3. Growth of a microsporidian parasite in cultured cells of tent caterpillars (Malacosoma).

The microsporidia associated with insects, like other obligate intracellular protozoa, are refractory to cultivation when isolated from the host. One way that this difficulty may be circumvented is by growing cells in vitro which will serve as a substrate for these organisms. There are several reports that the microsporidian parasites will grow to the spore stage in cultured cells (Trager, 1937; Gupta, 1964; Ishihara and Sohi, 1966; Ishihara, 1968; Shadduck, 1969).