Retrospective analysis of post-mortem findings in domestic ducks and geese from non-commercial flocks in Sweden, 2011-2020.

BACKGROUND: Small poultry flock ownership has become a popular hobby in Europe and North America in recent years but there is a general lack of information regarding bird health and welfare. This retrospective analysis of routine post-mortem cases of non-commercial anseriform poultry aimed at providing information on causes of mortality mostly in relation to mortality events. For this purpose, birds that were submitted for routine post-mortem diagnostics to the National Veterinary Institute (SVA) in Sweden in 2011-2020 were retrospectively reviewed to determine main causes of mortality. RESULTS: Records from 79 necropsy submissions involving 120 birds (domestic ducks n = 41, Muscovy ducks n = 45, hybrid ducks n = 2 and domestic geese n = 32) were retrieved and analysed. Most submissions (72.2%) represented flock disease events and unexpected mortality was the most common cause of submission (70.9% of submissions). Twenty-two submissions (27.8%) were referred by veterinarians. There was a wide range of diagnoses of infectious and noninfectious aetiologies. Infectious causes of mortality included parasitic (19.2%), bacterial (13.3%), fungal (10.0%) and viral infections (3.3%) (at bird level of all 120 birds). Some of these infections such as duck virus enteritis (DVE), highly pathogenic influenza (HPAI H5N8) in Muscovy ducks and leucocytozoonosis (Leucocytozoon sp.) in all three species were most likely acquired from contact with wild free-living waterfowl. Generalised yeast infection (Muscovy duck disease) was diagnosed in Muscovy ducks and in a Muscovy duck/domestic duck hybrid. Other diseases were related to generalised noninfectious causes (27.5% of all birds) including diseases such as kidney disease, amyloidosis, cardiac dilatation, reproductive diseases and idiopathic inflammatory conditions. Nutritional or management-related diseases were diagnosed in 14.2% of all birds including rickets and gastrointestinal impaction/obstruction. Congenital/developmental, neoplastic, toxic and traumatic causes of mortality were rare. CONCLUSIONS: The information obtained in this study can be used to identify and evaluate risks and help owners and veterinarians to prevent disease and provide adequate veterinary care for non-commercial anseriform poultry.

Post mortem findings and their relation to AA amyloidosis in free-ranging Herring gulls (Larus argentatus).

Since the late 1990s, high mortality and declining populations have been reported among sea birds including Herring gulls (Larus argentatus) from the Baltic Sea area in Northern Europe. Repeated BoNT type C/D botulism outbreaks have occurred, but it remains unclear whether this is the sole and primary cause of mortality. Thiamine deficiency has also been suggested as a causal or contributing factor. With this study, we aimed to investigate gross and microscopic pathology in Herring gulls from affected breeding sites in Sweden in search of contributing diseases. Herring gulls from Iceland served as controls. Necropsies and histopathology were performed on 75 birds, of which 12 showed signs of disease at the time of necropsy. Parasites of various classes and tissues were commonly observed independent of host age, e.g. oesophageal capillariosis and nematode infection in the proventriculus and gizzard with severe inflammation, air sac larid pentastomes and bursal trematodiasis in pre-fledglings. Gross and microscopic findings are described. Notably, amyloidosis was diagnosed in 93 and 33% of the adult birds from Sweden and Iceland, respectively (p<0.001), with more pronounced deposits in Swedish birds (p<0.001). Gastrointestinal deposits were observed in the walls of arteries or arterioles, and occasionally in villi near the mucosal surface. Amyloid was identified within the intestinal lumen in one severely affected gull suggesting the possibility of oral seeding and the existence of a primed state as previously described in some mammals and chickens. This could speculatively explain the high occurrence and previously reported rapid onset of amyloidosis upon inflammation or captivity in Herring gulls. Amyloid-induced malabsorbtion is also a possibility. The Herring gull SAA/AA protein sequence was shown to be highly conserved but differed at the N-terminus from other avian species.

Isolation of spirochetes of genus Treponema from pigs with ear necrosis.

Various ear lesions, often caused by ear biting, are common in pigs. Some herds have a high frequency of ear necrosis, a syndrome characterized by necrotic lesions along the rim of the pinna, often bilateral and sometimes resulting in loss of the entire ear. In samples from such lesions spirochetes have been observed microscopically but never isolated or identified. In this study two herds with periodic outbreaks of ear necrosis among weaners were investigated. Samples were collected from ear lesions and from the gingiva of the pigs. Spirochetes were observed in silver stained histological sections and by phase contrast microscope in scrapings from the necrotic lesions. From an ear lesion a pure spirochete isolate was obtained and identified as a yet unnamed species of genus Treponema, closely related to spirochetes found in digital dermatitis in cattle. From the oral samples two pure isolates were obtained. One of these isolates was identified as the same species as in the ear lesion and one as Treponema socranskii. Species identification was based on 16S rRNA gene sequences.