Veterinary Services

Fatty liver haemorrhagic syndrome was diagnosed in an adult bird in good condition that died suddenly. A bird that died in poor condition was found to have an adenocarcinoma of the reproductive tract. Four birds were received from another unit that had lost several birds over the preceding month.  A mixture of conditions was found, including avian pasteurellosis (fowl cholera), Staphylococcus aureus septicaemia, coccidiosis and egg yolk peritonitis.

Waterfowl

Four juvenile Muscovy ducks were found dead in a 24 hour period, having shown no prior signs of illness. No significant gross lesions were detected and bacterial cultures yielded no significant pathogens. Histopathology however revealed acute focal to diffuse necrosis of liver and lung, with intranuclear inclusion bodies present in both tissues. These changes were considered to be consistent with duck viral enteritis infection. This condition is usually seen in April to June, and Muscovy ducks appear to be highly susceptible. Some species of wild waterfowl such as mallard (Anas platyrhynchos) appear to be more resistant and can act as carriers, introducing the virus to ornamental collections of waterfowl.

Game birds

Two hen pheasants were submitted for necropsy following the deaths of 20 to 25 pheasants from a breeding unit of 1500 birds. Marked pallor of the kidneys was noted on postmortem examination, and histopathology demonstrated changes consistent with pheasant coronavirus-associated nephritis.

Three adult hen pheasants were submitted from an estate with breeding birds in laying pens. Mortality in the pens was not excessive but the gamekeeper wished to monitor the causes of mortality. One bird had gross lesions typical of infectious sinusitis and the second bird had gross lesions of egg yolk peritonitis. The third bird was in good condition with congested lungs and an enlarged mottled spleen. Histopathology of the spleen of this bird demonstrated multiple foci of necrosis around the sheathed capillaries, with a marked fibrin exudate. Many of the lymphoreticular cells were necrotic or degenerate, some with enlarged nuclei, marginalised chromatin and large amphophilic intranuclear inclusion bodies. These gross and histopathological findings are typical of "marble spleen disease". Previous studies at SAC have shown that these three conditions, sinusitis, egg yolk peritonitis and marble spleen disease, can be part of the "normal" mortality observed in adult pheasants in laying pens.

Wild birds

Two dead buzzards (Buteo buteo) and a dead stoat were found in close proximity to part of a rabbit carcase and a pigeon carcase. The breast muscle of the pigeon had been cut and partially removed, and a large quantity of dark granules was present on the surface of the breast muscle. Large quantities of similar dark granules were present on parts of the rabbit carcase (figure 5). Malicious poisoning was suspected, possibly involving carbofuran and the use of the pigeon and rabbit carcases as bait. Material was submitted for examination under the Wildlife Incident Investigation Scheme. Toxicological analysis by the Scottish Agricultural Science Agency (SASA) is underway. Poisoning was also considered in several other incidents, involving a dipper (Cinclus cinclus), a sparrow hawk (Accipiter nisus), a kestrel (Falco tinnunculus), two buzzards and nine siskins (Carduelis spinus).

Heavy growths of a non-lactose-fermenting E. coli were recovered from the siskins.  E. coli O86 is a well recognised cause of death in garden birds, especially in siskins and most commonly in the months March to May. Evidence of trauma was found in the dipper, kestrel, buzzards and sparrow hawk, possibly arising from collisions with vehicles or power lines.  However subsequent screening by SASA found low sub-lethal levels of the anticoagulant rodenticides bromodiolone and difenacoum in one buzzard and combined anticoagulant residues in the kestrel were considered to be within the anticipated lethal range.