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Biomedical subjects

M R Alley

Publications and source records attributed to M R Alley.

At least 19 recordsLinked to original sources
PubMed2006

Infectivity and persistence of an outbreak strain of Salmonella enterica serotype Typhimurium DT160 for house sparrows (Passer domesticus) in New Zealand.

AIM: To examine the infective dose, incubation period and disease progression of an isolate of Salmonella enterica serotype Typhimurium definitive type 160 (DT160) originating from a naturally-infected house sparrow (Passer domesticus) during an outbreak of the disease in New Zealand. METHODS: Thirty-six house sparrows captured from the wild and free of Salmonella spp were divided into six groups of six birds, housed individually, and inoculated orally with phosphate buffered saline (PBS) or 10(1), 10(2), 10(3), 10(5), 2 x 10(8) colony forming units (cfu) of the outbreak strain of S. Typhimurium DT160. The birds were observed for 10 days for clinical signs and/or mortality, and faecal samples were collected to determine excretion of S. Typhimurium. The birds were euthanised 11 days post-inoculation (p.i.) and a wide range of tissue samples were collected for histopathological examination, and culture and typing of Salmonella spp. Macro-restriction profiling by pulsed-field gel electrophoresis (PFGE) using XbaI was performed for the epidemiological typing of S. Typhimurium DT160 isolates. RESULTS: Mortality in house sparrows inoculated with S. Typhimurium DT160 was dose-dependent, and 2/6 birds inoculated with 10(5) cfu and all six birds inoculated with 2 x 10(8) cfu died during the study. Infected sparrows displayed few clinical signs, apart from diarrhoea and/or polyuria, fluffed plumage, and sitting on the floor of the cage. Faecal excretion of DT160 occurred briefly in two birds inoculated with 10(2) cfu and four birds inoculated with 10(3) cfu, on most days in five birds inoculated with 10(5) cfu, and continuously in six birds inoculated with 2 x 10(8) cfu. DT160 was isolated from the livers of three birds which received 10(3) cfu, five birds dosed with 10(5) cfu, and all six birds given 2 x 10(8) cfu. Following necropsy, histopathological lesions similar to those seen in the natural disease were observed in the liver or spleen of three birds which received 10(3) cfu, and all birds dosed with > or =10(5) cfu. CONCLUSION: The results indicate that an isolate of S. Typhimurium DT60 originating from house sparrows in New Zealand is pathogenic to these birds and that the response is dose dependent. The persistence and excretion of the pathogen may last for at least 10 days. This confirms that sparrows infected with DT160 could be a source of infection to humans and other in-contact animals.

Animals↗
PubMed2005

Fatal levamisole toxicosis of captive kiwi (Apteryx mantelli).

CASE HISTORY: Nine of 24 captive kiwi treated with oral levamisole at a dose between 25-43 mg/kg showed signs of respiratory distress. Six died within 4 h of treatment and the remaining three made a full recovery within 24 h. CLINICAL AND PATHOLOGICAL FINDINGS: Within 3-4 h of treatment, the affected birds had an elevated respiratory rate, mucoid nasal discharge and rapidly became comatose. Post mortem examination revealed accumulation of thick mucus in the oral cavity and trachea. There was severe pulmonary congestion and oedema and early bronchopneumonia in the lungs of five of the birds. In two birds, there was acute hepatic degeneration and necrosis and one bird had acute pancreatic degeneration and necrosis. DIAGNOSIS: Acute levamisole toxicity. CLINICAL RELEVANCE: Kiwi were acutely sensitive to levamisole toxicity at doses that are well within the safe range for domestic poultry. Levamisole should not be used as an anthelmintic in kiwi.

Animals↗
PubMed2005

Aspergillosis in a North Island robin (Petroica longipes).

CASE HISTORY: A 3-year-old female North Island robin (Petroica longipes) was found dead on Tiritiri Matangi Island during the breeding season. CLINICAL FINDINGS: The bird was in poor condition, and there was a 13 x 8 mm granulomatous mass in the thoracic cavity causing displacement of the heart and left lung. Histologically, the mass was a large granuloma infiltrated with fungal hyphae, and the liver contained multifocal aggregates of inflammatory cells. DIAGNOSIS: Thoracic aspergillosis and multifocal hepatitis. CLINICAL RELEVANCE: Determining the causes of death in populations of wild birds is often hampered by a lack of recovery of carcasses, autolysis and poor clinical history. In this case, the life history of the bird was known and recovery of the body was relatively swift. This is the first published description of aspergillosis in a free-living North Island robin.

