Pre-Erythrocytic Development of Plasmodium Lophurae in Various Hosts

Abstract
The pre-erythrocytic stages of P. lophurae were studied in turkeys, chickens, guinea fowl and ducks. They resembled the corresponding stages of P. gallinaceum very closely in morphology and like the latter were found to utilize the cells of the lymph-oid-macrophage system and fibroblasts as host cells. Al- though seen occasionally in heterophil granulocytes they did not attain maturity in this cell type. Degenerating pre-erythrocytic stages were observed in all 4 hosts, but the degree of abnormality differed and was found not to be correlated with the degree of parasitemia resulting from the inoculation of sporozoites. The pre-erythrocytic stages were least abnormal in guinea fowl, most abnormal in the duck, and intermediate in the turkey and chicken. This contrasts with the fact that low-grade, irregular parasitemias result in chicks and ducklings inoculated with large doses of sporozoites, whereas parasitemias reaching 30% of the erythrocytes result in turkeys inoculated even with small doses of sporozoites. Also guinea chicks inoculated with sporozoites exhibit low grade, persistent parasitemias. The degree of abnormality of the pre-erythrocytic stages thus becomes a measure of the inimical effects of the natural immunity of the host.