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At least 109 records · Page 6Linked to original sources
USGS2025

Exosomal micro RNA isolation in white-tailed deer (Odocoileus virginianus) for diagnostic biomarker discovery

Molecular approaches are becoming more prevalent for the diagnosis of neurodegenerative diseases in human medicine and can be extended to diagnosis of wildlife diseases such as chronic wasting disease and other prion diseases. These diseases have been associated with exosome-bound molecular biomarkers of disease progression, such as proteins and micro RNA molecules (miRNA). We tested and optimized a method for exosomal miRNA isolation from minimally invasive, small-volume serum samples obtained from white-tailed deer ( Odocoileus virginianus ). We confirmed the isolation of exosomes and optimized a commercially available benchtop kit to obtain sufficient and pure RNA for miRNA sequencing. The selected method for RNA extraction combines two 500- m L serum aliquots into one elution column and re-eluting the final product of the column. We identified 137 miRNA present in healthy white-tailed deer that can be used as a baseline to identify putative miRNA biomarkers of disease progression and mechanisms of infection in future comparative disease studies. This approach to biomarker discovery may help to inform biological processes in wildlife populations and provide alternatives to invasive or postmortem samples.

Journal of Wildlife Diseases↗
USGS2016

Concordance in diagnostic testing for respiratory pathogens of bighorn sheep

Reliable diagnostic tests are essential for disease investigation and management. This is particularly true for diseases of free-ranging wildlife where sampling is logistically difficult precluding retesting. Clinical assays for wildlife diseases frequently vary among laboratories because of lack of appropriate standardized commercial kits. Results of diagnostic testing may also be called into question when investigators report different etiologies for disease outbreaks, despite similar clinical and pathologic findings. To evaluate reliability of diagnostic testing for respiratory pathogens of bighorn sheep ( Ovis canadensis ), we conducted a series of ring tests across 6 laboratories routinely involved in detection of Mycoplasma ovipneumoniae , Pasteurellaceae, lktA (the Pasteurellaceae gene encoding leukotoxin), and 3 reference laboratories. Consistency of results for replicate samples within laboratories was high (median agreement = 1.0). Agreement between laboratories was high for polymerase chain reaction (PCR) detection of M. ovipneumoniae and culture isolation of Mannheimia spp. and Bibersteinia trehalosi (median agreement = 0.89–0.95, Kappa = 0.65–0.74), and lower for PCR detection of Mannheimia spp. lktA (median agreement = 0.58, Kappa = 0.12). Most errors on defined status samples were false negatives, suggesting test sensitivity was a greater problem than specificity. However, tests for M. haemolytica and lktA yielded some false positive results. Despite differences in testing protocols, median agreement among laboratories and correct classification of controls for most agents was ≥0.80, meeting or exceeding the standard required by federal proficiency testing programs. This information is valuable for interpreting test results, laboratory quality assessments, and advancing diagnosis of respiratory disease in wild sheep. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Wildlife Society Bulletin↗
USGS1995

Increased avian diseases with habitat change

Changes in disease patterns and trends reflect changing relationships between the affected species (host) and the causes of disease (agent). Host-agent interactions are closely linked to environmental factors that either enhance or reduce the potential for disease to occur. As a result, wildlife disease patterns and trends are, to a substantial extent, indicators of environmental quality and changing host-agent interactions within the environment being evaluated. The types, distribution, and frequency of diseases causing major avian die-offs have changed greatly during the 20th century. Too little is known to assess the changes of most avian diseases that result in chronic attrition rather than major die-offs, or about those that affect reproductive success, reduce body condition, or affect survival in other indirect ways. Nevertheless, the changing patterns and trends in highly visible avian diseases provide notice of problems needing attention. Information on the status of disease in wild birds was obtained from National Wildlife Health Center (NWHC) evaluations of the cause of death for more than 30,000 carcasses from across the United States during the past two decades, reports of avian mortality received from collaborators, the scientific literature, and NWHC field investigations of bird mortality. Comprehensive assessments of causes of wild bird mortality, magnitude of losses, and geographic distribution of specific diseases are not possible from these data, although we can identify general relationships for waterfowl and some other species.

