An intraerythrocytic virus and rickettsia of frogs from Algonquin Park, Ontario

Abstract

Two prokaryotic microorganisms were observed in the erythrocytes of frogs in a survey of blood parasites of six species of amphibians from a sphagnum bog adjacent to Lake Sasajewun, Algonquin Park, Ontario. A cytoplasmic virus was observed in 12 of 75 Rana catesbeiana and 1 of 75 Rana septentrionalis. The virus particles were hexagonal in section, measured 300–370 nm in diameter, and occurred in groups that were often surrounded by lamellar arrays of stacked membranes. Large spherical inclusions were seen in the erythrocytes of 2 of 57 Rana clamitans. In the electron microscope these inclusions were found to contain numerous rod-shaped prokaryotes which measured 1–1.7 μm × 200–300 nm. These organisms were ultrastructurally indistinguishable from rickettsiae.