COMPARISON OF ESEM AND SEM IN MORPHOLOGY STUDIES OF PARASITICVERTEBRATE NEMATODE

Ascaridoid nematode species Brevimulticaecum heterotis obtained by parasitological dissection from the African bonytongue, Heterotis niloticus (Osteoglossidae) collected in Senegal has been chosen for studies by scanning electron microscope to redescribe its external morphology. Scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM) were used for the study. For SEM, specimens were fixed with hot formalin. They were dehydrated, critical-point dried, mounted on stubs and coated with gold. For ESEM, fixed specimens were hydrated with water; desiccation was not applied. Quanta 3D FEG and Quanta 250 FEG in SEM and ESEM mode were used. Combination of both techniques brings new level to nematode investigation. While SEM remains unsubstitutable method for study of nematode morphology due to its ease of use, ESEM is an unexceptionable instrument when there is only one unique specimen that cannot be destroyed or must remain available for molecular studies.