SEARCH · Search USGS

Results for “Epidemics”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

USGS2019

Multi‐scale habitat selection of elk in response to beetle‐killed forest

Forests of the Rocky Mountains (USA and Canada) have experienced a large‐scale bark‐beetle ( Dendoctronus ponderosae ) epidemic that has led to widespread mortality of pine trees, followed by structural and compositional changes to the forest. The millions of dead trees resulting from this event likely have an effect on ecosystem processes, but currently those effects are mostly unclear. Changes to forest canopy and understory structure are likely to affect behavior and space use of large ungulates as forage abundance, thermal cover, and locomotive costs are presumably altered. We developed and tested hypotheses for how resource selection in summer of female elk ( Cervus canadensis ; n = 47; 2012–2016), the primary large mammal in our study area, was influenced by changes in canopy, understory vegetation, and downed logs in bark‐beetle affected forest in south‐central Wyoming, USA. We employed global positioning system (GPS) technology, an imagery‐derived land cover classification specifically depicting beetle‐affected forest, and on‐the‐ground forest measurements to develop resource and step selection functions. At the study area scale, elk avoided beetle‐killed forest during nearly all parts of the day and selected for intact conifer forest during the day. At the micro‐habitat scale, as canopy cover decreased in beetle‐killed areas, there was a concomitant increase in grass biomass and downed logs. Nevertheless, while in the forest, elk did not alter resource selection relative to changes in understory vegetation or downed logs. The boost in forage abundance within beetle‐killed areas was insufficient to overcome the presumed increases in energy expenditures associated with locomotion and thermoregulation in beetle‐killed forests. The bark‐beetle epidemic has altered how elk use the landscape and has resulted in a potential loss of forest habitat that elk use during the day. Our results indicate that habitat treatments (i.e., fire or harvest) that remove standing dead trees and downed logs in beetle‐killed forest would further facilitate understory growth while reducing the locomotion costs associated with foraging in beetle‐killed forest.

Wyoming, Colorado↗

USGS2021

Transient disease dynamics across ecological scales

Analyses of transient dynamics are critical to understanding infectious disease transmission and persistence. Identifying and predicting transients across scales, from within-host to community-level patterns, plays an important role in combating ongoing epidemics and mitigating the risk of future outbreaks. Moreover, greater emphases on non-asymptotic processes will enable timely evaluations of wildlife and human diseases and lead to improved surveillance efforts, preventive responses, and intervention strategies. Here, we explore the contributions of transient analyses in recent models spanning the fields of epidemiology, movement ecology, and parasitology. In addition to their roles in predicting epidemic patterns and endemic outbreaks, we explore transients in the contexts of pathogen transmission, resistance, and avoidance at various scales of the ecological hierarchy. Examples illustrate how (i) transient movement dynamics at the individual host level can modify opportunities for transmission events over time; (ii) within-host energetic processes often lead to transient dynamics in immunity, pathogen load, and transmission potential; (iii) transient connectivity between discrete populations in response to environmental factors and outbreak dynamics can affect disease spread across spatial networks; and (iv) increasing species richness in a community can provide transient protection to individuals against infection. Ultimately, we suggest that transient analyses offer deeper insights and raise new, interdisciplinary questions for disease research, consequently broadening the applications of dynamical models for outbreak preparedness and management.

Theoretical Ecology↗

USGS2011

Responses of soil and water chemistry to mountain pine beetle induced tree mortality in Grand County, Colorado, USA

Pine forest in northern Colorado and southern Wyoming, USA, are experiencing the most severe mountain pine beetle epidemic in recorded history, and possible degradation of drinking-water quality is a major concern. The objective of this study was to investigate possible changes in soil and water chemistry in Grand County, Colorado in response to the epidemic, and to identify major controlling influences on stream-water nutrients and C in areas affected by the mountain pine beetle. Soil moisture and soil N increased in soils beneath trees killed by the mountain pine beetle, reflecting reduced evapotranspiration and litter accumulation and decay. No significant changes in stream-water NO 3 - "> NO 3 - or dissolved organic C were observed; however, total N and total P increased, possibly due to litter breakdown or increased productivity related to warming air temperatures. Multiple-regression analyses indicated that % of basin affected by mountain pine beetles had minimal influence on stream-water NO 3 - "> NO 3 - and dissolved organic C; instead, other basin characteristics, such as percent of the basin classified as forest, were much more important.

