Skip to main content
Log in

Treatment of fish parasites

1. Praziquantel effective against Monogenea (Dactylogyrus vastator, dactylogyrus extensus, diplozoon paradoxum)

  • Original Investigations
  • Published:
Zeitschrift für Parasitenkunde Aims and scope Submit manuscript


In several experiments it was shown that praziquantel is effective against Monogenea (Dactylogyrus vastator, Dactylogyrus extensus) parasitizing the gills of pond-reared carp (Cyprinus carpio). Also, the effects of praziquantel onDiplozoon paradoxum from chub (Squalius cephalus) were investigated. Infested carp were incubated for 30, 60, 90, 120 or 180 min at 22° C in water containing 0 (control), 1, 5, 10, 100 μg praziquantel/ml. It was found that the drug caused irreversible alterations in the tegument of Monogenea within 30 min after exposure to at least 1 μg praziquantel/ml. The damage found in vitro resulted in vacuolisation of the parasites' teguments. The three species showed little differences in the grade of tegumental alternation:Dactylogyrus vastator showed vacuolisation of its tegument in all regions of its body, which was very marked in the opisthaptor and in the peduncle region. Parasites did not drop from the gills even when killed by treatment with praziquantel. InDactylogyrus extensus the opisthaptor region was especially affected. The worms usually lost their marginal hooklets as well as the large hooks. In contrast toDactylogyrus vastator, treated worms often dropped from gills.Diplozoon paradoxum was lesser sensitive to the drug. After incubation in 1 μg praziquantel/ml for 7 h the worms had a reduced motility. Doses of 10μg/ml and 150 μg/ml for 1.5 h led to severe damage of the tegument, especially in the region of the oral sucker. However, the drug is effective in treatment of this parasite.

It is suggested that therapy againstDactylogyrus vastator andDactylogyrus extensus in carp fingerlings may be done with 10 mg praziquantel/l for 3 h at 22° C during storage in smaller tanks.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others


  • Becker B, Mehlhorn H, Andrews P, Thomas H (1980a) Scanning and transmission electron microscope studies on the efficacy of praziquantel onHymenolepis nana (Cestoda) in vitro. Z Parasitenkd 61:121–133

    PubMed  Google Scholar 

  • Becker B, Mehlhorn H, Andrews P, Thomas H, Eckert J (1980b) Light and electron microscopic studies on the effect of praziquantel onSchistosoma mansoni, Dicrocoelium dentriticum andFasciola hepatica in vitro. Z Parasitenkd 63:113–128

    PubMed  Google Scholar 

  • Bricker CS, Depenbusch JW, Bennett JL (1982) Effects of praziquantel. Am J Trop Med Hyg 72:132–142

    Google Scholar 

  • Bychowsky BE (1957) Mobogenetic Trematodes; their Systematics and Phylogeny. American ed. W.J. Hargis, Institute of Biological Sciences, Washington D.C.

    Google Scholar 

  • Gönnert R, Andrews P (1977) Praziquantel, a new broad spectrum anti-schistosomal agent. Z Parasitenkd 52:129–150

    PubMed  Google Scholar 

  • Kollmann A (1966)Dactylogyrus extensus Müller et v Cleave, 1932 (Trematoda, Monogenoidea) auf Karpfen (Cyprinus carpio L) zum ersten Male in Westdeutschland nachgewiesen. Zool Anz 177:426–434

    Google Scholar 

  • Mehlhorn H, Kojima S, Rim HJ, Ruenwongsa P, Andrews P, Thomas H, Bunnag B (1983) Ultrastructural investigations on the effects of praziquantel on human trematodes from Asia:Clonorchis sinensis, Metagonimus yokogawai, Opisthorchis viverrini, Paragonimus westermani andSchistosoma japonicum. Drug Res 33, 1:91–98

    Google Scholar 

  • Paperna I (1964a) Adaptation ofDactylogyrus extensus (Mueller and Van Cleave, 1932) to ecological conditions of artifical ponds in Israel. J Parasitol 50:90–93

    Google Scholar 

  • Paperna I (1964b) Competitive exclusion ofDactylogyrus extensus byDactylogyrus vastator (Trematoda, Monogenea) on the gills of reared carp. J Parasitol 50:94–98

    Google Scholar 

  • Thomas H, Gönnert H (1977) The efficacy of praziquantel against cestodes in animals. Z Parasitenkd 52:117–127

    PubMed  Google Scholar 

  • Thomas H, Gönnert R (1978) The efficacy of praziquantel against cestodes in cats, dogs and sheep. Res Vet Sci 24:20–34

    PubMed  Google Scholar 

  • Wunder W (1926b)Dactylogyrus vastator (Nybelin) auf den Kiemen der Karpfenbrut. Ein Beitrag zu den Beziehungen zwischen Parasit und Wirt. Biol Ztrbl 46:748–755

    Google Scholar 

  • Wunder W (1929) DieDactylogyruskrankheit der Karpfenbrut, ihre Ursache und Bekämpfung. Z Fischerei 27:511–545

    Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and permissions

About this article

Cite this article

schmahl, G., Mehlhorn, H. Treatment of fish parasites. Z. Parasitenkd. 71, 727–737 (1985).

Download citation

  • Accepted:

  • Issue Date:

  • DOI: