In 1996 in the first five months of 1997 a total of 3479 day-old goslings were examined at the Central Veterinary Institute. The commonest findings were poor viability and growth retardation (Table 1). Of the bacterial diseases, paratyphoid was the most common, followed by colibacillosis and streptococcosis. A total of 2686 young goslings aged 1-8 weeks were examined in the period of study. The most frequent diagnosis was Derzsy's disease (Table 2). In the order of their incidence, the most frequent bacterial diseases were paratyphoid, mycoplasmosis, streptococcosis, colibacillosis, chlamydiosis, anatipestifer syndrome, and septicaemia caused by the erysipelas bacterium (Erysipelothrix rhusiopathiae). The clinical symptoms of the above-mentioned infectious diseases are summarised in Table 3, while the gross lesions and histopathological changes caused by them in Table 4. According to the authors' observations, anatipestifer syndrome usually occurred at the age of 2-3 weeks. Morbidity and mortality were around 2-5%. The affected goslings exhibited nervous symptoms (Figure 1). At necropsy, fine, hardly noticeable fibrin precipitation was seen in the pericardium, on the air sacs, and occasionally on the serosal surface of the liver and the other abdominal organs. Histopathological examination revealed the diffuse thickening of the leptomeninges covering the brain and spinal cord, their infiltration by inflammatory cells including histiocytes, lymphocytes and heterophilic granulocytes (Figure 2), and their serofibrinous imbibition. By bacterial culture Pasteurella anatipestifer (or, according to the recently proposed name, Riemerella anatipestifer) bacteria were isolated from the goslings showing nervous signs and from the dead birds. Mycoplasmosis occurred in young goslings, usually at 3-4 weeks of age. Morbidity was usually between 15 and 25% while mortality was 3-8%. At necropsy, deposition of fibrin was consistently seen on the surface of the air sacs and on the pericardium. Histopathologically, focal infiltration was observed in the epicardium, in the wall of the pericardium and the air sacs and, here and there, also in the serosa covering the lungs. Mononuclear cell infiltration of proliferative type (Figure 4) was detected in the lungs as well as in the wall of the parabronchi and air capillaries. The pathogen is easily recognisable by electron microscopy (Figure 5). Mycoplasma strain 1220 was most commonly detectable from this disease entity. Chlamydiosis occurred mostly in 3-4 weeks old goslings. Gross pathologically it was characterised by the presence of a few small necrotic foci in the liver and spleen. By histopathological examination, necrotic and inflammatory-necrotic foci could be recognised in the liver (Figure 6). The pathogens are detected by Stamp's staining as well as by immunofluorescence (Figure 7) and by an immunohistochemical method. By ultrastructural examination round elementary bodies and so-called reticulate bodies of larger size, loosened structure and containing nuclear primordia can be seen (Figure 8.) Streptococcosis was the most common in gosling of 2-3 weeks of age. At necropsy, the spleen was 3 or 4 times its normal size, compact to the touch, and showed a regular mottled pattern on its cut surface (Figure 9). The liver was invariably swollen, with numerous necrotic foci and haemorrhages on its surface and cut surface (Figure 10). Histopathological examination of the spleen and liver showed circumscribed or extensive necroses in which coccus-shaped bacteria could be recognised by Gram staining. The pathogen could be isolated in exuberant cultures from the bone marrow, spleen, liver, bile, kidney, heart blood, brain, pancreas and even from the intestinal lumen. Salmonellosis was seen both in day-old goslings and in growing geese. Necropsy revealed the formation of thick fibrinous pseudomembranes on the serosae of the thoracic and abdominal cavity (Figure 12), swelling of the liver and spleen (Figure 13), and acute enteritis. Fibrinous inflammation of the caecum and rectum, characterised by the formation of fibrin plugs, was also commonly encountered (Figure 14). The typing results of Salmonella strains isolated from geese in the period of study are shown in Table 5. Septicaemia caused by E. coli (coli septicaemia, colibacillosis) occurred both in day-old and in growing geese, but was less common than salmonellosis. In flocks of growing geese it was usually seen as a complication of other diseases. Septicaemia caused by Erysipelothrix rhusiopathiae is a relatively common condition in adult geese. It occurs mainly after plucking or as a result of other major stress factors impairing the birds' natural resistance. In young (5-6 weeks old) flocks it was observed only once in the study period. Clostridium septicum is one of the causative agents of malignant oedema in mammals. It rarely causes disease in poultry species. Such diseases have been described only in chickens and turkeys in the special literature. At our institute, disease and deaths caused by Cl. septicum were diagnosed in a 5-6 weeks old gosling flock.
|Translated title of the contribution||Differential diagnosis of the commonest bacterial diseases of young geese|
|Number of pages||10|
|Journal||Magyar Allatorvosok Lapja|
|Publication status||Published - Dec 1 1997|
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