[Bulinus truncatus, Planorbarius metidjensis and endemic bilharziosis in the southwestern Morocco].

Since Planorbarius metidjensis was recently found to be an experimental intermediate host of Schistosoma haematobium in the South-West of Morocco, a study on planorbid and B. truncatus was carried out from 1997 to 2005. Eleven planorbid populations were identified in 1997 in the Agadir province, all living at high altitude (from 340 to 1380 m). In contrast, most of the seven bulinid populations inhabited low-lying zones. Three annual generations of P. metidjensis (April-July June-September, and August-March) were noted in two populations (living in perennial bodies of water) in Imouzzer so that juvenile snails were present throughout the year. The dissection of numerous snails collected from these 18 populations between 1999 and 2005 revealed the absence of natural infections with S. haematobium. As most cases of human bilharziosis detected in the Agadir region between 1993 and 1997 are located in highlands, P. metidjensis might be the principal intermediate host of S. haematobium in districts at 500 m above sea level.