No abstract available.
Cartilage* ; Ear* ; Snails* ; Transplants*

Aims: Food safety and drug resistance in bacteria are both important issues globally. Consumption of escargot represents possible food safety problem especially when contaminated with an indicator and multi-drug resistant bacteria. Hence, this study aimed to identify and evaluate susceptibility of Enterobacteriaceae isolated from edible snails Archachatina marginata to antibiotics. Methodology and results: A total of 60 edible snails, A. marginata were purchased from local markets in three states of Nigeria. The edible snails were starved for three days and Enterobacteriaceae were isolated using microbiological procedures. Bacteria was identified by sequencing its partial 16S rRNA, while susceptibility of the bacteria to antibiotic was determined by disc diffusion method. Enterobacteriaceae obtained were Klebsiella (18), Escherichia (16), Citrobacter (10), Salmonella (7) and Enterobacter (5) species. Out of the 56 isolates obtained, 21 (37.5%) were resistant to amoxicillin and amoxicillin/clavulanic acid, 9 (16.07%) were resistant to tetracycline and 4 (7.14%) were resistant to co-trimoxazole. Conclusion, significance and impact of study The number of isolates which show resistant to different antibiotic classes was small. However, coliform bacteria (Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, and Enterobacter cloacae) isolated from edible snails represent a huge food safety risk to the consumers of edible snails. Hence, high hygienic practices are required for the consumers of edible snails to prevent infection with pathogenic bacteria.
Enterobacteriaceae--isolation & ; purification ; Snails

OBJECTIVETo identify Oncomelania hupensis snail habitats and areas with high transmission potential by GIS/RS.

METHODSMarshland areas near high endemic villages of schistosomiasis in the Poyang Lake region were selected. Corresponding map was digitized and (Landsat 5 TM) image was corrected according to the digital map. The image in dry seasons was calculated by both normalized difference vegetation index (NDVI) and tasseled cap model.

RESULTSResult showed that snails spots were distributed in class 6, 7 and 8. Farther analysis of both NDVI and tasseled cap model showed that the snail habitats were mainly distributed in the areas where NDVI value was more than 110, and in tasseled cap wetness value between -10 to 3 with correction rate 94.93%.

CONCLUSIONFirst step was to use unsupervised classification to define the class 6, 7 and 8 snail habitat environment. Second step was to extract the value by NDVI model, and to define a healthy vegetation as snail suspicious habitat when NDVI value was more than 110. Then the third step was to use tasseled cap wetness model to define the areas as snail habitats which value was between -10 to 3.

OBJECTIVETo observe the toxicity of Pulsatilla chinensis (Bunge) Regel saponins (PRS) against Oncomelania hupensis (O. hupensis).

METHODSO. hupensis snails were exposed to 40% and 80% of 24 h LC50 of PRS for 24 h, and then choline esterase (CHE), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) activities in cephalopodium and liver of snails were determined. Niclosamide (NIC) was used as the reference molluscicide. Zebra fish lethality test was evaluated to non-target aquatic species of PRS.

RESULTSThe molluscicidal activity of PRS (LC50 at 24 h: 0.48 mg/L) was similar to that of NIC (LC50 at 24 h: 0.16 mg/L). Significant alterations about CHE, ALP, and ALT activities both in the cephalopodium and the liver of snails were observed when O. hupensis was exposed to 40% and 80% LC50 of PRS or NIC for 24 h. PRS and NIC could not affect LDH activity in the cephalopodium and the liver. Lower toxicity to fish of PRS was observed up to the highest concentration tested than NIC.

CONCLUSIONPRS, as compared with the reference molluscicide NIC, is thought to be used for the control of harmful vector snails safely.

OBJECTIVETo study the effect of Oncomelania hupensis hupensis of niclosamide, and exploring the main influencing factors.

