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Biomedical subjects

A A Cunningham

Publications and source records attributed to A A Cunningham.

At least 19 recordsLinked to original sources
PubMed2006

Emerging epidemic diseases of frogs in Britain are dependent on the source of ranavirus agent and the route of exposure.

A series of transmission studies was conducted to investigate the aetiology, or aetiologies, of emerging fatal epidemic disease syndromes affecting the common frog (Rana temporaria) in Britain. The syndromes, characterized by skin ulceration or systemic haemorrhages, were induced upon exposure to lesion homogenates or cultured ranavirus. The re-isolation of ranavirus from experimentally affected frogs fulfilled Koch's postulates. Aeromonas hydrophila, previously associated with similar lesions, was not significant to disease development. Unexpectedly, disease outcomes were influenced by both the source of agent and the route of exposure, indicating that different ranaviruses with different tissue tropisms and pathogeneses (possibly similar to quasi-species in RNA virus populations) are circulating in the British common frog population. Our findings confirm that ranavirus disease has emerged as an important cause of amphibian mortality in Britain.

Aeromonas hydrophila↗
PubMed2006

Diclofenac disposition in Indian cow and goat with reference to Gyps vulture population declines.

Gyps vultures across India are declining rapidly and the NSAID diclofenac has been shown to be the major cause. Vultures scavenge livestock carcasses that have been treated with diclofenac within the days preceding death. We present data on diclofenac disposition in Indian cow and goat, and field data on the prevalence of diclofenac in carcases in the environment. In the disposition experiment, animals were treated with a single intramuscular injection of diclofenac at 1000 microg kg-1 bw. In cow, diclofenac was detectable in liver, kidney and intestine up to 71 h post-treatment; in plasma, half-life was 12.2 h. In goat, tissue residues were undetectable after 26 h. Prevalence of diclofenac in liver from 36 dead livestock collected in the field was 13.9%. Data suggest that diclofenac residues in Indian cow and goat are short-lived, but diclofenac prevalence in carcasses available to vultures may still be very high.

Animals↗
PubMed2006

Skeletal deformities and mortality in grey herons (Ardea cinerea) at Besthorpe heronry, Nottinghamshire.

Dead and sick grey heron chicks with multiple fractures of the leg and wing bones and/or bone deformities have been reported at Besthorpe Nature Reserve heronry in north Nottinghamshire since 1996. Forty-five grey heron carcases were examined, 35 from the Besthorpe colony and 10 from other colonies where bone disease was not known to occur. On the basis of the results of radiological studies, postmortem examinations, peripheral quantitative computed tomography scanning and four-point bending tests, it was concluded that the skeletal abnormalities were probably due to metabolic bone disease.

Animals↗
PubMed2005

Exposure of garden birds to aflatoxins in Britain.

Aflatoxins are potent biological toxins that have been shown to exert a range of acute and chronic pathological effects. Multiple mortality events of waterfowl caused by acute aflatoxicosis have been documented in the USA. However, international concern has recently been expressed regarding the potential effects of chronic exposure of wildlife species to low levels of dietary aflatoxin. This study documents for the first time the presence of hepatic aflatoxin residues in British wild birds: two passerine species, the house sparrow (Passer domesticus) and greenfinch (Carduelis chloris). Further research is required to investigate the source of the dietary aflatoxins and their pathological significance, if any, for wild birds in Britain.

Aflatoxins↗
PubMed2005

Acute and chronic gas bubble lesions in cetaceans stranded in the United Kingdom.

The first evidence suggestive of in vivo gas bubble formation in cetacea, including eight animals stranded in the UK, has recently been reported. This article presents the pathologic findings from these eight UK-stranded cetaceans and two additional UK-stranded cetacean cases in detail. Hepatic gas-filled cavitary lesions (0.2-6.0 cm diameter) involving approximately 5-90% of the liver volume were found in four (two juvenile, two adult) Risso's dolphins (Grampus griseus), three (two adult, one juvenile) common dolphins (Delphinus delphis), an adult Blainville's beaked whale (Mesoplodon densirostris), and an adult harbour porpoise (Phocoena phocoena). Histopathologic examination of the seven dolphin cases with gross liver cavities revealed variable degrees of pericavitary fibrosis, microscopic, intrahepatic, spherical, nonstaining cavities (typically 50-750 microm in diameter) consistent with gas emboli within distended portal vessels and sinusoids and associated with hepatic tissue compression, hemorrhages, fibrin/organizing thrombi, and foci of acute hepato-cellular necrosis. Two common dolphins also had multiple and bilateral gross renal cavities (2.0-9.0 mm diameter) that, microscopically, were consistent with acute (n = 2) and chronic (n = 1) arterial gas emboli-induced renal infarcts. Microscopic, bubblelike cavities were also found in mesenteric lymph node (n = 4), adrenal (n = 2), spleen (n = 2), pulmonary associated lymph node (n = 1), posterior cervical lymph node (n = 1), and thyroid (n = 1). No bacterial organisms were isolated from five of six cavitated livers and one of one cavitated kidneys. The etiology and pathogenesis of these lesions are not known, although a decompression-related mechanism involving embolism of intestinal gas or de novo gas bubble (emboli) development derived from tissues supersaturated with nitrogen is suspected.

