| malacological survey in the sirikit reservoir, the largest earthfilled dam in thailand. | ten species of freshwater molluscs were found in a malacological survey in the sirikit reservoir in 1985. among these species, tricula aperta or neotricula aperta, intermediate host of human schistosomes, bithynia (digoniostoma) siamensis goniomphalos and b. (d.) funiculata, the first intermediate host of opisthorchis viverrini were not found. it is revealed that most of the habitats in the sirikit reservoir are not suitable for the survival and colonization of molluscs. thus few species of edib ... | 1992 | 1439988 |
| malacological survey in the bhumibol reservoir, the first dam constructed in thailand. | twenty-five species of molluscs were found in a malacological survey in the bhumibol reservoir and in the ping river in front of the bhumibol dam and its tributaries in april and august 1985. among these species, tricula aperta or neotricula aperta, intermediate host of human schistosomes and bithynia (digoniostoma) siamensis goniomphalos and b. (d.) funiculata, the first intermediate host of human liver flukes, were not found. although some of the intermediate hosts of mammalian schistosomes, i ... | 1992 | 1523461 |
| survival of beta and gamma races of neotricula aperta snail intermediate hosts of schistosoma mekongi in raw waters. | beta and gamma races of neotricula aperta were exposed to naturally raw waters of the sirindhorn reservoir, mun river and mekong river in laboratory conditions and non supplement on food. snails of two races could withstand well in variable qualities of water within 48 hours. the survival rates of n. aperta in three sources of raw water were 100% for the beta race and 97 to 100% for the gamma race. | 1996 | 9280010 |
| infectivity of a cambodian isolate of schistosoma mekongi to neotricula aperta from northeast thailand. | all three strains of neotricula aperta (gastropoda: pomatiopsidae) sampled from populations in northeast thailand were found to be compatible with a schistosoma mekongi isolate from kratie district, eastern cambodia. the infection rates were: 3.0%, alpha-strain; 6.0%, beta-strain, and 20.5%, gamma-strain. the greater infectivity to the gamma-strain, over both the alpha- and beta-strains, was statistically significant. comparisons of infectivity patterns for the kratie isolate, with those describ ... | 1997 | 9705676 |
| sex chromosome differences among the three races (alpha, beta, gamma) of the snail intermediate host of schistosoma mekongi, neotricula aperta. | chromosome analyses were performed on three races (alpha, beta, gamma) of neotricula aperta which were previously reported to show variation in the chromosome number and pairing in meiosis. we used an air-drying method, which was more reliable for chromosome preparations from fresh animal tissues than a squash method. each of the races had the same number of chromosomes, 2n=33 for males, and 2n=34 for females. the sex determination system was xo type (male: 32+x, female: 32+xx). the sex chromoso ... | 2000 | 11077260 |
| schistosomiasis in the mekong region: epidemiology and phylogeography. | an account is given of progress made over the last 20 years in the study of mekong schistosomiasis, causative agent schistosoma mekongi (trematoda: digenea). emphasis is given to the discussion of work concerning the origin and subsequent dispersal of s. mekongi and related taxa, including relevant snails. the role of such phylogeographical data in schistosomiasis control and the prediction of areas at risk is examined. new palaeogeographical models are reviewed in relation to traditional explan ... | 2001 | 11757333 |
| schistosomiasis mekongi: from discovery to control. | in the mekong river basin, the first case of schistosomiasis was reported in 1957. in the 1960s, endemic areas of the infection, of which profiles were similar to those of schistosomiasis japonica, were discovered in khong island, laos, to kratie province, cambodia. a new intermediate snail host; neotricula aperta was identified and the mekong strain of schistosome was elevated to a new species: schistosoma mekongi in 1978. baseline epidemiological surveillance was performed and schistosomiasis ... | 2004 | 15081945 |
| schistosomes in the xe kong river of cambodia: the detection of schistosoma mekongi in a natural population of snails and observations on the intermediate host's distribution. | a natural population of neotricula aperta (gastropoda: pomatiopsidae) in the xe kong river of cambodia was found to be infected with schistosoma mekongi--apparently the first time this parasite has been found in snails outside the mekong river. only 0.14% of the n. aperta collected were found infected. potential habitats for n. aperta were examined in selected rivers of central and southern laos and cambodia, so that the density of n. aperta at each site could be estimated. at survey sites where ... | 2004 | 15119968 |
| high susceptibility of neotricula aperta gamma-strain from krakor and sdau in cambodia to schistosoma mekongi from khong island in laos. | neotricula aperta gamma-strain snails collected from krakor and sdau in cambodia were found to have the same or higher susceptibility to schistosoma mekongi as n. aperta originally isolated from khong in laos. infection rates of n. aperta gamma-strain snails exposed to 3 miracidia at week 8 were: khong gamma-strain, 22.6%; krakor gamma-strain, 33.3%; and sdau gamma-strain, 67.4%. at week 10, the sdau gamma-strain showed the highest infection rate of 83.3%. we thus found significantly high suscep ... | 2007 | 17317276 |
