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Molluscicidal effect of ivermectin on Biomphalaria glabrata
JOURNAL
OF INVERTEBRATE
PATHOLOGY
52, 354-355 (1988)
NOTES Molluscicidal
Effect of lvermectin
Avermectin, the macrocyclic lacton glycoside isolated from the soil-inhabiting microorganism Streptomyces avermitidis, has shown superior activity against a wide variety of arthropods (J. F. Price, Proc. Flu. State Hortic. Sot. 96, 287-291, 1983; J. T. Trumble and H. Nakakihara, Insect. Acaricide Tests 9, 62-63, 1984). The study of avermectin structure-function relationships led to the synthesis of 22,23dihydroavermectin B, (Ivermectin), which shows better biological activity on a broad array of invertebrates including parasitic nematodes and arthropods (T. Anke, 1986, In “Biotechnology,” Vol. 4, “Microbial Products II,” H. Pape and H.-J. Rehm, Eds., Verlag-Chemie, Weinheim). This note reports on the activity of avermectin under laboratory conditions against Biomphalaria glabrata, the snail vector of
on Biomphalaria
glabrata
repeated three times with 30 adult snails in 200 ml of water in 500-ml jars. Corrected mortality (against controls) of each Ivermectin concentration was subjected to log probit regression analysis to determine the LCso, LC,, and LG-,,,, respectively. The activity of Ivermectin against B. glabrata is presented in Figure 1, data of individual experiments summarized in Table 1. It is evident that tested snails were highly susceptible to Ivermectin in low concentrations: LCsO = 30 ng, L&,, = 42 ng, and LC ioo = 55 rig/ml- ’ 12 to 24 hr after treatment. The high efftciency of Ivermectin is evident from a comparison with synthetic molluscicides: Trifenmorph with LC,, = 0.25 ppm after a 24 hr of exposure (J. Duncan, Pharmac. Ther. 14, 67-69, 1981) and Niclosamide with LCg, = 3-8 ppm for 24 hr (E. A. Malek, 1980, “Snail Transmitted Schistosoma mansoni. Parasitic Diseases,” CRC Press, Boca RaIvermectin (Merck) was prepared as ton, Florida), the only molluscicides still on stock solution (100 p,g ml- ’ acetone) and the market (A. Fenwick, Parasitol. Today kept at 4°C. Working solutions of 100, 50, 3, 7&73, 1987). The efficiency of Ivermec35, and 25 rig/ml - ’ were prepared immedi- tin is approximately 60 to 120 times more ately before use. The molluscicidal bioassay method was generally the same as that described in K. Nakanishi and I. Kubo (Zsrue1 J. Chem. 16, 28-31, 1977). Groups of control animals were placed either in pure distilled water or in water containing the same volume of acetone as treated snails (100 @lOO ml-‘). Test snails were exposed to studied concentration of Ivermectin dissolved in acetone. Snails were considered dead when they were lying on the bottom not fixed to the cultivation jar and heart beat could not be observed microscopicalI I 1 ly. Dead molluscs in each jar were removed 25 35 50 100 and counted at 12-hr intervals. The experiConcentration lag ml-') ments were followed usually for 24 or 48 hr. FIG. 1. Dose response of Biomphalariu glabruta to The bioassay with each concentration was Ivermectin. Mortality after 24 hr of exposure. 354
0022-2011i88 $1.50 Copyright 8 I!288 by Academic Press, Inc. All rights of reproduction in any form reserved.
355
NOTES TABLE
MORTALITYOF Concentration of Ivermectin (rig/ml - ‘) Control (water) Control (water + acetone) 100 50 35 25
Biomphalaria
1
glabrata
EXPOSED
TO IVERMECTIN
% Mortality after exposure 12 hr 30 30 -
hr
36
100 100
-
-
IO -
70
15 20
24
hr
48
10
hr
Note. n = 90 snails in each experimental group. a Concentration of acetone = 100 ~I/100 ml water-‘.
toxic to B. glabrata than above mentioned chemicals. The high efficiency of Ivermectin under well-controlled laboratory conditions is encouraging. Under field conditions the application may be more complicated, but promising activities of the metabolites of Streptomycetes invite further investigations of similar substances also as molluscicides. KEY WORDS: Biomphalaria glabrata; Ivermectin; molluscicide. This study was supported in part financially by the
UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases. We wish to thank Mrs. Vera simov6 for her professional technical assistance.
