SARS-CoV-2 exposure in wild white-tailed deer (Odocoileus virginianus).

Widespread human SARS-CoV-2 infections combined with human-wildlife interactions create the potential for reverse zoonosis from humans to wildlife. We targeted white-tailed deer (Odocoileus virginianus) for serosurveillance based on evidence these deer have angiotensin-converting enzyme 2 receptors with high affinity for SARS-CoV-2, are permissive to infection, exhibit sustained viral shedding, can transmit to conspecifics, exhibit social behavior, and can be abundant near urban centers. We evaluated 624 prepandemic and postpandemic serum samples from wild deer from four US states for SARS-CoV-2 exposure. Antibodies were detected in 152 samples (40%) from 2021 using a surrogate virus neutralization test. A subset of samples tested with a SARS-CoV-2 virus neutralization test showed high concordance between tests. These data suggest white-tailed deer in the populations assessed have been exposed to SARS-CoV-2.

Role of candidate gene variants in modulating the risk and severity of alcoholic hepatitis.

BACKGROUND: Alcoholic hepatitis (AH) is a severe and life-threatening alcohol-associated liver disease. Only a minority of heavy drinkers acquires AH and severity varies among affected individuals, suggesting a genetic basis for the susceptibility to and severity of AH. METHODS: A cohort consisting of 211 patients with AH and 176 heavy drinking controls was genotyped for five variants in five candidate genes that have been associated with chronic liver diseases: rs738409 in patatin-like phospholipase domain-containing protein 3 (PNPLA3), rs72613567 in hydroxysteroid 17-beta dehydrogenase 13 (HSD17B13), rs58542926 in transmembrane 6 superfamily member 2 (TM6SF2), rs641738 in membrane bound O-acyltransferase domain containing 7 (MBOAT7), and a copy number variant in the haptoglobin (HP) gene. We tested the effects of individual variants and the combined/interacting effects of variants on AH risk and severity. RESULTS: We found significant associations between AH risk and the risk alleles of rs738409 (p = 0.0081) and HP (p = 0.0371), but not rs72613567 (p = 0.3132), rs58542926 (p = 0.2180), or rs641738 (p = 0.7630), after adjusting for patient's age and sex. A multiple regression model indicated that PNPLA3 rs738409:G [OR = 1.59 (95% CI: 1.15-2.22), p = 0.0055] and HP*2 [OR = 1.38 (95% CI: 1.04-1.82), p = 0.0245], when combined and adjusted for age and sex also had a large influence on AH risk among heavy drinkers. In the entire cohort, variants in PNPLA3 and HP were associated with increased total bilirubin and Model for End-stage Liver Disease (MELD) score, both measures of AH severity. The HSD17B13 rs72613567:AA allele was not found to reduce risk of AH in patients carrying the G allele of PNPLA3 rs738409 (p = 0.0921). CONCLUSION: PNPLA3 and HP genetic variants increase AH risk and are associated with total bilirubin and MELD score, surrogates of AH severity.

Effects of freshwater blue spaces may be beneficial for mental health: A first, ecological study in the North American Great Lakes region.

Research linking green space and mental health abounds. It also appears that oceanic blue spaces may be salutogenic, benefitting mental health through their expansive viewscapes, and possibly auditory and olfactory stimuli. Yet, it is unknown whether the same is true for freshwater bodies. In this ecological study, we explored associations between hospitalizations for anxiety/mood disorder in Michigan (>30,000) and proximity to the North American Great Lakes. As a sensitivity analysis, we examined associations for 15 different inland lake sizes. Results showed small, protective effects for distance to Great Lake (ß = 0.06, p<0.001) and percentage of inland lakes (ß = -0.04, p = 0.004). Unexpectedly, shorter distance to nearest inland lake was associated with higher anxiety/mood disorder hospitalizations. The protective effects of percentage area covered by inland lakes was observed for all lake sizes. These initial findings provide a foundation for future individual-level research with finer measurement of health outcomes and blue space exposure.

Stillbirth in the African Great Lakes region: A pooled analysis of Demographic and Health Surveys.

