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Efficacy of Praziquantel Bath Treatments for Monogenean Infections of the Rhinobatos typus
Author(s) -
Chisholm Leslie A.,
Whittington Ian D.
Publication year - 2002
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(2002)014<0230:eopbtf>2.0.co;2
Subject(s) - praziquantel , biology , gill , juvenile , anthelmintic , anatomy , helminths , in vivo , parasite hosting , zoology , fishery , ecology , fish <actinopterygii> , schistosomiasis , microbiology and biotechnology , world wide web , computer science
The efficacy of the anthelmintic Praziquantel in removing monocotylid monogeneans (Platyhelminthes) from the branchial tissue ( Neoheterocotyle rhinobatidis , N. rhynchobatis , and Troglocephalus rhinobatidis ) and nasal tissue ( Merizocotyle icopae ) of juvenile giant shovelnose rays Rhinobatos typus from Heron Island, Australia, was studied. Although effective in removing monogeneans in vivo from the skin and gills of the teleost yellow stripey Lutjanus carponotatus from the same locality, two 2‐h treatments using 20 mg/L Praziquantel was ineffective for the giant shovelnose ray. Adult monocotylids were removed, but many post‐oncomiracidia and some juveniles remained attached. Juvenile and adult N. rhinobatidis and T. rhinobatidis reacted similarly when exposed to 20 mg/L Praziquantel during in vitro experiments, exhibiting muscle contractions and dying after 12 and 14 h, respectively. We attribute the failure to remove small monogenean stages in vivo to the structure of the branchial and nasal tissues and the microhabitat and behavior of the parasites. Adults of each monogenean species were generally attached to more‐exposed sites on the branchial or nasal tissues and were affected by Praziquantel faster than the post‐oncomiracidia and juveniles, which were attached between the secondary lamellae of these tissues and thus able to retreat far down between them. This behavior apparently improves parasite survival in treatments of short duration and high concentration. Two 40‐h baths (48 h apart) in 5 mg/L Praziquantel in seawater were required to remove all parasites from branchial and nasal tissues.