Schistosoma haematobium in Guinea-Bissau: unacknowledged morbidity due to a particularly neglected parasite in a particularly neglected country.

Schistosomiasis is the major neglected tropical helminthic disease worldwide. Current knowledge on the epidemiology of schistosomiasis in Guinea-Bissau is scarce and regarding to the absence of Schistosoma haematobium (S.h.

Development of a sequential injection system for the determination of and in waters with different salinity: Application to estuaries in NW Portugal.

In this work, a sequential injection methodology for monitoring nitrite and nitrate in estuarine waters without any previous treatment is described. The developed system was applied to the measurement of nitrite and nitrate in estuarine waters of three rivers in the NW Portugal, allowing an automatic, fast (ca 60 h-1) and precise method (relative standard deviation lower than 2%). The procedure was based on the reaction between nitrite, sulfanilamide and N-(1-naphthyl)-ethylenediamine dihydrochloride (N1NED), whereas the determination of nitrate resulted from its reduction to nitrite, using an in-line cadmium column, followed by the same reaction.