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- Gillman, Anna, et al.
(författare)
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Oseltamivir-Resistant Influenza A (H1N1) Virus Strain with an H274Y Mutation in Neuraminidase Persists without Drug Pressure in Infected Mallards
- 2015
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Ingår i: Applied and Environmental Microbiology. - : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 81:7, s. 2378-2383
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Tidskriftsartikel (refereegranskat)abstract
- Influenza A virus (IAV) has its natural reservoir in wild waterfowl and emerging human IAVs often contain gene segments from avian viruses. The active drug metabolite of oseltamivir (oseltamivir carboxylate (OC)), stockpiled as Tamiflu® for influenza pandemic preparedness, is not removed by conventional sewage treatment and has been detected in river water. There, it may there exert evolutionary pressure on avian IAV in waterfowl, resulting in development of resistant viral variants. A resistant avian IAV can circulate among wild birds only if resistance does not restrict viral fitness and if the resistant virus can persist without continuous drug pressure. In this in vivo Mallard (Anas platyrhynchos) study we tested if an OC-resistant avian IAV strain (A(H1N1)/NA-H274Y) could retain resistance while drug pressure was gradually removed. Successively infected Mallards were exposed to decreasing levels of OC, and fecal samples were analyzed for neuraminidase sequence and phenotypic resistance. No reversion to wild-type virus was observed during the experiment, which included 17 days of viral transmission in 10 ducks exposed to OC concentrations below resistance induction levels. We conclude that resistance in avian IAV, induced by OC exposure of the natural host, can persist in absence of the drug. Thus, there is a risk that human pathogenic IAVs that evolve from IAVs circulating among wild birds may contain resistance mutations. An oseltamivir resistant pandemic IAV would be a substantial public health threat. Therefore, our observations underscore the need for prudent oseltamivir use, upgraded sewage treatment and resistance surveillance of IAV in wild birds.
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| 3. |
- Delisle Nyström, Christine, et al.
(författare)
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The paediatric option for BodPod to assess body composition in preschool children: what fat-free mass density values should be used?
- 2018
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Ingår i: British Journal of Nutrition. - : CAMBRIDGE UNIV PRESS. - 0007-1145 .- 1475-2662. ; 120:7, s. 797-802
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Tidskriftsartikel (refereegranskat)abstract
- Air displacement plethysmography utilises a two-component model to assess body composition, which relies on assumptions regarding the density of fat-free mass (FFM). To date, there is no evidence as to whether Lohmans or Wells et al.s FFM density values are more accurate in young children. Therefore, the aims of this study were to compare total body fat percentage (TBF%) assessed using the BodPod with both Lohmans and Wells et al.s FFM density values with TBF% from the three-component (3C) model in forty healthy Swedish children aged 5.5 years. Average TBF% calculated using Lohmans FFM density values underestimated TBF% in comparison with the corresponding value assessed using the 3C model (22.2 (SD 5.7) and 25.1 (SD 5.5)%, respectively; P amp;lt;0.001). No statistically significant difference was observed between TBF% assessed using Wells et al.s FFM density values and the 3C model (24.9 (so 5.5) and 251 (so 5.5)%, respectively; P= 0.614). The Bland and Altman plots for TBF% using both Lohmans and Wells et al.s FFM density values did not show any bias across the range of body fatness (Lohman: r0.056, P= 0.733 and Wells el al.: r-0.006, P= 0.970). These results indicate that Wells Cl al.s FFM density values should be used when assessing body composition with the paediatric option for BodPod in 5-year-old children. However, future studies are needed to confirm these results in other populations, including a wider age range of children.
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