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The Korean Journal of Parasitology Mar 2009A mathematical model for transmission of schistosomes is useful to predict effects of various control measures on suppression of these parasites. This review focuses on... (Review)
Review
A mathematical model for transmission of schistosomes is useful to predict effects of various control measures on suppression of these parasites. This review focuses on epidemiological and environmental factors in Schistosoma japonicum and Schistosoma mekongi infections and recent advances in mathematical models of Schistosoma transmission.
Topics: Animals; Asia, Southeastern; Communicable Disease Control; Disease Reservoirs; Humans; Models, Theoretical; Schistosoma; Schistosomiasis
PubMed: 19290084
DOI: 10.3347/kjp.2009.47.1.1 -
PLoS Neglected Tropical Diseases Mar 2008Schistosomiasis in humans along the lower Mekong River has proven a persistent public health problem in the region. The causative agent is the parasite Schistosoma...
BACKGROUND
Schistosomiasis in humans along the lower Mekong River has proven a persistent public health problem in the region. The causative agent is the parasite Schistosoma mekongi (Trematoda: Digenea). A new transmission focus is reported, as well as the first study of genetic variation among S. mekongi populations. The aim is to confirm the identity of the species involved at each known focus of Mekong schistosomiasis transmission, to examine historical relationships among the populations and related taxa, and to provide data for use (a priori) in further studies of the origins, radiation, and future dispersal capabilities of S. mekongi.
METHODOLOGY/PRINCIPAL FINDINGS
DNA sequence data are presented for four populations of S. mekongi from Cambodia and southern Laos, three of which were distinguishable at the COI (cox1) and 12S (rrnS) mitochondrial loci sampled. A phylogeny was estimated for these populations and the other members of the Schistosoma sinensium group. The study provides new DNA sequence data for three new populations and one new locus/population combination. A Bayesian approach is used to estimate divergence dates for events within the S. sinensium group and among the S. mekongi populations.
CONCLUSIONS/SIGNIFICANCE
The date estimates are consistent with phylogeographical hypotheses describing a Pliocene radiation of the S. sinensium group and a mid-Pleistocene invasion of Southeast Asia by S. mekongi. The date estimates also provide Bayesian priors for future work on the evolution of S. mekongi. The public health implications of S. mekongi transmission outside the lower Mekong River are also discussed.
Topics: Animals; Asia; Cambodia; DNA, Helminth; Evolution, Molecular; Geography; Laos; Phylogeny; Schistosoma; Schistosomiasis; Sequence Analysis, DNA
PubMed: 18350111
DOI: 10.1371/journal.pntd.0000200 -
PLoS Neglected Tropical Diseases Sep 2021Mekong schistosomiasis is a parasitic disease caused by the blood-dwelling fluke Schistosoma mekongi. This disease contributes to human morbidity and mortality in the...
BACKGROUND
Mekong schistosomiasis is a parasitic disease caused by the blood-dwelling fluke Schistosoma mekongi. This disease contributes to human morbidity and mortality in the Mekong region, posing a public health threat to people in the area. Currently, praziquantel (PZQ) is the drug of choice for the treatment of Mekong schistosomiasis. However, the molecular mechanisms of PZQ action remain unclear, and Schistosoma PZQ resistance has been reported occasionally. Through this research, we aimed to use a metabolomic approach to identify the potentially altered metabolic pathways in S. mekongi associated with PZQ treatment.
METHODOLOGY/PRINCIPAL FINDINGS
Adult stage S. mekongi were treated with 0, 20, 40, or 100 μg/mL PZQ in vitro. After an hour of exposure to PZQ, schistosome metabolites were extracted and studied with mass spectrometry. The metabolomic data for the treatment groups were analyzed with the XCMS online platform and compared with data for the no treatment group. After low, medium (IC50), and high doses of PZQ, we found changes in 1,007 metabolites, of which phosphatidylserine and anandamide were the major differential metabolites by multivariate and pairwise analysis. In the pathway analysis, arachidonic acid metabolism was found to be altered following PZQ treatment, indicating that this pathway may be affected by the drug and potentially considered as a novel target for anti-schistosomiasis drug development.