BACKGROUND: The aim of this study was to estimate the rate and predisposing factors associated with stillbirth in the African Great Lakes region (Burundi, Congo Democratic Republic, Kenya, Rwanda, Tanzania and Uganda). METHODS AND FINDINGS: Cross-sectional data from the most recent Demographic and Health Surveys (DHS) of countries in the African Great Lakes region were used in this study. DHS from Congo Democratic Republic was not included in the analyses because data was not collected for stillbirth in the country survey. A pooled sample of 57046 pregnancies of 7+ months' duration and 1002 stillbirths were included in the final analysis. The analyses were restricted to stillbirths reported in the 5 years preceding the surveys. Stillbirth was defined as foetal death in the third trimester (≥ 28 weeks' gestation). Multilevel logistic regression analyses that adjusted for cluster and survey weights were used to determine the factors associated with stillbirth in the Africa Great Lakes region. Health service variables and maternal medical condition variables were not included in the analysis because DHS do not collect data on these variables for pregnancies that did not result in a live birth. Burundi had the highest stillbirth rate per 1000 births [23% (95% CI: 20, 25)] within the region. Factors associated with stillbirth across the region were: no schooling [1.85 (95%Cl: 1.44, 2.38)] and primary education [1.64 (1.32, 2.05)], advanced maternal age [2.39 (95% CI: 1.59, 3.59)], smoking [1.99 (95% CI: 1.19, 3.32)] and drinking water from unimproved sources [1.18 (95% CI: 1.01, 1.37)]. CONCLUSION: To achieve Every Newborn Action Plan (ENAP) stillbirth target of 12 per 1000 births or less by 2030, policy interventions to prevent stillbirth should focus on promoting community-based socio-educational programmes which encourages a healthy lifestyle especially among uneducated women in the advanced age spectrum.

Exposure to human-associated fecal indicators and self-reported illness among swimmers at recreational beaches: a cohort study.

BACKGROUND: Fecal indicator bacteria used to assess illness risks in recreational waters (e.g., Escherichia coli, Enterococci) cannot discriminate among pollution sources. To address this limitation, human-associated Bacteroides markers have been proposed, but the risk of illness associated with the presence of these markers in recreational waters is unclear. Our objective was to estimate associations between human-associated Bacteroides markers in water and self-reported illness among swimmers at 6 U.S. beaches spanning 2003-2007. METHODS: We used data from a prospectively-enrolled cohort of 12,060 swimmers surveyed about beach activities and water exposure on the day of their beach visit. Ten to twelve days later, participants reported gastroinestinal, diarrheal, and respiratory illnesses experienced since the visit. Daily water samples were analyzed for the presence of human-associated Bacteroides genetic markers: HF183, BsteriF1, BuniF2, HumM2. We used model-based standardization to estimate risk differences (RD) and 95% confidence intervals (CI). We assessed whether the presence of Bacteroides markers were modifiers of the association between general Enterococcus and illness among swimmers using interaction contrast. RESULTS: Overall we observed inconsistent associations between the presence of Bacteroides markers and illness. There was a pattern of increased risks of gastrointestinal (RD = 1.9%; 95% CI: 0.1%, 3.7%), diarrheal (RD = 1.3%; 95% CI: -0.2%, 2.7%), and respiratory illnesses (RD = 1.1%; 95% CI: -0.2%, 2.5%) associated with BsteriF1. There was no evidence that Bacteroides markers acted as modifiers of Enterococcus and illness. Patterns were similar when stratified by water matrix. CONCLUSIONS: Quantitative measures of fecal pollution using Bacteroides, rather than presence-absence indicators, may be necessary to accurately assess human risk specific to the presence of human fecal pollution.

Potential distribution of the viral haemorrhagic septicaemia virus in the Great Lakes region.

