Generalized porcine cytomegalic inclusion disease: Distribution of cytomegalic cells and virus

Abstract

Inoculation of PCMV into gnotobiotic piglets produced both fatal and asymptomatic generalized infections. The fatal form was seen most commonly in pigs inoculated when less than 2 weeks old. Affected animals became lethargic and pale with anasarca. At necropsy there were widespread haemorrhages, particularly in the lungs and kidneys; interlobular oedema in the lungs was also a constant feature. In this form of the disease the virus showed a predilection for reticulo-endothelial cells, multiplying in lung macrophages, sinusoidal cells of the liver, spleen, lymph nodes and adrenal gland, and in capillary endothelium. In the asymptomatic form, observed in older pigs, basophilic intranuclear inclusions and associated cytomegaly occurred in epithelial cells, particularly in the mucous glands of the nasal mucosa and kidney tubule cells, but more rarely in the salivary, Harderian and lacrimal glands, seminiferous epithelium, epithelium of the ductus epididymis, mucous glands of the oesophagus, epithelial lining of duodenum and jejunum, and in hepatic cells. Virus isolation in pig lung macrophages detected an extra 20 per cent. of positive tissues, but was sometimes prevented by the toxicity of tissues for cell cultures.