Experimental vector.—Periplaneta americana, Formosa (Morischita and Tsuchimochi, 1926): Eleven of 15 cockroaches fed feces of a monkey [Macaca cyclopis (Swinhoe)] containing cysts of the amoeba voided live cysts in their own feces.
Entamoeba thomsoni Lucas
Synonymy.—Endamoeba thomsoni [Kudo, personal communication, 1957].
Natural hosts.—Blatta orientalis, England (Lucas, 1927a, 1928); U.S.A. (Taliaferro, 1928; McAdow, 1931); U.S.S.R. (Zasukhin, 1930); Germany (Chen, 1933).
Blattella germanica, U.S.A. (McAdow, 1931).
Periplaneta americana, England (Lucas, 1927a); U.S.A. (Smith and Barret, 1928; McAdow, 1931); Philippine Islands (Hegner and Chu, 1930).
The organism is found in the hind intestine and rectum of the cockroach. Smith and Barret (1928) developed a synthetic medium in which cultures of E. thomsoni were carried through successive transfers for 24 months.
Entamoeba sp.
Natural vector.—Periplaneta americana, Gold Coast Colony (Macfie, 1922): Under the heading "Entamoeba histolytica and E. coli" Macfie (p. [445]) stated, "The cockroaches used in these experiments had previously been carefully examined for amoebic infections a precaution which was doubly necessary, because some of these insects at Accra had been found naturally infected."
Experimental vectors.—Periplaneta americana, Gold Coast Colony (Macfie, 1922): Entamoeba, resembling E. coli, from feces of the monkey [Erythrocebus patas patas (Schreber)] were fed to cockroaches, and on the second to fourth days thereafter apparently healthy cysts were recovered in the cockroach feces.