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Biomedical subjects

Scott D Fitzgerald

Publications and source records attributed to Scott D Fitzgerald.

At least 19 recordsLinked to original sources
PubMed2007

Outbreaks of phaeohyphomycosis in the chinook salmon (Oncorhynchus tshawytscha) caused by Phoma herbarum.

Phoma herbarum has been associated with two outbreaks of systemic mycosis in hatchery-reared chinook salmon (Oncorhynchus tshawytscha) fingerlings. Affected fish exhibited abnormal swimming behavior, exophthalmia, multiple rounded areas of muscle softening, protruded hemorrhagic vents, and abdominal swelling. In all affected fish, swimbladders were filled with whitish creamy viscous fungal mass, surrounded by dark red areas in swimbladder walls, kidneys, and musculature. Clinical and histopathological examinations suggest that the infection may have started primarily in the swimbladder and then spread to the kidneys, gastrointestinal tract, and surrounding musculature. Consistent microscopical findings included broad septate branched fungal hyaline hyphae, 5-12 microm in diameter within the swimbladder, stomach, and often within and adjacent to blood vessels. Profuse growths of woolly brown fungal colonies were obtained from swimbladders and kidneys on Sabouraud medium. On corn meal agar the formation of pycnidia, characteristic of Phoma spp., was detected within 10 days of incubation. Morphological and molecular analyses identified this fungus as Phoma herbarum. This report underscores systemic fungal infections as a threat to raceway-raised salmon.

Air Sacs↗
PubMed2006

Patterns of antimicrobial susceptibility in Michigan wildlife and bovine isolates of Mycobacterium bovis.

The state of Michigan has recognized the presence of Mycobacterium bovis in its free-ranging white-tailed deer population since 1994. This endemic infection is primarily located in a 12-county area in the northeastern lower peninsula of Michigan. A statewide surveillance and eradication program of the disease has been in effect since 1994. Worldwide, Mycobacterium tuberculosis complex organisms have a known predilection toward development of antimicrobial resistance. The objective of this study was to investigate the antimicrobial susceptibility of M. bovis isolates from white-tailed deer in Michigan and detect any changes in susceptibility over time. M. bovis isolates from 2 fall hunting seasons (1999 and 2004) were used in this study. The fall season of 2004 marked the first documented case of direct transmission of M. bovis from a wild deer to a human in Michigan. Since M. bovis is a zoonotic disease, knowledge of susceptibility can expedite treatment options in humans. M. bovis isolates were obtained from 58 deer, 4 coyotes, 3 cattle, 2 raccoons, and 1 human case from the 2 years combined. Methods of susceptibility testing included 1% proportion agar plates and Bactec radiometric broth testing. M. bovis was found to be uniformly resistant to the antibiotic pyrazinamide; this resistance is common to all M. bovis isolates. No other antimicrobial resistance was found in any of the tested M. bovis isolates, which may be, in part, attributed to the lack of any significant treatment pressure in wildlife.

Animals↗
PubMed2006

Acute anhydrous ammonia intoxication in cattle.

Intoxication with anhydrous ammonia (AA) is a common occupation-related health problem affecting farmers and fertilizer applicators, however, very few descriptions of animal exposure to this toxicant exist. Thieves entered a feedlot and damaged a liquid AA storage tank, resulting in the accidental leakage of gas from a valve. Overnight, 12 cattle were found dead, with a total mortality of 64 cattle out of 260 on the premises dying or euthanized in < 1 week. Signs of affected cattle included blindness, drooling, inappetence, respiratory distress, recumbency, and death. Two cattle were submitted live for diagnostic evaluation 3 days after initial exposure. Gross lesions included corneal ulcers, fibrinonecrotizing rhinitis, hemorrhages within the nasal sinuses, and anterioventral bronchopneumonia. Microscopic lesions consisted predominantly of degeneration and necrosis of superficial epithelium lining nasal passages, trachea, and pulmonary airways. This case illustrates the acute AA effects on cattle, which is likely to be an increasingly encountered problem because of on-farm storage of AA and its access by illicit drug manufacturers.

