Collection and evaluation by phenotypic markers of morphotypes of intermediate hosts resistant to infectious forms of Fasciola hepatica

Abstract

The objective was to carry out the collection and evaluation using phenotypic markers of morphotypes of intermediate hosts resistant to infective forms of Fasciola hepatica. For this, 08 herds were used in La Encañada and Baños del Inca, presenting multiple resistance to Triclabendazole 12%, Closantel 10%, being susceptible to Nitroxynil 34%, analyzed by FECRTtechnique. With respect to network and cercaria of intermediate Hospederos collected in these herds, 16.6% were found in Lymnaea viatrix(n = 60) and Lymnaea schirazensis1.66% (n = 40) in La Encañada; and in Baños del Inca affecting Lymnaea viatrix60% (n = 100). Intermediary F1 hosts were artificially infected (n = 100), obtained from ovigerous masses, reared in the laboratory; against miracidium obtained from eggs incubated in containers wrapped in aluminum foil for 45 days at 18 ° C hatching by exposure to light for 5 minutes; trimiracidial infection was performed in multiwell plate for 4 hours; 45 days post inoculation, an cercaria emergency was examined, sacrificing the morphotypes; finding resistant in L. viatrix3.75% and L. schirazensis1.25%. The analysis of variance showed that there are significant differences in shell length and opening, the resistant ones being longer and narrower than the susceptible ones; the pigmentation of the mantle was concentrated in resistant, against susceptible; the oviposition behavior of parents was observed in F1 showing resistance to miracidium morphotypes from eggs deposited on land against susceptible ones attached to the aquarium wall. This shows that intermediate hosts can be used as biological miracidium controllers.