Symptom frequency and exposure to a cyanobacteria bloom in Florida.

This investigation was undertaken to characterize health effects associated with a major bloom of blue-green algae due to the proliferation Microcystis aeruginosa that occurred in Florida in 2018. Cyanobacteria produce multiple toxins, including the potent hepatotoxic microcystins (MCs), that have been reported to cause illness in exposed persons worldwide. Widespread exposure to toxins released by blue-green algae during the 2018 bloom was shown by the presence of MCs in the nasal passages of 95 percent of the individuals studied previously in south Florida (Schaefer et al., 2020). The current analyses were conducted to determine whether self-reported symptoms were associated with activity patterns, direct contact with water, residential, recreational, and occupational exposure. The 125 persons who participated in the initial study reported an average of 4.94 (± 4.87) symptoms. Those reported most commonly included rhinorrhea, sneezing, headache, sore throat and dry cough. Respiratory symptoms were reported by 74%, ocular symptoms by 62%, and gastrointestinal symptoms by 35% of respondents. Residential and recreational exposures were associated with increased risks of respiratory, gastrointestinal, or ocular symptoms in univariate and adjusted multivariable analyses. Residential exposure was significantly associated with increased reporting of dry cough (p = 0.03), dyspnea (p < 0.01) and wheezy respirations (p = 0.04). Among persons reporting gastrointestinal symptoms, nausea (p = 0.02) and abdominal pain (p < 0.01) were significantly associated with residential exposure. Recreational exposure was significantly associated with sore throat and eye irritation. The findings add to the evidence that exposure to cyanobacteria at concentrations encountered during an algal bloom is associated with a diverse array of symptoms and that inhalation of aerosols constitutes an important exposure pathway.

Exposure to microcystin among coastal residents during a cyanobacteria bloom in Florida.

Florida has experienced multiple cyanobacteria blooms in recent years the most severe of which occurred in 2016 and 2018. Several toxins are produced by proliferating cyanobacteria, including the hepatotoxin microcystin (MC). Harmful algal blooms (HABs) caused by cyanobacteria have the potential to impact public health. However, to date there have been limited attempts to quantify exposure in human populations. This study investigated potential exposure to the cyanobacterial toxin, MC by measuring concentrations in swabs of the nasal mucosa. In addition, the relationships between nasal concentrations of MC, environmental concentrations and activity patterns were assessed. Participants (n = 125) were recruited in 2018 during a cyanobacterial bloom of Microcystis aeruginosa and completed a questionnaire which included location, type, and duration of recreational or occupational contact with impacted waterways within the last 10 days. Water samples were collected concurrently. A sterile swab was used to collect a sample from the nasal mucosa. Concentrations of MC were measured by ELISA. Of the 121 participants who provided nasal swabs, 115 (95.0 %) had concentrations of MC above the limit of detection with a mean concentration of 0.61 + 0.75 ppb. There were significant differences (p < 0.01) in mean MC concentration between individuals with direct contact with impacted waters (0.77 + 0.88 ppb) compared to those with no recent contact (0.37 + 0.49 ppb). Higher concentrations were observed among occupationally exposed individuals. Nasal concentrations of MC varied significantly over time and location of exposure to the bloom, concordant with concentrations in water samples. The results suggest that inhalation of aerosols may be an important pathway for exposure to MC. Nasal MC concentrations were generally highest during periods when concentrations in the surrounding waters peaked. Further research is needed to characterize the public health implications of exposure to cyanobacterial blooms.

Seasonal distributions and other risk factors for Giardia duodenalis and Cryptosporidium spp. infections in dogs and cats in Chiang Mai, Thailand.

The objectives of this study were to explore risk factors associated with Giardia and Cryptosporidium infections in dogs and cats in Chiang Mai, Thailand, to describe the seasonal distributions of Giardia and Cryptosporidium prevalence, and to determine the potential for zoonotic transmission through genetic characterization of isolates. Fecal samples from 301 dogs and 66 cats were collected between August 2009 and February 2010. The presence of Giardia cysts and Cryptosporidium oocysts was determined using zinc sulfate centrifugal flotation and immunofluorescent assay (IFA). Genotype/species were determined by DNA sequence analyses of PCR products from Giardia glutamate dehydrogenase (gdh), beta-giardin (bg), and triosephosphateisomerase (tpi) and Cryptosporidium heat shock protein 70KDa (hsp70) and small subunit-rRNA (SSU-rRNA) genes. Information related to specific risk factors was collected from owners of each animal using a questionnaire. The risk factor data were analyzed for associations with Giardia and Cryptosporidium infections using logistic regression. The overall estimated prevalence of Giardia and Cryptosporidium in dogs was 25.2% and 7.6%, respectively and in cats, 27.3% and 12.1%, respectively. The estimated prevalence of Giardia infection in dogs in the rainy season (31.7%) was significantly higher than in the drier, winter season (17.2%) (p < 0.01). The estimated prevalence of Cryptosporidium infection in dogs and of Giardia and Cryptosporidium infections in cats was not associated with season (p > 0.05). Multivariable analysis indicated that Giardia cysts were more likely to be detected in fecal samples of dogs that resided in high-density environments, drank untreated water, were shedding Cryptosporidium oocysts, were having acute diarrhea or a history of chronic diarrhea, and were collected in the rainy season. All 19 Giardia PCR positive samples typed as G. duodenalis canine adapted genotypes (assemblages C or D). In cats, of six Giardia PCR positive samples, five typed as dog assemblages and one typed as assemblage AI. Of ten dogs with Cryptosporidium PCR positive samples, eight typed as C. canis, one as C. parvum (a zoonotic species) and one had both C. canis and C. parvum. Of three Cryptosporidium PCR positive samples in cats, one typed as C. felis and two typed as C. parvum. The presence of zoonotic G. duodenalis assemblage AI in a cat, and C. parvum in feces of dogs and cats suggests a potential role for a reservoir for zoonotic transmission. Whether or not these presences were from exposure to other animal or human hosts or environment are needed to be confirmed.

Mercury Exposure, Fish Consumption, and Perceived Risk among Pregnant Women in Coastal Florida.

Seafood consumption is the primary source of mercury (Hg) exposure, particularly among coastal populations. Hg exposure during pregnancy has been associated with cognitive impairment, as well as decrements in memory, attention, fine motor skills, and other markers of delayed neurodevelopment, although results are conflicting. High Hg hair concentrations in persons from coastal Florida, USA, have been previously reported. The purpose of the current study was to determine the concentrations of total Hg (THg) in the hair of pregnant women from this area and to assess the relationships between THg concentration, knowledge of the risks of mercury exposure, and dietary patterns among participants. Participants (n = 229) were recruited at prenatal clinics. Their mean total hair Hg concentration was 0.31 + 0.54 µg/g, lower or similar to US data for women of child-bearing age. Hair THg concentration was associated with consumption of locally caught fish and all seafood, a higher level of education, and first pregnancy. Eighty-five percent of women were aware of the risks of mercury exposure during pregnancy; over half reported a decrease in seafood consumption during pregnancy. Awareness of Hg in fish was marginally associated with lower hair THg concentration (p = 0.06) but reduction in seafood consumption during pregnancy was not.

Comparative Innate and Adaptive Immune Responses in Atlantic Bottlenose Dolphins (Tursiops truncatus) With Viral, Bacterial, and Fungal Infections.

Free-ranging Atlantic bottlenose dolphins (n = 360) from two southeastern U.S. estuarine sites were given comprehensive health examinations between 2003 and 2015 as part of a multi-disciplinary research project focused on individual and population health. The study sites (and sample sizes) included the Indian River Lagoon (IRL), Florida, USA (n = 246) and Charleston harbor and associated rivers (CHS), South Carolina, USA (n = 114). Results of a suite of clinicoimmunopathologic tests revealed that both populations have a high prevalence of infectious and neoplastic disease and a variety of abnormalities of their innate and adaptive immune systems. Subclinical infections with cetacean morbillivirus and Chlamydiaceae were detected serologically. Clinical evidence of orogenital papillomatosis was supported by the detection of a new strain of dolphin papillomavirus and herpesvirus by molecular pathology. Dolphins with cutaneous lobomycosis/lacaziasis were subsequently shown to be infected with a novel, uncultivated strain of Paracoccidioides brasiliensis, now established as the etiologic agent of this enigmatic disease in dolphins. In this review, innate and adaptive immunologic responses are compared between healthy dolphins and those with clinical and/or immunopathologic evidence of infection with these specific viral, bacterial, and fungal pathogens. A wide range of immunologic host responses was associated with each pathogen, reflecting the dynamic and complex interplay between the innate, humoral, and cell-mediated immune systems in the dolphin. Collectively, these studies document the comparative innate and adaptive immune responses to various types of infectious diseases in free-ranging Atlantic bottlenose dolphins. Evaluation of the type, pattern, and degree of immunologic response to these pathogens provides novel insight on disease immunopathogenesis in this species and as a comparative model. Importantly, the data suggest that in some cases infection may be associated with subclinical immunopathologic perturbations that could impact overall individual and population health.

