Actinomycosis n. (Med.) A chronic infectious disease of cattle and man due to infection with actinomycetes, especially by Actinomyces bovis in cattle and by Actinomyces israeli or Arachnia propionica in man. It is characterized by hard swellings usually in the mouth and jaw. In man the disease may also affect the abdomen or thorax. In cattle it is called also lumpy jaw or big jaw.
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