The synergistic action of imidacloprid and flumethrin and their release kinetics from collars applied for ectoparasite control in dogs and cats

<p>Abstract</p> <p>Background</p> <p>The control of tick and flea burdens in dogs and cats has become essential to the control of important and emerging vector borne diseases, some of which are zoonoses. Flea worry and flea bite hypersensitivity are additionally a significant disease entity in dogs and cats. Owner compliance in maintaining the pressure of control measures has been shown to be poor. For these reasons efforts are continuously being made to develop ectoparasiticides and application methods that are safe, effective and easy to apply for pet owners. A new polymer matrix collar has recently been developed which is registered for 8 months use in cats and dogs. The basic properties of this collar have been investigated in several <it>in vitro </it>and <it>in vivo </it>studies.</p> <p>Methods</p> <p>The effects of imidacloprid, flumethrin and the combination were evaluated in vitro by means of whole cell voltage clamp measurement experiments conducted on isolated neuron cells from <it>Spodoptera frugiperda</it>. The in vitro efficacy of the two compounds and the combination against three species of ticks and their life stages and fleas were evaluated in a dry surface glass vial assay. The kinetics of the compounds over time in the collar were evaluated by the change in mass of the collar and measurement of the surface concentrations and concentrations of the actives in the collar matrix by HPLC. Hair clipped from collar treated dogs and cats, collected at various time points, was used to assess the acaricidal efficacy of the actives ex vivo.</p> <p>Results</p> <p>An <it>in vitro </it>isolated insect nerve model demonstrated the synergistic neurotoxic effects of the pyrethroid flumethrin and the neonicotinoid imidacloprid. An <it>in vitro </it>glass vial efficacy and mortality study against various life stages of the ticks <it>Ixodes ricinus, Rhipicephalus sanguineus </it>and <it>Dermacentor reticulatus </it>and against the flea (<it>Ctenocephalides felis</it>) demonstrated that the combination of these products was highly effective against these parasites. The release kinetics of these actives from a neck collar (compounded with 10% imidacloprid and 4.5% flumethrin) was extensively studied in dogs and cats under laboratory and field conditions. Acaricidal concentrations of the actives were found to be consistently released from the collar matrix for 8 months. None of the collar studies in dogs or cats were associated with any significant collar related adverse event.</p> <p>Conclusion</p> <p>Here we demonstrated the synergism between the pyrethroid flumethrin and the neonicotinoid imidacloprid, both provided in therapeutically relevant doses by a slow release collar matrix system over 8 months. This collar is therefore a convenient and safe tool for a long-term protection against ectoparasites.</p

An experimental study of the effect of stainless steel cladding on the structural integrity of flawed steel plates in bending

A small crack near the inner surface of clad nuclear reactor pressure vessels is an important consideration in the safety assessment of the structural integrity of the vessel. Experimental results from tests on large clad and unclad plate specimens with surface flaws have shown that (1) a tough surface layer composed of cladding and/or heat-affected zone has arrested running flaws in clad plates under conditions where unclad plates have ruptured, and (2) the residual load-bearing capacity of clad plates with large subclad flaws significantly exceeded that of an unclad plate. The fracture surfaces of unclad plates suggest that the flaw evolves through alternately tunneling then breaking to the surface. In the case of clad plates, it is hypothesized that the tough, strong surface layer inhibits the tunneled flaw from propagating to the surface

Tourism and Infant-Directed Aggression in Tibetan Macaques (Macaca thibetana) at Mt. Huangshan, China

Previous studies of habituated Tibetan macaques (Macaca thibetana) at Mt. Huangshan, China demonstrated the negative impact that some tourism management strategies had on monkeys\u27 annual infant mortality, but data on precise causes and perpetrators of infant injuries were not available. We worked at the same site and recorded rates of aggression that older monkeys directed toward group infants as a function of tourist numbers and proximity. We found a negative correlation between the number of people on the viewing platform and the frequency of monkeys\u27 aggression toward the group\u27s infants, but the effect is slight. We noted that infant-directed aggression (IDA) was more likely to occur in the provisioning zone where tourists bounded the monkeys on two sides, despite the fact that infants spent very little time in that location. The alpha and beta males engaged in more IDA than expected, while the other three adult males, adult females, and juveniles exhibited less IDA than expected. Males\u27 IDA included biting, chasing, grabbing, and pushing. Adult females bit and grabbed mostly their own infants in the contexts of punishment and weaning. Juveniles\u27 IDA was uncommon and consisted mostly of open-mouth threats. To minimize the severity and frequency of male-toinfant IDA, we recommend that sections of the tourist viewing platform be closed off so that tourists do not surround the monkeys, particularly when infants are near the viewing platforms and tourist numbers are few. The rule against tourists feeding monkeys should also be strictly enforced, so that altercations between the highest-ranked males and other group members, particularly infants, are less likely to occur