Ammonia↗
PubMed2006

Effects of air cell injection of perfluorooctane sulfonate before incubation on development of the white leghorn chicken (Gallus domesticus) embryo.

Fifty white leghorn chicken (Gallus domesticus) eggs per group were injected with 0.1, 1.0, 10.0, or 20.0 microg perfluorooctane sulfonate (PFOS)/g egg before incubation to investigate the effects of PFOS on the developing embryo. Hatchlings were weighed, examined for gross developmental abnormalities, and transferred to a battery brooder, where they were raised for 7 d. Chicks were then weighed, and 20 birds per treatment were randomly chosen for necropsy. The brain, heart, kidneys, and liver were removed and weighed. Livers were processed further for determination of PFOS concentrations and histological assessment. Hatchability was reduced significantly in all treatment groups in a dose-dependent manner. The calculated median lethal dose was 4.9 microg PFOS/g egg. Perfluorooctane sulfonate did not affect posthatch body or organ weights. Exposure to PFOS caused pathological changes in the liver characterized by bile duct hyperplasia, periportal inflammation, and hepatic cell necrosis at doses as low as 1.0 microg PFOS/g egg. Perfluorooctane sulfonate concentrations in the liver increased in a dose-dependent manner. Based on reduced hatchability, the lowest-observed-adverse-effect level was 0.1 microg PFOS/g egg.

Alkanesulfonic Acids↗
PubMed2005

Managing the wildlife reservoir of Mycobacterium bovis: the Michigan, USA, experience.

Historical, social and economic factors combined to provide a focus where bovine tuberculosis has become established in free-ranging wildlife in northeastern lower Michigan. White-tailed deer, the primary reservoir and maintenance host of tuberculosis, are highly valued by the public, and particularly hunters, for cultural and economic reasons. Since 1995, significant progress has been made in defining and reducing the reservoir of tuberculosis in deer. As yet, no other wildlife species has been shown to play an epidemiologically important role in the disease cycle. The importance of deer and deer hunting to Michigan has uniquely shaped tuberculosis control policies, and poses ongoing challenges as wildlife managers strive to maintain momentum for broad control strategies, and develop focused strategies that are publicly acceptable. Even if momentum and funding can be maintained, tuberculosis will likely continue to be present for a decade or longer. Thus, cattle producers waiting for tuberculosis to be eradicated from wildlife to eliminate risks to their herds and markets face disappointment for the foreseeable future. Such unrealistic expectations also place Michigan's federal tuberculosis accreditation status at perpetual risk. Accredited free status is unlikely to be regained without accompanying changes in cattle management. In Michigan, management of tuberculosis has clearly demonstrated that social issues and public approval are likely to be the critical limiting factors in control.

Animals↗
PubMed2004

Reproductive responses of common carp (Cyprinus carpio) exposed in cages to influent of the Las Vegas Wash in Lake Mead, Nevada, from late winter to early spring.

The Las Vegas Wash (LW) delivers tertiary-treated municipal wastewater effluent, nonpotable shallow groundwater seepage, and runoff from the urbanized Las Vegas Valley to Las Vegas Bay (LX) of Lake Mead. To investigate the potential for contaminants in LW influent to produce effects indicative of endocrine disruption in vivo, adult male and female common carp (Cyprinus carpio) were exposed in cages for 42-48 d at four sites in Lake Mead: LW, LX, and two reference locations in the lake. End points examined included gonadosomatic index; gonad histology; concentrations of plasma vitellogenin (VTG) and plasma sex steroids (17beta-estradiol (E2), testosterone (T), 11-ketotestosterone (11-KT)); plasma estrogen:androgen ratios (E2:T, E2:11-KT), in vitro production of T by gonad tissue, and hepatopancreas ethoxyresorufin O-deethylase activity. Few differences among fish caged at different sites were potentially attributable to exposure to contaminants

Androgens↗
PubMed2004

The sensitivity of gross necropsy, caudal fold and comparative cervical tests for the diagnosis of bovine tuberculosis.

Bovine tuberculosis (bTb) was diagnosed in 22 cattle herds in the northeast comer of Michigan's lower peninsula. Of these 22 herds, 494 animals in 7 herds were examined by gross necropsy, histopathologic exam, mycobacterial culture, and polymerase chain reaction (PCR) assay performed only on samples that were histologically compatible for bTb. Results of culture and PCR assay interpreted in parallel were used as the reference test for calculation of the sensitivity of 1) the caudal fold test (CFT), 2) the caudal fold and comparative cervical skin tests used in series (CFTCCTSER), and 3) gross necropsy. Mycobacterium bovis was isolated from 43 animals. Using all 7 herds, the sensitivities of the CFT, the CFTCCTSER, and gross necropsy were 93.02%, 88.37%, and 86.05%, respectively. When the data were stratified by low- and moderate-prevalence herds, the sensitivities were 83.33%, 75.0%, and 83.33% in low-prevalence herds and 96.77%, 93.55%, and 87.10% in moderate-prevalence herds. The sensitivities of the 2 skin tests were slightly higher when 2 or more gross lesions were present, and the sensitivity of gross necropsy was significantly higher (P = 0.049). The sensitivity of the CFT was found to be notably higher than most estimates in other studies; however, a direct comparison was not possible because the amount of purified protein derivative and the reference methods were different in this study compared with other published studies. Although the sensitivities are high, 2 of the 7 herds (29%) would have had 1 or more positive animals left in the herd if a test-and-removal program had been used. This suggests that when positive herds are identified, selective culling of skin test reactors is a less acceptable disease control strategy than is complete depopulation.

Animals↗
PubMed2004

Utility of high-performance liquid chromatography in the characterization of iatrogenic sodium diatrizoate-induced seizures in a horse.

Diagnostic evaluation of a mildly ataxic young gelding Quarterhorse included a contrast myelogram. Unfortunately, sodium diatrizoate was inappropriately administered by intrathecal injection resulting in severe unrelenting seizure activity and necessitated the destruction of the animal. The contrast agent was identified by analyzing cerebrospinal fluid by high-performance liquid chromatography and confirmed with probe mass spectrometric analysis. This contrast agent is highly ionic, has high osmolarity, and also blocks neurotransmission at specific receptors; for these reasons it is contraindicated for use in myelography. This is the first report of intrathecal administration of this agent in a horse, although there has been a previous report of similar untoward reactions in a dog, and numerous cases have been reported in humans.

Animals↗
PubMed2004

A comprehensive study of Easter lily poisoning in cats.

This study was conducted with 3 objectives in mind: first, to identify the toxic fraction (aqueous or organic) in leaves and flowers; second, to identify diagnostic marker(s) of toxicosis in cats; and, third, to evaluate the morphologic effects of intoxication. The study was conducted in 2 phases. Phase 1 was to identify which extract, organic or aqueous, was nephrotoxic and also to determine the appropriate dose for use in the phase 2 studies. Results indicated that only the aqueous extracts of leaves and flowers were nephrotoxic and pancreotoxic. To identify the proximate toxic compound, cats in the phase 2 study were orally exposed to subfractions of the aqueous flower extract, 1 subfraction per cat. Results confirmed vomiting, depression, polyuria, polydipsia, azotemia, glucosuria, proteinuria, and isosthenuria as toxic effects of the Easter lily plant. Another significant finding in serum was elevated creatinine kinase. Significant histologic kidney changes included acute necrosis of proximal convoluted tubules and degeneration of pancreatic acinar cells. Renal ultrastructural changes included swollen mitochondria, megamitochondria, edema, and lipidosis. Subfraction IIa3 of the aqueous floral extract contained most of the toxic compound(s). These studies reproduced the clinical disease, identified the most toxic fraction of the Easter lily, and helped characterize the clinical pathology, histopathology, and ultrastructural pathology associated with the disease.