Animals↗
PubMed2005

Erysipelas in the critically endangered kakapo (Strigops habroptilus).

This paper describes the effect of a disease outbreak on the success of a translocation for conservation management in a critically endangered species. Three juvenile kakapo from a group of 19 translocated birds died within 72 h of transport between New Zealand offshore islands. Clinical findings, gross necropsy changes, cytology, histopathology and bacterial culture confirmed systemic disease caused by Erysipelothrix rhusiopathiae. On the island from which the kakapo were sourced, positive cultures of E. rhusiopathiae were obtained from the medulla of the ulna from 10 out of 15 seabird carcasses examined, suggesting that this could be the source of infection for the kakapo. Immediately after the diagnosis, all of the translocated birds were re-captured and treated with antibiotics. A vaccination programme has commenced using a commercial killed bacterin developed for turkeys. The disease outbreak has had costly implications for the population and conservation management of the species. This is the first report of erysipelas in wild parrots, and the first report of the management of erysipelas in a critically endangered wild population of birds.

Animals↗
PubMed2003

Identifying predators - a role for veterinary pathologists (abstract).

Predator identification has traditionally been the domain of ecologists who have relied on the feeding sign left by various predator species at the nest or carcass. Thus destructive animals such as cats and dogs can be distinguished from relatively clean predators such as mustelids and messy predators such as possums and rats. The presence of scats or foot imprints, and the location of the nest or carcass are also useful signs, however in many cases it may be impossible to distinguish between predators and scavengers. New technology such as time-lapse photography and video surveillance are valuable tools but still cannot monitor every event. Veterinary pathology can play a useful role by carefully examining and recording the site and severity of lesions and distinguishing between ante- and post mortem tissue damage, using histopathology if necessary. Distances between the canine teeth can be measured from bite marks in the skin and subcutaneous tissues, and mammalian fur on the claws and beak of larger birds can be identified by measuring fibre length and diameter.

Journal Article↗
PubMed2003

Experimental infection with BCG as a model of tuberculosis in the brushtail possum (Trichosurus vulpecula).

AIMS: To study the development and progression of lesions produced following experimental inoculations of possums with Bacille Calmette-Guérin (BCG) Pasteur Strain 1173P2 and to compare these with lesions that occurred following natural Mycobacterium bovis infection. METHODS: Possums were inoculated with 5 x 106 colony forming units (cfu) of BCG via the intra-dermal (I/D) route into the dorsum of the neck (n=38) or the left brachium (n=7),orally (n=10), via the endobronchial (E/B) route (n=12), or intravenously (I/V) (n=10, half of which received 5 x 106 cfu and half of which received 5 x 107 cfu of BCG). The possums were humanely killed between 1-4 weeks post inoculation (p.i.), and the nature and distribution of lesions examined grossly and histopathologically. RESULTS: The distribution of lesions following I/D inoculation via either route was similar to that of the natural disease, but there were few lesions in the lung. Endobronchial inoculation resulted in pulmonary disease but produced few lesions outside the respiratory tract. Lesions produced by I/V inoculation were similar in distribution to those seen in terminally ill tuberculous possums. No lesions were produced following oral inoculation. Regression of lesions commenced after 3 weeks p.i. CONCLUSIONS: Although the phenomenon of lesion resolution restricts the use of BCG to the study of early lesion development, it avoids the overwhelming disease induced using M. bovis and thus allows the early phases of the development and progression of tuberculosis in this species to be observed. Intradermal inoculation produced evidence that infection through the skin is associated with lesions in superficial lymph nodes, whereas pulmonary disease was associated with E/B inoculation. The results are consistent with the hypothesis that both percutaneous and respiratory routes are important in natural infection of possums with M. bovis.

Journal Article↗
PubMed2003

Bacterial sinusitis as a cause of beak deformity in an Antipodes Island parakeet (Cyanoramphus unicolor).