Colorado↗

USGS2008

Mineralogical and compositional characteristics of Late Permian coals from an area of high lung cancer rate in Xuan Wei, Yunnan, China: Occurrence and origin of quartz and chamosite

Some townships in Xuan Wei County, Yunnan Province, have one of the highest lung cancer mortality rates in China and the epidemic disease in the area has generally been attributed to the polycyclic aromatic hydrocarbons (PAHs) released from domestic coal burning. However, the cancer-causing culprit is not settled as Tian [Tian, L., 2005. Coal Combustion Emissions and Lung Cancer in Xuan Wei, China. Ph.D. thesis, University of California, Berkeley.] found nanometer quartz in these coals, soot emissions, and lung cancer tissues. We have conducted mineralogical and geochemical studies of the coals from Xuan Wei for the purpose of shedding light on the minerals which may be related to the epidemic lung cancer. In this paper, abundances, modes of occurrence, and origins of minerals and elements in the coals from two mines in Xuan Wei have been studied using optical microscope, low-temperature ashing, X-ray diffraction analysis, scanning electron microscope equipped with energy-dispersive X-ray spectrometer, and inductively-coupled plasma mass spectrometry. The minerals in the coals are mainly composed of quartz, chamosite, kaolinite, and calcite. The particle size of quartz is rather small, mostly less than 20????m and it is of authigenic origin. Chamosite occurs mainly as cell-fillings. The occurrence of quartz and chamosite indicates that they were derived from the hydrothermal fluids. Epigenetic calcite is derived from calcic fluids. Kaolinite is derived mainly from sediment source region of Kangdian Oldland to the west of coal basin. The composition of Xuan Wei coal is high in SiO2, Fe2O3, TiO2, CaO, MnO, V, Co, Ni, Cu, and Zn. The high SiO2 content is attributed to quartz, and the Fe2O3 content to chamosite. The high Mn and low Mg contents in the coal indicate the inputs of hydrothermal fluids. CaO occurs mainly in epigenetic calcite. Elements Ti, Co, Ni, Cu, Zn, and rare earth elements were derived from the basaltic rocks at sediment source region. ?? 2008 Elsevier B.V. All rights reserved.

International Journal of Coal Geology↗

USGS2014

Mountain pine beetle-caused mortality over eight years in two pine hosts in mixed conifer stands of the southern Rocky Mountains

Eruptive mountain pine beetle ( Dendroctonus ponderosae , MPB) populations have caused widespread mortality of pines throughout western North America since the late 1990s. Early work by A.D. Hopkins suggested that when alternate host species are available, MPB will prefer to breed in the host to which it has become adapted. In Colorado, epidemic MPB populations that originated in lodgepole pine expanded into mixed-conifer stands containing ponderosa pine, a related host. We evaluated the susceptibility of both hosts to successful MPB colonization in a survey of 19 sites in pine-dominated mixed-conifer stands spanning 140 km of the Front Range, CO, USA. In each of three 0.2-ha plots at each site, we (1) assessed trees in the annual flights of 2008–2011 to compare MPB-caused mortality between lodgepole and ponderosa pine; (2) recorded previous MPB-caused tree mortality from 2004–2007 to establish baseline mortality levels; and (3) measured characteristics of the stands (e.g. tree basal area) and sites (e.g. elevation, aspect) that might be correlated with MPB colonization. Uninfested average live basal area of lodgepole and ponderosa pine was 74% of total basal area before 2004. We found that for both species, annual percent basal area of attacked trees was greatest in one year (2009), and was lower in all other years (2004–2007, 2008, 2010, and 2011). Both pine species had similar average total mortality of 38–39% by 2011. Significant predictors of ponderosa pine mortality in a given year were basal area of uninfested ponderosa pine and the previous year’s mortality levels in both ponderosa and lodgepole pine. Lodgepole pine mortality was predicted by uninfested basal areas of both lodgepole and ponderosa pine, and the previous year’s lodgepole pine mortality. These results indicate host selection by MPB from lodgepole pine natal hosts into ponderosa pine the following year, but not the reverse. In both species, diameters of attacked trees within each year were similar, and were progressively smaller the last four years of the study period. Our results suggest that, in contrast to previous reports, ponderosa and lodgepole pine were equally susceptible to MPB infestation in the CO Front Range during our study period. This suggests that forest managers may anticipate similar impacts in both hosts during similar environmental conditions when epidemic-level MPB populations are active in mixed-pine stands.

