Long term cultivation of a simian malaria parasite (Plasmodium knowlesi) in a semi-automated apparatus

An apparatus is described and illustrated for the continuous semi-automated cultivation of Plasmodium knowlesi, The change of medium was automated and involved six operations. Parasites were maintained for 12 weeks, at which time the experiment ended. During this period, parasite density, morphology and serological specificity were monitored. Parasites retained synchromy and normal morphology only for the first cycle in culture. The maximum degree of morphological abnormality (90%) was reached at three weeks. Lysis of infected erythrocytes seemed to occur before full maturation of the parasites. Infected cells cultured for 31 days produced a normal, fulminating infection in a rhesus monkey.