Detection of latent murine nosematosis and growth of Nosema cuniculi in cell cultures

Administration of hydrocortisone to mice caused activation of latent nosematosis in at least 25% of the animals. The sporozoan parasite Nosema cuniculi could be demonstrated in the tissues of the internal organs and circulating blood by direct microscopic examination. Growth and multiplication of the parasite could be achieved in mouse embryo cell cultures, where the parasite infected and destroyed only about 2% of the cells, thus establishing a state of persistently infected cell culture. The parasite grown in cell culture retained its mouse pathogenicity.