In vivo and in vitro effects of imidacloprid on sheep keds (Melophagus ovinus): a light and electron microscopic study |
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Authors: | Heniz Mehlhorn Jochen D'Haese Norbert Mencke Olaf Hansen |
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Affiliation: | (1) Department of Zoology and Parasitology, Heinrich-Heine University, 40255 Düsseldorf, Germany, DE;(2) Bayer AG, BG-Animal Health, 51368 Leverkusen, Germany, DE |
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Abstract: | The effects of imidacloprid (Advantage) on sheep keds (Melophagus ovinus Linné 1758) were studied in vivo and in vitro by means of direct observation (monitored on video tape) and by light and electron microscopy. It was found that: 1. Imidacloprid acted rapidly on all motile stages of the sheep keds. Within 3–4 min after exposure they became immobile and their legs and the abdomen started tetanic trembling movements for 15–30 min, leading to death. 2. The compound is apparently taken up by the body, since it also acted on those sheep keds that had been exclusively exposed to imidacloprid-contaminated filter papers. 3. The compound is available and active for more than 1 month in the wool of sheep; even rainfall does not reduce its efficacy. Body contact between treated mother sheep and their lambs protects them from infestation with these ectoparasites. 4. The compound initiates an ultimately lethal destruction of the ganglia, nerve chords and related muscle fibers, as can be seen in electron micrographs. Received: 7 October 2000 / Accepted: 18 October 2000 |
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Keywords: | AbbreviationsAX Axon CA body cavity DE destruction of muscle fiber cytoplasm EN enlargement of space between contractile elements MF packages of contractile elements MI mitochondria N nucleus NU nucleolus RA remnant of axons RG remnant of glia cells RN remnant of the nucleus SH sheath of nerve bundles TR tracheoles |
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