Veterinary Services

Poultry

A cockerel and two hens of uncertain age were submitted from a small hobby flock over a period of ten days. Several birds had lost weight and died or appeared sick. Postmortem examination of one bird showed an enlarged liver with multiple haematomata. Subsequent liver histopathology demonstrated areas of parenchymal degeneration and hepatocyte necrosis associated with extensive deposits of amyloid. A second bird had an enlarged liver and histopathology showed changes suggestive of early Marek’s disease. A greatly enlarged spleen and thickening of the mesentery was noted in the third bird, with histopathological changes suggestive of an adenocarcinoma.

Wild Birds

Deaths in garden birds from trichomoniasis and salmonellosis were again seen in January. More unusual was the submission of an immature ivory gull (Pagophila eburnea) from Ayrshire. This species breeds in the high Arctic and usually has a circumpolar distribution, wintering at the edge of the ice pack, but this bird spent several weeks in Ayrshire before it became moribund and subsequently died. The bird was in poor body condition, and the trachea contained large numbers of mature and immature gapeworms (Syngamus species) (See Figure 6 at top right-hand side), causing a partial obstruction of the trachea. Gapeworms are not commonly found in UK gulls, although a related nematode Cyathostoma species can be found in the infraorbital sinuses of UK gulls. Ivory gulls feed on crustaceans and are opportunist scavengers, feeding on mammalian carcases and excreta. It is possible that this species of gull is not normally exposed to gapeworm eggs or larvae, but that this particular individual had to adapt its diet when in Scotland, thereby encountering a parasite to which it had no natural immunity. Another unusual visitor was a female bittern (Botaurus stellaris), found dead in Ross-shire. Starvation was considered to be the cause of death.

Starvation and parasitism was initially diagnosed in an immature buzzard (Buteo buteo) that was very thin and had large numbers of intestinal tapeworms. However the Scottish Agricultural Science Agency detected residues in the liver within the anticipated lethal range of the anticoagulant difenacoum and the diagnosis was revised to difenacoum toxicity, starvation and parasitism.

January also saw several reports of "die-offs" in auks, mostly razorbills (Alca torda) and guillemots (Uria aalge) off the Ayrshire coast. Examination of carcases suggested starvation, with no evidence of infectious disease. So-called "wrecks" are not uncommon on this stretch of coastline, and it has been suggested that starvation is occurring due to a combination of a reduction in sand eels and stormy weather making it difficult for the birds to catch their food.