RESUMO
Detection of IgG in urine is an efficient method comparable to that in serum for diagnosis of strongyloidiasis, but the effects of daily variation in urine dilution on diagnostic accuracy are not clearly known. This study evaluated the effects of urine concentration on the detection of parasite-specific IgG by urine enzyme-linked immunosorbent assay (ELISA), particularly in individuals with borderline results or false-negative diagnosis. Optimal concentration conditions were established by comparing Strongyloides-specific IgG antibody levels between unconcentrated and concentrated urine in participants with different infection intensities, namely, healthy control (HC), low-negative (LN), high-negative (HN), and low-positive (LP) groups. The optimal condition was selected and validated in a field trial study. The final urine concentration protocol required centrifugation at 4,000 × g at 4°C for 10 mins using the Amicon concentrator tube. This protocol was validated in groups of participants with various diagnoses according to urine ELISA and fecal examination (n = 148). The concentrated-urine ELISA increased the proportion of positive results in the LN group by 68.2% and by 100% in the HN group. Significantly elevated IgG antibody levels were seen in the LP group. In the group that was false negative by urine ELISA but positive by fecal examination (n = 28), concentrated-urine ELISA yielded 100% positive results. Overall, the frequency estimates of Strongyloides stercoralis were 23.6% by fecal culture, 27% by standard urine ELISA, and 90.5% by concentrated-urine ELISA. The concentration of urine samples prior to analysis by ELISA improved the sensitivity for diagnosis and is potentially useful in the diagnosis of strongyloidiasis in immunocompromised individuals or in low-prevalence areas.
Assuntos
Strongyloides stercoralis , Estrongiloidíase , Animais , Anticorpos Anti-Helmínticos , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Imunoglobulina G , Sensibilidade e Especificidade , Estrongiloidíase/diagnósticoRESUMO
The use of Strongyloides ratti as heterologous antigen for serodiagnosis of strongyloidiasis is preferable to Strongyloides from humans due to the ease and safety of antigen preparation. In Southeast Asia where Opisthorchis viverrini coexists with Strongyloides stercoralis, there has been no report in using S. ratti for serodiagnosis of S. stercoralis. In this study, performance of an enzyme-linked immunosorbent assay (ELISA) based on S. ratti was compared with that based on S. stercoralis for diagnosis of strongyloidiasis in areas where O. viverrini is co-endemic in Thailand. Of the 107 individuals, 50 (46.7 %) were positive for S. stercoralis by agar culture method and by ELISA; 82 (76.6 %) and 81 (75.7 %) were seropositive using S. ratti and S. stercoralis antigens, respectively. The levels of parasite-specific IgG to S. ratti and S. stercoralis antigen were significantly proportionally correlated (P < 0.001). Mixed infections with O. viverrini have little effect on diagnosis of strongyloidiasis. Of 42 subjects who were infected with other parasites, there were no cross-reaction with Angiostrongylus cantonensis, Taenia spp., hookworms, Paragonimus spp., Clonorchis sinensis, Ascaris lumbricoides except for Fasciola spp. (1 of 5), and Opisthorchis viverrini (5 of 20). In spite of cross-reactivities, the results suggest that the S. ratti antigen provides an useful option for diagnosis of strongyloidiasis in an endemic area of opisthorchiasis with high sensitivity comparable to the S. stercoralis antigen and provide a basis for effective control strategies for strongyloidiasis.
Assuntos
Antígenos de Helmintos/sangue , Strongyloides ratti/isolamento & purificação , Strongyloides stercoralis/isolamento & purificação , Estrongiloidíase/diagnóstico , Adulto , Animais , Antígenos de Helmintos/imunologia , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Larva/imunologia , Masculino , Pessoa de Meia-Idade , Opistorquíase/epidemiologia , Opistorquíase/parasitologia , Opisthorchis/imunologia , Opisthorchis/isolamento & purificação , Testes Sorológicos , Strongyloides ratti/imunologia , Strongyloides stercoralis/imunologia , Estrongiloidíase/sangue , Estrongiloidíase/parasitologia , Tailândia/epidemiologiaRESUMO
Strongyloidiasis, caused by Strongyloides stercoralis, is a neglected tropical disease with a global distribution. The infection can be fatal in immunocompromised individuals, and accurate diagnosis leading to timely treatment can save lives. Serodiagnosis is a sensitive method for diagnosis and is recommended for screening high-risk individuals. A point-of-care rapid test will facilitate the screening activities, especially in low-resource settings. This study aims to apply a new IgG4 immunochromatographic test using S. stercoralis recombinant antigen (SsRapid® cassette test) and to compare it with in-house IgG and IgG4 enzyme-linked immunosorbent assays (IgG- and IgG4-ELISAs) using native Strongyloides ratti antigen to investigate the epidemiology of strongyloidiasis in northeast Thailand. A total of 300 people participated, with 136 males and 164 females of a similar mean age. The reference tests were fecal examinations using the formalin-ethyl acetate concentration technique and an agar plate culture technique. The prevalence of S. stercoralis determined by SsRapid (81.7%) was significantly higher than that by fecal examinations (43.3%) or by antibody detection by IgG-ELISA (53.0%) or IgG4-ELISA (44.0%). The diagnostic sensitivities of SsRapid, IgG-ELISA, and IgG4-ELISA were found to be 93.9%, 77.7%, and 63.1%, respectively. The rate of positive tests by the SsRapid was significantly correlated to the levels of Strongyloides-specific IgG4 and IgG antibodies. By all diagnostic methods, male participants had a significantly higher prevalence of strongyloidiasis than females. Age was significantly associated with the concentration of specific serum IgG but not with the SsRapid grading score. In conclusion, SsRapid was shown to be a sensitive and valuable diagnostic test for the epidemiology study of strongyloidiasis.
Assuntos
Strongyloides stercoralis , Estrongiloidíase , Humanos , Animais , Feminino , Masculino , Estrongiloidíase/diagnóstico , Estrongiloidíase/epidemiologia , Imunoglobulina G , Tailândia/epidemiologia , Anticorpos Anti-Helmínticos , Testes Sorológicos , Ensaio de Imunoadsorção Enzimática/métodos , FezesRESUMO
Opisthorchis viverrini is considered as a carcinogenic parasite which is responsible for cholangiocarcinoma in Southeast Asia. Effective treatment and control of the parasite to reduce the risk of cancer requires efficient diagnostic methods. Because of the limitations involved in human studies, the present work is aimed at comparing diagnostic performance of copro-DNA detection by PCR and fecal examination by formalin-ethyl acetate concentration technique (FECT) during the course of O. viverrini infection and postcurative chemotherapy in experimentally infected hamsters. A manual method of DNA preparation from fecal specimens previously established in human studies was used in PCR analysis. Following infection with varying doses of metacercariae (5, 10, 25, and 50 cysts/animal), PCR analyses were positive as early as 3 weeks post-infection while FECT were negative. PCR tests were comparable to FECT regardless of intensity of infection beginning from 4 to 12 weeks post infection. In chemotherapeutic experiments, with reference to the presence of worm in liver, treatment failures were detected by PCR but not FECT in a group of hamsters infected with 10 cysts/animal. PCR and FECT both detected residual infection at 1 and 2 weeks post-treatment in the group of animals infected with five cysts per animal. High concordant results between diagnoses by PCR, FECT, and worm burden indicated that PCR is suitable for an early diagnosis, evaluation of drug efficacy, and also re-infection post-treatment.
Assuntos
DNA de Helmintos/isolamento & purificação , Monitoramento de Medicamentos/métodos , Fezes/parasitologia , Técnicas de Diagnóstico Molecular/métodos , Opistorquíase/diagnóstico , Opisthorchis/isolamento & purificação , Parasitologia/métodos , Animais , Anti-Helmínticos/administração & dosagem , Cricetinae , Modelos Animais de Doenças , Masculino , Mesocricetus , Opistorquíase/tratamento farmacológico , Opisthorchis/genética , Carga Parasitária , Reação em Cadeia da Polimerase/métodosRESUMO
Antigen detected in urine for the diagnosis of opisthorchiasis has a low daily variation; however, the longer term variability in antigen concentrations is unknown. In this study, we prospectively monitored Opisthorchis viverrini antigen concentrations for 30 consecutive days and at subsequent monthly intervals in a cohort of opisthorchiasis-positive individuals. On the basis of the monoclonal antibody-based ELISA, the profiles of antigen-positive rate and antigen concentration exhibited no significant change over 30 days with a mean proportion positive of 87.1% (range 73.7%-100%), and the average antigen concentration was 29.7 ± 2.2 ng/mL (mean ± SE). The urine antigen concentration at baseline was similar to the subsequent measurements at 2, 4, 6, and 10 months in the follow-up study (P > 0.05). The consistency and low daily and long-term fluctuation of O. viverrini antigen in urine demonstrates the reliability of urine assay for diagnosis of opisthorchiasis.
