25 research outputs found
Enhanced Immunogenicity, Mortality Protection, and Reduced Viral Brain Invasion by Alum Adjuvant with an H5N1 Split-Virion Vaccine in the Ferret
Pre-pandemic development of an inactivated, split-virion avian influenza vaccine is challenged by the lack of pre-existing immunity and the reduced immunogenicity of some H5 hemagglutinins compared to that of seasonal influenza vaccines. Identification of an acceptable effective adjuvant is needed to improve immunogenicity of a split-virion avian influenza vaccine.No serum antibodies were detected after vaccination with unadjuvanted vaccine, whereas alum-adjuvanted vaccination induced a robust antibody response. Survival after unadjuvanted dose regimens of 30 µg, 7.5 µg and 1.9 µg (21-day intervals) was 64%, 43%, and 43%, respectively, yet survivors experienced weight loss, fever and thrombocytopenia. Survival after unadjuvanted dose regimen of 22.5 µg (28-day intervals) was 0%, suggesting important differences in intervals in this model. In contrast to unadjuvanted survivors, either dose of alum-adjuvanted vaccine resulted in 93% survival with minimal morbidity and without fever or weight loss. The rarity of brain inflammation in alum-adjuvanted survivors, compared to high levels in unadjuvanted vaccine survivors, suggested that improved protection associated with the alum adjuvant was due to markedly reduced early viral invasion of the ferret brain.Alum adjuvant significantly improves efficacy of an H5N1 split-virion vaccine in the ferret model as measured by immunogenicity, mortality, morbidity, and brain invasion
Exhaled Aerosol Transmission of Pandemic and Seasonal H1N1 Influenza Viruses in the Ferret
Person-to-person transmission of influenza viruses occurs by contact (direct and fomites) and non-contact (droplet and small particle aerosol) routes, but the quantitative dynamics and relative contributions of these routes are incompletely understood. The transmissibility of influenza strains estimated from secondary attack rates in closed human populations is confounded by large variations in population susceptibilities. An experimental method to phenotype strains for transmissibility in an animal model could provide relative efficiencies of transmission. We developed an experimental method to detect exhaled viral aerosol transmission between unanesthetized infected and susceptible ferrets, measured aerosol particle size and number, and quantified the viral genomic RNA in the exhaled aerosol. During brief 3-hour exposures to exhaled viral aerosols in airflow-controlled chambers, three strains of pandemic 2009 H1N1 strains were frequently transmitted to susceptible ferrets. In contrast one seasonal H1N1 strain was not transmitted in spite of higher levels of viral RNA in the exhaled aerosol. Among three pandemic strains, the two strains causing weight loss and illness in the intranasally infected ‘donor’ ferrets were transmitted less efficiently from the donor than the strain causing no detectable illness, suggesting that the mucosal inflammatory response may attenuate viable exhaled virus. Although exhaled viral RNA remained constant, transmission efficiency diminished from day 1 to day 5 after donor infection. Thus, aerosol transmission between ferrets may be dependent on at least four characteristics of virus-host relationships including the level of exhaled virus, infectious particle size, mucosal inflammation, and viral replication efficiency in susceptible mucosa
Integrated monitoring of mola mola behaviour in space and time
Over the last decade, ocean sunfish movements have been monitored worldwide using various satellite tracking methods. This study reports the near-real time monitoring of finescale (< 10 m) behaviour of sunfish. The study was conducted in southern Portugal in May 2014 and involved satellite tags and underwater and surface robotic vehicles to measure both the movements and the contextual environment of the fish. A total of four individuals were tracked using custom-made GPS satellite tags providing geolocation estimates of fine-scale resolution. These accurate positions further informed sunfish areas of restricted search (ARS), which were directly correlated to steep thermal frontal zones. Simultaneously, and for two different occasions, an Autonomous Underwater Vehicle (AUV) videorecorded the path of the tracked fish and detected buoyant particles in the water column. Importantly, the densities of these particles were also directly correlated to steep thermal gradients. Thus, both sunfish foraging behaviour (ARS) and possibly prey densities, were found to be influenced by analogous environmental conditions. In addition, the dynamic structure of the water transited by the tracked individuals was described by a Lagrangian modelling approach. The model informed the distribution of zooplankton in the region, both horizontally and in the water column, and the resultant simulated densities positively correlated with sunfish ARS behaviour estimator (r(s) = 0.184, p < 0.001). The model also revealed that tracked fish opportunistically displace with respect to subsurface current flow. Thus, we show how physical forcing and current structure provide a rationale for a predator's finescale behaviour observed over a two weeks in May 2014
