Plasmodium Juxtanucleare

Disease: Chicken malaria.

Hosts: Chicken. Versiani and Gomes (1941) infected 1 of 3 turkeys experimentally, but were unable to infect the duck, guinea fowl, pigeon, canary, domestic sparrow, tico tico, or 3 other species of wild birds.

Location: Erythrocytes. The exo-erythrocytic stages are in endothelial cells.

Geographic Distribution: South America (Brazil), Mexico.

Morphology: This species has been described from Minas Gerais, Brazil by Versiani and Gomes (1941, 1943) and from Chiapas, Mexico by Beltran (1941a, 1943). The gametocytes and schizonts are round or irregular, relatively small, and usually in contact with the red cell nucleus. The schizonts produce 3 to 7 (usually 4) merozoites. The host cell is often distorted.

Life Cycle: The life cycle has not been completely studied. According to Beltran (1943), schizogony takes about 24 hours and its synchronicity is low. The prepatent period may vary from 2 to 38 days. Paraense (1947) saw exoerythrocytic stages in the endothelial cells. Culex quinquefasciatus was found to be a suitable experimental vector by Paraense (1944), but Aedes aegypti and A. lepidus are not.

Pathogenesis: This species is highly pathogenic. The Brazilian strain killed 75% of the infected young birds and 68% of the adults in 15 days to 9 months, and the Mexican strain killed 12 of 13 birds in 1 to 8 months. Affected birds do not show any marked signs. Shortly before death they appear listless and weak, with pale combs. Their temperature is not elevated. There are deposits of pigment in the liver and spleen. Versiani and Gomes (1943) observed a large amount of pericardial fluid, but Beltran (1943) did not.