I. Landau

Final stage of maturation of the erythrocytic schizonts of rodent Plasmodium in the lungs

Schizonts of all rodent Plasmodium studied (Plasmodium yoelii, P. chabaudi, P. vinckei) show a characteristic morphology when they are completely mature: rounded or slightly elongate merozoites, completely detached from the pigment mass. At this stage, they are localized principally in the spleen and the lungs but, in impression smears of these organs they show two different aspects. In the spleen, schizonts are either inside the host erythrocyte or extraglobular but still close to a pigment mass; free merozoites are rare. In the lungs, on the contrary, merozoites are often free and dispersed; electron microscopy showed them to lie against the endothelium. Work by physiologists has shown the blood circulation in the alveoli to be much slowed down. Free merozoites, lined against the endothelium of relatively rigid capillaries, are in the best possible conditions to make contact with the intact red blood cells. Lungs appear to be the privileged site for the invasion of erythrocytes by the merozoites.

Observations on early and late post-sporozoite tissue stages in primate malaria. V. The effect of pyrimethamine and proguanil upon tissue hypnozoites and schizonts of Plasmodium cynomolgi bastianellii

Two rhesus monkeys were each infected with 2.1 x 10(6) sporozoites of Plasmodium cynomolgi bastianellii; one was treated with 1.0 mg of pyrimethamine base per kg body weight for 5 d after sporozoite inoculation. A further 2 monkeys were each infected with 9.75 x 10(6) sporozoites of the same parasite; one was treated with 10 mg of proguanil per kg body weight for 4 out of 5 d after inoculation. The treated monkeys showed a delayed primary parasitaemia and relapses. In sections of liver biopsies taken 7.5 d after sporozoite inoculation, all monkeys showed numerous hypnozoites. However, there were no full grown schizonts and only rare retarded schizonts in the treated monkeys, in contrast to the untreated monkeys which had many mature or nearly mature schizonts. Later biopsies confirmed the continued presence of hypnozoites in all monkeys.

Description de Plasmodium aegyptensis n. sp. parasite présumé du Muridé Arvicanthis niloticus en Haute-Egypte

Plasmodium aegyptensis n. sp. est proche de P. vinckei Rodhain, 1952 ; il s’en differencie par sa plus petite taille, sa forme compacte, son pigment plus abondant et plus grossier, et le nombre plus faible de merozoites dans les rosaces.

Description d’Hepatocystis bainae n. sp. (Haemoproteidae) parasite d’Hipposideros galeritus Microchiroptère de Malaisie

Hepatocystis bainae n. sp. parasite du Microchiroptere de Malaisie, Hipposideros galeritus (Cantor) est decrit et differencie morphologiquement de H. rodhaini. Il est caracterise par des microgametocytes de type «xa0diffusxa0», des schizontes hepatiques de petite taille et la repartition de la colloide.

Observations ultrastructurales sur les formes sanguines et la sporogonie de plasmodiums de lémuriens malgaches.

The ultrastructure of blood stages and oocysts of Plasmodium coulangesi and P. percygarnhami, both parasites of Madagascan lemurs, was studied. The main results are: