Continental-scale dynamics of avian influenza in U.S. waterfowl are driven by demography, migration, and temperature.

Emerging diseases of wildlife origin are increasingly spilling over into humans and domestic animals. Surveillance and risk assessments for transmission between these populations are informed by a mechanistic understanding of the pathogens in wildlife reservoirs. For avian influenza viruses (AIV), much observational and experimental work in wildlife has been conducted at local scales, yet fully understanding their spread and distribution requires assessing the mechanisms acting at both local, (e.g., intrinsic epidemic dynamics), and continental scales, (e.g., long-distance migration). Here, we combined a large, continental-scale data set on low pathogenic, Type A AIV in the United States with a novel network-based application of bird banding/recovery data to investigate the migration-based drivers of AIV and their relative importance compared to well-characterized local drivers (e.g., demography, environmental persistence). We compared among regression models reflecting hypothesized ecological processes and evaluated their ability to predict AIV in space and time using within and out-of-sample validation. We found that predictors of AIV were associated with multiple mechanisms at local and continental scales. Hypotheses characterizing local epidemic dynamics were strongly supported, with age, the age-specific aggregation of migratory birds in an area and temperature being the best predictors of infection. Hypotheses defining larger, network-based features of the migration processes, such as clustering or between-cluster mixing explained less variation but were also supported. Therefore, our results support a role for local processes in driving the continental distribution of AIV.

Impact of body condition on influenza A virus infection dynamics in mallards following a secondary exposure.

Migratory waterfowl are often viewed as vehicles for the global spread of influenza A viruses (IAVs), with mallards (Anas platyrhynchos) implicated as particularly important reservoir hosts. The physical demands and energetic costs of migration have been shown to influence birds' body condition; poorer body condition may suppress immune function and affect the course of IAV infection. Our study evaluated the impact of body condition on immune function and viral shedding dynamics in mallards naturally exposed to an H9 IAV, and then secondarily exposed to an H4N6 IAV. Mallards were divided into three treatment groups of 10 birds per group, with each bird's body condition manipulated as a function of body weight by restricting food availability to achieve either a -10%, -20%, or control body weight class. We found that mallards exhibit moderate heterosubtypic immunity against an H4N6 IAV infection after an infection from an H9 IAV, and that body condition did not have an impact on shedding dynamics in response to a secondary exposure. Furthermore, body condition did not affect aspects of the innate and adaptive immune system, including the acute phase protein haptoglobin, heterophil/lymphocyte ratios, and antibody production. Contrary to recently proposed hypotheses and some experimental evidence, our data do not support relationships between body condition, infection and immunocompetence following a second exposure to IAV in mallards. Consequently, while annual migration may be a driver in the maintenance and spread of IAVs, the energetic demands of migration may not affect susceptibility in mallards.

Reserve networks based on richness hotspots and representation vary with scale.

While the importance of spatial scale in ecology is well established, few studies have investigated the impact of data grain on conservation planning outcomes. In this study, we compared species richness hotspot and representation networks developed at five grain sizes. We used species distribution maps for mammals and birds developed by the Arizona and New Mexico Gap Analysis Programs (GAP) to produce 1-km2, 100-kmn2, 625-km2, 2500-km2, and 10,000-km2 grid cell resolution distribution maps. We used these distribution maps to generate species richness and hotspot (95th quantile) maps for each taxon in each state. Species composition information at each grain size was used to develop two types of representation networks using the reserve selection software MARXAN. Reserve selection analyses were restricted to Arizona birds due to considerable computation requirements. We used MARXAN to create best reserve networks based on the minimum area required to represent each species at least once and equal area networks based on irreplaceability values. We also measured the median area of each species' distribution included in hotspot (mammals and birds of Arizona and New Mexico) and irreplaceability (Arizona birds) networks across all species. Mean area overlap between richness hotspot reserves identified at the five grain sizes was 29% (grand mean for four within-taxon/state comparisons), mean overlap for irreplaceability reserve networks was 32%, and mean overlap for best reserve networks was 53%. Hotspots for mammals and birds showed low overlap with a mean of 30%. Comparison of hotspots and irreplaceability networks showed very low overlap with a mean of 13%. For hotspots, median species distribution area protected within reserves declined monotonically from a high of 11% for 1-km2 networks down to 6% for 10,000-km2 networks. Irreplaceability networks showed a similar, but more variable, pattern of decline. This work clearly shows that map resolution has a profound effect on conservation planning outcomes and that hotspot and representation outcomes may be strikingly dissimilar. Thus, conservation planning is scale dependent, such that reserves developed using coarse-grained data do not subsume fine-grained reserves. Moreover, preserving both full species representation and species rich areas may require combined reserve design strategies.