Assuntos
Opistorquíase , Opisthorchis , Animais , Humanos , Opistorquíase/diagnóstico , Opistorquíase/epidemiologia , Estudos Prospectivos , Tailândia/epidemiologia , Seguimentos , Reprodutibilidade dos TestesRESUMO
Detection of anti-Strongyloides IgG in urine by enzyme-linked immunosorbent assay (ELISA) for diagnosis of strongyloidiasis reportedly has comparable performance to conventional serum assays. Initial comparisons of urine assays using commercial ELISA kits designated for serology have shown its diagnostic potential but sub-optimal accuracy. In the present study, we optimized urine ELISA protocols based on different antigen types and evaluated their accuracies in determining the epidemiology of strongyloidiasis in Northeast Thailand. Paired urine and fecal samples of 966 individuals from the study community were collected for three consecutive days and tested for strongyloidiasis. We compared three ELISA protocols using different antigens including crude S. stercoralis antigen (Ss-ELISA), crude S. ratti antigen (Sr-ELISA) and recombinant NIE antigen (NIE-ELISA) and fecal examination by agar plate-culture (APCT) technique and formalin-ethyl acetate concentration technique (FECT). The optimized ELISA protocols using three different antigen sources yielded significantly higher prevalence rates of strongyloidiasis (58.9-65.1%) than those by fecal examination methods (19.7%). The prevalence of strongyloidiasis determined by ELISA protocols significantly increased with age (p value < 0.0001) and males had higher prevalence than females (p value < 0.0001). Diagnostic agreements between ELISA protocols were moderate (κ = 0.461-0.586) and the agreement between each ELISA protocol and fecal examinations were slight (κ = 0.139-0.210). The results obtained by urine ELISA protocols using three different antigens showed comparable diagnostic performances, provided further supports for the utility of urine as an alternative clinical specimen for diagnosis of strongyloidiasis.
Assuntos
Parasitos , Strongyloides stercoralis , Estrongiloidíase , Masculino , Animais , Feminino , Humanos , Estrongiloidíase/diagnóstico , Estrongiloidíase/epidemiologia , Tailândia/epidemiologia , Anticorpos Anti-Helmínticos , Ensaio de Imunoadsorção Enzimática/métodos , Antígenos de Helmintos , Fezes , Proteínas Recombinantes , Imunoglobulina G , Sensibilidade e EspecificidadeRESUMO
Detection of worm antigen in urine is a sensitive diagnostic method for opisthorchiasis, particularly for light-intensity infections; however, the presence of eggs in feces is essential for validating results from the antigen assay. To address the issue of low sensitivity of fecal examination, we modified the protocol for the formalin-ethyl acetate concentration technique (FECT) and compared it against urine antigen measurements for detection of the parasite Opisthorchis viverrini. First, we optimized the FECT protocol by increasing the number of drops for examinations from the standard two drops to a maximum of eight. We were able to detect additional cases after examination of ≥ 3 drops, and the prevalence of O. viverrini saturated after examination of ≥ 5 drops. We then compared the optimized FECT protocol (examining five drops of suspension) against urine antigen detection for the diagnosis of opisthorchiasis in field-collected samples. The optimized FECT protocol detected O. viverrini eggs in 25 of 82 individuals (30.5%) who had positive urine antigen tests but were fecal egg negative by the standard FECT protocol. The optimized protocol also retrieved O. viverrini eggs in 2 of 80 antigen-negative cases (2.5%). In comparison with the composite reference standard (combined FECT and urine antigen detection), the diagnostic sensitivity of examining two and five drops of FECT and the urine assay was 58.2, 67, and 98.8%, respectively. Our results show that multiple examinations of fecal sediment increase the diagnostic sensitivity of FECT and thus provide further support for the reliability and utility of the antigen assay for diagnosis and screening of opisthorchiasis.
Assuntos
Opistorquíase , Opisthorchis , Animais , Opistorquíase/epidemiologia , Formaldeído , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fezes/parasitologia , Tailândia/epidemiologiaRESUMO
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 urinary Opisthorchis 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 with O. 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 of O. 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.