Colorado↗

USGS2023

A meta-analysis of the stony coral tissue loss disease microbiome finds key bacteria in unaffected and lesion tissue in diseased colonies

Stony coral tissue loss disease (SCTLD) has been causing significant whole colony mortality on reefs in Florida and the Caribbean. The cause of SCTLD remains unknown, with the limited concurrence of SCTLD-associated bacteria among studies. We conducted a meta-analysis of 16S ribosomal RNA gene datasets generated by 16 field and laboratory SCTLD studies to find consistent bacteria associated with SCTLD across disease zones (vulnerable, endemic, and epidemic), coral species, coral compartments (mucus, tissue, and skeleton), and colony health states (apparently healthy colony tissue (AH), and unaffected (DU) and lesion (DL) tissue from diseased colonies). We also evaluated bacteria in seawater and sediment, which may be sources of SCTLD transmission. Although AH colonies in endemic and epidemic zones harbor bacteria associated with SCTLD lesions, and aquaria and field samples had distinct microbial compositions, there were still clear differences in the microbial composition among AH, DU, and DL in the combined dataset. Alpha-diversity between AH and DL was not different; however, DU showed increased alpha-diversity compared to AH, indicating that, prior to lesion formation, corals may undergo a disturbance to the microbiome. This disturbance may be driven by Flavobacteriales, which were especially enriched in DU. In DL, Rhodobacterales and Peptostreptococcales–Tissierellales were prominent in structuring microbial interactions. We also predict an enrichment of an alpha-toxin in DL samples which is typically found in Clostridia. We provide a consensus of SCTLD-associated bacteria prior to and during lesion formation and identify how these taxa vary across studies, coral species, coral compartments, seawater, and sediment.

ISME Communications↗

USGS2022

Epidemiological differences between sexes affect management efficacy in simulated chronic wasting disease systems

Sex-based differences in physiology, behaviour and demography commonly result in differences in disease prevalence. However, sex differences in prevalence may reflect exposure rather than transmission, which could affect disease control programmes. One potential example is chronic wasting disease (CWD), which has been observed at greater prevalence among male than female deer. We used an age- and sex-structured simulation model to explore harvest-based management of CWD under three different transmission scenarios that all generate higher male prevalence: (1) increased male susceptibility, (2) high male-to-male transmission or (3) high female-to-male transmission. Both female and male harvests were required to limit CWD epidemics across all transmission scenarios (approximated by R 0 ), though invasion was more likely under high female-to-male transmission. In simulations, heavily male-biased harvests controlled CWD epidemics and maintained large host populations under high male-to-male transmission and increased male susceptibility scenarios. However, male-biased harvests were ineffective under high female-to-male transmission. Instead, female-biased harvests were able to limit disease transmission under high female-to-male transmission but incurred a trade-off with smaller population sizes. Synthesis and applications . Higher disease prevalence in a sex or age group may be due to higher exposure or susceptibility but does not necessarily indicate if that group is responsible for more disease transmission. We showed that multiple processes can result in the pattern of higher male prevalence, but that population-level management interventions must focus on the sex responsible for disease transmission, not just those that are most exposed.

Journal of Applied Ecology↗

USGS2022

Early treatment of white-nose syndrome is necessary to stop population decline

Since its introduction to North America, white-nose syndrome has been associated with declines greater than 90% in several bat species, prompting the development of treatments to reduce disease-related mortality. As treatment application is scaled up, predicting responses at the population level will help in the development of management plans. We develop a model allowing for the implementation of multiple treatment scenarios in bat populations at risk of severe mortality from white-nose syndrome. Our model allows for variation in over 10 parameters, including effectiveness of treatment, treatment-related disturbance, number of individuals treated, number of hibernacula treated, herd immunity and movement among hibernacula. Additionally, the model allows treatments to be applied to individuals, the hibernaculum or a combination of the two. We simulated treatments for populations of 1000, 10,000 and 100,000 individuals, with the distribution of individuals within hibernacula based on field surveys of Myotis lucifugus . When treatments are applied to individuals, we found that treatment success was most influenced by the number of bats effectively treated, the magnitude of disturbance and the year of first treatment relative to initial mortality. For treatments applied to hibernacula, we found year of first treatment relative to initial mortality, magnitude of disturbance and effectiveness of treatment to be the best predictors of success. Treatments have the potential to mitigate white-nose syndrome-related mortality, but application of treatments after initial mass mortality seems to be of limited benefit. Unknowns surrounding influential treatment parameters, such as disturbance to hibernating bats, created substantial variation across outcomes and highlight the importance of obtaining field estimates of parameters associated with treatments. Synthesis and applications : While treatment applications can increase survival from white-nose syndrome, their potential is strongly diminished when not applied before or during the early epidemic stages. Once the disease is established, increasing survival and reproduction through methods other than disease treatments could be a better option. In the United States, most areas yet to reach the late epidemic or established stage are in the west where bats do not aggregate in large colonies and treating a substantial number of individuals will be difficult.

