The Impact of Matching Vaccine Strains and Post-SARS Public Health Efforts on Reducing Influenza-Associated Mortality among the Elderly

Public health administrators do not have effective models to predict excess influenza-associated mortality and monitor viral changes associated with it. This study evaluated the effect of matching/mismatching vaccine strains, type/subtype pattern changes in Taiwan's influenza viruses, and the impact of post-SARS (severe acute respiratory syndrome) public health efforts on excess influenza-associated mortalities among the elderly. A negative binomial model was developed to estimate Taiwan's monthly influenza-associated mortality among the elderly. We calculated three winter and annual excess influenza-associated mortalities [pneumonia and influenza (P&I), respiratory and circulatory, and all-cause] from the 1999–2000 through the 2006–2007 influenza seasons. Obtaining influenza virus sequences from the months/years in which death from P&I was excessive, we investigated molecular variation in vaccine-mismatched influenza viruses by comparing hemagglutinin 1 (HA1) of the circulating and vaccine strains. We found that the higher the isolation rate of A (H3N2) and vaccine-mismatched influenza viruses, the greater the monthly P&I mortality. However, this significant positive association became negative for higher matching of A (H3N2) and public health efforts with post-SARS effect. Mean excess P&I mortality for winters was significantly higher before 2003 than after that year [mean ± S.D.: 1.44±1.35 vs. 0.35±1.13, p = 0.04]. Further analysis revealed that vaccine-matched circulating influenza A viruses were significantly associated with lower excess P&I mortality during post-SARS winters (i.e., 2005–2007) than during pre-SARS winters [0.03±0.06 vs. 1.57±1.27, p = 0.01]. Stratification of these vaccine-matching and post-SARS effect showed substantial trends toward lower elderly excess P&I mortalities in winters with either mismatching vaccines during the post-SARS period or matching vaccines during the pre-SARS period. Importantly, all three excess mortalities were at their highest in May, 2003, when inter-hospital nosocomial infections were peaking. Furthermore, vaccine-mismatched H3N2 viruses circulating in the years with high excess P&I mortality exhibited both a lower amino acid identity percentage of HA1 between vaccine and circulating strains and a higher numbers of variations at epitope B. Our model can help future decision makers to estimate excess P&I mortality effectively, select and test virus strains for antigenic variation, and evaluate public health strategy effectiveness

Mechanisms underlying the effects of marine herbivores : implications for a low intertidal kelp community

Rocky low intertidal communities structured by the canopy forming kelp Hedophyllum sessile and the generalist herbivore Katharina tunicata are typical of semiexposed coasts of British Columbia. Katharina tunicata is capable of removing the community supporting canopy formed by H. sessile . Mechanisms which determine and mediate the interaction between this alga and herbivore are investigated. Densities of Katharina tunicata were manipulated within the range of densities found on the shore, without the use of artificial barriers, and the percent cover, density, population structure and demography of Hedophyllum sessile were monitored to determine the effects of these manipulations. Differential susceptibility of H. sessile holdfast size classes are shown to account for the rapid decline of H. sessile abundance in areas of high chiton density. These data are used to quantify the mechanism referred to as 'an escape in size.' Several lines of evidence suggest that the mechanism of K. tunicata interaction with H. sessile adults is an indirect effect whereby holdfast integrity is degraded, making individuals of H. sessile more susceptible to wave-induced mortality. The implications of this mechanism for observed geographic variation in K. tunicata interaction strength are discussed. The potential role of polyphenolics (anti-herbivore secondary metabolites) in the interaction between Hedophyllum sessile and Katharina tunicata is examined. Three experiments determined that: (1) H. sessile is a phenolic-rich species (5-7% H. sessile dry weight), (2) induction of phenolic production does not occur within three days of simulated wounding, (3) individuals of H. sessile from areas of naturally high and low herbivore densities do not differ in phenolic content, and (4) juvenile H. sessile tissue contains significantly more phenolics than adult vegetative tissue but adult reproductive and vegetative tissues do not differ. These results are discussed in terms of both present-day and evolutionary ecological importance. By monitoring the Hedophyllum sessile understory community during the chiton density manipulation experiment, and performing descriptive investigations during the same time period, several direct and indirect interactions were revealed which are potentially important determinants of the structure of this community. These interactions are used to construct three interaction webs which distinguish between the interactions experienced by juvenile and adult H. sessile. A model of the annual successional trajectory of this low intertidal kelp community is used to summarize the findings of this thesis.Science, Faculty ofBotany, Department ofGraduat