CASE HISTORY: From 26 days of age, an Antipodes Island parakeet (Cyanoramphus unicolor) was noted to have a severe beak deformity and reduced bodyweight gain compared to its nest mate. The bird was euthanised at 43 days of age. CLINICAL AND PATHOLOGICAL FINDINGS: The beak abnormality consisted of distortion of the right nares and severe shortening resulting in deviation of the upper maxilla to the right and cranially. On sectioning the head, copious mucoid material was found in the infraorbital sinus and the bony sinus architecture was disrupted. Histopathological examination of the infraorbital sinuses revealed a large focus of chronic but active inflammation, bony lysis on the right side and pockets of a mixed population of bacteria. DIAGNOSIS: Severe beak deformity, likely secondary to bacterial sinusitis. CLINICAL RELEVANCE: The case illustrates the need to look for underlying aetiologies to beak malformation, particularly in young parrots. KEYWORDS: Sinusitis, beak malformation, Antipodes Island parakeet, parrot, beak growth.

Journal Article↗
PubMed2003

New Zealand sea lion (Phocarctos hookeri) epidemic 2002 (abstract).

The New Zealand sea lion is a threatened species and two unusual events contributed to a decrease in recruitment in 2002. The first was a marked reduction (20%) in the number of pups born at the principal Auckland Island rookeries. Secondly, the mortality rate for pups was significantly elevated and was 33% by the end of February, almost three times the mean for that time of the year. Counts of females at rookeries indicated that the lowered fecundity was possibly due to a scarcity of food resources, supported by the fact that male pups (n=50) in 2002 grew poorly with the lightest recorded liveweights for the previous 8 years. Lowered fecundity may also have resulted from infection leading to foetal death, seen in an adult by-catch female, or abortion. Necropsies were conducted on 126/133 pups that died at Sandy Bay and for many the cause of death was multifactorial and included stillbirth, trauma, malnutrition, and severe anaemia caused by hookworm (Uncinaria spp) infection. An unusual disease presentation seen for the first time in 2002 was characterised by systemic bacterial infection that caused suppurative polyarthritis, severe necrotising fasciitis, myositis and osteomyelitis, suppurative peritonitis, pleuritis, or meningitis. For 41 pups, this syndrome was the primary cause of death and for an additional 16 it was a contributing factor along with hookworm infection or trauma. A consistent isolate has been Klebsiella pneumoniae with frequent isolations of Salmonella spp.

Journal Article↗
PubMed2002

An epidemic of salmonellosis caused by Salmonella Typhimurium DT160 in wild birds and humans in New Zealand.

AIM: This study reports an outbreak of salmonellosis due to S. Typhimurium DT160 which caused extensive mortality in wild birds and enteric disease in humans in New Zealand during the winter and spring months of the year 2000. METHODS: Necropsies were performed and microbiological examinations undertaken on wild birds from populations in which mass mortality was reported, and on captive indigenous birds which died suddenly during the winter and spring of 2000. Affected tissues were examined histologically and isolates of S. Typhimurium were phage typed and examined using pulsedfield gel electrophoresis (PFGE). Isolates of S. Typhimurium obtained from cases of human enteric disease which occurred during these months were phage typed, examined using PFGE and compared with the bird isolates. RESULTS: Central and northern areas of the South Island and the southern North Island were worst affected with die-offs of several hundreds of sparrows and other birds reported in rural areas. Mortalities reached a peak in winter (July-August) 2000 and decreased to small numbers during the spring and early summer. The birds usually died of an acute septicaemia with multifocal necrotising lesions in the liver and spleen. Human cases throughout the country increased gradually over the same period. Isolates from birds, livestock and humans examined using PFGE were indistinguishable from one another. CONCLUSION: This strain of Salmonellahas emerged as a major cause of septicaemia in wild birds in New Zealand. Because of the close association between house sparrows (Passer domesticus) and humans, the organism also poses a serious zoonotic risk. The possibility that the infection may spread to involve indigenous species needs investigation.

Journal Article↗
PubMed2002

Squamous cell carcinoma in a tuatara (Sphenodon punctatus).

CASE HISTORY: A mature male tuatara was presented with a history of recurrent cloacal prolapse. CLINICAL AND PATHOLOGICAL FINDINGS: The prolapsed tissue included a 12 mm diameter mass, which histologically showed cords and nodules of neoplastic epithelial cells. DIAGNOSIS: The mass was diagnosed as a squamous cell carcinoma with ulceration of the overlying stratified squamous epithelium and diffuse inflammation of the surrounding dermis. CLINICAL RELEVANCE: This case presented a rare opportunity to investigate squamous cell carcinoma in a long-lived lower vertebrate species. Future recurrence or metastasis of the mass may add useful information to the current base of knowledge of the behaviour of malignant neoplasms in reptiles.

