Proviral DNA in the brains of goats infected with caprine arthritis-encephalitis virus.

Archive paraffin wax-embedded sections of brain from goats and kids naturally infected with caprine arthritis-encephalitis virus (CAEV) were examined. Severe leucoencephalitis was present, with infiltration of lymphocytes, plasma cells and macrophages into the white matter, meninges and choroid plexus. On both CAEV-positive and negative (control) tissues, in-situ polymerase chain reactions were used to amplify a DNA sequence specific to the proviral Pol region. In the infected tissues, strong hybridization signals were observed, mainly located in macrophages, microglial cells, astrocytes and oligodendrocytes, and in the ependymal epithelium and choroid plexus. Positive areas were also found in the spinal cord in endothelial cells of small blood vessels. Some neurons showed a positive reaction.

A conventional beagle dog model for acute and chronic infection with Helicobacter pylori.

Helicobacter pylori has been widely recognized as an important human pathogen responsible for chronic gastritis, peptic ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Little is known about the natural history of this infection since patients are usually recognized as having the infection only after years or decades of chronic disease. Several animal models of H. pylori infection, including those with different species of rodents, nonhuman primates, and germ-free animals, have been developed. Here we describe a new animal model in which the clinical, pathological, microbiological, and immunological aspects of human acute and chronic infection are mimicked and which allows us to monitor these aspects of infection within the same individuals. Conventional Beagle dogs were infected orally with a mouse-adapted strain of H. pylori and monitored for up to 24 weeks. Acute infection caused vomiting and diarrhea. The acute phase was followed by polymorphonuclear cell infiltration, interleukin 8 induction, mononuclear cell recruitment, and the appearance of a specific antibody response against H. pylori. The chronic phase was characterized by gastritis, epithelial alterations, superficial erosions, and the appearance of the typical macroscopic follicles that in humans are considered possible precursors of MALT lymphoma. In conclusion, infection in this model mimics closely human infection and allows us to study those phases that cannot be studied in humans. This new model can be a unique tool for learning more about the disease and for developing strategies for treatment and prevention.

Mortality in black siskins (Carduelis atrata) with systemic coccidiosis.

Ninety-five (97%) of 98 black siskins (Carduelis atrata) died within 2 months of arrival in Italy from South America with the following clinical sings: rapid weight loss, breast muscle atrophy, congested and distended abdomen, diarrhea, and lethargy. Macroscopically we observed hepato-splenomegaly, pulmonary congestion, and thickening of the interstinal wall. Histologically, lymphomonocytic transmural enteritis, interstitial mononuclear cell infiltrates in the lungs and in the liver, as well as activation of splenic follicles were common features. Large numbers of protozoa belonging to Isospora sp. were observed in various stages of their life-cycle in the intestinal epithelium, and some zoites were found in the extra-intestinal cellular infiltrate as well. No viral or bacterial pathogens were found.