What common parasites are found in river snails

River snail is the general name for the genus Margarya in the family Viviparidae, order Mesogastropoda, phylum Mollusca, distributed in the lakes of Yunnan and Jiangsu, and it is also a common name for the field snail (Cipangopaludina). It is rich in nutritional value and delicious in taste, and many friends love to eat it, but when eating it you need to pay attention to the parasites in river snails. Let us take a look at what parasites river snails have!

Schistosomes

Schistosomes, also called blood flukes, are flatworms that parasitize in the veins of the host. The eggs pass through the vein wall into the bladder and are excreted with urine. The larvae develop in the intermediate host snail, and the mature larvae enter the final host human body through the skin or mouth. Schistosoma mansoni lives in the veins of the large and small intestines, the eggs are excreted with feces, and the larvae enter the snail body, then return to the final host human body through the skin.

Angiostrongylus

Angiostrongylus is found almost throughout tropical and subtropical regions. Taiwan, China is an epidemic area of this disease. Under normal circumstances, rats are the final host of Angiostrongylus, snails and slugs are the intermediate hosts, and freshwater shrimp, fish, crabs, etc. can serve as paratenic hosts of this worm. In mainland China, the natural infection rate of the giant African snail is 29.7% and 24.76%, and that of the golden apple snail is 65.5%. People become infected by eating snails, slugs, fish, shrimp, etc. containing third-stage larvae.

Fasciola hepatica

The adult of Fasciola hepatica parasitizes in the liver bile ducts of cattle, sheep and other herbivorous animals and humans. The intermediate hosts are lymnaeid snails, and in China Galba truncatula is the most important. In the bile ducts, the eggs discharged by the adult are passed into the intestinal tract with bile, then discharged from the body together with the host's feces, fall into water, and develop into miracidia after 2 to 3 weeks at a suitable temperature. When they encounter the intermediate host lymnaeid snail, they quickly penetrate into its body and enter the liver.

Lung flukes

Lung flukes, also called Paragonimus westermani, have the first intermediate host being the Semisulcospira snail, and the second intermediate hosts being freshwater crabs and crayfish (parasitizing in the gills, muscles, etc.). People become infected by eating raw, drunken, or undercooked crabs or crayfish. The worms can enter the human lungs, abdomen, brain, subcutaneous tissue and other parts, and can cause symptoms such as cough, blood-stained sputum, chest pain, abdominal pain, headache, epilepsy, and subcutaneous lumps.