Genomic sequencing of a virus representing a novel type within the species Dyopipapillomavirus 1 in an Indian River Lagoon bottlenose dolphin.

Fecal samples collected from free-ranging Atlantic bottlenose dolphins (BDs) in the Indian River Lagoon of Florida were processed for viral discovery using a next-generation sequencing (NGS) approach. A 693-bp contig identified in the NGS data was nearly identical to the partial L1 gene sequence of a papillomavirus (PV) previously found in a penile papilloma in a killer whale (Orcinus orca). Based on this partial bottlenose dolphin papillomavirus (BDPV) sequence, a nested inverse PCR and primer-walking strategy was employed to generate the complete genome sequence. The full BDPV genome consisted of 7299 bp and displayed a typical PV genome organization. The BDPV E6 protein contained a PDZ-binding motif, which has been shown to be involved in carcinogenic transformation involving high-risk genital human PVs. Screening of 12 individual fecal samples using a specific endpoint PCR assay revealed that the feces from a single female BD displaying a genital papilloma was positive for the BDPV. Genetic analysis indicated that this BDPV (Tursiops truncatus papillomavirus 8; TtPV8) is a new type of Dyopipapillomavirus 1, previously sequenced from an isolate obtained from a penile papilloma in a harbor porpoise (Phocoena phocoena). Although only a partial L1 sequence has been determined for a PV detected in a killer whale genital papilloma, our finding of a nearly identical sequence in an Atlantic BD may indicate that members of this viral species are capable of host jumping. Future work is needed to determine if this virus is a high-risk PV that is capable of inducing carcinogenic transformation and whether it poses a significant health risk to wild delphinid populations.

Genomic characterization of a novel pegivirus species from free-ranging bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida.

We report the discovery of the first cetacean pegivirus (family Flaviviridae) using a next-generation sequencing approach. One of two infected bottlenose dolphins had elevated activities of liver enzymes, which may suggest hepatocellular injury. Further research is needed to determine the epidemiology and pathogenicity of dolphin pegivirus.

Complete Genome Sequencing of a Novel Type of Omikronpapillomavirus 1 in Indian River Lagoon Bottlenose Dolphins (Tursiops truncatus).

The genome sequence of a papillomavirus was determined from fecal samples collected from bottlenose dolphins in the Indian River Lagoon, FL. The genome was 7,772 bp and displayed a typical papillomavirus genome organization. Phylogenetic analysis supported the bottlenose dolphin papillomavirus as being a novel type of Omikronpapillomavirus1.

Prevalence and Multilocus Genotyping Analysis of Cryptosporidium and Giardia Isolates from Dogs in Chiang Mai, Thailand.

The occurrence and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis isolated from dogs in Chiang Mai, Thailand were determined. Fecal samples were collected from 109 dogs between July and August 2008. Cryptosporidium spp. infection was determined by immunofluorescent assay (IFA), PCR assays that amplify Cryptosporidium heat-shock protein 70 kDa (hsp70), and two PCR assays that amplify a small subunit-ribosomal RNA (SSU-rRNA). Giardiaduodenalis infection was identified using zinc sulfate centrifugal flotation, IFA, and four PCR assays that amplify the Giardia glutamate dehydrogenase (gdh), beta-giardin (bg), and generic and dog-specific assays of triosephosphate isomerase (tpi) genes. Overall prevalence of Cryptosporidium spp. and G.duodenalis was 31.2% and 45.9%, respectively. Sequence analysis of 22 Cryptosporidium-positive samples and 21 Giardia-positive samples revealed the presence of C.canis in 15, and C. parvum in 7, G. duodenalis Assemblage C in 8, D in 11, and mixed of C and D in 2 dogs. Dogs in Chiang Mai were commonly exposed to Cryptosporidium spp. and G. duodenalis. Cryptosporidium parvum can be isolated from the feces of dogs, and all G. duodenalis assemblages were dog-specific. Dogs could be a reservoir for a zoonotic Cryptosporidium infection in humans, but further studies will be required to determine the clinical and zoonotic importance.