Journal Article↗
PubMed2001

Complete genome sequence of Caulobacter crescentus.

The complete genome sequence of Caulobacter crescentus was determined to be 4,016,942 base pairs in a single circular chromosome encoding 3,767 genes. This organism, which grows in a dilute aquatic environment, coordinates the cell division cycle and multiple cell differentiation events. With the annotated genome sequence, a full description of the genetic network that controls bacterial differentiation, cell growth, and cell cycle progression is within reach. Two-component signal transduction proteins are known to play a significant role in cell cycle progression. Genome analysis revealed that the C. crescentus genome encodes a significantly higher number of these signaling proteins (105) than any bacterial genome sequenced thus far. Another regulatory mechanism involved in cell cycle progression is DNA methylation. The occurrence of the recognition sequence for an essential DNA methylating enzyme that is required for cell cycle regulation is severely limited and shows a bias to intergenic regions. The genome contains multiple clusters of genes encoding proteins essential for survival in a nutrient poor habitat. Included are those involved in chemotaxis, outer membrane channel function, degradation of aromatic ring compounds, and the breakdown of plant-derived carbon sources, in addition to many extracytoplasmic function sigma factors, providing the organism with the ability to respond to a wide range of environmental fluctuations. C. crescentus is, to our knowledge, the first free-living alpha-class proteobacterium to be sequenced and will serve as a foundation for exploring the biology of this group of bacteria, which includes the obligate endosymbiont and human pathogen Rickettsia prowazekii, the plant pathogen Agrobacterium tumefaciens, and the bovine and human pathogen Brucella abortus.

Adaptation, Biological↗
PubMed2001

The highly conserved domain of the Caulobacter McpA chemoreceptor is required for its polar localization.

We have fused GFP to the C-terminus of McpA to study chemoreceptor polar localization in Caulobacter crescentus. The full-length McpA-GFP fusion is polarly localized and methylated. The methylation is dependent on the chemoreceptor methyltransferase (cheR) and chemoreceptor methylesterase (cheB) genes present in the mcpA operon. C-terminal and internal deletions of McpA were constructed and fused to the N-terminus of GFP to identify the domains required for polar localization. When the R1 methylation domain was deleted, the McpA-GFP fusion was still polarly localized, suggesting that this domain is dispensable for polar localization. However, when the highly conserved domain (HCD), which is involved in interacting with CheW, was deleted either by an internal deletion or C-terminal deletion, the resulting McpA-GFP fusions were completely delocalized. When the mcpA operon, which contains the cheW and cheA homologues, was deleted, the full-length McpA-GFP fusion was delocalized. Although additional chemotaxis genes are required for the polar localization of McpA-GFP, the presence of the single polar flagellum is not required. However, in filamentous cells, which are frequently found in C. crescentus fliF mutants, the McpA-GFP fusion was observed at mid-cell positions.

Amino Acid Sequence↗
PubMed2001

Proteolysis of the Caulobacter McpA chemoreceptor is cell cycle regulated by a ClpX-dependent pathway.

Proteolysis is involved in cell differentiation and the progression through the cell cycle in Caulobacter crescentus. We have constitutively expressed the transmembrane chemoreceptor McpA from a multicopy plasmid to demonstrate that McpA degradation is modulated during the cell cycle. The level of McpA protein starts to decrease only when the swarmer cells differentiate into stalked cells. The reduction in McpA protein levels is maintained until the stalked cells develop into predivisional cells, at which point the level returns to that observed in swarmer cells. The cell-cycle-regulated degradation of McpA does not require the last 12 C-terminal amino acids, but it does require three amino acids (AAL) located 15 residues away from the C terminus. The ClpXP protease is essential in C. crescentus for viability, and thus, we tested McpA degradation in xylose conditional mutants. The effect on McpA degradation occurred within two generations from the start of ClpX depletion. The conditional mutants' growth rate was only slightly affected, suggesting that ClpX is directly involved in McpA proteolysis.

ATPases Associated with Diverse Cellular Activitie↗