Epidemiology of salmonellosis in garden birds in England and Wales, 1993 to 2003.

Salmonellosis has been reported as an important cause of mortality of garden birds in several countries, including Norway and Scotland. We investigated the frequency of the disease in garden birds submitted for postmortem examination by members of the public in England and Wales between 1993 and 2003, inclusive. We found salmonellosis to be the most frequent cause of death due to infectious disease in the garden birds submitted. This disease was confirmed in 7 of the 45 bird species that were examined postmortem, with the greenfinch (Carduelis chloris) and the house sparrow (Passer domesticus) most frequently affected. Salmonella Typhimurium definitive phage type (DT) 40, DT56 variant(v), and DT160 accounted for the majority of isolates. Salmonellosis incidents chiefly occurred in the English Midlands, the English/Welsh border region, and southern England. Variation in the temporal and spatial distribution of the phage types occurred over the study period. While birds were examined throughout the year, there was a marked winter seasonality in salmonellosis. A significant sex bias was observed in affected greenfinches, with males more frequently diagnosed with salmonellosis than females. No sex bias was observed for other affected species. Further research is required to determine if salmonellosis is an important constraint to the populations of affected species and if disease outbreaks are driven by human factors, such as provisioning.

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.

Exposure to heavy metals and infectious disease mortality in harbour porpoises from England and Wales.

We investigate whether long-term exposure to heavy metals, including immunosuppressive metals like mercury (Hg), is associated with infectious disease in a wild cetacean. Post-mortem investigations on 86 harbour porpoises, Phocoena phocoena, found dead along the coasts of England and Wales revealed that 49 of the porpoises were healthy when they died as a consequence of physical trauma (most frequently entrapment in fishing gear). In contrast, 37 porpoises died of infectious diseases caused by parasitic, bacterial, fungal and viral pathogens (most frequently pneumonia caused by lungworm and bacterial infections). We found that mean liver concentrations of Hg, selenium (Se), the Hg:Se molar ratio, and zinc (Zn) were significantly higher in the propoises that died of infectious disease compared to healthy porpoises that died from physical trauma. Liver concentrations of lead (Pb), cadmium (Cd), copper (Cu) and chromium (Cr) did not differ between the two groups. Hg, Se, and the Hg:Se molar ratio were also positively correlated with age. The association between Zn concentration and disease status may result from Zn redistribution in response to infection. Further work is required to evaluate whether chronic exposure to Hg may have presented a toxic challenge to the porpoises that succumbed to infectious disease.

Investigating potential associations between chronic exposure to polychlorinated biphenyls and infectious disease mortality in harbour porpoises from England and Wales.

Bioaccumulation of immunosuppressive organochlorines like polychlorinated biphenyls (PCBs) may pose a threat to the health and viability of cetacean populations. To investigate possible associations between chronic exposure to PCBs and infectious disease mortality in harbour porpoises Phocoena phocoena in UK waters, blubber concentrations of 25 individual chlorobiphenyl (CB) congeners in 34 healthy harbour porpoises that died due to physical trauma (mainly by-catch) were compared with CB concentrations in 33 animals that died due to infectious disease. The infectious disease group had significantly greater total 25 CBs (sigma 25CBs) concentrations than the physical trauma group (P < 0.001). The mean sigma 25CBs concentration in animals that died due to physical trauma was 13.6 mg kg-1 extractable lipid whereas the mean concentration in the infectious disease group was 31.1 mg kg-1 extractable lipid. The relationship between higher sigma 25CBs and the infectious disease group was not confounded by age, sex, nutritional status, season, location or year of stranding. In addition, adult females had significantly lower sigma 25CBs levels than adult males (P < 0.05) due to maternal transfer of CBs to offspring. These findings are consistent with the hypothesis that chronic PCB exposure predisposes harbour porpoises in UK waters to infectious disease mortality, although further research is required to test these associations more robustly.

Entanglement in fishing gear and other causes of death in cetaceans stranded on the coasts of England and Wales.

Between August 1990 and September 1995 the carcases of 422 cetaceans of 12 species that had died around the coasts of England and Wales were examined. There were 234 harbour porpoises (Phocoena phocoena), 138 common dolphins (Delphinus delphis), and 50 individuals of 10 other species of dolphins and whales. The cause of death was diagnosed in the harbour porpoises and common dolphins was entanglement in fishing gear (bycatch). Of the cases in which the cause of death was established, 66 (38 per cent) of 176 harbour porpoises, 86 (80 percent) of 108 common dolphins, and six (19 per cent) of 31 individuals of other species had been bycaught. Neonatal starvation, pneumonia and generalised infections accounted for a further 31 per cent of the diagnosed causes of death in harbour porpoises. The proportion of stranded common dolphins that had been bycaught was consistently high except during 1995, but the proportion of stranded harbour porpoises which had been bycaught increased in each successive year.

Antibodies to Brucella in marine mammals around the coast of England and Wales.