Health and Environmental Risk Assessment Project for bottlenose dolphins Tursiops truncatus from the southeastern USA. I. Infectious diseases.

From 2003 to 2015, 360 free-ranging Atlantic bottlenose dolphins Tursiops truncatus inhabiting the Indian River Lagoon (IRL, n = 246), Florida, and coastal waters of Charleston (CHS, n = 114), South Carolina, USA, were captured, given comprehensive health examinations, and released as part of a multidisciplinary and multi-institutional study of individual and population health. The aim of this review is to summarize the substantial health data generated by this study and to examine morbidity between capture sites and over time. The IRL and CHS dolphin populations are affected by complex infectious and neoplastic diseases often associated with immunologic disturbances. We found evidence of infection with cetacean morbillivirus, dolphin papilloma and herpes viruses, Chlamydiaceae, a novel uncultivated strain of Paracoccidioides brasiliensis (recently identified as the causal agent of dolphin lobomycosis/lacaziasis), and other pathogens. This is the first long-term study documenting the various types, progression, seroprevalence, and pathologic interrelationships of infectious diseases in dolphins from the southeastern USA. Additionally, the study has demonstrated that the bottlenose dolphin is a valuable sentinel animal that may reflect environmental health concerns and parallel emerging public health issues.

Health and Environmental Risk Assessment Project for bottlenose dolphins Tursiops truncatus from the southeastern USA. II. Environmental aspects.

Bottlenose dolphins Tursiops truncatus are the most common apex predators found in coastal and estuarine ecosystems along the southeastern coast of the USA, where these animals are exposed to multiple chemical pollutants and microbial agents. In this review, we summarize the results of investigations of environmental exposures evaluated in 360 free-ranging dolphins between 2003 and 2015. Bottlenose dolphins inhabiting the Indian River Lagoon, Florida (IRL, n = 246), and coastal waters of Charleston, South Carolina (CHS, n = 114), were captured, given comprehensive health examinations, and released as part of a multidisciplinary and multi-institutional study of individual and population health. High concentrations of persistent organic pollutants including legacy contaminants (DDT and other pesticides, polychlorinated biphenyl compounds) as well as 'emerging' contaminants (polybrominated diphenyl ethers, perfluorinated compounds) were detected in dolphins from CHS, with lower concentrations in the IRL. Conversely, the concentrations of mercury in the blood and skin of IRL dolphins were among the highest reported worldwide and approximately 5 times as high as those found in CHS dolphins. A high prevalence of resistance to antibiotics commonly used in humans and animals was detected in bacteria isolated from fecal, blowhole, and/or gastric samples at both sites, including methicillin-resistant Staphylococcus aureus (MRSA) at CHS. Collectively, these studies illustrate the importance of long-term surveillance of estuarine populations of bottlenose dolphins and reaffirm their important role as sentinels for marine ecosystems and public health.

The environment as a driver of immune and endocrine responses in dolphins (Tursiops truncatus).

Immune and endocrine responses play a critical role in allowing animals to adjust to environmental perturbations. We measured immune and endocrine related markers in multiple samples from individuals from two managed-care care dolphin groups (n = 82 samples from 17 dolphins and single samples collected from two wild dolphin populations: Indian River Lagoon, (IRL) FL (n = 26); and Charleston, (CHS) SC (n = 19). The immune systems of wild dolphins were more upregulated than those of managed-care-dolphins as shown by higher concentrations of IgG and increases in lysozyme, NK cell function, pathogen antibody titers and leukocyte cytokine transcript levels. Collectively, managed-care care dolphins had significantly lower levels of transcripts encoding pro-inflammatory cytokine TNF, anti-viral MX1 and INFα and regulatory IL-10. IL-2Rα and CD69, markers of lymphocyte activation, were both lower in managed-care care dolphins. IL-4, a cytokine associated with TH2 activity, was lower in managed-care care dolphins compared to the free-ranging dolphins. Differences in immune parameters appear to reflect the environmental conditions under which these four dolphin populations live which vary widely in temperature, nutrition, veterinary care, pathogen/contaminant exposures, etc. Many of the differences found were consistent with reduced pathogenic antigenic stimulation in managed-care care dolphins compared to wild dolphins. Managed-care care dolphins had relatively low TH2 lymphocyte activity and fewer circulating eosinophils compared to wild dolphins. Both of these immunologic parameters are associated with exposure to helminth parasites which is uncommon in managed-care care dolphins. Less consistent trends were observed in a suite of hormones but significant differences were found for cortisol, ACTH, total T4, free T3, and epinephrine. While the underlying mechanisms are likely multiple and complex, the marked differences observed in the immune and endocrine systems of wild and managed-care care dolphins appear to be shaped by their environment.