Assuntos
Opistorquíase , Opisthorchis , Animais , Humanos , Opistorquíase/diagnóstico , Opistorquíase/tratamento farmacológico , Opistorquíase/epidemiologia , Testes de Diagnóstico Rápido , Sensibilidade e Especificidade , Praziquantel/uso terapêutico , Tailândia/epidemiologiaRESUMO
BACKGROUND: Detection of parasite-specific IgG in urine is a sensitive method for diagnosis of strongyloidiasis and gives similar accuracy to serum IgG. However, there are no data concerning detection of IgG subclass in urine. To further explore the utility of diagnosis from urine samples, we evaluated the diagnostic performance of IgG4 in urine compared with parasitological and other immunological methods. METHODS: The urine and sera included proven strongyloidiasis (group 1, n = 93), other parasitic infections (group 2, n = 40) and parasite negatives (group 3, n = 93). The performance of Strongyloides-specific IgG4 in urine for diagnosis of strongyloidiasis using fecal examinations as the reference standard was assessed. RESULTS: With fecal examination as a gold standard, Strongyloides-specific IgG4 in urine had 91.4% sensitivity and 93.2% specificity while serum IgG4 had 93.6% sensitivity and 91.0% specificity. IgG4 in both urine and serum had almost perfect diagnostic agreements with fecal examination (Cohen's kappa coefficient was > 0.8). Cross-reactivity to Opisthorchis viverrini and Taenia spp. of IgG4 in urine were 7.5% and 12.5% in serum. Concurrent analyses of total IgG in urine and serum showed that the sensitivities (97.9-100%) and specificities (88.7-91.0%) were similar (P > 0.05). The sensitivity for parasitological examination by the formalin-ethyl acetate concentration technique (FECT) was 49.5% and that for agar plate culture technique (APC) it was 92.6%. CONCLUSION: Our findings showed that specific IgG4 detection in urine yielded similar diagnostic performance to the same biomarkers in serum. This suggests that accurate diagnosis of strongyloidiasis can be performed using urine samples and IgG4 is a valid choice of diagnostic marker. Further assessment is required to assess the utility of urine IgG4 for measuring the response treatment in strongyloidiasis.
Assuntos
Líquidos Corporais , Estrongiloidíase , Humanos , Animais , Estrongiloidíase/diagnóstico , Strongyloides , Reações Cruzadas , Imunoglobulina GRESUMO
Infection by Opisthorchis viverrini causes significant health problems, including cholangiocarcinoma (CCA); thus control and elimination of this trematode is an important strategy for the reduction of CCA. Currently, urine and copro antigen detection is more sensitive than parasitological examination of the feces for the diagnosis of opisthorchiasis. Given limitations in human studies, we used an animal model to quantify the parasite antigen profiles in urine and feces in O. viverrine-infected hamsters, and postdrug treatment. The positive detections of O. viverrini antigen began from week 1 in urine and week 2 in feces after infection until week 28 of the study. The recoveries of O. viverrini worms were detected starting from week 1 and eggs of O. viverrini were detected in feces from week 3 after infection and remained detectable throughout the study period. There was a significant positive correlation of urine and copro antigen levels with the number of fecal egg counts (P < 0.01) and worm recovery (P < 0.01). In the drug-treatment experiment, treatment of infected hamsters with praziquantel significantly reduced worm burden, fecal egg output, and antigen in urine and feces compared with the untreated controls (P < 0.001). At 4 weeks posttreatment, the egg and worm reduction rates were 100% and 95.5%, respectively. The positive antigen detections in urine and feces corresponded with partial worm clearance from praziquantel treatment. This study demonstrated a direct link of urine and copro antigen tests with worms infecting the liver thereby reaffirming the reliability of urine and copro antigen assay in opisthorchiasis diagnosis.
RESUMO
Antigen detection in urine using an enzyme-linked immunosorbent assay (ELISA) is more sensitive than fecal examination for diagnosis of opisthorchiasis and for assessment of the effects of drug treatment. It is not known whether day-to-day variation of urine composition, including levels of Opisthorchis viverrini antigen, influences the urine assay. We investigated this topic with the cooperation of participants from two localities in Northeast Thailand. Project participants were screened for parasite infections for three consecutive days using the quantitative formalin-ethyl acetate concentration technique (FECT) to detect O. viverrini eggs and the urine ELISA for detection of O. viverrini antigen. A subset of participants (n = 801) with matched fecal and urine samples were analyzed for comparison of inter-day prevalence estimates and the performance of the urine assay compared against FECT for diagnosis of opisthorchiasis. The daily prevalence measured by the urine assay ranged between 29.0%-30.2% while those by FECT ranged between 11.9%-20.2%. The cumulative three-day prevalence estimate determined by the urine antigen assay was 30.3%, which was significantly higher than that by FECT (20.2%, p < 0.05). A significant positive correlation was found between the concentration of antigen in urine and fecal egg counts (p < 0.001). Overall, the urine assay had better diagnostic performance for opisthorchiasis than fecal examination by FECT. The high sensitivity plus negligible daily variation of O. viverrini antigen in urine indicates the utility of the urine assay for diagnosis, as well as population screening, of opisthorchiasis.
