Biomphalaria straminea

Biomphalaria straminea is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails.

Biomphalaria straminea
Shells of Biomphalaria straminea
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Superorder:	Hygrophila
Family:	Planorbidae
Genus:	Biomphalaria
Species:	B. straminea
Binomial name
Biomphalaria straminea (Dunker, 1848)
Synonyms
Planorbis stramineus

This snail is a medically important pest,^[1] because an intermediate host for the parasite Schistosoma mansoni and a vector of schistosomiasis.^[2]

The history of these discoveries was summarized by Paraense (2001).^[3]

The shell of this species, like all planorbids is sinistral in coiling, but is carried upside down and thus appears to be dextral.

Distribution

Biomphalaria glabrata is a Neotropical^[1] species. It occurs in:

• Caribbean: Saint Lucia – reported since 1993^[4]
• northeast of Brazil

This species has recently expanded its native range.^[1] As an introduced species, it occurs in:

• Hong Kong and Southern China - firstly collected in 1973^[5] in the Lam Tsuen valley in Hong Kong, in has now been identified at a number of locations in Hong Kong and Guangdong Province.^[6]

Phylogeny

To allow comparisons with other mollusc genomes, a high-quality genome assembly for B. straminea together with accompanying transcriptomes has been sequenced, producing a 1.005 Gb in size reference genome consisting of 36 chromosomes.^[7]

A cladogram showing phylogenic relations of species in the genus Biomphalaria:^[8]

Biomphalaria

Biomphalaria stanleyi Biomphalaria pfeifferi Biomphalaria camerunensis Nilotic species complex Biomphalaria sudanica Biomphalaria choanomphala Biomphalaria alexandrina Biomphalaria smithi Biomphalaria glabrata Biomphalaria straminea complex Biomphalaria kuhniana Biomphalaria straminea Biomphalaria straminea Biomphalaria intermedia Biomphalaria amazonica Biomphalaria sp. Biomphalaria tenagophila Biomphalaria occidentalis Biomphalaria prona Biomphalaria andecola Biomphalaria sp. (? Biomphalaria havanensis) Biomphalaria sp. (? Biomphalaria havanensis) Biomphalaria temascalensis Biomphalaria obstructa Biomphalaria helophila Biomphalaria peregrina Biomphalaria schrammi

Parasites

Biomphalaria straminea is an intermediate host for Schistosoma mansoni and a vector of intestinal schistosomiasis. Schistosoma mansoni came to Neotropics from Africa in context of the slave trade.^[8] Schistosoma mansoni was not able to infect Biomphalaria straminea previously and it has adapted to this host.^[8]