Cutaneous Granulomas in Dolphins Caused by Novel Uncultivated Paracoccidioides brasiliensis.

Cutaneous granulomas in dolphins were believed to be caused by Lacazia loboi, which also causes a similar disease in humans. This hypothesis was recently challenged by reports that fungal DNA sequences from dolphins grouped this pathogen with Paracoccidioides brasiliensis. We conducted phylogenetic analysis of fungi from 6 bottlenose dolphins (Tursiops truncatus) with cutaneous granulomas and chains of yeast cells in infected tissues. Kex gene sequences of P. brasiliensis from dolphins showed 100% homology with sequences from cultivated P. brasiliensis, 73% with those of L. loboi, and 93% with those of P. lutzii. Parsimony analysis placed DNA sequences from dolphins within a cluster with human P. brasiliensis strains. This cluster was the sister taxon to P. lutzii and L. loboi. Our molecular data support previous findings and suggest that a novel uncultivated strain of P. brasiliensis restricted to cutaneous lesions in dolphins is probably the cause of lacaziosis/lobomycosis, herein referred to as paracoccidioidomycosis ceti.

Toward the identification, characterization and experimental culture of Lacazia loboi from Atlantic bottlenose dolphin (Tursiops truncatus).

Lobomycosis (lacaziosis) is a chronic, granulomatous, fungal infection of the skin and subcutaneous tissues of humans and dolphins. To date, the causative agent, the yeast-like organism Lacazia loboi, has not been grown in the laboratory, and there have been no recent reports describing attempts to culture the organism. As a result, studies on the efficacy of therapeutics and potential environmental reservoirs have not been conducted. Therefore, the objective of the current study was to utilize both classical and novel microbiological methods in order to stimulate growth of Lacazia cells collected from dolphin lesions. This included the experimental inoculation of novel media, cell culture, and the use of artificial skin matrices. Although unsuccessful, the methods and results of this study provide important insight into new approaches that could be utilized in future investigations of this elusive organism.

Mucocutaneous lesions in free-ranging Atlantic bottlenose dolphins Tursiops truncatus from the southeastern USA.

Mucocutaneous lesions were biopsied from free-ranging Atlantic bottlenose dolphins Tursiops truncatus inhabiting the Indian River Lagoon (IRL), Florida, and estuarine waters of Charleston (CHS), South Carolina, USA, between 2003 and 2013. A total of 78 incisional biopsies from 58 dolphins (n=43 IRL, n=15 CHS) were examined. Thirteen dolphins had 2 lesions biopsied at the same examination, and 6 dolphins were re-examined and re-biopsied at time intervals varying from 1 to 8 yr. Biopsy sites included the skin (n=47), tongue (n=2), and genital mucosa (n=29). Pathologic diagnoses were: orogenital sessile papilloma (39.7%), cutaneous lobomycosis (16.7%), tattoo skin disease (TSD; 15.4%), nonspecific chronic to chronic-active dermatitis (15.4%), and epidermal hyperplasia (12.8%). Pathologic diagnoses from dolphins with 2 lesions were predominately orogenital sessile papillomas (n=9) with nonspecific chronic to chronic-active dermatitis (n=4), TSD (n=3), lobomycosis (n=1), and epidermal hyperplasia (n=1). Persistent pathologic diagnoses from the same dolphins re-examined and re-biopsied at different times included genital sessile papillomas (n=3), lobomycosis (n=2), and nonspecific dermatitis (n=2). This is the first study documenting the various types, combined prevalence, and progression of mucocutaneous lesions in dolphins from the southeastern USA. The data support other published findings describing the health patterns in dolphins from these geographic regions. Potential health impacts related to the observed suite of lesions are important for the IRL and CHS dolphin populations, since previous studies have indicated that both populations are affected by complex infectious diseases often associated with immunologic disturbances and anthropogenic contaminants.