Viral haemorrhagic septicaemia virus (VHSV) genotype IVb has been responsible for large-scale fish mortality events in the Great Lakes of North America. Anticipating the areas of potential VHSV occurrence is key to designing epidemiological surveillance and disease prevention strategies in the Great Lakes basin. We explored the environmental features that could shape the distribution of VHSV, based on remote sensing and climate data via ecological niche modelling. Variables included temperature measured during the day and night, precipitation, vegetation, bathymetry, solar radiation and topographic wetness. VHSV occurrences were obtained from available reports of virus confirmation in laboratory facilities. We fit a Maxent model using VHSV-IVb reports and environmental variables under different parameterizations to identify the best model to determine potential VHSV occurrence based on environmental suitability. VHSV reports were generated from both passive and active surveillance. VHSV occurrences were most abundant near shore sites. We were, however, able to capture the environmental signature of VHSV based on the environmental variables employed in our model, allowing us to identify patterns of VHSV potential occurrence. Our findings suggest that VHSV is not at an ecological equilibrium and more areas could be affected, including areas not in close geographic proximity to past VHSV reports.

Flavobacterium psychrophilum Infections in Salmonid Broodstock and Hatchery-Propagated Stocks of the Great Lakes Basin.

Bacterial coldwater disease (BCWD), caused by Flavobacterium psychrophilum, threatens wild and propagated salmonids worldwide and leads to substantial economic losses. In addition to being horizontally transmitted, F. psychrophilum can be passed from infected parents to their progeny, furthering the negative impacts of this pathogen. In Michigan, both feral and captive salmonid broodstocks are the gamete sources used in fishery propagation efforts. A 5-year study was initiated to follow the prevalence of systemic F. psychrophilum infections in feral broodstocks of four species (steelhead Oncorhynchus mykiss [potadromous Rainbow Trout]; Coho Salmon O. kisutch; Chinook Salmon O. tshawytscha; and Atlantic Salmon Salmo salar) residing in three Great Lakes watersheds. Additionally, captive broodstocks of four species (Rainbow Trout, Brown Trout Salmo trutta, Lake Trout Salvelinus namaycush, and Brook Trout Salvelinus fontinalis) maintained at two facilities were assessed for the presence of F. psychrophilum. The resultant offspring from each broodstock population were sampled for F. psychrophilum infections multiple times throughout hatchery residency. Using selective flavobacterial culture and PCR confirmation, F. psychrophilum was detected in all broodstocks except the captive Lake Trout and Brook Trout. Logistic regression analysis demonstrated that among the infected feral broodstocks, Chinook Salmon from the Lake Michigan watershed had the highest prevalence of systemic F. psychrophilum infection (mean = 63.2%). Among the captive broodstocks, the Gilchrist Creek strain of Brown Trout had the highest infection prevalence (mean = 5%). Collectively, the captive broodstocks were found to have significantly lower infection prevalence than the feral broodstocks. Despite the high prevalence of systemic F. psychrophilum infections in many broodstock populations, the bacterium was rarely detected in their progeny during hatchery rearing. However, heavy losses associated with clinical BCWD outbreaks did occur. Collectively, our results reinforce that BCWD continues to threaten Great Lakes basin salmonids.

Incidence and Location of Pain in Young, Active Patients Following Hip Arthroplasty.

Persistent pain following hip arthroplasty remains a concern, especially in young, active patients. Four hundred twenty patients less than 60 years of age with a pre-symptomatic UCLA score ≥ 6 (196 total hip arthroplasty [THA]; 224 surface replacement arthroplasty [SRA]) completed a pain-drawing questionnaire investigating the location, severity, and frequency of pain around the hip. At a mean of 2.9 years of follow-up, 40% reported pain in at least one location around the hip. There was no difference in the incidence of groin pain between SRA and THA patients (32% vs. 29%, P=0.6), but THA patients had a greater incidence of anterior (25% vs. 8%, P<0.001) and lateral (20% vs. 10%, P=0.01) thigh pain. A high percentage of young, active patients experience persistent pain following hip arthroplasty.

Polyphasic characterization reveals the presence of novel fish-associated Chryseobacterium spp. in the Great Lakes of North America.

