Encephalitozoonosis in arctic lemmings.

Encephalitozoonosis was identified for the first time in arctic lemmings (Dicrostonyx stevensoni and crosses of D. stevensoni and Dicrostonyx rubricatus). The most common clinical findings were circling, torticollis, posterior paralysis, depression, blindness and death related to parasitic granulomas in many tissues. Granulomas were most frequent in the central nervous system, but were seen in many other tissues throughout the body. Granulomas were characterized by collections of macrophages and varying numbers of lymphocytes and neutrophils with or without necrosis of parenchymal tissue. Most granulomas contained protozoon cysts with ultrastructural characteristics of Encephalitozoon cuniculi. Protozoon cysts were seen in vascular endothelium in many tissues accompanied by minimal or no inflammatory reaction.

Use of subcutaneously implanted chambers in calves for in vivo study of isolates of Moraxella bovis.

Selected cultures of Moraxella bovis were studied in calves, using chambers fabricated from a semipermeable membrane supported and protected by perforated plastic golf balls. Plain balls, semipermeable membrane-covered balls, and balls that contained bags fabricated from semipermeable membranes were surgically implanted subcutaneously in calves at a site approximately 25 cm ventral to the paralumbar fossa and cranial to the prefemoral lymph node. After calves recovered from surgery, chambers were inoculated with different cultures of M bovis. Cultural examination of samples taken from inoculated chambers indicated that M bovis cultures were maintained within the chambers for variable times, depending on the characteristics of the culture inoculated. A smooth (piliated) culture dissociated into a rough (nonpiliated) culture after 4 weeks of incubation within a chamber but none of the rough cultures became smooth. The technique offers a method to study the in vivo variations in a series of cultures or strains of microorganisms under the influence of the same host factors. The selective permeability of the chamber may be controlled by using membranes of different porosities to control the flow of entering or exiting dialysate.