Book chapter↗
USGS2017

The USGS National Wildlife Health Center: Advancing wildlife and ecosystem health

In 1975, the Federal government responded to the need for establishing national expertise in wildlife health by creating the National Wildlife Health Center (NWHC), a facility within the Department of the Interior; the NWHC is the only national center dedicated to wildlife disease detection, control, and prevention. Its mission is to provide national leadership to safeguard wildlife and ecosystem health through active partnerships and exceptional science. Comparisons are often made between the NWHC, which strives to protect the health of our Nation’s wildlife, and the Centers for Disease Control and Prevention (CDC), which strive to protect public health. The NWHC, a science center of the U.S. Geological Survey (USGS) with specialized laboratories, works to safeguard the Nation’s wildlife from diseases by studying the causes and drivers of these threats, and by developing strategies to prevent and manage them. In addition to the main campus, located in Madison, Wisconsin, the NWHC also operates the Honolulu Field Station that addresses wildlife health issues in Hawaii and the Pacific Region.

Fact Sheet↗
USGS2024

Seroprevalence, blood chemistry, and patterns of canine parvovirus, distemper virus, plague, and tularemia in free-ranging coyotes (Canis latrans) in northern New Mexico, USA.

Wildlife diseases have implications for ecology, conservation, human health, and health of domestic animals. They may impact wildlife health and population dynamics. Exposure rates of coyotes ( Canis latrans ) to pathogens such as Yersinia pestis , the cause of plague, may reflect prevalence rates in both rodent prey and human populations. We captured coyotes in north-central New Mexico during 2005–2008 and collected blood samples for serologic surveys. We tested for antibodies against canine distemper virus (CDV, Canine morbillivirus ), canine parvovirus (CPV, Carnivore protoparvovirus ), plague, tularemia ( Francisella tularensis ), and for canine heartworm ( Dirofilaria immitis ) antigen. Serum biochemistry variables that fell outside reference ranges were probably related to capture stress. We detected antibodies to parvovirus in 32/32 samples (100%), and to Y. pestis in 26/31 (84%). More than half 19/32 (59%) had antibodies against CDV, and 5/31 (39%) had antibodies against F. tularensis . We did not detect any heartworm antigens ( n = 9). Pathogen prevalence was similar between sexes and among the three coyote packs in the study area. Parvovirus exposure appeared to happen early in life, and prevalence of antibodies against CDV increased with increasing age class. Exposure to Y. pestis and F. tularensis occurred across all age classes. The high coyote seroprevalence rates observed for CPV, Y. pestis , and CDV may indicate high prevalence in sympatric vertebrate populations, with implications for regional wildlife conservation as well as risk to humans via zoonotic transmission.

New Mexico↗
USGSDate not supplied

Perspectives on the diagnosis, epizootiology, and control of the 1973 duck plague epizootic in wild waterfowl at Lake Andes, South Dakota

An epizootic of duck plague occurred in early 1973 in a population of 163,500 wild waterfowl, primarily mallards (Anas platyrhynchos), wintering on Lake Andes and the nearby Missouri River in southeastern South Dakota (USA). The diagnosis was based on pathologic lesions and confirmed by virus isolation. Control measures included quarantine, attempts to reduce virus contamination of the area, dispersal of waterfowl, and monitoring of wild waterfowl populations for mortality. The epizootic resulted in documented mortality of 18% and estimated mortality of 26% of the waterfowl at risk. Prompt implementation of control measures might have limited mortality to approximately 8%. Losses during the epizootic were equivalent to 0.12% of the annual mortality in the North American 1996 fall population of 80,000,000 wild ducks. The most likely sources of the infection were free-flying wild mallard or American black duck (Anas rubripes) carriers from the upper midwestern or northeastern United States. Duck plague serum neutralization antibodies were demonstrated in 31% of 395 apparently healthy mallards sampled prior to dispersal of the flock at Lake Andes, suggesting that tens of thousands of potential duck plague carriers entered the wild waterfowl populations of all four major flyways. Consequently, the absence of major epizootics of duck plague in wild waterfowl in the subsequent two decades is evidence that substantial numbers of duck plague carriers can occur in wild waterfowl populations without resulting in epizootic mortalities. The failure to isolate duck plague virus from apparently healthy mallards sampled during the epizootic raises questions concerning the validity of conclusions regarding the status of duck plague in wild waterfowl based upon negative results of random surveys conducted in the absence of epizootics. © Wildlife Disease Association 1997.

