Morphological and molecular identification of the invasive freshwater snail Physa acuta (Gastropoda: Physidae) into Llanquihue Lake, Chilean Patagonia

Identification of freshwater snail species and survey of their trematode infections in Ordos, China

In order to investigate and study the species and distribution of freshwater snails in Ordos area of Inner Mongolia, as well as the trematode infection in different periods, and to provide a scientific basis for the effective prevention and control of livestock trematodiasis. In this paper, freshwater snails distributed in Ordos were widely collected for morphological identification, and PCR amplification of freshwater snails COI gene and ITS2 gene was carried out with the help of molecular biology. At the same time, microscopic examination was used to observe the trematode infection of freshwater snails in two different periods from May to July and July to September, and the molecular biology of the trematodes was identified. The results showed that the 1796 freshwater snails collected belonged to two orders, three families and four genera, i.e. Bellamya, Radix, Galba, and Gyraulus. Microscopic examination of snails showed that the infection rate of trematode larvae from July to September was significantly higher than that from May to July. The collected trematodes were identified as five species, namely Cotylurus marcogliesei, Fasciola hepatica, Fasciola gigantica, Paramphistomum cervi, and Parastrigea robusta. The combination of freshwater snail species in Ordos and the infection of trematode in snails showed that a large number of freshwater snails were infected with trematodes, especially from July to September, when there is more rain and suitable climate, which causes serious harm to local livestock.

<i>PHYSELLA ACUTA </i>(DRAPARNAUD, 1805) (MOLLUSCA: GASTROPODA: PHYSIDAE) IN THE ĐANHIM RIVER BASIN (LÂM ĐỒNG PROVINCE, VIETNAM): GENETIC AND MORPHOLOGICAL IDENTIFICATION

Invasive freshwater molluscs of the genus Physella (Gastropoda: Physidae) were discovered in the basin of the Dong Nai River, Vietnam for the first time. Based on the analysis of morphological features and the nucleotide sequence of the fragment of the COI mitochondrial gene, these molluscs were identified as belonging to the species Physella acuta (Draparnaud, 1805). The paper summarizes the available information on the distribution of this species in the waterbodies of Vietnam, provides the morphological characteristics of the studied individuals, and compares them with other populations of the species found in tropic and subtropic regions. It is shown that, despite the more than twenty-year history of registration of Physella acuta in Vietnam, the species remains relatively rare in the country's waterbodies. The presence in the studied sample of individuals of different size groups suggests that, in the basin of the Dong Nai River, self-reproducing population of Physella acuta has been established.