Animals such as mammals and birds are often susceptible to parasite infestations/infections. These parasites may be ectoparasites, such as insects, and endoparasites such as filariae and other worms. Domesticated animals, such as cats and dogs, are often infested with one or more of the following ectoparasites:                fleas (e.g. Ctenocephalides spp., such as Ctenocephalides felis and the like);        ticks (e.g. Rhipicephalus spp., Ixodes spp., Dermacentor spp., Amblyoma spp., and the like);        mites (e.g. Demodex spp., Sarcoptes spp., Otodectes spp., and the like);        lice (e.g. Trichodectes spp., Cheyletiella spp., Lignonathus spp. and the like);        mosquitoes (Aedes spp., Culux spp., Anopheles spp. and the like); and        flies (Hematobia spp., Musca spp., Stomoxys spp., Dematobia spp., Coclyomia spp. and the like).        
Fleas are a particular problem because not only do they adversely affect the health of the animal or human, but they also cause a great deal of psychological stress. Moreover, fleas are also vectors of pathogenic agents in animals and humans, such as dog tapeworm (Dipylidium caninum).
Similarly, ticks are also harmful to the physical and psychological health of the animal or human. However, the most serious problem associated with ticks is that they are the vector of pathogenic agents in both humans and animals. Major diseases which are caused by ticks include borrelioses (Lyme disease caused by Borrelia burgdorferi), babesioses (or piroplasmoses caused by Babesia spp.) and rickettsioses (also known as Rocky Mountain spotted fever). Ticks also release toxins which cause inflammation or paralysis in the host. Occasionally, these toxins are fatal to the host.
Likewise, farm animals are also susceptible to parasite infestations. For example, cattle are affected by a large number of parasites. A parasite which is very prevalent among farm animals is the tick genus Rhipicephalus, especially those of the species microplus (cattle tick), decoloratus and annulatus. Ticks such as Rhipicephalus microplus (formerly Boophilus microplus) are particularly difficult to control because they live in the pasture where farm animals graze. This species of ticks is considered a one-host tick and spends immature and adult stages on one animal before the female engorges and falls off the host to lay eggs in the environment. The life cycle of the tick is approximately three to four weeks. In addition to cattle, Rhipicephalus microplus may infest found on buffalo, horses, donkeys, goats, sheep, deer, pigs, and dogs. A heavy tick burden on animals can decrease production and damage hides as well as transmit diseases such as babesiosis (“cattle fever”) and anaplasmosis caused by protozoan parasites.
Animals and humans also suffer from endoparasitic infections including, for example, helminthiasis which is most frequently caused by a group of parasitic worms categorized as cestodes (tapeworm), nematodes (roundworm) and trematodes (flatworm or flukes). These parasites adversely affect the nutrition of the animal and cause severe economic losses in pigs, sheep, horses, and cattle as well as affecting domestic animals and poultry. Other parasites which occur in the gastrointestinal tract of animals and humans include Ancylostoma, Necator, Ascaris, Strongyloides, Trichinella, Capillaria, Toxocara, Toxascaris, Trichiris, Enterobius and parasites which are found in the blood or other tissues and organs such as filarial worms and the extra intestinal stages of Strogyloides, Toxocara and Trichinella. 
Recently, isoxazole and isoxazoline-containing compounds have been demonstrated to be effective against parasites that harm animals. For example, US 2010/0234219 A1 (to DuPont) discloses isoxazoline compounds according to Formula (I) below, which are active against ectoparasites and/or endoparasites.
In addition, published patent application nos. US 2010/0254960 A1, WO 2007/070606 A2, WO 2007/123855 A2, WO 2010/003923 A1, U.S. Pat. No. 7,951,828 & U.S. Pat. No. 7,662,972, US 2010/0137372 A1, US 2010/0179194 A2, US 2011/0086886 A2, US 2011/0059988 A1, US 2010/0179195 A1 and WO 2007/075459 A2 and U.S. Pat. Nos. 7,951,828 and 7,662,972 describe various other parasiticidal isoxazoline compounds. WO 2012/089623 describes topical localized isoxazoline formulations comprising glycofurol.
Notwithstanding the compositions comprising isoxazoline active agents alone or in combination with other active agents described in the documents above, there is a need for veterinary compositions and methods with improved efficacy, bioavailability, and spectrum of coverage to protect animals against endoparasites and/or ectoparasites. Optimal compositions should provide contact and/or systemic activity, be efficacious, have a quick onset of activity, have a long duration of activity, and be safe to the animal recipient and their human owners. This invention addresses this need.
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