Performance of Mini Parasep® SF stool concentrator kit, Kato-Katz, and formalin-ethyl acetate concentration methods for diagnosis of opisthorchiasis in Northeast Thailand.

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.

Prevalence and risk factors for Opisthorchis viverrini infections in upper Northeast Thailand.

Opisthorchis viverrini is an ongoing public health problem in Northeast Thailand. Despite continuous efforts for decades by healthcare organizations to overcome this problem, infection rates remain high. To enable related personnel to identify and address the various issues effectively, a cross-sectional study was performed to investigate prevalence and risk factors for opisthorchiasis. The target group was 3,916 Thai residents of Northeast Thailand who were 15 or over. Participants were recruited using the 30 clusters sampling technique. The data were gathered through questionnaires, focus group discussions, in-depth interviews, and stool examinations for parasite eggs (using the Modified Kato Katz method). The data were analyzed using descriptive and inference statistics; in order to ascertain the risk factors and test them using the odds ratio and multiple logistic regressions. The prevalence of opisthorchiasis was 22.7% (95%CI: 0.26 to 0.24). The province with the highest prevalence was Nakhorn Phanom (40.9%; female to male ratio =1:1.2). The age group with the highest prevalence was 40-49 year olds. All age groups had a prevalence >20%. Four of seven provinces had a prevalence >20%. The factors related to opisthorchiasis were (a) sex, (b) age (especially > 50), (c) proximity and duration living near a water body, and (d) eating raw and/or fermented fish. In order to reduce the prevalence of opisthorchiasis, the focus in populations living in upper Northeast Thailand should be changing their eating behaviors as appropriate to their tradition and context.

Randomized comparative trial of two high-dose albendazole regimens for uncomplicated human strongyloidiasis.

A randomized trial study was conducted comparing the efficacy of two high-dose regimens of albendazole for the treatment of uncomplicated human strongyloidiasis. Agar plate culture (APC) was used as an evaluation technique for coprological diagnosis. All 115 subjects infected with Strongyloides stercoralis from 7 provinces in northeastern Thailand were divided randomly into two groups. Regimen-1 group received albendazole 800 mg/day twice daily for 3 consecutive days, and regimen-2 group received the same dose for 5 consecutive days. For each regimen, the same treatment was repeated once 7 days later. Stools were parasitologically examined at 14 days, and 10 days after the second course of treatment, respectively. A coprological cure rate of 87.9% (51/58) was obtained in the regimen-1 group, with 89.5% (51/57) in the regimen-2 group, which was not statistically significantly different (P = 0.794). The mild adverse effects were not statistically different between the two groups, at 8.6% and 8.8%, respectively (P = 0.977). We therefore suggest albendazole treatment using regimen 1 should be recommended. However, the use of new effective drugs should be considered, especially in hyperinfective strongyloidiasis.

Prevalence of Strongyloides stercoralis infection in northeastern Thailand (agar plate culture detection).

UNLABELLED: The prevalence of Strongyloides stercoralis infection was studied in the rural and urban populations of 19 provinces of Northeastern Thailand. A total of 1233 fecal samples was collected from July to September 2002 and examined using agar plate culture method. The overall prevalence of S. stercoralis was 23.5 per cent with the highest infection rate in Kalasin Province (61.0%), predominantly among 60 year olds and older (28.0%), and in males (32.8%). The factors associated with Strongyloides infection were sex (males) and age (the over 19 year-old age group). CONCLUSION: S. stercoralis infection remains highly prevalent among the population of northeastern Thailand as confirmed by the agar plate culture method. The authors recommend that a program for effective strongyloidiasis control should have a justifiable priority.