Anaplasma marginale in bovine erythrocyte cultures

Bovine erythrocytes infected with Anaplasma marginale were standardized with normal bovine erythrocytes at 1.4% and 3.5% parasitemia and cultured under low oxygen pressure at 37 C. The number of erythrocytes infected by A marginale appeared to increase 3.3-fold by day 11 and 4.5-fold by day 3, as determined by microscopic examination of Giemsa-stained thin films of the culture suspension. Anaplasma parasites in experimental cultures were proven to be viable and pathogenic by calf inoculation for up to 16 days.