• Parasites, Hosts and Diseases
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• v.27 no.3
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• pp.203-212
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• 1989

The development of Echinestcma cinetorchis in several snail species reared in laboratory aquaria was observed. The eggs from adult cukes collected from the intestine of rats were cultivated to miracidia, and exposed to Hippeutis sp. snails. Observations were made for cercarial shedding from the exposed snails. The cercariae shed from the snails were again exposed to several species of fresh water snails in order to observe metacercarial formation in the snails and their infectivity to final hosts. The results obtained in this study were as follows: 1. Twenty miracidia were exposed to each snail of Hippeutis sp. About 58.3% of the above snails (7 out of 12) were dead before shedding the cercariae, anti the remainder shed the cercariae for a period of 7 to 9 days before death. 2. Cercarial shedding from the infected snails started from the 25th day after the exposure to mi.acidia, and the total number of cercariae shed per snail was 684 in average (range; 482-904). 3. The sixte of refine developed in the infected Hippeutis sp. snails was 1$, 242{\times}214{\;}{\mu}m$ in average, and the number of rediae per snail was 350 in average (range; 120-510). 4. About 40 to 50 cercariae shed from the Hippeutis sp. snails were each exposed to several species of snails reared in the laboratory. The metacercarial formation was confirmed by dissecting the infected snails, 12 to 16 days after the infection. The infectivity to each snail species was 100% in Hippeutis sp. (recovery rate; 56.7%) and Radix auricuzaria coreana (recovery rate; 66.4%), 66.7% in Physa acute (recovery rate; 37.5%), and 50% in Cipangopaludina sp. (recovery rate; 8.0%), respectively. 5. The swimming cercariae attached first at the cephalo-podial part of the snails and then migrated to the mantle, internal organ s and hemocele areas to form the metacercariae. 6. Adult worms of E. cinetorchis were obtained from the rats infected with the metacercariae encysted in the experimental snails. Summarising the above results, it is suggested that the mud-snail (Cipangopaludina sp.) may play an important role as a source of human infection with E. cinetorchis in Korea, and that several species of fresh water snails are involved in the life cycle as a second intermediate host.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.277-283
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• 1993

In the present study, observations were made on the life-history of Lymnaea viridis under laboratory conditions, involving incubation period of the eggs and their hatching rate, shell length of the newly hatched snails, sexual maturity, size of the snails when the snail produced the first egg-mass, the number of eggs in each egg-mass, egg-laying, ovipostion, growth rate of the snails, and longevity of the snail. At temperatures between $19.8^{\circ}C$ to $22.5^{\circ}C$, incubation period of the eggs occupied 10~12 days, and after beginning of hatching, all young snails emerged completely from the egg-mass within 5 days. The hatching rate was 88%. The average shell length of the newly hatched snails was about 0.064cm. The rate of growth was extraordinarily rapid under good laboratory conditions. When two snails were reared in one culture vessel($20{\times}15{\times}5cm$) with blue-green algae at about $22^{\circ}C$, snail growth was optimal, taking 37 days to reach 1.2cm in shell length. Sexual maturity reached in about 19 days. The size of the snails at sexual maturity was $0.78{\pm}0.05cm$ in length and $0.47{\pm}0.04cm$ in width. The first egg-masses produced were $0.59{\pm}0.22cm$ in length and $0.34{\pm}0.08cm$ in width, and contained 7~38 eggs. The eggs are usually laid in water. The egg-laying was affected by food and temperature. Snails fed with blue-green algae at about $22^{\circ}C$ produced larger egg-masses than the snails fed with fish food at about $26^{\circ}C$. Under conditions of continuous activity and growth, the maximum expectation of life appears to be 109~350(mean 230) days. And the shell length of snails at death were 1.39~1.64cm.

• International Journal of Industrial Entomology and Biomaterials
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• v.43 no.2
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• pp.78-84
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• 2021

We explored the indigenous local knowledge associated with the use of snails by Baiga people in Baihar tehsil of Balaghat district in central India through interview with a semi-structured questionnaire. Results revealed that Baiga people widely accept snails of 3-5 morpho-groups belonging to Ampullariidae, and Viviparidae family as food. Besides, use of snail as therapeutic agents for ailments like body ache, joint pain, digestion, weakness of bones etc. were found common. Hand-picking of snails from the wild environments as well as agriculture field was the primary way of harvesting edible snails. We advocate the development of a farming system for the continuous supply of snails as a food resource, advancement of scientific investigation of functional properties of them, economic progress of the region and therefore the overall sustainability.