VLADIM~RMATHA JAROSLAV WEISER Department of Insect Pathology Institute of Entomology Czechoslovak Academy of Science BraniSovskri 31 CS-370 OS (SeskP Budt’jovice Czechoslovakia Received
May
26, 1987; accepted
Febuary
4, 1988
OF INVERTEBRATE
PATHOLOGY
52, 354-355 (1988)
NOTES Molluscicidal
Effect of lvermectin
Avermectin, the macrocyclic lacton glycoside isolated from the soil-inhabiting microorganism Streptomyces avermitidis, has shown superior activity against a wide variety of arthropods (J. F. Price, Proc. Flu. State Hortic. Sot. 96, 287-291, 1983; J. T. Trumble and H. Nakakihara, Insect. Acaricide Tests 9, 62-63, 1984). The study of avermectin structure-function relationships led to the synthesis of 22,23dihydroavermectin B, (Ivermectin), which shows better biological activity on a broad array of invertebrates including parasitic nematodes and arthropods (T. Anke, 1986, In “Biotechnology,” Vol. 4, “Microbial Products II,” H. Pape and H.-J. Rehm, Eds., Verlag-Chemie, Weinheim). This note reports on the activity of avermectin under laboratory conditions against Biomphalaria glabrata, the snail vector of
on Biomphalaria
glabrata
repeated three times with 30 adult snails in 200 ml of water in 500-ml jars. Corrected mortality (against controls) of each Ivermectin concentration was subjected to log probit regression analysis to determine the LCso, LC,, and LG-,,,, respectively. The activity of Ivermectin against B. glabrata is presented in Figure 1, data of individual experiments summarized in Table 1. It is evident that tested snails were highly susceptible to Ivermectin in low concentrations: LCsO = 30 ng, L&,, = 42 ng, and LC ioo = 55 rig/ml- ’ 12 to 24 hr after treatment. The high efftciency of Ivermectin is evident from a comparison with synthetic molluscicides: Trifenmorph with LC,, = 0.25 ppm after a 24 hr of exposure (J. Duncan, Pharmac. Ther. 14, 67-69, 1981) and Niclosamide with LCg, = 3-8 ppm for 24 hr (E. A. Malek, 1980, “Snail Transmitted Schistosoma mansoni. Parasitic Diseases,” CRC Press, Boca RaIvermectin (Merck) was prepared as ton, Florida), the only molluscicides still on stock solution (100 p,g ml- ’ acetone) and the market (A. Fenwick, Parasitol. Today kept at 4°C. Working solutions of 100, 50, 3, 7&73, 1987). The efficiency of Ivermec35, and 25 rig/ml - ’ were prepared immedi- tin is approximately 60 to 120 times more ately before use. The molluscicidal bioassay method was generally the same as that described in K. Nakanishi and I. Kubo (Zsrue1 J. Chem. 16, 28-31, 1977). Groups of control animals were placed either in pure distilled water or in water containing the same volume of acetone as treated snails (100 @lOO ml-‘). Test snails were exposed to studied concentration of Ivermectin dissolved in acetone. Snails were considered dead when they were lying on the bottom not fixed to the cultivation jar and heart beat could not be observed microscopicalI I 1 ly. Dead molluscs in each jar were removed 25 35 50 100 and counted at 12-hr intervals. The experiConcentration lag ml-') ments were followed usually for 24 or 48 hr. FIG. 1. Dose response of Biomphalariu glabruta to The bioassay with each concentration was Ivermectin. Mortality after 24 hr of exposure. 354
0022-2011i88 $1.50 Copyright 8 I!288 by Academic Press, Inc. All rights of reproduction in any form reserved.
355
NOTES TABLE
MORTALITYOF Concentration of Ivermectin (rig/ml - ‘) Control (water) Control (water + acetone) 100 50 35 25
Biomphalaria
1
glabrata
EXPOSED
TO IVERMECTIN
% Mortality after exposure 12 hr 30 30 -
hr
36
100 100
-
-
IO -
70
15 20
24
hr
48
10
hr
Note. n = 90 snails in each experimental group. a Concentration of acetone = 100 ~I/100 ml water-‘.
toxic to B. glabrata than above mentioned chemicals. The high efficiency of Ivermectin under well-controlled laboratory conditions is encouraging. Under field conditions the application may be more complicated, but promising activities of the metabolites of Streptomycetes invite further investigations of similar substances also as molluscicides. KEY WORDS: Biomphalaria glabrata; Ivermectin; molluscicide. This study was supported in part financially by the
UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases. We wish to thank Mrs. Vera simov6 for her professional technical assistance.
VLADIM~RMATHA JAROSLAV WEISER Department of Insect Pathology Institute of Entomology Czechoslovak Academy of Science BraniSovskri 31 CS-370 OS (SeskP Budt’jovice Czechoslovakia Received
May
26, 1987; accepted
Febuary
4, 1988