Contrasting effects of coastal upwelling on growth and recruitment of nearshore Pacific rockfishes (genus Sebastes)

Knowledge of processes underlying recruitment is critical for understanding marine population dynamics and their response to ocean climate. We investigated the relationship between coastal upwelling and early life history of Black Rockfish (Sebastes melanops) and CQB Rockfishes (a species complex including S. caurinus, S. maliger and S. auriculatus) over six years on the west coast of Vancouver Island, Canada. We examined otoliths to determine birth and settlement dates, pelagic durations, and pre- and post-settlement growth rates. High CQB Rockfish recruitment in 2005 was associated with prolonged downwelling and warm ocean temperatures, late birth dates, fast pre-settlement growth, short pelagic durations, and small size-at-settlement. In contrast, high Black Rockfish recruitment in 2006 was associated with strong upwelling and cool temperatures, slow pre-settlement growth and protracted pelagic durations. Pre-settlement growth of both Rockfishes increased with high sea surface temperature, but was unrelated to chlorophyll-a concentration. Our results indicate that the same oceanographic conditions give rise to fast pre-settlement growth and short pelagic durations for both species, but that different factors lead to strong recruitment in each.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Indirect effects of sea otters on rockfish (Sebastes spp.) in giant kelp forests

Sea otters are a classic example of a predator controlling ecosystem productivity through cascading effects on basal, habitat-forming kelp species. However, their indirect effects on other kelp-associated taxa like fishes are poorly understood. We examined the effects of sea otter (Enhydra lutris) reintroduction along the west coast of Vancouver Island, Canada on giant kelp (Macrocystis pyrifera) distributions and the trophic niches and growth of two common kelp forest fishes, black (Sebastes melanops) and copper (S. caurinus) rockfishes. We sampled 47 kelp forests, and found that red sea urchins (Strongylocentrotus franciscanus) were eliminated in the presence of otters, and that kelp forests were 3.7 times deeper and 18.8 times larger. Despite order-of-magnitude differences in kelp forest size, adult black and copper rockfishes contained less kelp-derived carbon in their tissues (as measured by stable isotopes of C and N) in regions with otters. Adults of both species had higher mean trophic positions in the presence of otters, indicating more frequent consumption of higher trophic level prey such as fishes. Smaller trophic niche space of rockfishes in the presence of otters indicated a higher degree of trophic specialization. Juvenile black rockfishes rapidly shifted to higher kelp-carbon contents, trophic positions, and body condition factors after settling in kelp forests. The relationships of growth to length, percentage of kelp carbon, and trophic position varied between the two regions, indicating that potential effects of kelp forest size on trophic ontogeny may also affect individual performance. Our results provide evidence that the indirect effects of otters on rockfishes arise largely through the creation of habitat for fishes and other prey rather than a direct trophic connection through invertebrates or other consumers of kelp productivity

Data from: Oceanographic drivers of offspring abundance may increase or decrease variance in reproductive success in a temperate marine fish

In species that reproduce into uncertain environments, the relationship between mean reproductive success (the abundance of new recruits) and the variance in reproductive success (whether adults contribute disproportionally more offspring) may not be straightforward because of stochastic environmental processes that create high variance in reproductive success among adults. In this study we investigated the relationships between oceanography, reproductive success, and reproductive variance in the black rockfish, Sebastes melanops, a long-lived temperate reef fish with pelagic larvae. We quantified black rockfish recruitment, genetic diversity, and growth rates from otolith microstructure over 5 years (2005-2009) during which oceanographic conditions differed. We used cross-correlations to determine windows of time during which oceanographic variables were significantly correlated with the resulting abundance or genetic diversity of recruits. We found that warmer ocean temperatures were positively correlated with the abundance of recruits, as well as the effective number of breeders. In contrast, the strength of coastal upwelling during settlement was positively correlated with the annual abundance of new recruits, but was negatively correlated with the effective number of breeders. Larval growth rates were explained substantially more by temperature than by upwelling, and suggested that temperature affected survival through growth, while upwelling affected survival through transport. Our results indicated that cold ocean temperatures and intense upwelling caused sweepstakes-like processes to operate on black rockfish populations, despite high abundances of recruits. We propose that a decoupling of the mean and variance in reproductive success may be characteristic of organisms that reproduce into uncertain environments

Data_Recruits.Genotypes.ByYear

Microsatellite genotypes of Sebastes melanops recruits collected from Barkley Sound, British Columbia in GENEPOP format

Appendix B. ANOVA tables for factors affecting juvenile rockfish growth.

ANOVA tables for factors affecting juvenile rockfish growth