Assuntos
Opistorquíase , Opisthorchis , Animais , Antígenos de Helmintos/análise , Fezes/química , Humanos , Opistorquíase/diagnóstico , Opistorquíase/epidemiologia , Opistorquíase/parasitologia , Tailândia/epidemiologiaRESUMO
BACKGROUND: Control and elimination of the liver fluke (Opisthorchis viverrini) is a primary preventive strategy against cholangiocarcinoma in Southeast Asia. A sensitive parasitological diagnostic method is required to facilitate a surveillance and control program. In this study, we evaluated the performance of Mini Parasep® SF stool concentrator kit (stool kit) compared with Kato-Katz (KK) and the quantitative formalin-ethyl acetate concentration technique (FECT) for detection of O. viverrini and co-endemic parasitic infections. METHODS: A cross-sectional survey for parasitic infection in residents aged > 15 years in a community in Kalasin province, Northeast Thailand, was conducted in 2018. Fecal samples were collected and screened by KK method, and a subset of samples was further examined by the stool kit and FECT methods. The results were analyzed for prevalence of parasitic infections in addition to the diagnostic performance of the methods for qualitative and quantitative detection of helminthiases. RESULTS: The initial survey of parasitic infection determined by the KK method (n = 567) showed the prevalence of O. viverrini was 32.63%, followed by Taenia 2.65%, echinostomes 1.76%, hookworms 1.41%, Trichuris trichiura 0.53% and Strongyloides stercoralis 0.53%. Within a subset of samples tested with multiple diagnostics (n = 150), the detection rates of O. viverrini by the stool kit, FECT and KK methods were 27.3%, 30.7% and 28.7%, respectively. The diagnostic sensitivity for opisthorchiasis was similar for FECT (75.5%), KK(66.0%) and the stool kit (67.3%). For other parasitic infections, FECT and stool kit methods performed better than KK, particularly in detecting minute intestinal flukes (MIF), S. stercoralis and coinfections. When measuring the intensity of O. viverrini infection (fecal egg counts), the stool kit results showed a significant positive correlation with KK and FECT (P < 0.05). CONCLUSIONS: As the stool kit is simple to use and shows a comparable performance to FECT, it may serve as an alternative method of fecal examination for screening of helminthiasis including opisthorchiasis.
Assuntos
Helmintíase , Opistorquíase , Opisthorchis , Acetatos , Animais , Estudos Transversais , Fezes/parasitologia , Formaldeído , Helmintíase/diagnóstico , Helmintíase/epidemiologia , Helmintíase/parasitologia , Opistorquíase/diagnóstico , Opistorquíase/epidemiologia , Opistorquíase/parasitologia , Prevalência , Sensibilidade e Especificidade , Tailândia/epidemiologiaRESUMO
Concomitant immunity and its consequence against infection play roles in regulating worm burdens in helminthiasis. Under natural conditions, this immunity is generated by exposure to repeated low dose or trickle infection. In this study, concomitant immunity was induced in mice exposed repeatedly to infection with Echinostoma malayanum and its protective effect on a challenge infection evaluated. A profile of worm burden from exposure to 10 metacercariae/mouse/week rose rapidly during the first 2 weeks reaching a plateau from week 3 to 8 post infection. Based on a cumulative dose of infection, worm recoveries were around 75% in the first 2 weeks, dropped to 50% at week 3 and 19% at week 8. After week 2, adult worm burden was constant and no juvenile worms were found after week 3 of the experiment. To examine the effect of resistance against reinfection, mice in the experimental group were primarily infected with 10 metacercariae/week for 5 weeks, treated with praziquantel and were challenged with 75 metacercariae/animal. The number of worms recovered from the experimental groups was significantly lower than that from naïve control groups beginning from 24 h to 28 days post challenge. The worms in the experimental group showed growth retardation and the proportion of adult worms was lower than that in the control animals especially during the first 3 weeks of the experiment. Parasite fecundity was also suppressed compared with that in the control group. The selective effects of protective immunity on establishment, growth, and fecundity of challenged worms affected the population dynamics of E. malayanum which is a similar phenomenon to concomitant immunity in schistosomiasis.
