Biomphalaria glabrata

Biomphalaria glabrata is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails. Biomphalaria glabrata is an intermediate snail host for the trematode Schistosoma mansoni, which is one of the main schistosomes that infect humans. This snail is a medically important pest, because of transferring the disease intestinal schistosomiasis, the most widespread of all types of schistosomiasis. The parasite Schistosoma mansoni (which these snails and other Biomphalaria snails carry) infects about 83.31 million people worldwide. Biomphalaria glabrata/Schistosoma mansoni provides a useful model system for investigating the intimate interactions between host and parasite. There is a great deal of information available about this snail, because it has been, and continues to be, under intensive study by many malacologists, parasitologists and other researchers, on account of its medical significance. The shell of this species, like all planorbids, is sinistral in coiling, but it is carried upside down, and thus it appears to be dextral. Biomphalaria glabrata is a Neotropical species. Its native distribution includes the Caribbean: Puerto Rico, Dominican Republic, Saint Lucia, Haiti (first report in 1891), Martinique, Guadeloupe, Antigua, Vieques, Saint Martin, Saint Kitts, Curaçao, Dominica (it was probably replaced by other Biomphalaria species in Dominica or it was eradicated), Montserrat and in South America: Venezuela, Suriname, French Guiana and Brazil. This species has recently expanded its native range, but there is reduced its abundance in the Caribbean, because of competition with non-indigenous species and environmental change. It inhabits new localities in the time of flooding.