Recent reports suggest an emergence of novel Chryseobacterium spp. associated with aquaculture-reared fish worldwide. Herein, we report on multiple Chryseobacterium spp. infecting Great Lakes fishes that are highly similar to previously detected isolates from Europe, Africa, and Asia but have never before been reported in North America. Polyphasic characterization, which included extensive physiological, morphological, and biochemical analyses, fatty acid profiling, and phylogenetic analyses based upon partial 16S rRNA gene sequences, highlighted the diversity of Great Lakes' fish-associated chryseobacteria and also suggested that at least 2 taxa represent potentially novel Chryseobacterium spp. Screening for the ability of representative chryseobacteria to elicit lesions in experimentally challenged fish showed that they induced varying degrees of pathology, some of which were severe and resulted in host death. Median lethal dose (LD50) experiments for the isolate that elicited the most extensive pathology (Chryseobacterium sp. T28) demonstrated that the LD50 exceeded 4.5 × 108 cfu, thereby suggesting its role as a facultative fish-pathogenic bacterium. Histopathological changes in T28-infected fish included epithelial hyperplasia of the secondary lamellae and interlamellar space that resulted in secondary lamellar fusion, monocytic infiltrate, and mucus cell hyperplasia, all of which are consistent with branchitis, along with monocytic myositis, hemorrhage within the muscle, liver, adipose tissue, and ovaries, spongiosis of white matter of the brain, multifocal edema within the granular cell layer of the cerebellar cortex, and renal tubular degeneration and necrosis. The findings of this study underscore the widespread presence of chryseobacteria infecting Great Lakes fish.

Deciphering the biodiversity of fish-pathogenic Flavobacterium spp. recovered from the Great Lakes basin.

Flavobacterial diseases negatively impact wild and cultured fishes worldwide. We recently reported on the presence of a large and diverse group of flavobacteria, many of which were associated with lesions in a number of Great Lakes fish species. Herein, we report on the characterization of 65 fish-associated Flavobacterium spp. isolates using 16S rRNA gene sequence analysis and phylogenetic analyses based upon neighbor-joining and Bayesian methodologies. Thirteen isolates were identified as the newly described fish-associated F. plurextorum, F. spartansii, and F. tructae, while 3 isolates were similar to F. frigidimaris; however, the remaining Flavobacterium spp. isolates did not conclusively match any described Flavobacterium spp. and thus were suspected as comprising novel flavobacterial species. A more comprehensive polyphasic characterization was undertaken on 6 isolates, representing a range of association with disease signs in hatchery-raised or free-ranging fish and genetic distinctness. Polyphasic characterization included physiological, morphological, and biochemical analyses, as well as additional phylogenetic analyses based upon near-complete sequencing of the 16S rRNA gene. Our findings demonstrated that that at least 5 of the 6 isolates are most likely novel species within the genus Flavobacterium that have never before been reported from fish. Pilot experimental challenge studies suggested that some of these Flavobacterium spp. can cause pathological lesions in fish and were re-isolated from the brains, spleens, livers, and kidneys of experimentally infected fish. The findings underscore the growing number and heterogeneity of flavobacteria now known to be capable of infecting fish.

A survey of gross pathologic conditions in cull cows at slaughter in the Great Lakes region of the United States.

The prevalence and severity of multiple gross pathologic lesions and abnormalities in cull dairy and beef cows was evaluated at a commercial abattoir in the Great Lakes region of the United States; 1,461 cattle were examined at slaughter over the course of 3 production days and evaluated for the occurrence and severity of lung, liver, rumen, and carcass abnormalities and pathologies. Of the 1,461 cattle examined at slaughter, 87% were classified as Holstein cows and 13% were classified as other cows. Liver abscesses were observed in 32% of the population and over half were classified as severe (18.5% population prevalence). The frequency distribution of cattle observed with a liver abscess was not different among production days. Severe ruminal lesions and rumenitis scars were observed in 10.0% of the population, and 25.1% of cattle were observed to have short or denuded papillae. Severe bovine respiratory disease complex lesions were observed in 10.3% of cattle. The most common reason for USDA postmortem carcass condemnation was malignant lymphoma (9 of 41). Only 45.9% of carcasses were free from bruising. Results indicate that ruminal acidosis and bovine respiratory disease complex occur at a relatively high frequency in this population. Although cows are routinely culled for reproductive failure or low milk production, the underlying reason may be causally related to these relatively prevalent conditions. Further investigation is warranted to assess this relationship and to examine the use of specific health intervention strategies within this demographic of cattle.

Viral hemorrhagic septicemia IVb status in the United States: inferences from surveillance activities and regional context.

