Development of Gametocytes from Extra-erythrocytic Forms in Plasmodium gallinaceum

Abstract

IT was shown in a previous paper¹ that if fowls inoculated with emulsions of organs containing extra-erythrocytic forms of Plasmodium gallinaceum are subjected to intense and continuous quinine treatment (150 gm./kgm. body weight quinine hydrochloride daily), they eventually become heavily infected with extra-erythrocytic forms in the complete absence of erythrocytic schizogony. During quinine treatment the red cells become infected with small non-pigmented parasites derived directly from extra-erythrocytic forms. These small non-pigmented forms do not develop further unless the quinine is stopped or the dose diminished, in which case they undergo the normal cycle of development in red cells. The same results are obtained in birds subjected to the bites of infected mosquitoes, Ædes ægypti, and to continued intensive quinine treatment. With the interruption of quinine treatment the parasites in the red cells, all derived from extra-erythrocytic forms, undergo normal development which can be readily followed by examining the blood at various intervals.