METHODSThe samples of Oncomelania hupensis hupensis were collected from 37 sampling sites in 33 counties of 10 provinces by means of stratified random sampling methods in accordance with the categories of Oncomelania hupensis hupensis habitats. Samples were randomly located into study group and control group. Oncomelania hupensis hupensis of the study group was marinated in different concentration liquor of niclosamide which was confected with water for 24 hours or 48 hours, then LC50 of niclosamide by which Oncomelania hupensis hupensis was killed and amount calculated. The influencing factors of the mortality of Oncomelania hupensis hupensis in the study group was statistically analyzed by 2 test and by multiple logistic regression using SPSS 13.0 statistical software.

RESULTSThe mortality of Oncomelania hupensis hupensis of the two test groups which were marinated in 0.5 mg/L liquor for 48 hours and 1.0 mg/L liquor for 24 hours was 100%. The effect of Oncomelania hupensis hupensis killed by niclosamide was markedly reduced along with the reduction of drug concentration. The average LC50 rates of niclosamide liquor by which Oncomelania hupensis hupensis killed for the 24 hours and 48 hours in the study group, were 0.0939 mg/L and 0.0625 mg/L, respectively. There was significant difference between the two test groups (chi(2) = 5.001, P <0.01) . In determinate range of concentration, the mortality of Oncomelania hupensis hupensis showed significant difference among the geographic types of habitat ( chi(2) = 4.264, P < 0.05). By means of multiple logistic regression using SPSS 13.0 statistical software, the estimate value of coefficient of regression on the influence factors, drug concentration, test time and the geographic types of habitat were 2. 047 ( OR = 5. 573), 0.263 ( OR = 2.924) and 0. 187- 0.210 ( OR = 1.969- 2. 560), respectively.

CONCLUSIONNiclosamide could kill Oncomelania hupensis hupensis effectively. The main influencing factors on the efficacy of niclosamide by which Oncomelania hupensis hupensis was killed, appeared to be drug concentration, time of testing and the geographic types of habitat.

OBJECTIVETo explore the genetic diversity among populations of Oncomelania hupensis.

METHODSAmplified fragment length polymorphism method was used to amplify the genomic DNA pools of twenty five snail populations from ten provinces, and the genetic diversities among these snail populations were analyzed.

RESULTSThe coefficient rates of similarity (GS(DICE)) among twenty five snail populations were ranged was from 0.694 to 0.831 while Nei's unbiased genetic identity was from 0.635 to 0.799. Genetic distance D from 0.169 to 0.306, and Nei's unbiased genetic distance from 0.225 to 0.452. Genetic variation among smooth-shell snail populations was higher than that of ribbed shell snail populations. Twenty five snail populations were divided into three groups: group A including smooth-shell snail from Fuqing of Fujian province and Yizhou of Guangxi province while group B consisted of smooth-shell snail from Dali of Yunnan province and Xichang, Puge, Danleng, Pujiang, Guanghan of Sichuan. Group C was composed of other seventeen snail populations from the Yangtze River drainage below the Three Gorges.

CONCLUSIONBig genetic variation was found among these populations of Oncomelania hupensis. The clustering result of snail populations in genomic level was consistent basically with geographical distribution.

OBJECTIVETo study the environmental changes of new snail habitual by using multi-temporal relative radiometric normalized TM images taken in Wuzhoutou of Nanchang, Jiangxi province.

METHODSTM images of Poyang Lake were collected on 3rd April 1998, 16th April 2000 and 5th May 2004. Taking images in 2004 as a reference, the TM images in 1998 and 2000 were radiometric normalized. The images were analyzed to trace the vegetation background and snail historical information.

RESULTSThe vegetation coverage rate of Wuzhaoutou on April 3rd in 1998 was 4.76%, but the vegetation coverage rates of Wuzhoutou on April 16th in 2000 and May 5th in 2004 were above 80%; the NDVI values of Wuzhoutou on April 3rd in 1998 were around -0.4 to 0.2, but the NDVI values of Wuzhoutou on April 16th in 2000 and May 5th in 2004 were mainly around 0.2 to 0.6, which had statistical difference with that in 1998 (q = 162.285321, P < 0.01 and q = 161.669725, P < 0.01). The greenness of three images have statistical differences(q = 178.679245, P < 0.01; q = 130.320755, P < 0.01 and q = - 48.358491, P < 0.01).