The United States (U.S.) response to viral hemorrhagic septicemia virus (VHSV) IVb emergence in the Laurentian Great Lakes (GL) included risk-based surveillance for cost-effective decision support regarding the health of fish populations in open systems. All U.S. VHSV IVb isolations to date derive from free-ranging fish from GL States. Most originate in the region designated by US Geological Survey hydrologic unit code (HUC) 04, with the exception of two detections in neighboring Upper Mississippi (HUC 05) and Ohio (HUC 07) regions. For States outside the GL system, disease probability was assessed using multiple evidence sources. None substantiated VHSV IVb absence using surveillance alone, in part due to the limited temporal relevance of data in open systems. However, Bayesian odds risk-based analysis of surveillance and population context, coupled with exclusions where water temperatures likely preclude viral replication, achieved VHSV IVb freedom assurance for 14 non-GL States by the end of 2012, with partial evidence obtained for another 17 States. The non-GL region (defined as the aggregate of 4-digit HUCs located outside of GL States) met disease freedom targets for 2012 and is projected to maintain this status through 2016 without additional active surveillance. Projections hinge on continued basic biosecurity conditions such as movement restrictions and passive surveillance. Areas with navigable waterway connections to VHSV IVb-affected HUCs (and conducive water temperatures) should receive priority for resources in future surveillance or capacity building efforts. However, 6 years of absence of detections in non-GL States suggests that existing controls limit pathogen spread, and that even spread via natural pathways (e.g., water movement or migratory fish) appears contained to the Great Lakes system. This report exemplifies the cost-effective use of risk-based surveillance in decision support to assess and manage aquatic animal population health in open systems.

Extreme precipitation and beach closures in the great lakes region: evaluating risk among the elderly.

As a result of climate change, extreme precipitation events are expected to increase in frequency and intensity. Runoff from these extreme events poses threats to water quality and human health. We investigated the impact of extreme precipitation and beach closings on the risk of gastrointestinal illness (GI)-related hospital admissions among individuals 65 and older in 12 Great Lakes cities from 2000 to 2006. Poisson regression models were fit in each city, controlling for temperature and long-term time trends. City-specific estimates were combined to form an overall regional risk estimate. Approximately 40,000 GI-related hospital admissions and over 100 beach closure days were recorded from May through September during the study period. Extreme precipitation (≥90th percentile) occurring the previous day (lag 1) is significantly associated with beach closures in 8 of the 12 cities (p < 0.05). However, no association was observed between beach closures and GI-related hospital admissions. These results support previous work linking extreme precipitation to compromised recreational water quality.

Quantitative risk analysis for potentially resistant E. coli in surface waters caused by antibiotic use in agricultural systems.

Antibiotics are frequently used in agricultural systems to promote livestock health and to control bacterial contaminants. Given the upsurge of the resistant fecal indicator bacteria (FIB) in the surface waters, a novel statistical method namely, microbial risk assessment (MRA) was performed, to evaluate the probability of infection by resistant FIB on populations exposed to recreational waters. Diarrheagenic Escherichia coli, except E. coli O157:H7, were selected for their prevalence in aquatic ecosystem. A comparative study between a typical E. coli pathway and a case scenario aggravated by antibiotic use has been performed via Crystal Ball® software in an effort to analyze a set of available inputs provided by the US institutions including E. coli concentrations in US Great Lakes through using random sampling and probability distributions. Results from forecasting a possible worst-case scenario dose-response, accounted for an approximate 50% chance for 20% of the exposed human populations to be infected by recreational water in the U.S. However, in a typical scenario, there is a 50% chance of infection for only 1% of the exposed human populations. The uncertain variable, E. coli concentration accounted for approximately 92.1% in a typical scenario as the major contributing factor of the dose-response model. Resistant FIB in recreational waters that are exacerbated by a low dose of antibiotic pollutants would increase the adverse health effects in exposed human populations by 10 fold.

Prevalence of avian paramyxovirus 1 and avian influenza virus in double-crested Cormorants (Phalacrocorax auritus) in eastern North America.

