[Behavior of abiotic factors and rhythm of emission of cercaria of Fasciola hepatica in Fossaria cubensis in transmission sites].

Sampling of Fossaria cubensis, main host of Fasciola hepatica in Cuba was carried out in 3 transmission sites. A higher mollusk density was found in dairies numbers 6 and 9, coinciding with the higher values of total hardness and carbonate hardness. Ammonium, nitrite, and nitrite ions showed lower values in dairy number 6. Temperature and pH did not show significant differences in the 3 biotopes. The mollusks of dairy number 6 began to emit cercarias on the 26th day after being collected; they showed an emission peak at 9 a.m. and an average of 60 cercarias emitted by each mollusk at that time of the day.