CONCLUSIONCombining with the snail survey, the TM images could be an effective measure for setting up models to forecast the areas where snails might live to control the Schistosomiasis epidemic.

Animals ; Environmental Monitoring ; methods ; Geographic Information Systems ; Snails

The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual snails were examined for parasitic infections. The results showed that 12 snail species were found to host larval stages of trematodes with an overall prevalence of 4.7%. The infected specimens included 7 types at the cercarial stage; cercariae, megalurous cercariae, echinostome cercariae, furcocercous cercariae, parapleurolophocercous cercariae, virgulate cercariae, and xiphidiocercariae. Regarding molecular identification, ITS2 sequence data of each larval trematode were analyzed, and a dendrogram was constructed using the neighbor-joining method with 10,000 replicates. The dendrogram was separated into 6 clades (order/family), including Echinostomatida/Echinostomatidae, Echinostomatida/Philophthalmidae, Opisthorchiida/Heterophyidae, Plagiorchiida/Prosthogonimidae, Plagiorchiida/Lecithodendriidae, and Strigeatida/Cyathocotylidae. These findings were used to confirm morphological characteristics and evolutionary trends of each type of cercariae discovered in Nakhon Nayok province. Furthermore, this investigation confirmed that the ITS2 data of cercariae could be used to study on phylogenetic relationships or to determine classification of this species at order and/or family level when possible.
Cercaria* ; Classification ; Fresh Water* ; Humans ; Methods ; Prevalence ; Snails* ; Thailand*

OBJECTIVETo explore the impact of the impoundment of Three Gorges reservoir on Oncomelania snail habitats of Poyang Lake.

METHODSFour counties with schistosomiasis endemic around the Poyang Lake, naming as Xingzi, Duchang, Jinxian and Xinjian, were selected as study areas. The average daily water level of four major hydrological stations near the above 4 counties from 1997 to 2008 were collected, as well as the elevation of 215 marshlands with snails in those 4 counties, the data of schistosomiasis endemic situation and snail survey of 4 counties in the year before the impoundment of Three Gorges reservoir (2002) and the 6th year after the impoundment of Three Gorges reservoir (2008). The fluctuations of water levels of Poyang Lake, flooding day of marshland with snails as well as the changes of the indicators in snail survey and prevention and control measures before and after the impoundment of Three Gorges reservoir were compared.

RESULTSBefore the impoundment of Three Gorges reservoir, the fluctuations of average water level of the four hydrological stations around Poyang Lake was 6.91-12.93 m; which reduced to 5.72 - 10.75 m after the impoundment. The D-value of the fluctuations of average water level was (1.06 ± 0.47) m. The date of the annual maximum water level delayed by an average of 12 d; while the date of annual minimum water level arrived an average of 12 d earlier than the impoundment of Three Gorges reservoir. The average flooding days of marshland with snails were separately (100.04 ± 42.06) d before the impoundment and (64.13 ± 22.30) d after the impoundment. The difference was statistically significant (t = 3.70, P < 0.05). The density of snails in the 4 counties around Poyang Lake was 0.8437/0.1 m(2) after the impoundment; declining by 31.04% from the snail density (1.2234/0.1 m(2)) before the impoundment. The density of infectious snails was 0.0014/0.1 m(2) after the impoundment; dropping by 67.34% from it (0.0042/0.1 m(2)) before the impoundment; the infection rate of snails was separately 0.34% after the impoundment and 0.16% before the impoundment. The difference was statistically significant (χ(2) = 53.25, P < 0.05). The coverage rate of chemotherapy increased from 4.45% (35 558/798 200) in 2002 to 9.80% (79 457/810 400) in 2008; the difference was statistically significant (χ(2) = 17 336.63, P < 0.05). The coverage rate of snail killing increased from 1.35% (389.04/28 824.66) in 2002 to 7.49% (2260.90/30 166.22) in 2008; the difference was also statistically significant (χ(2) = 28 824.66, P < 0.05).

CONCLUSIONThe impact of the impoundment of Three Gorges reservoir shortened the flooding days of marshland with snails and helped the prevention and control of schistosomiasis in Poyang Lake regions as the environment went against the breeding of the snails.