monoperoxysulfate and Fish-Diseases

Gyrodactylus salaris is a monogenean, which has collapsed tens of wild Atlantic salmon populations. One of the means of preventing the spread of the parasite is the disinfection of the fishing equipment, which is used in the rivers having susceptible salmon populations. Little is known about the dosage of disinfectants against G. salaris. There are not standards for the testing of disinfectants against multicellular parasites. The present investigation developed a method to test disinfectants and examined the effectiveness of heated water and a commercially available disinfectant (Virkon S) in killing G. salaris. Individual G. salaris worms were followed under the microscope during treatment with heated water or Virkon S disinfectant blend. The logarithm of the time needed to kill the parasite was used as a dependent variable in linear regression. The upper 99.98 % prediction line for the dependent variable was used to obtain a value resembling the time needed for a 4 log reduction of the microbial pathogen, which is commonly used as a criterion for disinfectants. Also 6 log reduction was applied.. Exposure to a relatively low temperature was found to kill the parasite. Even 5-50 min treatment (=10-100 times the 99.98 % upper prediction value) with heated water at 40 °C might be used. This would enable the utilisation of hot tap water in the disinfection of fishing gear. The present practice of 1 % Virkon S for 15 min was also found to kill the parasite.. The follow-up of single parasites of a test population and the use of the calculated upper predictive line in the regression analysis offers a method to analyse the effects of disinfectants on parasites like G. salaris. The results of our tests give possibilities for using disinfection methods, which may be more acceptable by the fishermen than the present ones.

Topics: Animals; Anthelmintics; Disinfectants; Fish Diseases; Hot Temperature; Peroxides; Platyhelminths; Salmo salar; Sulfuric Acids

A range of commercially available disinfectants were tested for efficacy against salmonid alphavirus under a range of different conditions including variations in concentration, temperature, contact time, water type and presence or absence of organic matter. Testing was based on the protocol defined in the draft European Standard prEN 14675, for which the effective standard is a 4 log(10) reduction in viral titre. All disinfectants were found to be effective under at least some of the conditions tested. However, the presence of organic matter in particular was shown to be detrimental in some cases, either through rendering some disinfectants ineffective, or by production of a visible inhomogeneity.

Topics: Alphavirus; Alphavirus Infections; Animals; Disinfectants; Fish Diseases; Nedocromil; Peroxides; Salmonidae; Sulfuric Acids; Toxicity Tests, Acute