Following the isolation of previously unrecognised species of Brucella from stranded seals and cetaceans in Scotland and northern England, a serological survey was carried out to investigate the range of marine mammal species which may have been exposed to Brucella species around the coasts of England and Wales, the prevalence of infection and the temporal and geographical distribution of seropositive animals. Serum collected from 153 stranded marine mammals from the coasts of England and Wales between 1989 and 1995 were tested by competitive and indirect ELISA. Positive titres were recorded for six of 62 (10 per cent) grey seals (Halichoerus grypus), one of 12 (8 per cent) common seals (Phoca vitulina), 11 of 35 (31 per cent) harbour porpoises (Phocoena phocoena) and nine of 29 (31 per cent) common dolphins (Delphinus delphis) tested. Positive titres were also found in a striped dolphin (Stenella coeruleoalba), a bottlenose dolphin (Tursiops truncatus), a killer whale (Orcinus orca) and a pilot whale (Globicephala melas). The seropositive animals were from all around the coasts of England and Wales and the first seropositive sample was from a common dolphin in 1990.

Special challenges of maintaining wildlife in captivity in Europe and Asia.

In the second half of the 20th century, populations of many wild animal species have been established in captivity for various purposes (e.g. education, conservation, research, farming) and many are kept as companion animals. With continuing human pressure on the environment, captive or semi-captive management is likely to become a component in the conservation of an increasing range of species throughout Europe and Asia. The management of small and divided populations (some of which may be in zoos while some are free-ranging) requires careful control to minimise loss of genetic diversity. This, in turn, may require movements of animals or germplasm between sub-populations. A potentially serious hazard associated with these translocations is the accidental introduction of infectious agents into populations which have hitherto been geographically or ecologically isolated from these agents. When planning translocations, the state veterinary authorities of both importing and exporting countries should be contacted at an early stage for details of legal requirements in relation to animal health, welfare and conservation. Animal health legislation is mostly aimed at preventing disease in man and domestic animals, and further disease control measures may be required when translocating wild animals. In addition to the need for efforts in ensuring genetic diversity and disease control, good husbandry and welfare can often be challenging in species about which relatively little is known. A variety of organisations are involved in coordinating captive breeding programmes in Europe and Asia, and some of these organisations and the routes through which they can be identified are mentioned here.

Health and welfare of rehabilitated juvenile hedgehogs (Erinaceus europaeus) before and after release into the wild.

Thirteen wild caught juvenile hedgehogs were treated and overwintered in a rehabilitation centre and 12 were released into the wild and monitored by radiotelemetry. Clinical examinations were carried out before they were released and twice afterwards, and any hedgehogs found dead were examined post mortem. The health of the animals was generally good but dental disease, obesity and minor injuries were common. One hedgehog died before it was released and had cardiovascular and respiratory lesions, and one was euthanased 28 days after its release and had verminous enteritis and parasitic bronchitis. Three hedgehogs were killed by badgers, two were killed by road traffic and four were known to have survived when the study ended.

Hematology of fledgling Manx shearwaters (Puffinus puffinus) with and without 'puffinosis'.

Hematological parameters were measured in 14 fledgling Manx shearwaters (Puffinus puffinus), with the disease puffinosis and in 10 birds that did not have the disease, on the Island of Skomer between 2 and 11 September 1991. The mean plasma fibrinogen concentration was significantly higher in the diseased birds and some of these had abnormally elevated monocyte counts. No other significant differences were observed.

Epidemiological observations on spongiform encephalopathies in captive wild animals in the British Isles.

Since 1986, scrapie-like spongiform encephalopathy has been diagnosed in 19 captive wild animals of eight species at or from eight zoological collections in the British Isles. The affected animals have comprised members of the family Bovidae: one nyala (Tragelaphus angasi), four eland (Taurotragus oryx), and six greater kudu (Tragelaphus strepsiceros), one gemsbok (Oryx gazella), one Arabian oryx (Oryx leucoryx), and one scimitar-horned oryx (Oryx dammah), and members of the family Felidae: four cheetah (Acinonyx jubatus) and one puma (Felis concolor). In addition, three cases of a spongiform encephalopathy of unknown aetiology have been reported in ostriches (Struthio camellus) from two zoos in north west Germany. Three features suggest that some of these cases may have been caused by the agent of bovine spongiform encephalopathy (BSE). First, they have been temporally and geographically coincident with the BSE epidemic. Secondly, in all the ungulates for which details are available, it is possible that either the affected animal itself, or the herd into which it was born or moved, had been exposed to proprietary feeds containing ruminant-derived protein or other potentially contaminated material, and all the carnivores had been fed parts of cattle carcases judged unfit for human consumption. Thirdly, the pathological results of inoculating mice with a homogenate of fixed brain tissue from the nyala and from one greater kudu were similar to the results of inoculating mice with BSE brain tissue.

Food consumption in relation to bodyweight in captive snakes.

The weekly food consumption of 25 captive snakes of nine species fed on freshly killed laboratory mice was measured for periods of three to eight weeks. Their ad libitum intake was found to vary in proportion to their initial body weight (w) raised to an exponent close to and not significantly different from 0.75 (mean [SE] 0.79 [0.064]. However, the food consumption in relation to w varied between animals, and the rates of change in bodyweight relative to w0.75 during the measurement period were highly correlated with food consumption (r = 0.801, P < 0.001). From the regression describing the relationship between these variables, the mean food requirement for maintenance was estimated at 4.2 g day-1 kg-0.75 and the mean rate of weight loss when fasting was estimated at 2.0 g day-1 kg-0.75. The mean weight gain for each gram of food eaten above maintenance level was estimated to be 0.46 g. The limits, in relation to w, within which the ad libitum food consumption of snakes can be predicted from these results with 95 per cent probability are estimated.