rnekongi is not endemic,the POC-CCA test yielded(presumably)false positive results for 6.0%(n=22)and 2.5%(n=9)of study participants,respectively,while all of the Kato-Katz tests were negative.POC-CCA positive test results were significantly associated with O.viverrini infection(1.69,95%confidence interval(CI):1.02-2.77,P=0.042),increased leukocytes(adjusted Odds Ratio(aOR)=1.58,95%CI:1.15-2.17,P=0.005)and hematuria(aOR=1.50,95%CI:1.07-2.10,P=0.019)if the observed trace was counted as a positive test result.Two pregnant women from Champasack province had POC-CCA positive tests.Conclusions:We observed a cross-reaction between the POC-CCA test and O.viverrini infection.To some extent,we can confirm previous observations asserting that POC-CCA provides false positive results among patients with urinary tract infections and hematuria.In S.mekongi-endemic areas,POC-CCA can be applied cautiously for surveillance purposes,keeping in mind the considerable risk of false positive results and its unknown sensitivity.