Abstract:
Ichthyophthirius multifiliis commonly known as "Ich" or "white spot" is a ciliated protozoan parasite, which belongs to the class Oligohymenophora that can grow to a diameter of around one millimeter. This size represents one of the largest protozoan parasites for fish and it is visible without magnification. Ich begins its life cycle as a tomont, which settles at the bottom of the aquarium attaching itself to any type of media. After attachment these tomonts undergo mitosis, which results in hundreds of ciliated theronts. These theronts are free swimming, and upon contact with a fish host embed themselves in the skin and gills. It is critical for the theronts to find a host within 48 hours in order to survive. Once attached they enlarge and form a visible "white spot." This final stage of I. multifiliis is known as trophont. For the aquarium fish Pseudotropheus tropheops and P. elongatus, having been isolated from other varieties of fish for two years, became infested with "white spot" by the introduction of another aquarium fish, P. zebra, which was acquired from another source. Addition of P. zebra to the above fish tank stressed the resident chichlids and infested them with I. multifiliis. Within three days the infestation of ICH spread across the entire surface of the host body and onto the gills. Treatment with methylene blue for four days was ineffective in eliminating the infestation. There is no proven chemotherapy for patent infestations of I. multifilliis. Observations under light microscopy showed an infestation level of approximately 8 ciliates per field at 100X. This high level of I. multifilliis was the major cause of the death of P. tropheops and P. elongatus. Infested gills were fixed with 10% buffered formalin and 2.5% buffered glutaraldehyde. Infested gills were then sectioned and stained to understand histopathology. Gills fixed with glutaraldehyde were prepared for closer study using scanning electron microscopy to determine host-parasite relationship.
Page(s):
53-62
DOI:
DOI not available
Published:
Journal: Proceedings of Parasitology, Volume: 41, Issue: 0, Year: 2006