Field preservation of monogenean parasites for molecular and morphological analyses

In the present work we examined the efficacy of three different chemical solutions (EtOH 70%, DMSO-NaCl solution, and Longmire buffer) in field preservation of fish gills to be subsequently screened for monogenean specimens destined to morphological and molecular analyses. Degree of difficulty in collecting monogeneans from gills, morphological state of parasites, integrity of their DNA and reliability of sequence reading were observed and qualitatively compared to those of gills and parasites stored in 5% formalin and 99% ethanol. Data were collected over a period of 2 months. Storage in Longmire buffer resulted in dissociation of gills and parasites, while both DMSO and 70% ethanol provided a fine physical and molecular preservation of gills and monogeneans, allowing rapid collection of parasites from lamellae, and easy extraction, amplification and sequencing of parasitic DNA.