Taxonomy, Ecology and Population Genetics of Opisthorchis viverrini and Its Intermediate Hosts

Petney, Trevor N.; Andrews, Ross H.; Saijuntha, Weerachai; Tesana, Smarn; Prasopdee, Sattrachai; Kiatsopit, Nadda; Sithithaworn, Paiboon

doi:10.1016/bs.apar.2018.05.001

Cited by 28 publications

(11 citation statements)

References 133 publications

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“…8,12 Indeed, a high diversity of cyprinid fish has been reported to serve as the intermediate host of O. viverrini in Southeast Asia; as many as 47 species have been recorded from Lao PDR and 46 from Thailand, with many species being shared in both countries. 21 Among the cyprinid fish, the most common genera infected with O. viverrini metacercariae are Cyclocheilichthys, Puntius, and Hampala in both Lao PDR and Thailand. 10,12,13,22 In our study, O. viverrini metacercariae were found throughout the year in these genera, namely in the species, C. armatus, H. dispar, and P. brevis.…”

Section: Transmission Of O Viverrini In Endemic Areas In Southeastmentioning

confidence: 99%

Infection Dynamics of Opisthorchis viverrini Metacercariae in Cyprinid Fishes from Two Endemic Areas in Thailand and Lao PDR

Namsanor

Kiatsopit

Laha

et al. 2020

The American Journal of Tropical Medicine and Hygiene

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The infection dynamics of Opisthorchis viverrini metacercariae was analyzed in cyprinid fish from endemic areas in Mukdahan Province, Thailand, and Khammouane Province, Lao PDR. The fish were collected during the cool-dry (November-February), hot-dry (March-May), and rainy (June-October) seasons in 2017. They were examined by the digestion method, and the infection status was statistically analyzed by study area, season, and fish size. The prevalence (no. of fish positive/no. of fish examined × 100) and metacercarial intensities (no. of metacercariae detected/no. of fish positive) of O. viverrini in both study areas depended on season, being high in the cool-dry season and varying in the hotdry and rainy seasons. In Mukdahan Province, the average prevalence was 18.3% (range 11.0-46.7%, n = 420) and the intensity was 4.07 ± 5.86 cysts/fish (mean ± SD), whereas in Khammouane Province, the prevalence was 51.9% (range 9.1-70.6%, n = 673) and the intensity was 6.67 ± 12.88 cysts/fish. Among the cyprinid fish species examined, the infection was associated with fish body size and predominantly found in Hampala dispar (86.5%), Cyclocheilichthys armatus (73.2%), and Puntius brevis (42.7%). The distribution of O. viverrini metacercariae in fish was skewed, with most of the fish having a low worm burden with an average of four to six cysts/fish. The findings that seasonality, sampling locality, fish size, and species of fish play roles in the risk of O. viverrini infection imply that these host and environmental factors are important for the transmission dynamics and control of O. viverrini.

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Section: Transmission Of O Viverrini In Endemic Areas In Southeastmentioning

confidence: 99%

Infection Dynamics of Opisthorchis viverrini Metacercariae in Cyprinid Fishes from Two Endemic Areas in Thailand and Lao PDR

Namsanor

Kiatsopit

Laha

et al. 2020

The American Journal of Tropical Medicine and Hygiene

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“…Bithynia siamensis is classified into two different subspecies, Bithynia siamensis siamensis and Bithynia siamensis goniomphalos, based on certain morphological characteristics and differences in geographical distribution. 14 These species/subspecies are present in O. viverrini-endemic areas in Thailand, that is, B. funiculata in the north, B. s. siamensis in the central area, and B. s. goniomphalos in the northeast Thailand, 14 and B. s. goniomphalos sensu lato 15 have been reported throughout the Lower Mekong Basin. Bithynia siamensis goniomphalos and B. funiculata are most frequently inhabited in shallow freshwater environments such as rice fields, roadside ponds, and irrigation canals with an underlying red-yellow podzolic soil.…”

Section: Introductionmentioning

confidence: 99%

Influence of Water Irrigation Schemes and Seasonality on Transmission Dynamics of Opisthorchis viverrini in the Snail Intermediate Host, Bithynia siamensis goniomphalos in Rice Paddy Fields in Northeast Thailand

Kopolrat

Sithithaworn

Kiatsopit

et al. 2020

The American Journal of Tropical Medicine and Hygiene

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Opisthorchis viverrini is a fish-borne zoonotic trematode that causes significant public health problems in Southeast Asia. Its life cycle requires Bithynia snails as the first intermediate hosts, fish, and human and/or carnivore hosts. This study assessed impacts of land use practice for rice cultivation and seasonality on the transmission dynamics of O. viverrini in Bithynia siamensis goniomphalos in rice paddy field habitats. The transmission of O. viverrini cercariae in B. s. goniomphalos was monitored at monthly intervals over a 4-year period from January 2010 to December 2013. From a total of 59,727 snails examined by standard cercarial shedding, the prevalence of O. viverrini was 0.7% (range, 0.0-4.1%). The prevalence of O. viverrini infection in B. s. goniomphalos varied with the amount of rainfall, with peaks of infection occurring in the cool-dry season, that is, after each rainy season. A shift of peak prevalence from cool-dry to hot-dry season observed in 2013 was associated with the increase in preceding water irrigation to support the production of second annual rice crop. Significant positive correlations were found between the prevalence and intensity of cercarial infection and the size of snails. Our results revealed substantial variation between years so that to have a clear understanding of the population dynamics of this complex system, studies should be conducted over an extended period (> 1 year). Results from this study highlight that water irrigation schemes in rice paddy cultivation and seasonality have a significant effect on the prevalence of O. viverrini in B. s. goniomphalos.

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“…Currently, O. viverrini infections are maily light (eggs/gram feces < 50) and spread across extensive geographical regions, especially in North and Northeastern Thailand, where control programs have been implemented for decades [ 2 , 8 , 9 ]. Screening of individuals with opisthorchiasis for surveillance and control in endemic areas has traditionally relied on conventional parasitological methods, i.e., Kato-thick smear [ 10 ], formalin-ethyl acetate concentration technique (FECT), Kato-Katz (KK) method and simple smear method [ 11 ]. These methods are known to have several drawbacks, including limited analytical sensitivity, i.e., low-intensity infections can go undetected and may require repeated fecal examination over several days.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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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. Graphical abstract

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Taxonomy, Ecology and Population Genetics of Opisthorchis viverrini and Its Intermediate Hosts

Cited by 28 publications

References 133 publications

Infection Dynamics of Opisthorchis viverrini Metacercariae in Cyprinid Fishes from Two Endemic Areas in Thailand and Lao PDR

Infection Dynamics of Opisthorchis viverrini Metacercariae in Cyprinid Fishes from Two Endemic Areas in Thailand and Lao PDR

Influence of Water Irrigation Schemes and Seasonality on Transmission Dynamics of Opisthorchis viverrini in the Snail Intermediate Host, Bithynia siamensis goniomphalos in Rice Paddy Fields in Northeast Thailand

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

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