Although it is well established that wild birds, such as cormorants, carry virulent avian paramyxovirus serotype 1 (APMV-1; causative agent of Newcastle disease) and avian influenza virus (AIV), the prevalence of these viruses among Double-crested Cormorants (Phalacrocorax auritus) in the Great Lakes region of North America has not been rigorously studied. We determined the prevalences of APMV-1 and AIV in Double-crested Cormorants from the interior population of eastern North America. From 2009 to 2011, oropharyngeal and cloacal swabs and serum samples were collected from 1,957 individual Double-crested Cormorants, ranging from chicks to breeding adults, on breeding colony sites in Michigan, Wisconsin, and Mississippi, USA, and Ontario, Canada, as well as on the wintering grounds of migratory populations in Mississippi, USA. Prevalence of antibodies to APMV-1 in after-hatch year birds was consistently high across all three years, ranging from 86.3% to 91.6%. Antibody prevalences in chicks were much lower: 1.7, 15.3, and 16.4% in 2009, 2010, and 2011, respectively. Virulent APMV-1 was detected in six chicks sampled in 2010 in Ontario, Canada. Only one adult was positive for AIV-specific antibodies and five individuals were positive for AIV matrix protein, but the latter were negative for H5 and H7 AIV subtypes. We provide further evidence that Double-crested Cormorants play an important role in the maintenance and circulation of APMV-1 in the wild, but are unlikely to be involved in the circulation of AIV.

Low prevalence of Cyprinid Herpesvirus 3 Found in common carp (Cyprinus carpio carpio) collected from nine locations in the Great Lakes.

Cyprinid herpesvirus 3 (CyHV3) is a viral disease of fish first detected in the United States in 1998. Since that time, mortality events in common carp (Cyprinus carpio carpio) have occurred in several locations within the Great Lakes basin, but not within the Great Lakes themselves. We sampled 675 carp from 20 sites across the Great Lakes and Lake St. Clair, Michigan, USA, between 19 July and 26 September 2010. We tested the gill and a pooled internal organ sample from each fish for CyHV3 with the use of a quantitative polymerase chain reaction (qPCR) assay. Virus was detected in 18 fish from nine sites in four lakes (Lakes Michigan, Huron, St. Clair, and Ontario). Tissues from these 18 fish were also tested for CyHV3 with the use of the PCR assay recommended by the World Organization for Animal Health; amplification was achieved from two fish and confirmation by sequencing of CyHV3 from one fish collected in Lake St. Clair. The results of this study suggest that CyHV3 is present in the Great Lakes.

Regional differences in drug use rates among American Indian youth.

BACKGROUND: Research over the past several decades has shown that, compared to other American ethnic and racial groups, American Indian (AI) youth use alcohol and other drugs at significantly higher rates than their non-AI peers. However, to date, much of the research on AI adolescent substance use has been limited in the types of data used. METHODS: We used a national sample of AI youth living on or near reservations to estimate how lifetime and 30-day use of four substances (alcohol, marijuana, inhalants, and methamphetamine) differ by gender, grade in school, and region of the country. RESULTS: Female use was equal to or greater than use by otherwise similar males for all substances assessed. Substance use also increased as grade increased except in the case of inhalants, where use peaked in the 8th grade and then decreased. Regional differences proved to be one of the most salient findings in that individuals in the Northern Plains and Upper Great Lakes were more likely to have used substances at much higher rates than those living in the Southwest and Oklahoma, except in the case of methamphetamine, where individuals in the Southwest were most likely to have used. CONCLUSIONS: It is clear that substance use continues to be a problem for AI youth although the severity of use differs by region of the country, grade, and gender. Future research is needed to better understand the reasons behind these differences. Such research will aid in the development of targeted, regionally tailored prevention.

Emergence of Viral hemorrhagic septicemia virus in the North American Great Lakes region is associated with low viral genetic diversity.