Genetic relatedness of deer mice (Peromyscus maniculatus) infected with Sin Nombre virus.

The deer mouse (Peromyscus maniculatus) is the primary rodent host of Sin Nombre virus (SNV), the principal etiologic agent of hantavirus pulmonary syndrome in the United States. Many characteristics of SNV infections of deer mice are unknown. To better understand the transmission mechanisms of SNV in deer mice, we conducted mark-recapture sampling and genetic analyses to study deer mouse population density and genetic relatedness from 2001 to 2002. We genotyped each deer mouse at 10 microsatellite loci to estimate relatedness among SNV-infected and SNV-uninfected groups, demographic categories, and individuals. Estimates of average overall population densities ranged from 1.15 to 14.95 deer mice/ha. Estimates of average population densities of SNV-infected deer mice ranged from 0 to 1.55 deer mice/ha. When evaluated as groups at one of two study sites, SNV-infected deer mice were more related to one another, on average, than they were to their uninfected cohorts. Pairwise coefficients of relatedness among individuals indicated that several deer mice infected with SNV were closely related. Most infected mice were males. These results are consistent with the hypothesis that transmission of SNV often is associated with breeding activities and aggression among males during the breeding season and suggest that post-birth behavioral associations among adults and juveniles may be a factor in the transmission of SNV.

Analyses of gene flow among populations of deer mice (Peromyscus maniculatus) at sites near hantavirus pulmonary syndrome case-patient residences.

Gene flow and potential for Sin Nombre virus (SNV) trafficking of the deer mouse (Peromyscus maniculatus) was studied in Delta and Mesa counties of western Colorado (USA). The study areas included Grand Mesa and surrounding grazing and agricultural areas. This area has several natural potential barriers to rodent gene flow, including rivers, cliffs, and mountains. Ten study sites were utilized in a spatially nested design ranging from 0.65-81 km apart; four of these sites were at or near human hantavirus pulmonary syndrome (HPS) case-patient residences. One HPS case occurred on the north side of Grand Mesa in 1993; the other three (two confirmed, one presumptive) occurred on the south side of Grand Mesa between 1999-2000. Blood and tissue samples were collected from each of 221 deer mice captured from 1999-2000. Blood samples were tested for IgG antibody to SNV. At least one deer mouse had antibody to SNV at nine of 10 sites. Genomic DNA was isolated from tissue samples and alleles at six microsatellite loci were amplified by polymerase chain reaction (PCR). Polymorphisms were resolved on denaturing polyacrylamide gels and visualized by silver staining. Traditional population genetic analyses of this study indicated moderate population subdivision among the populations surveyed, slight evidence of isolation by distance, and that the Gunnison River system may hinder gene flow in this area. Application of assignment tests indicated that approximately 73-85% of mice were assigned to their population of capture. Many of the misclassifications occurred among sites less than 1 km apart; however, some long-distance misclassifications were noted. Additionally, some misclassifications were noted among study sites on different sides of the Gunnison River system, indicating that the riparian corridor of this system may facilitate some gene flow. Overall, these data indicate that SNV trafficking is more likely at the local level, but some long-distance trafficking may be possible, especially where select habitat variables favor long-distance movements.

Stochasticity in natural forage production affects use of urban areas by black bears: implications to management of human-bear conflicts.