Animals↗
PubMed2004

Tissue tropism and bursal transformation ability of subgroup J avian leukosis virus in White Leghorn chickens.

In Experiment 1, a monoclonal antibody against the envelope glycoprotein (gp85) of subgroup J avian leukosis virus (ALV-J) was used to study the distribution of ALV-J in various tissues of White Leghorn chickens inoculated as embryos with the strain ADOL-Hcl of ALV-J. At 2 and 6 wk of age, various tissues from infected and control uninfected chickens were tested for the presence of ALV-J gp85 by immunohistochemistry. In Experiment 2, using the methyl green-pyronine (MGP) stain, sections of bursa of Fabricius (BF) from chickens of line 15I5 x 7(1), inoculated with ALV-J or Rous-associated virus-1 (RAV-1), a subgroup A ALV, at hatch were examined for transformation of bursal follicles at 4 and 10 wk of age. In Experiment 1, specific staining indicative of the presence of ALV-J gp85 was noted at both 2 and 6 wk of age in the adrenal gland, bursa, gonads, heart, kidney, liver, bone marrow, nerve, pancreas, proventriculus, spleen, and thymus. In Experiment 2, by 10 wk of age, transformed bursal follicles were detected in MGP-stained sections of BF in only one of five (20%) chickens inoculated with ALV-J at hatch, compared with five of five (100%) chickens inoculated with RAV-1. The data demonstrate distribution of ALV-J gp85 in various tissues of White Leghorn chickens experimentally inoculated as embryos with the virus. The data also confirm our previous observation that ALV-J is capable of inducing transformation of bursal follicles, albeit the incidence is less frequent than that induced by subgroup A ALV.

Animals↗
PubMed2004

Estimating the true prevalence of Mycobacterium bovis in hunter-harvested white-tailed deer in Michigan.

Apparent prevalence, although useful as a consistent index, may underestimate the true prevalence of disease. In Michigan, the ability to estimate the true prevalence of bovine tuberculosis (TB; caused by Mycobacterium bovis) in free-ranging white-tailed deer (Odocoileus virginianus) will become increasingly important to accurately assess progress towards eradication. Our objectives were threefold: to estimate the true prevalence of M. bovis in free-ranging deer in Michigan, to evaluate the effectiveness of existing TB surveillance methods, and to indirectly assess whether TB epidemiologic data from captive cervid herds can be meaningfully extrapolated to free-ranging populations. The study population consisted of all free-ranging deer submitted for TB testing in 2001 from six townships in northeastern Lower Michigan. Tissue samples of tonsil and cranial lymph nodes were collected bilaterally from all deer eligible for the study that did not have gross lesions suggestive of TB (n = 701). Samples were subjected to histopathologic, acid-fast (AF) staining, mycobacterial culture, and polymerase chain reaction (PCR) testing. Seven deer cultured positive for M. bovis that would not have been detected by current surveillance, yielding apparent and true prevalence estimates (95% confidence limits) of 2.7% (1.6, 3.8) and 3.6% (2.3, 4.9), respectively. The sensitivity, specificity, and positive and negative predictive values of the current surveillance protocol were 75, 100, 100, and 99%, respectively. Histologic lesions were present only in tonsils, and ranged from simple necrosis to caseation, suppuration, and granuloma formation. Acid-fast staining and PCR detected M. bovis in only one of the seven culture-positive deer. Our study provides the first estimate of the true prevalence of M. bovis in Michigan's free-ranging deer population and suggests modest underestimation of that prevalence by current surveillance. This study also suggests that caution is warranted when extrapolating epidemiologic data on TB in captive cervids to free-ranging populations and confirms the pivotal role of the tonsil in early infections.