Mercury concentrations in Atlantic bottlenose dolphins (Tursiops truncatus) inhabiting the Indian River Lagoon, Florida: Patterns of spatial and temporal distribution.

Bottlenose dolphins (Tursiops truncatus) inhabiting the Indian River Lagoon, FL (IRL) have tissue mercury concentrations among the highest reported worldwide. Analysis of total mercury (THg) concentrations in blood collected between 2003 and 2012 showed a significant linear decrease over time (p=0.04). Significant differences in the spatial distribution of THg in resident IRL dolphins were also observed with a general gradient in concentration from north to south. Evaluation of local biogeochemistry and accumulation of mercury in prey species is needed to better understand factors influencing the distribution of Hg in the apex predator. Analyses of temporal and spatial patterns of exposure to THg in this sentinel species may have implications for both ecosystem and public health in the region.

Atlantic Bottlenose Dolphins (Tursiops truncatus) as A Sentinel for Exposure to Mercury in Humans: Closing the Loop.

Mercury (Hg) is a ubiquitous global contaminant with important public health implications. Mercury is released from a variety of anthropogenic, industrial processes, enters the earth's atmosphere and is re-deposited onto the earth's surface in rainfall. Much of this Hg enters the oceans which cover the majority of the earth's surface. In the marine environment, inorganic Hg is converted to the most toxic form of the element, methylmercury, and biomagnified through the trophic levels of the food web. The bottlenose dolphin (Tursiops truncatus) is the apex predator in many estuarine and coastal ecosystems. Due to their long life span and trophic position, bottlenose dolphins bioaccumulate high concentrations of contaminants including Hg, thus making them an important sentinel species for ecosystem and public health. Bottlenose dolphins in Florida bioaccumulate high concentrations of Hg in their blood, skin and internal organs. The concentrations of Hg in blood and skin of bottlenose dolphins of the Indian River Lagoon, FL (IRL) are among the highest reported world-wide. In previous studies, we demonstrated associations between concentrations of total Hg in the blood and skin of IRL dolphins and markers of endocrine, renal, hepatic, hematologic and immune system dysfunction. The predominant manifestation of exposure to mercury in humans is neurotoxicity. During the 1950s and 1960s, residents of Minamata bay, Japan were exposed to high concentrations of methyl mercury as the result of ingestion of fish and shellfish that had become contaminated in this infamous environmental disaster. Affected adults had severe motor and sensory abnormalities often leading to death. Methyl mercury crosses the placenta during pregnancy. Children exposed in utero were born with multiple congenital anomalies and also suffered from neurologic disorders. Significantly, local cats that consumed Hg contaminated fish developed severe signs of neurotoxicity which led to their subsequent description as the "dancing cats of Minamata bay". Unfortunately, the cause of these strange manifestations in cats was not recognized in time to prevent hundreds of additional cases from occurring. More recent studies have shown that exposure to mercury as a result of seafood consumption during pregnancy may result in multiple cognitive and neurodevelopmental effects in children. The levels of mercury found in bottlenose dolphins and the health effects we identified alerted us to the possibility of an important public health hazard. The IRL occupies 40 percent of the east coast of Florida and is bordered by counties with approximately 2.5 million human inhabitants. Therefore, we hypothesized that local inhabitants in communities bordering the IRL could be at risk of exposure to Hg from the consumption of fish and shellfish. We measured hair Hg in 135 local residents and found a mean concentration of 1.53 µg/g which was higher than that from previous studies of sport fishermen and coastal residents in other states. Over 50% of participants had a hair Hg concentration which exceeded the U.S. EPA exposure guideline. Hair Hg concentration was directly related to the frequency of seafood consumption and to the proportion of fish and shellfish obtained from local recreational sources. This study clearly exemplifies the importance of an animal sentinel in identifying a public health hazard and is virtually unique in "closing the loop" between animal and human health.

Proximity to natural gas wells and reported health status: results of a household survey in Washington County, Pennsylvania.