Assuntos
Echinostoma/imunologia , Equinostomíase/imunologia , Animais , Echinostoma/crescimento & desenvolvimento , Echinostoma/fisiologia , Equinostomíase/parasitologia , Fezes/parasitologia , Fertilidade/imunologia , Intestino Delgado/parasitologia , Masculino , Camundongos , Contagem de Ovos de Parasitas , RecidivaRESUMO
Recent systematic studies of Opisthorchis viverrini based on multilocus enzyme electrophoresis (MEE) have shown that there are at least five genetic groups and possibly two cryptic species occurring in Thailand and Lao PDR each associated with a specific wetland system. A study based on mitochondrial DNA (mtDNA) gene analyses of an O. viverrini population from Savannakhet (SV, Lao PDR) clustered with several isolates from Thailand and Lao PDR although they originated from different river wetland systems. We used MEE to re-examine whether O. viverrini from SV was similar genetically to isolates from Thailand and Lao PDR. The allelic profiles of O. viverrini from SV and five different wetlands representing defined genetic groups of O. viverrini were recorded at 24 enzyme loci as opposed to only two loci of mtDNA. Contrary to previous studies, O. viverrini from SV was found to have fixed genetic differences at six to eight of the 24 loci examined (24.50-35.42%). Allelic data indicated that O. viverrini from SV differed from isolates in the Nam Ngum River wetland in Lao PDR (29.33% fixed genetic differences) and clustered with O. viverrini from Nakhon Phanom and Sakon Nakhon within the Songkram River wetland in Thailand but had fixed genetic differences from these at 24.5% of loci examined. Our data confirm the association between genetic groups of O. viverrini and specific wetland systems, and raise important questions regarding the significance of the genetic differences and relationships of O. viverrini from these wetlands.
Assuntos
Eletroforese/métodos , Enzimas/análise , Proteínas de Helminto/análise , Opisthorchis/classificação , Opisthorchis/enzimologia , Parasitologia/métodos , Alelos , Animais , Análise por Conglomerados , DNA de Helmintos/genética , DNA Mitocondrial/genética , Genótipo , Geografia , Laos , Opisthorchis/genética , Opisthorchis/isolamento & purificaçãoRESUMO
Recent work has found urine analysis to be as sensitive as serology for diagnosis of strongyloidiasis. Here, we examined the daily variation of Strongyloides-specific IgG in urine by qualitative and quantitative ELISA and its effects on diagnostic accuracy and reliability. In the first part of the study, matched urine and fecal samples were collected from project participants in northeast Thailand for three consecutive days. Urine samples were analyzed for Strongyloides-specific IgG by ELISA using Strongyloides ratti as the antigen source. Performance of urine ELISA was compared with parasitological diagnosis by agar plate culture technique (APCT) and formalin-ethyl acetate concentration technique (FECT). In the second part of the study, urine IgG levels were compared daily for thirty consecutive days. The prevalence of Strongyloides infection, as measured by urine ELISA for three consecutive days, was significantly higher than that found using parasitological methods (63.1% vs. 22%). There was slight daily variation in prevalence estimates according to urine ELISA while there were significant variations according to parasitological examination methods over three consecutive days. For the 3-day experiment, urine ELISA had 83-86% diagnostic sensitivity when compared with the fecal examination method or with a composite standard (combined results from fecal examination methods (APCT or FECT) and/or urine ELISA). The levels of parasite-specific IgG in urine were stable throughout both the 3-day and the 30-day studies. In conclusion, diagnosis of strongyloidiasis by urine ELISA is more sensitive than by fecal methods, with minimal daily variation for qualitative and quantitative diagnosis. Urine ELISA has potential for clinical diagnosis and population screening of strongyloidiasis.