Ecological commonalities among pelagic fishes: comparison of freshwater ciscoes and marine herring and sprat
Systematic comparisons of the ecology between functionally similar fish species from freshwater and marine aquatic systems are surprisingly rare. Here, we discuss commonalities and differences in evolutionary history, population genetics, reproduction and life history, ecological interactions, behavioural ecology and physiological ecology of temperate and Arctic freshwater coregonids (vendace and ciscoes, Coregonus spp.) and marine clupeids (herring, Clupea harengus, and sprat, Sprattus sprattus). We further elucidate potential effects of climate warming on these groups of fish based on the ecological features of coregonids and clupeids documented in the previous parts of the review. These freshwater and marine fishes share a surprisingly high number of similarities. Both groups are relatively short-lived, pelagic planktivorous fishes. The genetic differentiation of local populations is weak and seems to be in part correlated to an astonishing variability of spawning times. The discrete thermal window of each species influences habitat use, diel vertical migrations and supposedly also life history variations. Complex life cycles and preference for cool or cold water make all species vulnerable to the effects of global warming. It is suggested that future research on the functional interdependence between spawning time, life history characteristics, thermal windows and genetic differentiation may profit from a systematic comparison of the patterns found in either coregonids or clupeids
Gammaherpesvirus-Induced Lung Pathology Is Altered in the Absence of Macrophages
The purpose of this study was to examine the lung pathogenesis of murine gammaherpesvirus (MHV-68) infection in mice that lack CC chemokine receptor CCR2, an important receptor for macrophage recruitment to sites of inflammation. BALB/c and CCR2 −/− mice were inoculated intranasally (i.n.) with MHV-68 and samples were collected during acute infection (6 dpi) and following viral clearance (12 dpi). Immunohistochemistry was used to determine which cells types responded to MHV-68 infection in the lungs. Lung pathology in infected BALB/c mice was characterized by a mixed inflammatory cell infiltrate, necrosis, and increased alveolar macrophages by 12 dpi. Immunohistochemistry showed intense positive staining for macrophages. CCR2 −/− mice showed greater inflammation in the lungs at 12 dpi than did BALB/c mice, with more necrosis and diffuse neutrophil infiltrates in the alveoli. Immunohistochemistry demonstrated much less macrophage infiltration in the CCR2 −/− mice than in the BALB/c mice. These studies show that CCR2 is involved in macrophage recruitment in response to MHV-68 infection and illustrates how impairments in macrophage function affect the normal inflammatory response to this viral infection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41345/1/408_2004_Article_2535.pd
Devensian Late-glacial environmental change in the Gordano Valley, North Somerset, England: A rare archive for southwest Britain
The Late-glacial and Holocene environmental history of the Gordano Valley, North Somerset, UK has been reconstructed using pollen, sediment particle size and mineralogical analyses and radiocarbon dating. A Devensian sediment ridge across the valley confined the waters of a small lake, within which the initial sedimentation was minerogenic. Radiocarbon dating of overlying organic-rich deposits suggests that this began late in the Dimlington Stadial c. 18,000-15,000 Cal. BP. Petrographic analyses indicate the minerogenic sediments were partly wind-blown in origin. Climatic amelioration during the Windermere Interstadial c. 15,000 Cal. BP encouraged a shift from minerogenic to biogenic sedimentation. A brief return to minerogenic sedimentation between c. 10,400 and c. 9,520 Cal. BP was followed by uninterrupted fen peat accumulation throughout the Holocene. The later minerogenic horizon appears to represent the Loch Lomond Stadial. Few stratigraphic sequences preserving the complete Devensian Late-glacial-Holocene transition exist in southwest Britain, making the sedimentary archive of the Gordano Valley valuable regionally for reconstructing Late-glacial climate change. © 2007 Springer Science+Business Media B.V