Animals↗
PubMed2004

Mortality of globally threatened Sarus cranes Grus antigon from monocrotophos poisoning in India.

Globally threatened Sarus cranes Grus antigon are resident at Keoladeo National Park World Heritage site and the surrounding area near Bharatpur, Western Rajasthan, India. In winter, they are joined by c. 200 wintering common cranes Grus grus. On 23 November 2000, 15 Sarus cranes and three common cranes were found dead in a field adjacent to the park, where wheat seed had been sown the previous day. Chemical analyses of seed samples from the field and the cranes' alimentary tract contents identified residues of the organophosphate insecticide monocrotophos. Monocrotophos concentrations of 0.8 and 1.8 ppm were found in wheat samples, and 0.2-0.74 ppm (x=0.33) in the alimentary tract contents of five of the seven cranes examined. No other organophosphate or organochlorine pesticides were detected. We conclude that the cranes died from monocrotophos poisoning after eating treated seed. We discuss similar incidents of avian mortality, and recommend that measures be taken to reduce these.

Animal Feed↗
PubMed2003

Parasitism by Dermocystidium ranae in a population of Rana esculenta complex in Central Italy and description of Amphibiocystidium n. gen.

We report the enigmatic parasite Dermocystidium ranae in a green frog population (Solomeo, Umbria, Italy) of the Rana esculenta complex, consisting of the parental species R. lessonae (L) and hybrid form R. esculenta (E). In this population a rapid 50% decline of the parental form L was observed. Large dermal U-shaped cysts of D. ranae were found primarily on the ventral aspect of infected individuals, with a significantly higher incidence of infection in the parental species compared to the clonal hybrid. In each form, however, there was little pathological change associated with infection, and the cause of the recent declines of R. lessonae at this site remains unknown. In this paper we present the first ultrastructural description of an amphibian Dermocystidium sp. and we review the taxonomy of Dermocystidium, Dermosporidium and Dermomycoides spp. from amphibians. We conclude that Dermosporidium multigranulare Broz & Kulda, 1954 is synonymous with Dermocystidium ranae Guyénot & Naville, 1922 and, due to lack of sufficient differences between genera and significant dissimilarities with fish Dermocystidium spp., the 3 amphibian genera are synonymous. We propose that they should be designated to a new genus, Amphibiocystidium n. gen., and Dermocystidium retained for those species parasitic in fish.

Animals↗
PubMed2002

First identification of a ranavirus from green pythons (Chondropython viridis).

Ten juvenile green pythons (Chondropython viridis) died or were euthanized shortly after having been illegally imported into Australia from Indonesia in 1998. Histologic examination of two of the three snakes that died revealed moderately severe chronic ulceration of the nasal mucosa and focal or periacinar degeneration and necrosis of the liver. In addition there was severe necrotizing inflammation of the pharyngeal submucosa accompanied by numerous macrophages, heterophils, and edema. An iridovirus was isolated in culture from several tissues and characterized by immunohistochemistry, electron microscopy, enzyme-linked immunosorbent Assay, polyacrylamide gel electrophoresis, polymerase chain reaction and sequence analysis, restriction endonuclease digestion, and DNA hybridization. This is the first report of a systemic ranavirus infection in any species of snake and is a new member of the genus, Ranavirus.

Amino Acid Sequence↗
PubMed2001

Status of wildlife health monitoring in the United Kingdom.

There is a clear need to monitor the health of wildlife in the UK, to help to understand the population dynamics of endangered species and to detect any harm to the welfare of wild animals caused by human beings. Despite previous proposals, there has been little progress in the development of a national programme of monitoring. With notable exceptions, the current schemes for investigating the morbidity and mortality of wild animals cover only limited groups of animals and are fragmented and uncoordinated. They consist of statutory schemes of restricted scope, and studies in universities, institutes and wildlife rehabilitation centres with limited funding. As a result, significant disease incidents may remain undetected and others may not be investigated fully, posing risks to the welfare and conservation of wildlife, the welfare of domestic animals, and in some cases to human health. Coordinated national schemes for the surveillance of the health of wildlife are already established in France, the USA and Canada and their best characteristics could be used to develop a scheme for the UK.

