, 2009 and Meijer et al., 2009), are now appearing in the 2009 pandemic virus (Duan et al., 2010, Hamelin et al., 2010 and Ujike
et al., 2011). New broad-spectrum counter-measures, which do not result in virus resistance, are urgently required. Oseltamivir was preclinically tested in ferrets and these animals are the preferred model for studying study new viruses and investigating oseltamivir-resistant strains (Boltz et al., 2008, Govorkova et al., 2006, Govorkova et al., 2011, Hamelin et al., 2010, Herlocher et al., 2004, Itoh et al., this website 2009 and Mendel et al., 1998). Thus we have used this model to compare the protective abilities of cloned DI 244/PR8 and oseltamivir. Data presented here show that a single
intranasal dose of 2 μg of DI RNA is overall more effective than 10 doses of 2.5 mg/kg bodyweight administered twice daily over five days (25 mg/kg in total) of oseltamivir at ameliorating the effects of pandemic influenza virus A/California/04/09 (H1N1). Ferret work was conducted according to UK Home Office legislation and was approved by the local ethical committee. Thirty outbred male ferrets (Mustela putorius furo), 3–4 months of age, selleck screening library weighing 860–1367 g (mean 1082 g), were obtained from Highgate Farm, UK. They were seronegative for antibodies to A/Cal as determined by haemagglutination-inhibition. Ferrets were separated into 4 groups each comprising five animals: groups were treated intranasally with +300 μg active 244 DI virus and infected with A/Cal 2 h later, treated with oseltamivir by oral gavage (see below) and infected with A/Cal
2 h later, infected with A/Cal, and inoculated with saline. An identifier chip (idENTICHIP, Bio-Thermo) was inserted subcutaneously into the scruff of each animal. Ferrets receiving 244 DI virus (see below) were Low-density-lipoprotein receptor kinase sedated by isoflurane inhalation before intranasal delivery of 500 μl (250 μl per nostril) of a single dose of 2 μg of 244 RNA in 300 μg of carrier virus. Ferrets receiving oseltamivir treatment were given 2.5 mg/kg bodyweight administered by oral gavage twice-daily every twelve hours (5 mg/kg bodyweight/day) over a period of five days as used by others ( Govorkova et al., 2007 and Hurt et al., 2010), which is comparable to an oral prophylactic human dose of 75 mg/kg bodyweight/day ( Ward et al., 2005). Oseltamivir phosphate was acquired as oseltamivir powder (Roche) for oral suspension and was reconstituted with sterile water to a final concentration of 12 mg/ml. The volume of oseltamivir solution required for each ferret was calculated from the weight of each ferret recorded each morning on the day of administration. This oseltamivir dose and schedule protected ferrets from the highly virulent H5N1 virus (A/Vietnam/1023/04) when administered at 4 h after infection and then twice daily for 5 days ( Govorkova et al., 2007).