Ultrastructural Changes In The Haemonchus Contortus Cuticle Exposed To Acacia Mearnsii Extract

The parasite Haemonchus contortus is one of the most pathogenic for small ruminants in tropical and subtropical regions worldwide, including Brazil. The objective of this study was to evaluate the structural changes induced in adult H. contortus after in vitro contact with Acacia mearnsii extract (AE), using scanning electron microscopy. Adult nematodes were collected from a naturally infected lamb. In the in vitro assay the parasites were placed in contact with AE (100 mg ml(-1)), for two hours at 37 degrees C. The nematodes used in the assays (exposed to AE and the negative controls) were analyzed using an electron scanning microscope (quadruplicate per treatment). In all replicates, similar morphological alterations were observed on the entire extension of the cuticle of the specimens that remained in contact with the EA in vitro assays, none significant lesion was observed in the negative control (not exposed to AE). These results indicate the direct action of EA on the cuticle of H. contortus in in vitro trials.