• Parasites, Hosts and Diseases
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• v.52 no.6
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• pp.645-652
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• 2014

Fasciola hepatica is a trematode that causes zoonosis mainly in cattle and sheep and occasionally in humans. Fascioliasis has been reported in Korea; however, determining F. hepatica infection in snails has not been done recently. Thus, using PCR, we evaluated the prevalence of F. hepatica infection in snails at 4 large water-dropwort fields. Among 349 examined snails, F. hepatica-specific internal transcribed space 1 (ITS-1) and/or ITS-2 markers were detected in 12 snails and confirmed using sequence analysis. Morphologically, 213 of 349 collected snails were dextral shelled, which is the same aperture as the lymnaeid snail, the vectorial host for F. hepatica. Among the 12 F. hepatica-infected snails, 6 were known first intermediate hosts in Korea (Lymnaea viridis and L. ollula) and the remaining 6 (Lymnaea sp.) were potentially a new first intermediate host in Korea. It has been shown that the overall prevalence of the snails contaminated with F. hepatica in water-dropwort fields was 3.4%; however, the prevalence varied among the fields. This is the first study to estimate the prevalence of F. hepatica infection using the vectorial capacity of the snails in Korea.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.371-381
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• 2023

The effectiveness of plant-based attractants was studied using large traps, which attracted relatively more snails in agricultural water drainage ditches and rice-cultivating environments, although their effectiveness in rice fields and lakes was limited. The rate began to rise after three hours of observation. Watermelon peel exhibited the highest apple snail attraction rate (13.8%), followed by potatoes (10.0%), and apple peel (8.8%). These values significantly differed from the attraction rate attributed to papaya leaves (F=3.84; P=0.0387). After 24 h, watermelon peel and apple peel indicated a higher rate of attraction (23.4% and 21.7%, respectively), which were significantly different compared with those of papaya leaves and potatoes (F=9.94; P=0.00455). Large bait traps outperformed funnel traps in capturing golden apple snails and trapped a significant number of snails measuring over 1 cm in size. Watermelon peel was the most effective attractant for a large bait trap, followed by apple peel, potatoes, and papaya leaves. On average, 110 snails were captured in the lure net. However, potatoes, apple peels, and papaya leaves caught an average of 93, 80, and 79 snails, respectively. Among the attractants, the lure effect of the snails was not significantly different. The efficiency of large bait traps in capturing snails, regardless of the plant attractant employed, followed the order: apple peel > watermelon peel and potatoes > papaya leaves > melon > Korean melon. Watermelon peel is highly recommended for farmer use, as well as apple peel and potatoes. Utilizing these snail attractants may contribute positively to developing a safe and environment-friendly integrated pest management strategy.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.129-137
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• 2008

Alien apple snails (Pomacea canaliculata, Pomacea insularus) used in environmentally-friendly agriculture are different from indigenous snails found in Korea. Due to high herbicidal effects and cost-effectiveness, the number of farmers using the snails has been growing every year since 2000. Moreover, in 2008, because of the outbreaks of avian influenza throughout the country from March to May, 2008, central and local governments recommended the use of alien apple snails in agriculture as an alternative to the ducks-oriented environmentally-friendly agriculture. Therefore, it is expected that the use of alien apple snails in agriculture should be expanded in a near future. Since alien apple snails lay eggs with 95.8% of eclosion rate, they are considered to be potential pests unlike indigenous snails. In addition, Japan, Taiwan and most of the southeast Asian countries had already experienced severe ecological and agricultural damage by the alien apple snails. Subsequently, International Union for Conservation of Nature and Natural Resources (IUCN) designated P. canaliculata as one of "the 100 of the world's worst invasive alien species". It seems highly likely that the alien apple snails in Korea pose a potential threat to conservation of ecosystem and biodiversity since the snails were either found or invaded into the natural environments in some regions of Gangwon-Do and southern parts of Korean Peninsula. However, just recently, agricultural authorities and farmers using alien apple snails in agriculture opposed a proposition of designating the alien apple snails as an ecosystem-disturbing animal described by the Wildlife Protection Act. This is because there has been no concrete evidence of the ecological risk imposed by the alien snails up to now in Korea. Subsequently, in this paper, we analysed the ecological and agricultural risks imposed by the alien snails from the studies done in domestic and abroad. In addition, we proposed an urgent need and reasoning for ecological risk management of the alien snails at the national level as well as using the snails in agriculture.

