Parasitology. What is a parasite?. Definition: An animal which lives in (endoparasite) or on (ectoparasite) another animal (the host). Is almost always a different species from the host Depends on the host for food an causes some degree of injury. General characteristics.
Adult stage parasite infects host
Able to infect primary host
Transmission and spread into the environment
Growth and developmental stage (may not cause damage to the host)
Suggests parasites on gills
suggests protozoan or worm infestation (internal or external)
Lethargy or listlessness
Suggests gill parasite
Fish at bottom
Suggests gill parasite, especially “Ich”
Indicative of external parasite
Indicative of gill parasite
Excess mucus, fish “shimmies”/quivers, or is off feed
General indication of diseaseSigns of Parasitic infections
-Irritation (flashing) -Erosion of scales
-Erythema (reddening) -Hemorrhaging
-Excess mucus production -white spots on skin
Found in marine and freshwater environments
Only infects salmonids
Clinical signs vary among infected salmonid species
Identified by spore size, shape, and location
Ovoid, spherical, or lenticular spores
Usually cysts form around spores
is often referred to as the “catfish trematode”
Misnomer because there are about 30 trematodes found in the channel catfish and because it is also found in the fathead minnow
B. B. acheilognathii, whole worm (living) from farmed carp, Israel.
C. Embryonated eggs of b.
D. Ligula sp. from Rastrineobola argenteus from L. Victoria. Infected fish are recognized by their inflated abdomen (top fish) and may accommodate even three worms (bottom group).
C. philippinensis egg
C. philippinensis adult
Leech with brood attached
Glochidia attaching to gill tissue