Animals↗
PubMed2004

Sarcoptic mange in raccoons in Michigan.

Sarcoptic mange is a cause of pruritic skin disease in domestic dogs and a wide range of wildlife species. We describe sarcoptic mange in free-ranging raccoons (Procyon lotor). Three adult raccoons from upper Wayne County, Michigan (USA), were captured, killed, and submitted for diagnostic evaluation. The animals were intensely pruritic, and two had advanced alopecic and crusting lesions over their dorsum and hind limbs. Skin scrapings and skin biopsies revealed crusting and hyperkeratotic dermatitis with high numbers of Sarcoptes scabiei adults, larvae, nymphs, and eggs. These raccoons were not otherwise debilitated, with minimal internal parasites, good body condition, and no evidence of infectious bacterial or viral diseases. Because sarcoptic mange is highly contagious and affects many species, including humans, transiently, it is important that wildlife biologists and rehabilitators include sarcoptic mange in their differential list for raccoons exhibiting pruritus and alopecia.

Alopecia↗
PubMed2004

Mercury and persistent organic pollutant concentrations in African fish eagles, marabou storks, and Nile tilapia in Uganda.

The purpose of this research was to evaluate persistent organic pollutant (POP) and mercury concentrations in tissues of African fish eagles (Haliaeetus vocifer) and Nile tilapia (Oreochromis niloticus) from Lake Victoria near Entebbe and Lake Mburo, Uganda. Marabou stork (Leptoptilos crumeniferus) nestlings from urban Kampala (40 km from Entebbe) also were sampled for POPs and mercury. Total mercury was measured in the breast feathers of eight nestling and 10 adult African fish eagles from Lake Mburo, 10 nestling and five adult African fish eagles from Lake Victoria near Entebbe, and 20 nestling marabou storks from Kampala from June 2002 through January 2003. Mercury concentrations in all samples were below levels associated with adverse effects in similar species. Mercury concentrations were significantly higher in eagle adults and nestlings from Entebbe than in adults and nestlings from Lake Mburo (P< or =0.05). No significant differences (P> or =0.05) were found in mercury concentrations between sexes or between the entire fish eagle population sampled at Entebbe and marabou stork nestlings sampled at nearby Kampala. Plasma samples from the same birds were analyzed for 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane, aldrin, hexachlorocyclohexane (alpha-HCH), dieldrin, endrin, heptachlor and their metabolites, as well as total polychlorinated biphenyls (PCBs). Nile tilapia whole-body cross sections collected from Lake Mburo (n=3) and Lake Victoria near Entebbe (n=8) also were analyzed for these POPs and mercury. No samples contained POPs or PCBs at the limits of detection except for 4,4'-1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene in five adult eagle plasma samples (0.0026+/-0.0015 ppm wet weight) and five Nile tilapia samples (0.002+/-0.001 ppm wet weight) from Entebbe.

Animals↗
PubMed2004

Clinical pathology and morphometrics of African fish eagles in Uganda.

Packed cell volumes (PCVs) and plasma chemistry parameters were measured in 15 adult and 18 nestling African fish eagles (Haliaeetus vocifer) sampled from June 2002 through January 2003 in Uganda. Morphologic measurements were obtained from 15 adult eagles. All eagles were examined for blood parasites and sexed by examination of DNA from red blood cells. Ten adults and eight nestlings were sampled from Lake Mburo and five adults and 10 nestlings were sampled from Lake Victoria near Entebbe, Uganda. Analysis of variance was conducted to assess the association between site, age, sex, and plasma chemistry parameters and the association between sex and morphologic characteristics. Plasma chemistry values for nestling and adult African fish eagles were similar to those reported for other captive and free-ranging eagle species. Packed cell volumes for nestling African fish eagles were markedly lower than values reported for nestlings of other eagle species, although the mean estimated age of nestlings sampled also was lower. A significant association (P < or =0.05) was found between PCV of nestling eagles and study site (lower at Lake Mburo) but no association was found between PCV and nestling body weight (P> or =0.05). An unidentified Plasmodium sp. was present in erythrocytes of three nestlings from Lake Mburo. No other blood parasites were seen. There was significant variation (P< or =0.05) in PCV, calcium, phosphorous, potassium, cholesterol concentrations, and creatine kinase activity between adults and nestlings; all were lower in adults. Aspartate transaminase activity was higher in adults. Like other Haliaeetus sp., body weight, bill depth, culmen length, footpad length, and hallux length as well as bill depth measurements were significantly (P < or = 0.05) greater for females than males. The objective of the study was to provide baseline biologic and physiologic information that may prove useful in the management and study of captive and wild populations of African fish eagles.