| the evaluation of control measures against schistosoma mekongi in cambodia by a mathematical model. | we constructed a mathematical model for the transmission of schistosoma mekongi in cambodia. the simulation of the model will be instrumental in planning schistosomiasis control measures. the model includes two definitive hosts, humans and dogs, as animal reservoirs. dogs are recognized to play an important role in schistosomiasis transmission in cambodia. for the purpose of dealing with age-specific prevalence and intensity of infection, the human population was classified into eight age catego ... | 2008 | 18486538 |
| the distribution of mekong schistosomiasis, past and future: preliminary indications from an analysis of genetic variation in the intermediate host. | neotricula aperta is the only known intermediate host of schistosoma mekongi which infects humans in cambodia and the southern tip of lao pdr. dna-sequence data (partial rrnl, i.e., mitochondrial 16s large ribosomal-rna gene) were obtained for 359 n. aperta snails sampled at 31 localities in cambodia, lao pdr and thailand. a nested clade analysis was performed to detect and evaluate any geographical patterns in the observed variation and to identify genetic subpopulations or clades. coalescent s ... | 2008 | 18499512 |
| schistosoma mekongi in cambodia and lao people's democratic republic. | schistosomiasis found in communities along the mekong river in cambodia and lao people's democratic republic (lao pdr) is caused by the blood fluke schistosoma mekongi. early observations on patients in 1957 revealed severe intestinal and hepatosplenic disease. high mortality rates and widespread disease were reported from the provinces of northern cambodia (stung treng and kratié) and southern lao pdr (champasack) in the early 1970s and 1990s. control programmes built around mass drug administr ... | 2010 | 20624532 |
| analysis of the effectiveness of control measures against schistosoma mekongi using an intra- and inter-village model in champasak province, lao pdr. | schistosomiasis mekongi is prevalent in the khong district of lao pdr, made up of one big island, khong, and numerous small islands in the mekong river. schistosoma mekongi is spread by neotricula aperta as the intermediate host along the mekong river. therefore, even if an epidemic of s. mekongi were stamped out in a certain village, infection may recur if the source of infection is a village located in the upper reaches of the mekong river. the purpose of this study was to construct a mathemat ... | 2011 | 21820079 |
| malacological investigation of the fully operational nam theun 2 hydroelectric dam project in khammouane province, central lao pdr. | we conducted a malacological investigation in four districts of the nam theun 2 (nt2) hydroelectric dam project area, khammouane province, central lao pdr (nakai, gnommalath, mahaxai and xe bang fai), after the first and second years of full operation in march 2010 and november 2011 to determine health risks for humans. a total 10,863 snail specimens (10 families/23 species) from 57 sampling stations and 12,902 snail specimens (eight families/21 species) from 66 sampling stations were collected ... | 2015 | 26863858 |
| observations on neotricula aperta (gastropoda: pomatiopsidae) population densities in thailand and central laos: implications for the spread of mekong schistosomiasis. | the snail neotricula aperta transmits mekong schistosomiasis in southern laos and cambodia, with about 1.5 million people at risk of infection. plans are under consideration for at least 12 hydroelectric power dams on the lower mekong river and much controversy surrounds predictions of their environmental impacts. unfortunately, there are almost no ecological data (such as long-term population trend studies) available for n. aperta which could be used in impact assessment. predictions currently ... | 2012 | 22720904 |
| a new population and habitat for neotricula aperta in the mekong river of northeastern thailand: a dna sequence-based phylogenetic assessment confirms identifications and interpopulation relationships. | neotricula aperta (gastropoda: pomatiopsidae), the snail intermediate host of schistosoma mekongi, is found in cambodia, laos, and thailand. we update information on the distribution of this species in the mekong river and its tributary, the mun river, in thailand. dna sequences of a portion of the mitochondrial cytochrome c oxidase subunit 1 were obtained from n. aperta collected from different locations and used to confirm species and strain identities. specimens of the β-strain were found in ... | 2015 | 25487731 |
| a population growth trend analysis for neotricula aperta, the snail intermediate host of schistosoma mekongi, after construction of the pak-mun dam. | the pak-mun dam is a controversial hydro-power project on the mun river in northeast thailand. the dam is sited in a habitat of the freshwater snail neotricula aperta, which is the intermediate host for the parasitic blood-fluke schistosoma mekongi causing mekong schistosomiasis in humans in cambodia and laos. few data are available which can be used to assess the effects of water resource development on n. aperta. the aim of this study was to obtain data and to analyze the possible impact of th ... | 2013 | 24244775 |