Assuntos
Anticorpos Anti-Helmínticos/urina , Fezes/parasitologia , Estrongiloidíase/diagnóstico , Urina/parasitologia , Adulto , Animais , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Feminino , Formaldeído , Humanos , Imunoglobulina G/urina , Masculino , Pessoa de Meia-Idade , Prevalência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Manejo de Espécimes/métodos , Strongyloides ratti , Strongyloides stercoralis , Tailândia/epidemiologiaRESUMO
Strongyloides stercoralis affects more than half a billion people worldwide, and hyperinfection in immunocompromised patients can be fatal. Elimination of this neglected tropical disease requires field-applicable diagnostic tools. We conducted a laboratory evaluation of a lateral flow rapid dipstick test (SsRapid™) using sera samples from a Strongyloides-endemic area in northeast Thailand. Group 1 was S. stercoralis-positive and larvae- and/or antibody-positive (according to the IgG ELISA) (N = 100). Group 2 had negative fecal examination and IgG ELISA results (N = 25). Group 3 had other parasitic infections and negative IgG ELISA results (N = 25). The results showed good diagnostic sensitivity (82%) and excellent specificity (96%). Suggested improvements in the SsRapid™ test include increased diagnostic sensitivity and conversion to the more robust cassette format. Field studies should be performed as well.
Assuntos
Anticorpos Anti-Helmínticos/imunologia , Imunoglobulina G/imunologia , Strongyloides stercoralis/imunologia , Estrongiloidíase/diagnóstico , Animais , Anticorpos Anti-Helmínticos/sangue , Fezes/parasitologia , Proteínas de Helminto , Humanos , Proteínas Recombinantes , Sensibilidade e Especificidade , Testes Sorológicos , Estrongiloidíase/sangue , TailândiaRESUMO
Human strongyloidiasis is one of the neglected tropical diseases caused by infection with soil-transmitted helminth Strongyloides stercoralis. Conventional stool examination, a method commonly used for diagnosis of S. stercoralis, has low sensitivity, especially in the case of light infections. Herein, we developed the droplet digital polymerase chain reaction (ddPCR) assay to detect S. stercoralis larvae in stool and compared its performance with real-time PCR and stool examination techniques (formalin ethyl-acetate concentration technique [FECT] and agar plate culture [APC]). The ddPCR results showed 98% sensitivity and 90% specificity, and real-time PCR showed 82% sensitivity and 76.7% specificity when compared with the microscopic methods. Moreover, ddPCR could detect a single S. stercoralis larva in feces, and cross-reactions with other parasites were not observed. In conclusion, a novel ddPCR method exhibited high sensitivity and specificity for detection of S. stercoralis in stool samples. This technique may help to improve diagnosis, particularly in cases with light infection. In addition, ddPCR technique might be useful for screening patients before starting immunosuppressive drug therapy, and follow-up after treatment of strongyloidiasis.
Assuntos
Fezes/parasitologia , Reação em Cadeia da Polimerase/normas , Strongyloides stercoralis/isolamento & purificação , Estrongiloidíase/diagnóstico , Estrongiloidíase/parasitologia , Animais , Reações Cruzadas , Reação em Cadeia da Polimerase/métodos , Strongyloides stercoralis/genéticaRESUMO
BACKGROUND: A urine antigen assay was applied to evaluate chemotherapeutic outcomes and reinfection patterns of opisthorchiasis in Thailand. METHODS: We used a prospective study design by following opisthorchiasis subjects at baseline and post-treatment using a urine antigen assay and faecal examination by the formalin-ethyl acetate concentration technique (FECT). RESULTS: The antigen of Opisthorchis viverrini in urine diminished within 4 weeks after praziquantel treatment. Concurrent faecal examinations by FECT showed that faecal eggs were negative at 4 weeks after treatment. In a subsequent study, reinfection rates and intensity patterns of O. viverrini were evaluated at 48 weeks after praziquantel treatment. Within a group of subjects with curative treatment (n=137), 16.8% became reinfected according to FECT and 27.7% according to the urine antigen assay (p<0.05). There were significant correlations in intensity of infection between pretreatment and at 48 weeks post-treatment in both faecal egg counts and antigen levels in urine. CONCLUSIONS: The results suggested that in addition to screening, the urine antigen assay is an efficient tool for monitoring outcomes of drug treatment and reinfection in opisthorchiasis. Due to the ease of urine sample collection and handling, the urine assay becomes an alternative method to faecal examination for diagnosis and monitoring of opisthorchiasis.