South Dakota↗
USGS2008

Demographic effects of canine parvovirus on a free-ranging wolf population over 30 years

We followed the course of canine parvovinis (CPV) antibody prevalence in a subpopulation of wolves (Canis 1upus) in northeastern Minnesota from 1973, when antibodies were first detected, through 2004. Annual early pup survival was reduced by 70%, and wolf population change was related to CPV antibody prevalence. In the greater Minnesota population of 3,000 wolves, pup survival was reduced by 40-60%. This reduction limited the Minnesota wolf population rate of increase to about 4% per year compared with increases of 16-58% in other populations. Because it is young wolves that disperse, reduced pup survival may have caused reduced dispersal and reduced recolonization of new range in Minnesota. ?? Wildlife Disease Association 2008.

Journal of Wildlife Diseases↗
USGS2008

Hepatic minerals of white-tailed and mule deer in the southern Black Hills, South Dakota

Because there is a paucity of information on the mineral requirements of free-ranging deer, data are needed from clinically healthy deer to provide a basis for the diagnosis of mineral deficiencies. To our knowledge, no reports are available on baseline hepatic mineral concentrations from sympatric white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus) using different habitats in the Northern Great Plains. We assessed variation in hepatic minerals of female white-tailed deer (n=42) and mule deer (n=41). Deer were collected in February and August 2002 and 2003 from study areas in Custer and Pennington Counties, South Dakota, in and adjacent to a wildfire burn. Hepatic samples were tested for levels (parts per million; ppm) of aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), boron (B), cadmium (Cd), calcium (Ca), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), magnesium (Mg), manganese (Mn), mercury (Hg), molybdenum (Mo), nickel (Ni), phosphorus (P), potassium (K), selenium (Se), sodium (Na), sulfur (S), thalium (T1), and zinc (Zn). We predicted that variability in element concentrations would occur between burned and unburned habitat due to changes in plant communities and thereby forage availability. We determined that Zn, Cu, and Ba values differed (P???0.05) between habitats. Because of the nutritional demands of gestation and lactation, we hypothesized that elemental concentrations would vary depending on reproductive status; Cd, Cu, Ca, P, Mn, Mo, Na, and Zn values differed (P???0.05) by reproductive status. We also hypothesized that, due to variation in feeding strategies and morphology between deer species, hepatic elemental concentrations would reflect dietary differences; Ca, Cu, K, Co, Mo, Se, and Zn differed (P???0.05) between species. Further research is needed to determine causes of variation in hepatic mineral levels due to habitat, reproductive status, and species. ?? Wildlife Disease Association 2008.

Journal of Wildlife Diseases↗
USGS2006

Wild bird mortality and West Nile virus surveillance: Biases associated with detection, reporting, and carcass persistence

Surveillance targeting dead wild birds, in particular American crows (Corvus brachyrhynchos), plays a critical role in West Nile virus (WNV) surveillance in the United States. Using crow decoy surrogates, detection and reporting of crow carcasses within urban and rural environments of DeKalb County, Georgia were assessed for potential biases that might occur in the county's WNV surveillance program. In each of two replicated trials, during July and September 2003, 400 decoys were labeled with reporting instructions and distributed along randomly chosen routes throughout designated urban and rural areas within DeKalb County. Information-theoretic methods were used to compare alternative models incorporating the effects of area and trial on probabilities of detection and reporting. The model with the best empirical support included the effects of area on both detection and reporting of decoys. The proportion of decoys detected in the urban area (0.605, SE=0.024) was approximately twice that of the rural area (0.293, SE =0.023), and the proportion of decoys reported in the urban area (0.273, SE =0.023) was approximately three times that of the rural area (0.103, SE=0.028). These results suggest that human density and associated factors can substantially influence dead crow detection and reporting and, thus, the perceived distribution of WNV. In a second and separate study, the persistence and fate of American crow and house sparrow (Passer domesticus) carcasses were assessed in urban and rural environments in Athens-Clarke, Madison, and Oconee counties, Georgia. Two replicated trials using 96 carcasses of each species were conducted during July and September 2004. For a portion of the carcasses, motion sensitive cameras were used to monitor scavenging species visits. Most carcasses (82%) disappeared or were decayed by the end of the 6-day study. Carcass persistence averaged 1.6 days in rural areas and 2.1 days in urban areas. We analyzed carcass persistence rates using a known-fate model framework in program MARK. Model selection based on Akaike's Information Criteria (AIC) indicated that the best model explaining carcass persistence rates included species and number of days of exposure; however, the model including area and number of days of exposure received approximately equal support. Model-averaged carcass persistence rates were higher for urban areas and for crow carcasses. Six mammalian and one avian species were documented scavenging upon carcasses. Dead wild birds could represent potential sources of oral WNV exposure to these scavenging species. Species composition of the scavenger assemblage was similar in urban and rural areas but "scavenging pressure" was greater in rural areas. ?? Wildlife Disease Association 2006.