• The Korean Journal of Malacology
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• v.2 no.1
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• pp.13-25
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• 1986

One of the most medically important snail species of Korea is Semisulcospira spp., a member of the freshwater prosobranch family pleuroceridae. The parasites that these snails transmit to humans are mainly Paragonimus westermani and Metagonimus yokogawoi. On the other hand, Semisulcospira snails are edible as a foodstuff in Korea. The present study was first aimed to detect out residual pesticides in the snails collected at the endemic and non-endemic areas of paragonimiasis in Korea and to make relationship to the detectability of larval trematodes shed from the snails. In addition, water specimens from the habitats where the snails were collected were sampled and analysed to elucidate environmental conditions of the habitats. This malaco-ecological survey was done at 7 endemic and 3 non-endemic areas of paragonimiasis for about more than 2 years, May, 1984 through October, 1986. All the water smaples both from the endemic and non-endemic areas of paragonimiasis showed normal ranges of the criteria of upper freshwater streams, with lower B.O.D. (0.4~2.0 ppm) and higher D.O. values (9.5~11.0 ppm) than those in the large river systems Infection rate of digenetic trematodes in total snails collected was 6.7%, but no Paragonimus cercaria was detected out at all even in the endemic areas of paragonimiasis. The ecological factors affecting Paragonimus larvae in the snails were also discussed. A total of 9 chlorinated hydrocarbon pesticieds was targeted to detect out from the tissues of snails. Out of 9 pesticides, aldrin, beta-BHC, p, p-DDT, dieldrin, DDE, lindane, heptachlor and heptachlor epoxide were eluted from the snails. The highest levels of the pesticides were mostly detected out in the snails collected from the Donghae-Chun area of Haman and the Kangwha area of Kyongki-Do, where the lowest infection rates of trematode cercariae (0~0.5%) were revealed. The possibilities that the residual pesticides in the freshwater animals including Semisulcospira snails might be transferable to humans were also discussed.

• The Korean Journal of Malacology
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• v.13 no.2
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• pp.117-123
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• 1997

S study on the distribution of land snails in Kangweon-Do was carried out from May 1990 to July 1995. Mirus sp, and Aegista gottschei kongoensis were unrecorded in Korea and south Korea, respectively, As a result of this stududy, 21 families and 62 species of land snails are reported from Kangweon-Do, Korea.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.358-366
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• 2003

Some N-p-substituted phenyl uracil-5-sulphonamide derivatives have been synthesized to be evaluated as molluscicides against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni. Schistosoma mansoni infected mice were treated with hemolymph obtained from pre-treated Biomphalaria alexandrina snails with the products 4a, 10a, 10b and 4b or obtained from non-treated snails. The selection of the concentration based on the predetermined dose which caused mortality of less than 50% of snails/24 h. $LC_{50}$ of compounds 4a, 10a, 10b and 4b was 50, 100, 200 and 50 ppm respectively. The result showed that immuno-stimulatory effect of treated hemolymph with compounds 4a, 10a and 4b was related to significant protective effects (44.4, 34.6 and 50.4% reduction in worm burden respectively). In addition, mean total worm burdens were significantly reduced in non treated hemolymph by 33.8%. The effect of hemolymph obtained from treated or non treated snails on S. mansoni adult worms antigens was studied by indirect immunofluorescence technique using chronic mouse sera (CMS). The results indicated that there was a strong reaction with epitopes in gut epithelium, tubercles, teigument and subtegumental musculature of untreated and treated S. mansoni adult worms antigens. Therefore, treatment of hemolymph obtained from pre-treated snails with compounds 4a, 10a, and 4b can stimulate specific immune response and induce protective effects against S. mansoni infection.

• Parasites, Hosts and Diseases
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• v.59 no.2
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• pp.121-129
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• 2021

We aimed to explore the population dynamics of snail in 3 sites of the White Nile in Sudan. More specifically, we aimed to investigate the annual patterns of snail populations that act as intermediate hosts of schistosomes and monthly snail infection rates and ecological characteristics presumably related to snail populations. We collected snails for 1 year monthly at 3 different shore sites in the vicinity of El Shajara along the White Nile river in Khartoum State, Sudan. In addition, we measured air and water temperatures, water turbidities, vegetation coverages, and water depths and current speeds. Most of the collected snails were Biomphalaria pfeifferi and Bulinus truncatus. The population densities of snails and their infection rates varied across survey sites. The collected snails liberated S. mansoni and S. haematobium cercariae as well as Amphistome and Echinostome cercariae. Infected snails were found during March-June. The ecological characteristics found to be associated with the absence of snails population were: high turbidity, deep water, low vegetation coverage (near absence of vegetation), high water temperature, and high current speed. To our knowledge, this is the first longitudinal study of the snail population and ecological characteristics in the main basin of the White Nile river.