Assuntos
Antígenos de Helmintos/química , Antígenos de Helmintos/urina , Opistorquíase/tratamento farmacológico , Opistorquíase/parasitologia , Opisthorchis/efeitos dos fármacos , Praziquantel/uso terapêutico , Animais , Fezes/parasitologia , Humanos , Opistorquíase/diagnóstico , Opistorquíase/epidemiologia , Opisthorchis/isolamento & purificação , Praziquantel/farmacologia , Praziquantel/urina , Estudos Prospectivos , Reinfecção , Tailândia , Resultado do TratamentoRESUMO
Kaempferia parviflora Wall. ex Baker (KP), Krachaidam in Thai or Thai ginseng, is a herbal medicine that has many potential pharmacological effects. The effect of KP extract on blood glucose level in rodent was reported. This study focused on the oral glucose tolerance test and pharmacokinetic study in healthy volunteers administered with KP extract (90 and 180 mg/day, placebo). The oral glucose tolerance tests were performed at baselines and 28-days of administration. The pharmacokinetics were determined after a single dose administration of the tested products using 3,5,7,3',4'-pentamethoxyflavone (PMF) and 5,7,4'-trimethoxylflavone (TMF) as markers. The results showed that glucose metabolism via oral glucose tolerance test was not affected by KP extract. Blood glucose levels of volunteers at 120 min after glucose loading were able to be returned to initial levels in placebo, KP 90 mg/day, and KP 180 mg/day groups both at baseline and 28-days of administration. The results of the pharmacokinetic study revealed that only TMF and PMF, but not 5,7-dimethoxyflavone (DMF) levels could be detected in human blood. The given doses of KP extract at 90 and 180 mg/day showed a linear dose-relationship of blood PMF concentration whereas blood TMF was detected only at high given dose (180 mg/day). The half-lives of PMF and TMF were 2-3 h. The maximum concentration (Cmax), area under the curve of blood concentration and time (AUC), and time to maximum concentration (Tmax) values of PMF and TMF estimated for the 180 mg/day dose were 71.2 ± 11.3, 63.0 ± 18.0 ng/mL; 291.9 ± 48.2, 412.2 ± 203.7 ngâh/mL; and 4.02 ± 0.37, 6.03 ± 0.96 h, respectively. PMF was quickly eliminated with higher Ke and Cl than TMF at the dose of 180 mg/day of KP extract. In conclusion, the results demonstrated that KP extract had no effect on the glucose tolerance test. In addition, this is the first demonstration of the pharmacokinetic parameters of methoxyflavones of KP extract in healthy volunteers. The data suggest the safety of the KP extract and will be of benefit for further clinical trials using KP extract as food and sport supplements as well as a drug in health product development.
Assuntos
Glicemia/metabolismo , Carboidratos da Dieta/metabolismo , Flavonas/farmacocinética , Teste de Tolerância a Glucose , Extratos Vegetais/farmacocinética , Zingiberaceae/química , Adulto , Área Sob a Curva , Biomarcadores/sangue , Método Duplo-Cego , Feminino , Flavonas/sangue , Flavonas/farmacologia , Voluntários Saudáveis , Humanos , Masculino , Panax , Extratos Vegetais/sangue , Extratos Vegetais/farmacologia , TailândiaRESUMO
Background: The use of targeted specific genes in therapeutic and treatment decisions has been considered for lung cancer. The epidermal growth factor receptor (EGFR) gene, which is over expressed in non-small cell lung cancer (NSCLC), was considered as one of the targeted specific genes. EGFR mutations in exons 1821, which encode a portion of the EGFR kinase domain, were found in NSCLC patients and were associated with the response of EGFRtyrosine kinase inhibitors (EGFR-TKIs). Therefore, a molecular technique for EGFR mutation detection has important benefits for therapy in NSCLC patients. This study aims to determine the EGFR mutations in patients with NSCLC using polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) in exons 18-21. Methods: DNA samples were extracted from formalin fixed paraffin embedded tissues of NSCLC patients who attended hospital. The extracted DNA was used as a template for the EGFR gene amplification. Results: Occurrence of EGFR mutations were found in 29 out of 50 cases (58%).The frequency of EGFR mutations by first PCR at exon 18, 19, 20 and 21 were 6 (12%), 19 (38%) 20 (40%) and at 21 (42%), respectively. By PCR-SSCP, the frequencies of EGFR mutations at exon 18, 19, 20 and 21 were 3(6%), 18(36%), 23(46%) and 13(26%), respectively. All of the mutations found were in agreement with DNA sequencings. Conclusion: The high frequency of EGFR mutations in NSCLC suggests that PCR-SSCP is a efficient screening method and useful for treatment plan.