Journal of Wildlife Diseases↗
USGS2024

Chronic wasting disease alters the movement behavior and habitat use of mule deer during clinical stages of infection

Integrating host movement and pathogen data is a central issue in wildlife disease ecology that will allow for a better understanding of disease transmission. We examined how adult female mule deer ( Odocoileus hemionus ) responded behaviorally to infection with chronic wasting disease (CWD). We compared movement and habitat use of CWD-infected deer ( n = 18) to those that succumbed to starvation (and were CWD-negative by ELISA and IHC; n = 8) and others in which CWD was not detected ( n = 111, including animals that survived the duration of the study) using GPS collar data from two distinct populations collared in central Wyoming, USA during 2018–2022. CWD and predation were the leading causes of mortality during our study (32/91 deaths attributed to CWD and 27/91 deaths attributed to predation). Deer infected with CWD moved slower and used lower elevation areas closer to rivers in the months preceding death compared with uninfected deer that did not succumb to starvation. Although CWD-infected deer and those that died of starvation moved at similar speeds during the final months of life, CWD-infected deer used areas closer to streams with less herbaceous biomass than starved deer. These behavioral differences may allow for the development of predictive models of disease status from movement data, which will be useful to supplement field and laboratory diagnostics or when mortalities cannot be quickly retrieved to assess cause-specific mortality. Furthermore, identifying individuals who are sick before predation events could help to assess the extent to which disease mortality is compensatory with predation. Finally, infected animals began to slow down around 4 months prior to death from CWD. Our approach for detecting the timing of infection-induced shifts in movement behavior may be useful in application to other disease systems to better understand the response of wildlife to infectious disease.

Wyoming↗
USGS2008

Trichinella murrelli in scavenging mammals from south-central Wisconsin, USA

Tissues and serum from 59 raccoons (Procyon lotor), 42 coyotes (Canis latrans), and seven Striped Skunks (Mephitis mephitis) collected in Dane and Iowa Counties, Wisconsin, USA, between October 2005 and March 2006 were microscopically and serologically examined for the presence of Trichinella spp. Encapsulated larvae were found on compression slides prepared from tongue tissues from a few animals. Complete tissue digestion of tongues revealed that 19% of the raccoons, 26% of the coyotes, and none of the seven skunks tested were infected with Trichinella spp. Cats were subsequently experimentally infected by feeding them the raccoon tissues containing muscle larvae, and muscle larvae isolated from the collected tongues were experimentally transmitted to mice. Multiplex polymerase chain reaction analysis of the isolated muscle larvae demonstrated two distinct bands migrating at 127 base pairs (bp) and 316 bp in all samples, which together are diagnostic for Trichinella murrelli; the isolates were assigned Istituto Superiore di Sanita (ISS) codes ISS1656 through ISS1667, and ISS1708 through ISS1710 by the International Trichinella Reference Centre. These findings extend the geographic range of T. murrelli into Wisconsin, USA. ?? Wildlife Disease Association 2008.

Journal of Wildlife Diseases↗
USGS2022

Plague circulation in small mammals elevates extinction risk for the endangered Peñasco least chipmunk