Journal of Applied Ecology↗

USGS2024

Matching decision support modeling frameworks to disease emergence stages and associated management objectives

Wildlife disease management decisions often require rapid responses to situations that are fraught with uncertainty. By recognizing that management is implemented to achieve specific objectives, resource managers and science partners can identify an analysis technique and develop a monitoring plan to evaluate management effectiveness. For emerging infectious diseases, objectives may take several distinct forms, dependent on the perceived stage of disease emergence (i.e., pre-epidemic, early outbreak, mid-epidemic, and endemic), the expected rate of spread, and the anticipated effect of the disease on host populations. Identifying modeling techniques and metrics that are linked to management objectives will require early and consistent communication between managers and science partners. We link modeling approaches that can be used to forecast and evaluate the performance of intervention strategies with a range of disease management objectives. Our aim is to help scientists recognize alternative modeling approaches which may better align with different forms of disease management objectives, and to help managers evaluate the relevance of proposed modeling approaches to their specified objectives for disease management. Recognizing that disease management objectives can take different forms, and thus require different modeling approaches, can help wildlife disease response teams (i.e., natural resource managers, scientists, and stakeholders working collaboratively) better prepare and respond to disease threats.

Conservation Science and Practice↗

USGS2017

Inferring infection hazard in wildlife populations by linking data across individual and population scales

Our ability to infer unobservable disease-dynamic processes such as force of infection (infection hazard for susceptible hosts) has transformed our understanding of disease transmission mechanisms and capacity to predict disease dynamics. Conventional methods for inferring FOI estimate a time-averaged value and are based on population-level processes. Because many pathogens exhibit epidemic cycling and FOI is the result of processes acting across the scales of individuals and populations, a flexible framework that extends to epidemic dynamics and links within-host processes to FOI is needed. Specifically, within-host antibody kinetics in wildlife hosts can be short-lived and produce patterns that are repeatable across individuals, suggesting individual-level antibody concentrations could be used to infer time since infection and hence FOI. Using simulations and case studies (influenza A in lesser snow geese and Yersinia pestis in coyotes), we argue that with careful experimental and surveillance design, the population-level FOI signal can be recovered from individual-level antibody kinetics, despite substantial individual-level variation. In addition to improving inference, the cross-scale quantitative antibody approach we describe can reveal insights into drivers of individual-based variation in disease response, and the role of poorly understood processes such as secondary infections, in population-level dynamics of disease.

Ecology Letters↗

USGS2018

Optimal treatment allocations in space and time for online control of anemerging infectious disease

A key component in controlling the spread of an epidemic is deciding where, when and to whom to apply an intervention. We develop a framework for using data to inform these decisions in realtime. We formalize a treatment allocation strategy as a sequence of functions, one per treatment period, that map up‐to‐date information on the spread of an infectious disease to a subset of locations where treatment should be allocated. An optimal allocation strategy optimizes some cumulative outcome, e.g. the number of uninfected locations, the geographic footprint of the disease or the cost of the epidemic. Estimation of an optimal allocation strategy for an emerging infectious disease is challenging because spatial proximity induces interference between locations, the number of possible allocations is exponential in the number of locations, and because disease dynamics and intervention effectiveness are unknown at outbreak. We derive a Bayesian on‐line estimator of the optimal allocation strategy that combines simulation–optimization with Thompson sampling. The estimator proposed performs favourably in simulation experiments. This work is motivated by and illustrated using data on the spread of white nose syndrome, which is a highly fatal infectious disease devastating bat populations in North America.

