, 2006). One could explain this as an effect of parasite strain sub-structuring

leading to differential transmission among definitive host species. In contrast, Rudge et al. (2009) BLZ945 datasheet reported a clustering of isolates from dogs and bovines in marshland areas and humans, rodents and dogs in highland areas of China, but often found little differentiation among parasite sub-populations of different host types in sympatry. These authors suggested that patterns may differ even among local villages or between years ( Rudge et al., 2009). In contrast to S. japonicum, S. mekongi is regarded as a parasite maintained mostly through transmission via human populations. S. mekongi uses the snail Neotricula aperta as its intermediate host and published records identify the following foci of S. mekongi transmission: Ban Hat-Xai-Khoun, Khong Island, southern Laos ( Harinasuta and Kruatrachue, 1962); Kratie in Kratie

Province, northeastern Cambodia, approximately 180 km downstream of Khong Island ( Audebaud et al., 1968); and San Dan, Sambour District, also in Kratie Province ( Biays et al., 1999). All the aforementioned sites lie along the lower Mekong River. More recently, transmission of the parasite has been discovered in tributaries of the Mekong river, but also within the Mekong Basin, namely at Sa Dao in the Xe Kong river of Cambodia ( Attwood et al., 2004). The potential human population at risk from check details Mekong schistosomiasis is currently over 1.5 million ( Attwood et al., 2008), with around 800 people infected in Laos and around 2000 in Cambodia (crude estimates

based on prevalence data in Urbani et al., 2002 and Muth et al., 2010). At Sa Dao, no human infections were detected in 2004, but the disease re-emerged in 2005 ( Sinuon et al., 2007). In addition, in 2004 the prevalence of infection among N. aperta collected at Sa Dao was 0.14% ( Attwood et al., 2004). Similarly, despite an almost eight-fold reduction in the prevalence in the human population at Khong Island in Laos (1969–2003), the estimated prevalence in the local N. aperta populations had changed little ( Attwood et al., 2001). These observations Hydroxychloroquine suggest that there may be a significant zoonotic component to the transmission of S. mekongi. Prevalences of 12.2% and 3.6% for pigs (in Laos) and dogs (in Cambodia), respectively, provide direct evidence for the importance of reservoir hosts ( Strandgaard et al., 2001 and Matsumoto et al., 2002). Surveys of cows, water buffalo, pigs, horses and field rats in 5 villages of Kratié Province (Cambodia) failed to detect any infection with S. mekongi (see ( Matsumoto et al., 2002). Historical surveys have detected no natural infections in water buffalo ( Schneider, 1976) and reported a similar prevalence in dogs at Kratié ( Iijima et al., 1971), suggesting that the recent findings represent a long term equilibrium state. Human schistosomiasis in Malaysia is caused by S. malayensis.