Viral hemorrhagic septicemia virus (VHSV) is a fish rhabdovirus that causes disease in a broad range of marine and freshwater hosts. The known geographic range includes the Northern Atlantic and Pacific Oceans, and recently it has invaded the Great Lakes region of North America. The goal of this work was to characterize genetic diversity of Great Lakes VHSV isolates at the early stage of this viral emergence by comparing a partial glycoprotein (G) gene sequence (669 nt) of 108 isolates collected from 2003 to 2009 from 31 species and at 37 sites. Phylogenetic analysis showed that all isolates fell into sub-lineage IVb within the major VHSV genetic group IV. Among these 108 isolates, genetic diversity was low, with a maximum of 1.05% within the 669 nt region. There were 11 unique sequences, designated vcG001 to vcG011. Two dominant sequence types, vcG001 and vcG002, accounted for 90% (97 of 108) of the isolates. The vcG001 isolates were most widespread. We saw no apparent association of sequence type with host or year of isolation, but we did note a spatial pattern, in which vcG002 isolates were more prevalent in the easternmost sub-regions, including inland New York state and the St. Lawrence Seaway. Different sequence types were found among isolates from single disease outbreaks, and mixtures of types were evident within 2 isolates from individual fish. Overall, the genetic diversity of VHSV in the Great Lakes region was found to be extremely low, consistent with an introduction of a new virus into a geographic region with previously naive host populations.

Detection of VHSV IVb within the gonads of Great Lakes fish using in situ hybridization.

Viral haemorrhagic septicaemia virus (VHSV) genotype IVb was recently detected as the cause of numerous mortality events in Great Lakes fish. In situ hybridization was used to examine the gonads from 13 fish, including freshwater drum Aplodinotus grunniens and muskellunge Esox masquinongy that were infected naturally, as well as rainbow trout Oncorhynchus mykiss and fathead minnows Pimphales promelas, which were experimentally infected. Although the ovaries and testes of fish infected by VHSV IVb had few lesions, viral RNA was present in the ovaries of the rainbow trout and fathead minnow and was abundant in the gonads of muskellunge and in the ovaries of freshwater drum. Viral RNA was present mainly surrounding yolk vacuoles/granules or adjacent to the germinal vesicle, with lesser amounts found within the germinal vesicle, in the mesovarium and/or tunica albuginea and blood vessels of the ovary. Viral RNA was also found in and surrounding primary and secondary spermatocytes of the muskellunge.

Spatio-temporal dynamics of gastrointestinal helminths infecting four lake whitefish (Coregonus clupeaformis) stocks in northern lakes Michigan and Huron, U.S.A.

This study was undertaken to identify the community composition, structure, and dynamics of helminths infecting the gastrointestinal tract (GIT) of lake whitefish (Coregonus clupeaformis) collected from 4 sites in northern lakes Huron (Cheboygan and De Tour Village) and Michigan (Big Bay de Noc and Naubinway) from fall 2003 through summer 2006. A total of 21,203 helminths was retrieved from the GITs of 1,284 lake whitefish. Approximately 42% (SE  =  1.4%) of the examined lake whitefish were infected with at least 1 helminth species in their GIT, with a mean intensity of 39.4 worms/fish (SE  =  0.3) and a mean abundance of 16.4 worms/fish (SE  =  0.1). Collected helminths appeared to be generalists and consisted of 2 phyla (Acanthocephala and Cestoda) and 5 species (Acanthocephalus dirus, Neoechinorhynchus tumidus, Echinorhynchus salmonis, Cyathocephalus truncatus, and Bothriocephalus sp.). Lake whitefish from Lake Huron on average had greater infection prevalences, abundances, and intensities than did fish from Lake Michigan. Infection parameters for each of the helminth species generally followed the same pattern observed for the combined data. Acanthocephalus dirus was the most prevalent and abundant helminth in lake whitefish GITs, although intensity of infection was the greatest for C. truncatus. Helminth infection parameters often peaked in the spring while diversity was greatest in the winter samples. There was substantial temporal variability in helminth infections with prevalences, abundances, and intensities often fluctuating widely on consecutive sampling occasions. Analysis of the GIT helminth community composition suggested that 3 (Big Bay de Noc, De Tour Village, and Cheboygan) of the 4 primary spawning sites, overall, had similar community compositions. The reason for the observed spatial and temporal variability in the lake whitefish GIT helminth infections remains to be elucidated. The findings of this study represent the most comprehensive parasitological study ever conducted on lake whitefish in the Great Lakes and will provide valuable information for future comparisons.