The tissue samples (containing, for example, metacercariae of some trematode) can be immersed in a digestion solution (0.85% NaCl in distilled water with 1% pepsin and 1% HCl, pH 2) for one hour at 37 °C.

Thank you very much sir Vitor.

Basically the method involves taking a sample of fish, and subjecting the action of pepsin and hydrochloric acid and incubating at 37 ° C with gentle agitation, until it reaches a digestion soft, then the sample is passed through a mesh and observed the residues are retained between which Anisakis larvae found in the case that the fish were infected. This method allows you to check the viability of the larvae, when placed specimens recovered in the filtration in Petri dishes and are candled to less than 37 ° C, the larvae live show signature moves.

This technique is not suitable for industrial inspections and is only recommended for the examination of a small number of copies or when you want an accurate analysis because its sensitivity is high and as just explained is able to distinguish the living from the dead parasites .

Thanks Dr. Sanchez. I would like to ask how will I transport the fish samples, because the sampling area is about 12 hours by bus from our laboratory. How will I preserved the fish after collection? Does preserving it to 10% formalin will not affect the tissue digestion? Or freshly collected samples should always be required for this procedure? Thanks

What do you expect to find?. to anisakis formalin is not necessary, just use refrigerators with Freez'Pack

Actually my sample is a freshwater goby and i want to isolate metacercariae.

But the cysts of some trematodes are not digested by pepsin.You may use in this case trypsin at 37degree C and pH8.Excystment occurs in 60-90 minutes.

Interesting debate!

Thank you for the comments. Anyone has experience with the isolation and concentration of protozoa (ex. Amyloodinium) from gills?

Thank you!