BACKGROUND: Little is known about the environmental and public health impact of unconventional natural gas extraction activities, including hydraulic fracturing, that occur near residential areas. OBJECTIVES: Our aim was to assess the relationship between household proximity to natural gas wells and reported health symptoms. METHODS: We conducted a hypothesis-generating health symptom survey of 492 persons in 180 randomly selected households with ground-fed wells in an area of active natural gas drilling. Gas well proximity for each household was compared with the prevalence and frequency of reported dermal, respiratory, gastrointestinal, cardiovascular, and neurological symptoms. RESULTS: The number of reported health symptoms per person was higher among residents living < 1 km (mean ± SD, 3.27 ± 3.72) compared with > 2 km from the nearest gas well (mean ± SD, 1.60 ± 2.14; p = 0.0002). In a model that adjusted for age, sex, household education, smoking, awareness of environmental risk, work type, and animals in house, reported skin conditions were more common in households < 1 km compared with > 2 km from the nearest gas well (odds ratio = 4.1; 95% CI: 1.4, 12.3; p = 0.01). Upper respiratory symptoms were also more frequently reported in persons living in households < 1 km from gas wells (39%) compared with households 1-2 km or > 2 km from the nearest well (31 and 18%, respectively) (p = 0.004). No equivalent correlation was found between well proximity and other reported groups of respiratory, neurological, cardiovascular, or gastrointestinal conditions. CONCLUSION: Although these results should be viewed as hypothesis generating, and the population studied was limited to households with a ground-fed water supply, proximity of natural gas wells may be associated with the prevalence of health symptoms including dermal and respiratory conditions in residents living near natural gas extraction activities. Further study of these associations, including the role of specific air and water exposures, is warranted.

Stress response of wild bottlenose dolphins (Tursiops truncatus) during capture-release health assessment studies.

There is a growing concern about the impacts of stress in marine mammals as they face a greater array of threats. The stress response of free-ranging dolphins (Tursiops truncatus) was examined by measuring their physiologic response to capture and handling. Samples were collected from 168 dolphins during capture-release health assessments 2003-2007 at two study sites: Charleston, SC (CHS) and the Indian River Lagoon, FL (IRL). Adrenocorticotropic hormone (ACTH), cortisol, aldosterone (ALD) and catecholamines (epinephrine (EPI), norepinephrine (NOR), dopamine (DA)), were measured in blood and cortisol in urine. Mean time to collect pre-examination samples after netting the animals was 22min; post-examination samples were taken prior to release (mean 1h 37min). EPI and DA concentrations decreased significantly with increased time to blood sampling. ACTH and cortisol levels increased from the initial capture event to the post-examination sample. EPI concentrations increased significantly with increasing time to the pre-examination sample and decreased significantly with time between the pre- and post-examination sample. Cortisol concentrations increased between the pre- and post-examination in CHS dolphins. Age- and sex-adjusted mean pre-examination values of catecholamines were significantly higher in CHS dolphins; ALD was higher in IRL dolphins. Significant differences related to age or sex included higher NOR concentrations in males; higher ALD and urine cortisol levels in juveniles than adults. Wild dolphins exhibited a typical mammalian response to acute stress of capture and restraint. Further studies that relate hormone levels to biological and health endpoints are warranted.

Hair mercury concentrations and fish consumption patterns in Florida residents.

Mercury exposure through the consumption of fish and shellfish represents a significant public health concern in the United States. Recent research has demonstrated higher seafood consumption and subsequent increased risk of methylmercury exposure among subpopulations living in coastal areas. The identification of high concentrations of total mercury in blood and skin among resident Atlantic bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon (IRL), a coastal estuary in Florida, alerted us to a potential public health hazard in the contiguous human population. Therefore, we analyzed hair mercury concentrations of residents living along the IRL and ascertained their sources and patterns of seafood consumption. The total mean mercury concentration for 135 residents was 1.53 ± 1.89 µg/g. The concentration of hair mercury among males (2.02 ± 2.38 µg/g) was significantly higher than that for females (0.96 ± 0.74 µg/g) (p < 0.01). Log transformed hair mercury concentration was significantly associated with the frequency of total seafood consumption (p < 0.01). Individuals who reported consuming seafood once a day or more were 3.71 (95% CI 0.84-16.38) times more likely to have a total hair mercury concentration over 1.0 µg/g, which corresponds approximately to the U.S. EPA reference dose, compared to those who consumed seafood once a week or less. Hair mercury concentration was also significantly higher among individuals who obtained all or most of their seafood from local recreational sources (p < 0.01). The elevated human mercury concentrations mirror the elevated concentrations observed in resident dolphins in the same geographical region. The current study is one of the first to apply the concept of a sentinel animal to a contiguous human population.