The rapid expansion of global urban development is increasing opportunities for wildlife to forage and become dependent on anthropogenic resources. Wildlife using urban areas are often perceived dichotomously as urban or not, with some individuals removed in the belief that dependency on anthropogenic resources is irreversible and can lead to increased human-wildlife conflict. For American black bears (Ursus americanus), little is known about the degree of bear urbanization and its ecological mechanisms to guide the management of human-bear conflicts. Using 6 years of GPS location and activity data from bears in Aspen, Colorado, USA, we evaluated the degree of bear urbanization and the factors that best explained its variations. We estimated space use, activity patterns, survival, and reproduction and modeled their relationship with ecological covariates related to bear characteristics and natural food availability. Space use and activity patterns were dependent on natural food availability (good or poor food years), where bears used higher human density areas and became more nocturnal in poor food years. Patterns were reversible, i.e., individuals using urban areas in poor food years used wildland areas in subsequent good food years. While reproductive output was similar across years, survival was lower in poor food years when bears used urban areas to a greater extent. Our findings suggest that bear use of urban areas is reversible and fluctuates with the availability of natural food resources, and that removal of urban individuals in times of food failures has the potential to negatively affect bear populations. Given that under current predictions urbanization is expected to increase by 11% across American black bear range, and that natural food failure years are expected to increase in frequency with global climate change, alternative methods of reducing urban human-bear conflict are required if the goal is to prevent urban areas from becoming population sinks.

The carrot or the stick? Evaluation of education and enforcement as management tools for human-wildlife conflicts.

Evidence-based decision-making is critical for implementing conservation actions, especially for human-wildlife conflicts, which have been increasing worldwide. Conservation practitioners recognize that long-term solutions should include altering human behaviors, and public education and enforcement of wildlife-related laws are two management actions frequently implemented, but with little empirical evidence evaluating their success. We used a system where human-black bear conflicts were common, to experimentally test the efficacy of education and enforcement in altering human behavior to better secure attractants (garbage) from bears. We conducted 3 experiments in Aspen CO, USA to evaluate: 1) on-site education in communal dwellings and construction sites, 2) Bear Aware educational campaign in residential neighborhoods, and 3) elevated law enforcement at two levels in the core business area of Aspen. We measured human behaviors as the response including: violation of local wildlife ordinances, garbage availability to bears, and change in use of bear-resistance refuse containers. As implemented, we found little support for education, or enforcement in the form of daily patrolling in changing human behavior, but found more support for proactive enforcement, i.e., dispensing warning notices. More broadly we demonstrated the value of gathering evidence before and after implementing conservation actions, and the dangers of measuring responses in the absence of ecological knowledge. We recommend development of more effective educational methods, application of proactive enforcement, and continued evaluation of tools by directly measuring change in human behavior. We provide empirical evidence adding to the conservation managers' toolbox, informing policy makers, and promoting solutions to human-wildlife conflicts.

Communicating breast cancer risk: patient perceptions of provider discussions.

This study investigated the relationship between breast cancer risk communication delivered by providers and patient knowledge, perceptions, and screening practices. Telephone interviews were conducted with 141 African American (n = 71) and white (n = 70) first-degree relatives of breast cancer patients who received medical services at 2 university medical centers in North Carolina during 1994-95. Multiple items assessed subjects' reports of discussions with providers about family history and personal risk, knowledge of breast cancer risk factors, risk perceptions, breast cancer concerns, and screening practices. African American (AA) women were less likely than white women to report being informed of their increased personal risk of breast cancer because of family history. After controlling for education level, AA women aged > or = 50 years were less likely than white women to have ever had a mammogram. Both AA and white women who discussed family history and risk with their providers were significantly more likely to have had a mammogram within the past 2 years. Although these discussions seemed to increase participants' perceived risk of developing breast cancer, they did not promote knowledge of risk factors or increase levels of cancer concern. Study results indicate that provider discussions about family history and personal risk, accompanied by increases in risk perception, promote patient compliance with screening goals. Findings suggest that accurate knowledge about specific breast cancer risk factors may not be necessary to achieve screening compliance. However, additional studies are needed to investigate the relationship between knowledge of breast cancer risk factors and the adoption of behaviors associated with reducing breast cancer risk.