Wildlife diseases are a major concern for species survival around the world. Vector-borne diseases, in particular, are problematic for both humans and wildlife. Plague is an introduced disease to North America where many species have low natural resistance to infection by the causative bacterium, Yersinia pestis . Plague in the United States is often associated with large-scale epizootic events that impact rodent populations. However, we need more information regarding the effects of plague at enzootic levels and in species that rarely if ever experience epizootic events. New Mexico is a state that experiences regular epizootic plague events in several species of rodents but comparatively less is known about enzootic plague impacts within rodent communities in New Mexico. The Peñasco least chipmunk ( Neotamias minimus atristriatus ) is state-listed as endangered in New Mexico and is a candidate for listing under the federal Endangered Species Act. It likely has been extirpated from the southern portion of its range and is now observed only at high elevations in isolated areas in the White Mountains. We evaluated plague presence in the more abundant small mammal species associated with these chipmunks. We used an F1 antigen plague-specific vaccine and a placebo injection to test whether plague was present and reducing survival in western deer mouse ( Peromyscus sonoriensis ) and vole ( Microtus spp.) populations in the Lincoln National Forest. The effect of plague on survival differed among years and sites. Monthly apparent survival was up to 60 % higher for rodents given the vaccine compared to those given a placebo. Our results suggest that plague is likely impacting the small mammal community in the Lincoln National Forest and is even present at higher elevation sites where the Peñasco least chipmunk was most recently extirpated. Because least chipmunks are highly susceptible to plague, our results suggest that this disease may be an important factor in the population decline of the Peñasco least chipmunk.

New Mexico↗
USGS2006

Spatial epidemiology of chronic wasting disease in Wisconsin white-tailed deer

Chronic wasting disease (CWD) is a fatal, emerging disease of cervids associated with transmissible protease-resistant prion proteins. The potential for CWD to cause dramatic declines in deer and elk populations and perceived human health risks associated with consuming CWD-contaminated venison have led wildlife agencies to embark on extensive CWD control programs, typically involving culling to reduce deer populations. We characterized the spatial distribution of CWD in white-tailed deer (Odocoileus virginianus) in Wisconsin to facilitate CWD management. We found that CWD prevalence declined with distance from a central location, was locally correlated at a scale of 3.6 km, and was correlated with deer habitat abundance. The latter result is consistent with patterns expected for a positive relationship between density and prevalence of CWD. We recommend management activities focused on culling in geographic areas with high prevalence to have the greatest probability of removing infected individuals. Further research is needed to elucidate the factors in envolved in CWD spread and infection rates, especially the role of density-dependent transmission. ?? Wildlife Disease Association 2006.

Wisconsin↗
USGS2023

A minimally invasive, field-applicable CRISPR/Cas biosensor to aid in the detection of Pseudogymnoascus destructans, the causative fungal agent of white-nose syndrome in bats

The accessibility to CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein) genetic tools has given rise to applications beyond site-directed genome editing for the detection of DNA and RNA. These tools include precise diagnostic detection of human disease pathogens, such as SARS-CoV-2 and Zika virus. Despite the technology being rapid and cost-effective, the use of CRISPR/Cas tools in the surveillance of the causative agents of wildlife diseases has not been prominent. This study presents the development of a minimally invasive, field-applicable and user-friendly CRISPR/Cas-based biosensor for the detection of Pseudogymnoascus destructans ( Pd ), the causative fungal agent of white-nose syndrome (WNS), an infectious disease that has killed more than five million bats in North America since its discovery in 2006. The biosensor assay combines a recombinase polymerase amplification (RPA) step followed by CRISPR/Cas12a nuclease cleavage to detect Pd DNA from bat dermal swab and guano samples. The biosensor had similar detection results when compared to quantitative PCR in distinguishing Pd- positive versus negative field samples. Although bat dermal swabs could be analysed with the biosensor without nucleic acid extraction, DNA extraction was needed when screening guano samples to overcome inhibitors. This assay can be applied to help with more rapid delineation of Pd- positive sites in the field to inform management decisions. With further optimization, this technology has broad translation potential to wildlife disease-associated pathogen detection and monitoring applications.

Molecular Ecology Resources↗
USGS2008

A blood survey of elements, viral antibodies, and hemoparasites in wintering Harlequin Ducks (Histrionicus histrionicus) and Barrow's Goldeneyes (Bucephala islandica)

Twenty-eight Harlequin Ducks (Histrionicus histrionicus) and 26 Barrow's Goldeneyes (Bucephala islandica) were captured in Prince William Sound, Alaska, between 1 and 15 March 2005. Blood was collected for quantification of element concentrations, prevalence of antibodies to several viruses, and hemoparasite prevalence and identification. Although we found selenium concentrations that have been associated with selenosis in some birds (???.0 ppm ww), our findings contribute to a growing literature describing relatively high selenium in apparently healthy birds in marine environments. Avian influenza virus antibodies were detected in the plasma of 28% of the ducks. No antibodies against adenovirus, reovirus, or paramyxovirus 1 were detected. Several hemoparasite species were identified in 7% of ducks. Our findings are similar to those in other free-living marine waterfowl and do not indicate unusual concerns for the health of these species in this area in late winter. ?? Wildlife Disease Association 2008.