Animal Diseases↗
PubMed2001

Anthropogenic environmental change and the emergence of infectious diseases in wildlife.

By using the criteria that define emerging infectious diseases (EIDs) of humans, we can identify a similar group of EIDs in wildlife. In the current review we highlight an important series of wildlife EIDs: amphibian chytridiomycosis; diseases of marine invertebrates and vertebrates and two recently-emerged viral zoonoses, Nipah virus disease and West Nile virus disease. These exemplify the varied etiology, pathogenesis, zoonotic potential and ecological impact of wildlife EIDs. Strikingly similar underlying factors drive disease emergence in both human and wildlife populations. These are predominantly ecological and almost entirely the product of human environmental change. The implications of wildlife EIDs are twofold: emerging wildlife diseases cause direct and indirect loss of biodiversity and add to the threat of zoonotic disease emergence. Since human environmental changes are largely responsible for their emergence, the threats wildlife EIDs pose to biodiversity and human health represent yet another consequence of anthropogenic influence on ecosystems. We identify key areas where existing expertise in ecology, conservation biology, wildlife biology, veterinary medicine and the impact of environmental change would augment programs to investigate emerging diseases of humans, and we comment on the need for greater medical and microbiological input into the study of wildlife diseases.

Animal Diseases↗
PubMed2001

Preductal aortic coarctation and patent ductus arteriosus in a Sumatran tiger (Panthera tigris sumatrae) cub.

Preductal aortic coarctation and patent ductus arteriosus are described in a neonatal Sumatran tiger, Panthera tigris sumatrae. Eight days postpartum, the cub appeared weak, and it was separated from the dam for hand rearing. On examination it was dehydrated and hypothermic. Despite treatment, the animal's condition worsened and the cub died 12 days postpartum. Gross postmortem and histologic examinations revealed a preductal aortic coarctation and patent ductus arteriosus with a patent foramen ovale and moderate dilatation of the right ventricle of the heart. Focal pneumonia and mild hepatitis were also present; however, diffuse pulmonary congestion and edema were considered to be the proximate cause of death.

Animals↗
PubMed2000

Emerging infectious diseases of wildlife--threats to biodiversity and human health.

Emerging infectious diseases (EIDs) of free-living wild animals can be classified into three major groups on the basis of key epizootiological criteria: (i) EIDs associated with "spill-over" from domestic animals to wildlife populations living in proximity; (ii) EIDs related directly to human intervention, via host or parasite translocations; and (iii) EIDs with no overt human or domestic animal involvement. These phenomena have two major biological implications: first, many wildlife species are reservoirs of pathogens that threaten domestic animal and human health; second, wildlife EIDs pose a substantial threat to the conservation of global biodiversity.

Agriculture↗
PubMed2000

Comparative studies of piscine and amphibian iridoviruses.

A total of 30 iridoviruses collected from Australia, South-East Asia, North America, South America and Europe were characterised. With the exception of the South-East Asian iridoviruses all viruses were found to belong to the genus Ranavirus. All viruses, except those originating from South-East Asia, cross-reacted with antisera against epizootic haematopoietic necrosis virus (EHNV). Viruses or virus-infected cells were examined using electron microscopy, SDS PAGE, restriction endonuclease (RE) digestion, DNA hybridisation, and DNA sequencing. Data from RE digestion of genomic DNA, and from the sequencing of PCR products indicated that the viruses generally grouped according to their geographic and taxonomic (i.e. amphibian or fish) origin. The one exception to this was the viruses from the United Kingdom that grouped with the North American ranaviruses. The differences between specified genomic regions were small. To assess the validity of the differences in sequence homology, similar studies were performed with different isolates from two viruses (EHNV and Guatopo virus (GV), collected from different animals at different locations and time). The sequence data showed complete homology for the isolates for any one virus over the 200 and 586 bp regions examined. Collectively, the data showed that the coding region for the major coat protein (MCP) is stable for any one species (e.g. EHNV).

Amphibians↗
PubMed1998

Chytridiomycosis causes amphibian mortality associated with population declines in the rain forests of Australia and Central America.

Epidermal changes caused by a chytridiomycete fungus (Chytridiomycota; Chytridiales) were found in sick and dead adult anurans collected from montane rain forests in Queensland (Australia) and Panama during mass mortality events associated with significant population declines. We also have found this new disease associated with morbidity and mortality in wild and captive anurans from additional locations in Australia and Central America. This is the first report of parasitism of a vertebrate by a member of the phylum Chytridiomycota. Experimental data support the conclusion that cutaneous chytridiomycosis is a fatal disease of anurans, and we hypothesize that it is the proximate cause of these recent amphibian declines.

Animals↗