Molecular identification of species of molluscs of the genus Bulinus
Mollusks (snails) of the genus Bulinus participate as intermediate hosts of urinary esquistosomiasdis in Africa, Madagascar, and adjacent regions (Middle East). Identifying the species of Bulinus is important, not all intermediate hosts of schistosomiasis caused by Schistosoma species group haemoatobium. Although this parasitosis is not peculiar to Spain, they are being described many clinical cases in immigrants from areas where this parasitic disease is endemic. These individuals infected eggs can be removed with urine, and if they do in freshwater areas where intermedarios host is found, it autochthonous biological cycle, could be established upon completion of their life cycle.
In this parasitosis, eggs eliminated by the definitive host (man or animal, depending on the species) in contact with fresh water, they release a larval form ciliated, the miracidium, entering some species of Bulinus, which act as intermediate hosts, It allows the development of the larval stages sporocysts, redias and cercariae. Cercariae, tailed, are released from mollusks and actively swim to penetrate the skin of the definitive host. Cercariae, to penetrate the skin, lose their tails and become schistosomula. The schistosomula is carried by the venous return to the right heart chambers, and after passing through the pulmonary circulation, reach cardiac cavidadesc left, allowing them to be driven with blood flow to mesenteric and vesical plexuses where will locate and mature into adult worms.
There are three types of schistosomiasis, produced by three groups of helminth species: Schistosoma mansoni, universal distribution, Schistosoma haematobium (Africa, Madagascar and adycentes regions) and Schistosoma japonicum (Far East).
The group of species of Schistosoma haematobium (S. haematobium, S. and S. interdigitale guiniensis) produces urinary schistosomiasis, by the tendency of these helminths to unicate in the pelvic plexus (bladder, ....), And lay eggs in bladder wall, where they form granulomas which later lead to their elimination with urine to begin the transmission cycle.
They have been described at least 36 Bulinus species classified into four species groups: group Bulinus africanus, Bulinus forskalii group, group and group Bulinus reticulatus Bulinus truncatus / tropicus. Some of these species are: Bulinus africanus group (B. africanus, B. and B. globosus nasutus); Bulinus forskalii (forskalii B., B. and B. Barthi cernicus); Bulinus reticulatus (B. wrighti); Bulinus truncatus / tropicus (B. truncatus, B. natalensis, B. nyassanus).
Differentiation into groups of species and individual species can be performed by morphological characteristics; but difficulties for it, have been developed in recent decades other identification methods based on allozyme studies and molecular studies.
For molecular idebntificación coding intergenic region of the ITS2 ITS2 ribosomal RNA gene (ITS2) nuclear sequences and gene sequences Coli oxidase gene, mitochondrial DNA encoding the subunit I of cytochrome c -COI- studied ( mitochondrial Cytochrome c Oxidase Subunit I).
In our laboratory we carry out the identification of the species of Bulinus, by amplification and sequencing of the genes encoding the ITS2 nuclear and mitochondrial COI.