Electron Microscopy as Unreplaceable Method in Parasitology: SEM and ESEM Utilization

Systematic parasitology studies diversity and its origin. It includes mainly collection, naming, classification and describing of different species of parasites as well as a reconstruction of their evolutionary history. SEM is very important method in study and describing new species or redescribing insufficiently described species of parasites, because it empower opportunities for more detailed studies of their outer morphology. This method was applied in our research mainly for study of several species of parasitic roundworm (Nematoda) and one species of spiny headed worm (Acanthocephala). Our second topic concerning with SEM in parasitology is orangutan self-medication by plants with mechanical influence. However this method condemns parasite samples for destroying and do not allow other using of it. In case of specimens deficiency, environmental scanning electron microscopy (ESEM) is helpful. It would speed up a preparation of sample and is not invasive so valuable specimens can be used for other types of taxonomical studies. Non-invasivity of this method is shown in. Two species of already fixed roundworms (Multicaecum heterotis, Contracaecum osculatum) and one species of spiny headed worm (Corynosoma pseudohamanni) were documented also by ESEM. The samples were examined on a non-commercial ESEM AQUASEM II, they were placed to the Peltier specimen holder with silicon surface, into a drop of water. Observation conditions were: beam accelerating voltage 20 kV, probe current 50 pA, sample temperature 2°C, water vapour pressure 680 Pa. ESEM seems to be good alternative to classical SEM, in a case of lack of samples or need to use samples for molecular study or depositing them as type material in museum