CONCLUSIONS/SIGNIFICANCE
Our findings suggest that arachidonic acid metabolism is a possible target in the parasiticidal effects of PZQ against S. mekongi. Identifying potential targets of the effective drug PZQ provides an interesting viewpoint for the discovery and development of new agents that could enhance the prevention and treatment of schistosomiasis.
Topics: Animals; Anthelmintics; Arachidonic Acid; Drug Resistance; Female; Humans; Life Cycle Stages; Mice; Mice, Inbred ICR; Praziquantel; Schistosoma; Schistosomiasis
PubMed: 34473691
DOI: 10.1371/journal.pntd.0009706 -
PLoS Neglected Tropical Diseases 2012Schistosomiasis and opisthorchiasis are of public health importance in Southeast Asia. Praziquantel (PZQ) is the drug of choice for morbidity control but few dose... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Schistosomiasis and opisthorchiasis are of public health importance in Southeast Asia. Praziquantel (PZQ) is the drug of choice for morbidity control but few dose comparisons have been made.
METHODOLOGY
Ninety-three schoolchildren were enrolled in an area of Lao PDR where Schistosoma mekongi and Opisthorchis viverrini coexist for a PZQ dose-comparison trial. Prevalence and intensity of infections were determined by a rigorous diagnostic effort (3 stool specimens, each examined with triplicate Kato-Katz) before and 28-30 days after treatment. Ninety children with full baseline data were randomized to receive PZQ: the 40 mg/kg standard single dose (n = 45) or a 75 mg/kg total dose (50 mg/kg+25 mg/kg, 4 hours apart; n = 45). Adverse events were assessed at 3 and 24 hours posttreatment.
PRINCIPAL FINDINGS
Baseline infection prevalence of S. mekongi and O. viverrini were 87.8% and 98.9%, respectively. S. mekongi cure rates were 75.0% (95% confidence interval (CI): 56.6-88.5%) and 80.8% (95% CI: 60.6-93.4%) for 40 mg/kg and 75 mg/kg PZQ, respectively (P = 0.60). O. viverrini cure rates were significantly different at 71.4% (95% CI: 53.4-84.4%) and 96.6% (95% CI: not defined), respectively (P = 0.009). Egg reduction rates (ERRs) against O. viverrini were very high for both doses (>99%), but slightly lower for S. mekongi at 40 mg/kg (96.4% vs. 98.1%) and not influenced by increasing diagnostic effort. O. viverrini cure rates would have been overestimated and no statistical difference between doses found if efficacy was based on a minimum sampling effort (single Kato-Katz before and after treatment). Adverse events were common (96%), mainly mild with no significant differences between the two treatment groups.
CONCLUSIONS/SIGNIFICANCE
Cure rate from the 75 mg/kg PZQ dose was more efficacious than 40 mg/kg against O. viverrini but not against S. mekongi infections, while ERRs were similar for both doses.
TRIAL REGISTRATION
Controlled-Trials.com ISRCTN57714676.
Topics: Adolescent; Animals; Anthelmintics; Child; Female; Humans; Laos; Male; Opisthorchiasis; Opisthorchis; Praziquantel; Schistosoma; Schistosomiasis; Treatment Outcome
PubMed: 22848766
DOI: 10.1371/journal.pntd.0001726 -
Frontiers in Medicine 2020Significantly increased imported schistosomiasis cases have been reported in China as the economy grows. The aim of this study is to review and summarize the current...