Journal of the Royal Statistical Society. Series C↗

USGS2020

Threats posed by the Fungal Kingdom to humans, wildlife, and agriculture

The Fungal Kingdom includes at least six million eukaryotic species and is remarkable with respect to its profound impact on global health, biodiversity, ecology, agriculture, manufacturing, and biomedical research. Approximately 625 fungal species have been reported to infect vertebrates, 200 of which can be human-associated, either as commensals and members of our microbiome or as pathogens that cause infectious diseases. These organisms pose a growing threat to human health with the global increase in the incidence of invasive fungal infections, prevalence of fungal allergy, and the evolution of fungal pathogens resistant to some or all current classes of antifungals. More broadly, there has been an unprecedented and worldwide emergence of fungal pathogens impacting animal and plant biodiversity. Approximately 8,000 species of fungi and Oomycetes are associated with plant disease. Indeed, across agriculture, such fungal diseases of plants include new devastating epidemics of trees and jeopardize food security worldwide by causing epidemics in staple and commodity crops that feed billions. Further, ingestion of mycotoxins contributes to ill health and causes cancer. Coordinated international research efforts, enhanced technology translation, and greater policy outreach by scientists are needed to more fully understand the biology and drivers that underlie the emergence of fungal diseases and to mitigate against their impacts. Here, we focus on poignant examples of emerging fungal threats in each of three areas: human health, wildlife biodiversity, and food security.

mBio↗

USGS2007

Genetic diversity of infectious hematopoietic necrosis virus from Feather River and Lake Oroville, California, and virulence of selected isolates for Chinook salmon and rainbow trout

Infectious hematopoietic necrosis virus (IHNV) is a significant pathogen of young salmonid fishes worldwide but particularly within the historical range of the Pacific Northwest and California. In the Sacramento and San Joaquin River drainages of California, IHNV outbreaks in juvenile Chinook salmon Oncorhynchus tshawytscha have been observed regularly at large production hatcheries, including Coleman National Fish Hatchery (established in 1941) and Feather River State Fish Hatchery (FRH; established in 1967), since facility operations began. Recent severe epidemics at the FRH in 1998 and 2000-2002 prompted investigations into the characteristics and potential sources of virus at this facility. Both phylogenetic analyses of a variable portion of the glycoprotein gene and serologic comparisons based on neutralization with three polyclonal rabbit sera were used to characterize 82 IHNV isolates from the Feather River watershed between 1969 and 2004. All isolates examined were in the L genogroup and belonged to one of three serologic groups typical of IHNV from California. The IHNV isolates from the Feather River area demonstrated a maximum nucleotide sequence divergence of 4.0%, and new isolates appeared to emerge from previous isolates rather than by the introduction of more diverse subgroups from exogenous sources. The earliest isolates examined from the watershed formed the subgroup LI, which disappeared coincidently with a temporal shift to new genetic and serologic types of the larger subgroup LII. Experimental challenges demonstrated no significant differences in the virulence for juvenile Chinook salmon and rainbow trout O. mykiss from selected isolates representing the principal types of IHNV found historically and from recent epidemics at FRH. While most isolates were equally virulent for both host species, one isolate was found to be more virulent for Chinook salmon than for rainbow trout. ?? Copyright by the American Fisheries Society 2007.

Journal of Aquatic Animal Health↗

USGS2020

Operational earthquake forecasting during the 2019 Ridgecrest, California, earthquake sequence with the UCERF3-ETAS model

The first Uniform California Earthquake Rupture Forecast, Version 3–epidemic‐type aftershock sequence (UCERF3‐ETAS) aftershock simulations were running on a high‐performance computing cluster within 33 min of the 4 July 2019 M 6.4 Searles Valley earthquake. UCERF3‐ETAS, an extension of the third Uniform California Earthquake Rupture Forecast (UCERF3), is the first comprehensive, fault‐based, epidemic‐type aftershock sequence (ETAS) model. It produces ensembles of synthetic aftershock sequences both on and off explicitly modeled UCERF3 faults to answer a key question repeatedly asked during the Ridgecrest sequence: What are the chances that the earthquake that just occurred will turn out to be the foreshock of an even bigger event?

California↗

USGS1988

Ducks Get Sick Too!

When it comes to getting sick, wild waterfowl—which include ducks, geese, and swans—are a lot like people. We are all vulnerable to a wide variety of diseases. Some diseases that affect waterfowl, such as avian botulism, have been recognized for many decades as a major cause of death. Others, such as duck plague, are relative newcomers to the known roster of waterfowl diseases. Unfortunately, the number of waterfowl diseases as well as disease-breeding conditions are on the increase. As human development has expanded and encroached on wetlands, more and more waterfowl have been forced into less and less habitat. The resulting crowding can promote the spread of infectious disease caused by toxicants and other noninfectious agents. Although millions of waterfowl die of disease each year, it is often difficult to "see" the disease process occurring. Sick and dying birds usually seek cover to hide, and predators and scavengers eventually devour most of them. When disease becomes epidemic (a disease epidemic in animals is called an epizootic) and sick and dead birds become too numerous for predators and scavengers to eliminate, the disease process becomes far more noticeable. The diseases described in this booklet are among the most common causes of death in wild waterfowl, and include examples of those cause by bacteria, viruses, parasites, fungi, and toxic substances.

