Oseltamivir-Resistant Pandemic A/H1N1 Virus Is as Virulent as Its Wild-Type Counterpart in Mice and Ferrets

The neuraminidase inhibitor oseltamivir is currently used for treatment of patients infected with the pandemic A/H1N1 (pH1N1) influenza virus, although drug-resistant mutants can emerge rapidly and possibly be transmitted. We describe the characteristics of a pair of oseltamivir-resistant and oseltamivir-susceptible pH1N1 clinical isolates that differed by a single change (H274Y) in the neuraminidase protein. Viral fitness of pH1N1 isolates was assessed in vitro by determining replication kinetics in MDCK α2,6 cells and in vivo by performing experimental infections of BALB/c mice and ferrets. Despite slightly reduced propagation of the mutant isolate in vitro during the first 24 h, the wild-type (WT) and mutant resistant viruses induced similar maximum weight loss in mice and ferrets with an identical pyrexic response in ferrets (AUC of 233.9 and 233.2, P = 0.5156). Similarly, comparable titers were obtained for the WT and the mutant strains on days 1, 3, 6 and 9 post-infection in mouse lungs and on days 1–7 in ferret nasal washes. A more important perivascular (day 6) and pleural (days 6 and 12) inflammation was noted in the lungs of mice infected with the H274Y mutant, which correlated with increased pulmonary levels of IL-6 and KC. Such increased levels of IL-6 were also observed in lymph nodes of ferrets infected with the mutant strain. Furthermore, the H274Y mutant strain was transmitted to ferrets. In conclusion, viral fitness of the H274Y pH1N1 isolate is not substantially altered and has the potential to induce severe disease and to disseminate

Evaluation and Interpretation of Genetic Effective Population Size of Delta Smelt from 2011–2014

Delta Smelt have collapsed demographically, but little is known about their current genetic status. We used 12 microsatellite loci to evaluate two measures of the effective population size (Ne) of Delta Smelt. Ne is a measure that offers predictive power regarding the loss of genetic diversity in a population over time, as well as the short and long-term genetic risks for loss of fitness resulting from low diversity. We found that the Ne of Delta Smelt is too high to accurately estimate with the data (upper 95% confidence intervals were infinity), but the lower confidence intervals of NeLD (linkage disequilibrium Ne) were above 1,000, while some of the lower confidence intervals of NeV (variance Ne) were below 1,000. We interpret this to indicate that Delta Smelt are not declining because of genetic factors, and are not at immediate risk of losing genetic diversity from low Ne. We caution that these estimates are from a short-term data set estimated from a population that has already been declining for decades, and that it is likely that Delta Smelt have lost diversity. We suggest continuing efforts to maximize abundance to prevent further loss of genetic diversity

Evaluation and Interpretation of Genetic Effective Population Size of Delta Smelt from 2011–2014

Delta Smelt have collapsed demographically, but little is known about their current genetic status. We used 12 microsatellite loci to evaluate two measures of the effective population size (Ne) of Delta Smelt. Ne is a measure that offers predictive power regarding the loss of genetic diversity in a population over time, as well as the short and long-term genetic risks for loss of fitness resulting from low diversity. We found that the Ne of Delta Smelt is too high to accurately estimate with the data (upper 95% confidence intervals were infinity), but the lower confidence intervals of NeLD (linkage disequilibrium Ne) were above 1,000, while some of the lower confidence intervals of NeV (variance Ne) were below 1,000. We interpret this to indicate that Delta Smelt are not declining because of genetic factors, and are not at immediate risk of losing genetic diversity from low Ne. We caution that these estimates are from a short-term data set estimated from a population that has already been declining for decades, and that it is likely that Delta Smelt have lost diversity. We suggest continuing efforts to maximize abundance to prevent further loss of genetic diversity

Detection of Adult Green Sturgeon Using Environmental DNA Analysis.

Environmental DNA (eDNA) is an emerging sampling method that has been used successfully for detection of rare aquatic species. The Identification of sampling tools that are less stressful for target organisms has become increasingly important for rare and endangered species. A decline in abundance of the Southern Distinct Population Segment (DPS) of North American Green Sturgeon located in California's Central Valley has led to its listing as Threatened under the Federal Endangered Species Act in 2006. While visual surveys of spawning Green Sturgeon in the Central Valley are effective at monitoring fish densities in concentrated pool habitats, results do not scale well to the watershed level, providing limited spatial and temporal context. Unlike most traditional survey methods, environmental DNA analysis provides a relatively quick, inexpensive tool that could efficiently monitor the presence and distribution of aquatic species. We positively identified Green Sturgeon DNA at two locations of known presence in the Sacramento River, proving that eDNA can be effective for monitoring the presence of adult sturgeon. While further study is needed to understand uncertainties of the sampling method, our study represents the first documented detection of Green Sturgeon eDNA, indicating that eDNA analysis could provide a new tool for monitoring Green Sturgeon distribution in the Central Valley, complimenting traditional on-going survey methods

Environmental DNA sampling locations on the Sacramento River, CA.

<p>Environmental DNA sampling locations on the Sacramento River, CA.</p

PEGylation of a Vesicular Stomatitis Virus G Pseudotyped Lentivirus Vector Prevents Inactivation in Serum

One disadvantage of vesicular stomatitis virus G (VSV-G) pseudotyped lentivirus vectors for clinical application is inactivation of the vector by human serum complement. To prevent this, monomethoxypoly(ethylene) glycol was conjugated to a VSV-G-human immunodeficiency virus vector expressing Escherichia coli beta-galactosidase. The modification did not affect transduction efficiency in vitro and protected the vector from inactivation in complement-active human and mouse sera. Blood from mice dosed intravenously with either the unmodified or the PEGylated virus particles was assayed for active vector by a limiting-dilution assay to evaluate transduction efficiency and for p24, an indicator of the total number of virus particles present. PEGylation extended the circulation half-life of active vector by a factor of 5 and reduced the rate of vector inactivation in the serum by a factor of 1,000. Pharmacokinetic profiles for the total number of virus particles present in the circulation were unaffected by PEGylation. Modification of the vector with poly(ethylene) glycol significantly enhanced transduction efficiency in the bone marrow and in the spleen 14 days after systemic administration of the virus. These results, in concert with the pharmacokinetic profiles, indicate that PEGylation does protect the virus from inactivation in the serum and, as a result, improves the transduction efficiency of VSV-G pseudotyped lentivirus vectors in susceptible organs in vivo