Alaska↗
USGS2006

Sampling blood from big brown bats (Eptesicus fuscus) in the field with and without anesthesia: Impacts on survival

Blood was collected from wild big brown bats (Eptesicus fuscus) with and without anesthesia in Fort Collins, Colorado in 2004 to assess the impacts of these procedures on short-term survival and 1-yr return rates. Short-term survival and 1-yr return rates after release were passively monitored using PIT tag detection hoops placed at selected buildings. Comparison of 14-day maximum likelihood survival estimates from bats not bled (142 adult females, 62 volant juveniles), and bats sampled for blood with anesthesia (96 adult females, 23 volant juveniles) and without anesthesia (112 adult females, 22 volant juveniles) indicated no adverse effects of either treatment (juveniles: X2=53.38, df=41, P=0.09; adults: X2=39.09, df=44, P=0.68). Return rates of bats one year after sampling were similar among adult female controls (75.4%, n=142, 95% CI=67.4-82.2%), females sampled for blood with anesthesia (83.0%, n=112, 95% CI=74.8-89.5%), and females sampled without anesthesia (87.5%, n=96, 95% CI=79.2-93.4%). Lack of an effect was also noted in 1-yr return rates of juvenile females. These data suggest that the use of anesthesia during sampling of blood has no advantages in terms of enhancement of survival in big brown bats. ?? Wildlife Disease Association 2006.

Journal of Wildlife Diseases↗
USGS2008

Pathology, physiologic parameters, tissue contaminants, and tissue thiamine in morbid and healthy central Florida adult American alligators (Alligator mississippiensis)

An investigation of adult alligator (Alligator mississippiensis) mortalities in Lake Griffin, central Florida, was conducted from 1998-2004. Alligator mortality was highest in the months of April and May and annual death count peaked in 2000. Bacterial pathogens, heavy metals, and pesticides were not linked with the mortalities. Blood chemistry did not point to any clinical diagnosis, although differences between impaired and normal animals were noted. Captured alligators with signs of neurologic impairment displayed unresponsive and uncoordinated behavior. Three of 21 impaired Lake Griffin alligators were found to have neural lesions characteristic of thiamine deficiency in the telencephalon, particularly the dorsal ventricular ridge. In some cases, lesions were found in the thalamus, and parts of the midbrain. Liver and muscle tissue concentrations of thiamine (vitamin B"1) were lowest in impaired Lake Griffin alligators when compared to unimpaired alligators or to alligators from Lake Woodruff. The consumption of thiaminase-positive gizzard shad (Dorosoma cepedianum) is thought to have been the cause of the low tissue thiamine and resulting mortalities. ?? Wildlife Disease Association 2008.

Journal of Wildlife Diseases↗
USGS2008

General and specialized media routinely employed for primary isolation of bacterial pathogens of fishes

There are a number of significant diseases among cultured and free-ranging freshwater fishes that have a bacterial etiology; these represent a variety of gram-negative and gram-positive genera. Confirmatory diagnosis of these diseases involves primary isolation of the causative bacterium on bacteriologic media. Frequently used "general" bacteriologic media simply provide the essential nutrients for growth. For most of the major pathogens, however, there are differential and/or selective media that facilitate primary recovery. Some specialized media are available as "ready-to-use" from suppliers, while others must be prepared. Differential media employ various types of indicator systems, such as pH indicators, that allow diagnosticians to observe assimilation of selected substrates. An advantage to the use of differential media for primary isolation is that they hasten bacterial characterization by yielding the appropriate positive or negative result for a particular substrate, often leading to a presumptive identification. Selective media also incorporate agent(s) that inhibit the growth of contaminants typically encountered with samples from aquatic environments. Media that incorporate differential and/or selective components are ideally based on characters that are unique to the targeted bacterium, and their use can reduce the time associated with diagnosis and facilitate early intervention in affected fish populations. In this review, the concepts of general and differential/selective bacteriologic media and their use and development for fish pathogens are discussed. The media routinely employed for primary isolation of the significant bacterial pathogens of fishes are presented. ?? Wildlife Disease Association 2008.

Journal of Wildlife Diseases↗