Significantly increased imported schistosomiasis cases have been reported in China as the economy grows. The aim of this study is to review and summarize the current status, clinical features, and transmission risk of imported infections of and in China. A retrospective study was performed to review all information regarding the imported cases of schistosomiasis collected from published literature and the database of the National Notifiable Disease Report System from 1979 to 2019. The characterization of epidemiological and clinical features was analyzed. A total of 355 cases of imported schistosomiasis have been reported in 15 provinces (autonomous regions, municipalities) in China since 1979, including 78 cases of infection with (21.97%), 262 cases with (73.80%), and 15 cases with unidentified species. Eosinophilia was the most common sign of the infection with (91.03%). The parasitological findings were confirmed in 89.74% (70/78) of cases infected with and 32.06% (84/262) of cases infected with . There was no imported case of infection of , or reported in China during this period. Praziquantel is the best therapeutic drug for curing imported schistosomiasis. In addition, , the intermediate host of , has already been found in Guangdong province in south China. There is a rising risk that the existence of the intermediate host and the imported cases of infection could cause the spread of the infections and make these endemic. Thus, better understanding of the clinical features and the transmission pattern of these infections would assist Chinese physicians in the diagnosis and treatment of these imported schistosomiasis cases.
PubMed: 33195303
DOI: 10.3389/fmed.2020.553487 -
PLoS Neglected Tropical Diseases May 2022Schistosomiasis, an acute and chronic parasitic disease caused by human pathogenic Schistosoma species, is a neglected tropical disease affecting more than 220 million...
BACKGROUND
Schistosomiasis, an acute and chronic parasitic disease caused by human pathogenic Schistosoma species, is a neglected tropical disease affecting more than 220 million people worldwide. For diagnosis of schistosomiasis, stool and urine microscopy for egg detection is still the recommended method, however sensitivity of these methods is limited. Therefore, other methods like molecular detection of DNA in stool, detection of circulating cathodic antigen in urine or circulating anodic antigen in urine and serum, as well as serological tests have gained more attention. This study examines the sensitivity and specificity of a rapid diagnostic test based on immunochromatography (Schistosoma ICT IgG-IgM, LD Bio, Lyon, France) for simultaneous detection of specific IgG and IgM antibodies in serum, against Schistosoma spp. in endemic and non-endemic populations.
METHODOLOGY/PRINCIPAL FINDINGS
Frozen banked serum samples from patients with confirmed schistosomiasis, patients with other helminth infections, patients with seropositive rheumatoid arthritis and healthy blood donors were used to assess the sensitivity and the specificity of the Schistosoma ICT IgG-IgM rapid diagnostic test. The test showed a sensitivity of 100% in patients with parasitologically confirmed schistosomiasis, irrespective of the species (S. mansoni, S. haematobium, S. japonicum, S. mekongi). In healthy blood donors and patients with rheumatoid factor positive rheumatoid arthritis from Europe, specificity was 100%. However, in serum samples of patients with other tissue invasive helminth infections, the test showed some cross-reactivity, resulting in a specificity of 85%.
CONCLUSION/SIGNIFICANCE
With its high sensitivity, the Schistosoma ICT IgG-IgM rapid diagnostic test is a suitable screening test for detection of Schistosoma specific antibodies, including S. mekongi. However, in populations with a high prevalence of co-infection with other tissue invasive helminths, positive results should be confirmed with other diagnostic assays due to the test's imperfect specificity.
Topics: Animals; Antibodies, Helminth; Antigens, Helminth; Arthritis, Rheumatoid; Feces; Humans; Immunoglobulin G; Immunoglobulin M; Microscopy; Schistosoma mansoni; Schistosomiasis; Schistosomiasis mansoni; Sensitivity and Specificity; Urinalysis
PubMed: 35622871
DOI: 10.1371/journal.pntd.0010463 -
IDCases 2022Schistosomiasis is a parasitic trematode infection spread by snails with multiple species causing human disease. Infection can cause liver disease, including fibrosis...
Schistosomiasis is a parasitic trematode infection spread by snails with multiple species causing human disease. Infection can cause liver disease, including fibrosis and portal hypertension, and has been linked to malignancies such as bladder and colorectal cancer. We describe a case of a geographically limited form of schistosomiasis, in a Laotian immigrant who presented with both hepatic fibrosis and rectal cancer, with numerous schistosome eggs present in the patient's rectal resection. We believe this case is the first report of a rectal carcinoma arising in the setting of infection.
PubMed: 35036322
DOI: 10.1016/j.idcr.2022.e01383 -
Frontiers in Cellular and Infection... 2022Mekong schistosomiasis is a parasitic disease caused by blood flukes in the Lao People's Democratic Republic and in Cambodia. The standard method for diagnosis of...
