The involvement of fusobacteria in a wide range of human and animal infecti
on has long been recognised. Slow-growing anaerobes, often in polymicrobial
culture, they are not always identified but are present mainly in the orop
harynx, from where they are bloodborne to other sites or aspirated into the
lung. Fusobacterium nucleatum is commonly found in periodontal disease and
produces tissue irritants such as butyric acid, proteases and cytokines. I
t has strong adhesive properties due to the presence of lectins, and these
outer-membrane proteins mediate adhesion to epithelia and tooth surfaces, a
nd coagglutination with other suspected pathogens. F. necrophorum may cause
necrotising tonsillitis and septicaemia, leading to the spread of infectio
n and the development of abscesses in the lung and brain-a form of Lemierre
's syndrome. Calf diphtheria, foot rot and other infections in animals are
well defined, with the pathogenic mechanisms involving leucotoxins, endotox
ins and adhesins. A foul smell produced by butyric acid and other metabolic
products is common to all fusobacterial infections. Identification using s
imple tests is within the scope of most laboratories.