Report↗

USGS1906

Quality of water in the upper Ohio River basin and at Erie, Pennsylvania

This paper discusses the quality of water on the most important tributaries of Ohio River in Pennsylvania, New York, West Virginia, and Maryland, and the nature of the water supply at Erie, Pa. The amount and character of the pollution is described and the results of drinking contaminated water as shown by typhoid statistics are indicated. The conditions on the tributaries of Ohio River in Ohio are discussed in Water-Supply and Irrigation Paper No. 79, United States Geological Survey, pages 129-187. The water supplies and sewerage of small towns high up toward the head of a large drainage system do not in many cases receive the attention they should. Epidemics of a waterborne disease which affect large municipalities near the mouth of the river and therefore attract attention must necessarily have their origin in the pollution of the watershed above. It is evident, therefore, that adequate sanitation of the small towns and a water supply as carefully guarded as that of a large city would prevent disease at its very source and be far less expensive than the costly battles which are waged against epidemics in huge centers of population after disease has broken out. Typhoid fever statistics for small towns in this section are seldom available and are more or less unreliable at best. The few figures given show the existence of virulent typhoid fever in most towns of the drainage areas in certain years, and as these towns drain into the streams the liability ofthe water to infection is evident. The significance of typhoid fever death rates will be better understood from the statistics presented below, which have been collated from a number of cities having excellent water supplies.

Water Supply Paper↗

USGS2013

Emergence of MD type infectious hematopoietic necrosis virus in Washington State coastal steelhead trout

Infectious hematopoietic necrosis virus (IHNV) occurs in North America as 3 major phylogenetic groups designated U, M, and L. In coastal Washington State, IHNV has historically consisted of U genogroup viruses found predominantly in sockeye salmon Oncorhynchus nerka . M genogroup IHNV, which has host-specific virulence for rainbow and steelhead trout O. mykiss , was detected only once in coastal Washington prior to 2007, in an epidemic among juvenile steelhead trout in 1997. Beginning in 2007 and continuing through 2011, there were 8 IHNV epidemics in juvenile steelhead trout, involving 7 different fish culture facilities in 4 separate watersheds. During the same time period, IHNV was also detected in asymptomatic adult steelhead trout from 6 coastal watersheds. Genetic typing of 283 recent virus isolates from coastal Washington revealed that the great majority were in the M genogroup of IHNV and that there were 2 distinct waves of viral emergence between the years 2007 and 2011. IHNV type mG110M was dominant in coastal steelhead trout during 2007 to 2009, and type mG139M was dominant between 2010 and 2011. Phylogenetic analysis of viral isolates indicated that all coastal M genogroup viruses detected in 1997 and 2007 to 2011 were part of the MD subgroup and that several novel genetic variants related to the dominant types arose in the coastal sites. Comparison of spatial and temporal incidence of coastal MD viruses with that of the rest of the Pacific Northwest indicated that the likely source of the emergent viruses was Columbia River Basin steelhead trout.

Washington↗

USGS2009

Rise and fall over 26 years of a marine epizootic in Hawaiian green sea turtles

Estimates of chronic disease prevalence are needed to improve our understanding of marine disease epizootiology, which is poorly known for marine megafauna such as marine turtles. An emerging worldwide threat to green sea turtles ( Chelonia mydas ) is fibropapillomatosis (FP), which is a pandemic tumor-forming disease associated with herpesviruses. We report on a 26-yr FP epidemic in the Hawaiian Archipelago and show that apparent disease prevalence in the world's main endemic hot spot increased rapidly following a late 1980s outbreak, peaked during the mid-1990s, and then declined steadily ever since. While this disease is a major cause of sea turtle stranding in Hawaiian waters and can be fatal, we also show that long-term tumor regression can occur even for turtles with advanced FP. The endemic Hawaiian green turtle stock was severely depleted by overexploitation prior to protection under the US Endangered Species Act in 1978. This stock has increased significantly ever since, despite exposure to a major chronic disease epidemic that is currently declining.

Journal of Wildlife Diseases↗