Pseudotuberculosis
The pseudo-tuberculosis ( caseous lymphadenitis , caseous lymphadenitis ) is a tuberculosis -like, bacterial infectious disease of sheep and goats caused by Corynebacterium pseudotuberculosis is caused. It usually occurs sporadically in older animals and usually remains clinically without any signs. The purulent-cheesy changes in the lymph nodes and internal organs are usually only noticed at slaughter.
Pathogen and occurrence
The pathogen, Corynebacterium pseudotuberculosis , is a gram- positive, rod-shaped bacterium that was discovered by Edmond Nocard in 1885 . It is considered to be facultative pathogenic and is extremely resistant and therefore infectious for a long time in the environment.
Pseudotuberculosis occurs all over the world and occurs mostly as an individual animal disease, and also occurs more frequently under poor housing conditions. Older animals are most commonly affected.
It is excreted via pus from broken lymph nodes and via the feces. The transmission usually takes place via wounds, such as those that can occur when sheep are sheared, which are contaminated with material containing pathogens (excrement, soil). Infection via the belly button ( omphalogen ), the bloodstream ( hematogenous ), the intestine ( enterogenic ) or via the airways ( aerogenic ) through inhalation of pathogen-containing dust is also less common .
Clinical picture
The disease usually has no symptoms and is only diagnosed at slaughter. Only if superficial lymph nodes are involved can non-painful, visible swellings of the lymph nodes occur. When these lymph nodes are opened, a yellow-green pus pours out .
Less often, enlargement of the lymph nodes can lead to compression of the windpipe and thus to breathing problems or tympania if the mesenteric lymph nodes are affected . Very rarely, inflammation of the udder , uterine lining, or central nervous pseudotuberculosis can occur. In the rare pseudotuberculosis of lambs, umbilical inflammation , joint inflammation and abscesses in the liver can occur.
In the pathological section, purulent lymph node abscesses are noticed, which are filled with a cheesy to mortar-like mass. A concentric layering of these abscesses (like onion skin), which are surrounded by a thick capsule of connective tissue , is typical . In internal organs ( lungs , liver , spleen , kidneys , udder , testicles ) greenish cheesy foci can appear, which can also calcify.
therapy
Since the disease is usually not noticed clinically, no therapy is initiated. If the superficial lymph nodes break open, they can be surgically removed or treated with antiseptics .
The main focus is therefore on prophylaxis , in particular the avoidance or antiseptic treatment of injuries, stall hygiene and disinfection measures (especially the intermediate disinfection of the instruments for sheep shearing). A pathogen-specific vaccination can be carried out in the event of increased occurrence in a herd .
literature
- H.-J. Selbitz: Corynebacterium . In A. Rolle and A. Mayr (eds.): Medical microbiology, infection and epidemic theory . Enke, Stuttgart, 7th edition 2001. ISBN 3-432-84686-X