Mekong schistosomiasis is a parasitic disease caused by blood flukes in the Lao People's Democratic Republic and in Cambodia. The standard method for diagnosis of schistosomiasis is detection of parasite eggs from patient samples. However, this method is not sufficient to detect asymptomatic patients, low egg numbers, or early infection. Therefore, diagnostic methods with higher sensitivity at the early stage of the disease are needed to fill this gap. The aim of this study was to identify potential biomarkers of early schistosomiasis using an untargeted metabolomics approach. Serum of uninfected and -infected mice was collected at 2, 4, and 8 weeks post-infection. Samples were extracted for metabolites and analyzed with a liquid chromatography-tandem mass spectrometer. Metabolites were annotated with the MS-DIAL platform and analyzed with Metaboanalyst bioinformatic tools. Multivariate analysis distinguished between metabolites from the different experimental conditions. Biomarker screening was performed using three methods: correlation coefficient analysis; feature important detection with a random forest algorithm; and receiver operating characteristic (ROC) curve analysis. Three compounds were identified as potential biomarkers at the early stage of the disease: heptadecanoyl ethanolamide; picrotin; and theophylline. The levels of these three compounds changed significantly during early-stage infection, and therefore these molecules may be promising schistosomiasis markers. These findings may help to improve early diagnosis of schistosomiasis, thus reducing the burden on patients and limiting spread of the disease in endemic areas.
Topics: Animals; Early Diagnosis; Humans; Laos; Metabolomics; Mice; Schistosoma; Schistosomiasis
PubMed: 36061860
DOI: 10.3389/fcimb.2022.910177 -
Acta Tropica Jan 2015Reaching the goal of control, elimination and eradication of the Neglected Tropical Disease in a foreseeable future provides significant challenges at the ground level... (Review)
Review
Reaching the goal of control, elimination and eradication of the Neglected Tropical Disease in a foreseeable future provides significant challenges at the ground level especially regarding helminthiasis. Helminths are still mainly diagnoses by egg identification in stool, methods with low sensitivity and for most species low specificity. Cross-sectoral collaboration with regard to zoonoses is almost non-existing and cross-validation by inter-laboratory evaluation of diagnostic tests is not a common practice. The aim of this review was to elucidate the dilemma of helminth diagnosis using zoonotic trematodes as examples. Much progress has been made improving the diagnostic sensitivity of Opisthorchis and Clonorchis using DNA-based techniques but the specificity of these tests is still a challenge due to the many most common but neglected intestinal trematodes. The burden of these diseases and ways to control them remains to be elucidated. Although efficacious drugs are available, the effectiveness of mass drug administration remains to be assessed. The importance of animal reservoirs and ways to control the diseases in animals are yet unknown. Diagnostic challenges regarding Schistosoma japonicum and Schistosoma mekongi include the many light infections and the persisting influx from the animal reservoirs. The sensitivity of the faecal based techniques suited morbidity control but will be insufficient for elimination of the helminths. More accurate diagnostic tools are required and new algorithms for detection and progression of helminth elimination will be needed. Standardized inter-laboratory test validation, inter-sectoral collaboration and establishment of an international One Health diagnostic platform, sharing best practices on diagnosis of helminth zoonoses, could all significantly contribute to control and elimination of these diseases.
Topics: Animals; Feces; Humans; Neglected Diseases; Sensitivity and Specificity; Trematoda; Trematode Infections; Zoonoses
PubMed: 23886849
DOI: 10.1016/j.actatropica.2013.07.006 -
Infectious Diseases of Poverty Aug 2020The 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... (Comparative Study)
Comparative 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. mekongi 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.
Topics: Adolescent; Adult; Animals; Antigens, Helminth; Child; Cross-Sectional Studies; Feces; Female; Humans; Laos; Male; Middle Aged; Opisthorchis; Point-of-Care Testing; Schistosoma; Schistosomiasis; Sensitivity and Specificity
PubMed: 32787912
DOI: 10.1186/s40249-020-00733-z