Aging↗
PubMed2004

Clinical pathology of nestling marabou storks in Uganda.

Packed cell volumes (PCV) and plasma chemistry parameters were measured in 20 nestling marabou storks (Leptoptilos crumeniferus) in January 2003 that were a part of a colony located in the center of the city of Kampala, Uganda. There were no significant differences (P> or =0.05) in plasma chemistry values or PCV between sexes with the exception of globulin and total plasma protein values, which were higher in females. There were significant differences (P< or =0.05) in blood glucose, creatine kinase, and globulin levels between birds of different body weight. Total plasma protein, uric acid, phosphorous, and creatine kinase were generally higher relative to published data on other avian species, including nestling white storks (Ciconia ciconia).

Aging↗
PubMed2003

Prevalence and tissue distribution of Besnoitia darlingi cysts in the Virginia opossum (Didelphis virginiana) in Michigan.

Specimens of Virginia opossums (Didelphis virginiana) in Michigan were examined over 1 year to document the presence of Besnoitia darlingi cysts. Cyst morphology, prevalence, seasonal variation, and tissue sites of isolation were studied. Histology and ultrastructural features of the detected cysts and bradyzoites were consistent with B. darlingi. In the opossums, B. darlingi had intracellular tissue cysts. Tissue cysts had a mean diameter of 560 microm and were separated from the host tissue by a thick (5-20 microm) cyst wall. Overall prevalence of B. darlingi cysts in opossums was 10.9% (15/137). Variations in the prevalence were detected during spring (3/17; 17.6%), summer (10/34; 29.4%), and fall (2/60; 3.3%). No cysts were detected in the specimens examined during winter (0/26; 0%). Numerous B. darlingi cysts were detected in ears, conjunctiva, tongue, abdominal muscles, diaphragm, stomach, heart, liver, kidney, lung, and spleen. Cysts were detected mainly in adult female opossums that were debilitated. Ear was the most frequent organ from which the cysts were reported (10/15; 66.7%) when compared individually with other body tissues (P<0.05).

Animals↗
PubMed2003

Effects of temperature and host cell type on the in vitro growth and development of Sarcocystis falcatula.

The growth and development of Sarcocystis falcatula in four different cultured cell lines [vero cells, bovine turbinate (BT) cells, equine dermal (ED) cells, and human Hep-2 cells] inoculated with culture-derived merozoites are described. Parasite yields, viability, and plaque forming efficiency were used to compare the growth between different cell lines. Additionally, each cell line was tested at two temperatures of incubation (35 degrees C and 37 degrees C). Based on yield, viability, and plaque forming efficiency, vero cells and BT cells supported growth of S. falcatula better than ED cells and Hep-2 cells. During an 18-day culture period, vero cells produced a mean total of 1.3x10(7) S. falcatula merozoites/T25 flask, BT cells 1.1x10(7), ED cells 0.9x10(7), and Hep-2 cells 0.7x10(7) merozoites/T25 flask. All experimental cell lines grew equally well at 35 degrees C and 37 degrees C. The type of host cells but not the temperature of incubation had a profound effect on the in vitro growth and proliferation of S. falcatula.

Animals↗