Annales de parasitologie humaine et comparee最新文献

The cellular dynamic against deposited Schistosoma haematobium eggs was studied in the submucosa and muscularis of the lower ureteral segments of Saudi patients with chronic urinary schistosomiasis. This dynamic activity was greatly affected by the damaged phase of the egg embryo. Freshly deposited eggs with "healthy" embryos were entirely surrounded by long cytoplasmic extensions of fibroblasts. Eggs with partially damaged embryos were surrounded by plasma cells which were focally adhered to spines of egg-shells and releasing their granular contents over their surface. Eggs with "dead" embryos, or empty egg-shells, were surrounded by actively mobile macrophages possessing numerous lysosomes, phagocytic vacuoles, and convoluted surface projections. After "peeling" off the outer and intermediate shell layers, macrophages invaded into eggs and fused together forming multinucleate giant macrophages. This study showed that the fibroblastic extensions acted as barriers between the parasite eggs or their products, and the host tissue; the plasma cell secretion over the egg surface may be involved in the migration of macrophages towards deposited eggs; and macrophages were the only dynamic cells responsible for the egg-shell invasion possibly for elimination.

The effect of ivermectin was studied on two filaria-vector pairs, Brugia malayi-Aedes aegypti and Litomosoides sigmodontis-Bdellonyssus bacoti. The rodent hosts, respectively Mastomys coucha and Meriones unguiculatus, were treated with ivermectin doses of 0.05 mg/kg, or 0.2 mg/kg or 2 mg/kg. Batches of vectors were fed on rodents, infected or not, treated or not, from H7 to D43 post-ivermectin. Vector survival was observed and dissections were performed to study the filarial development. It appears that ivermectin has no systemic effect on vectors, or very little. The drug acts on transmission because it affects the microfilariae. Transmission of L. sigmodontis is blocked because microfilariae are eliminated from the blood. Transmission of B. malayi is blocked although microfilaremia remains present at a low level. Two particular features are observed: microfilariae are hyper-ingested, but they do not cross the stomach wall (in contrast, they cross at a high rate in the control batch of Aedes, due to the "stomach wall limitation"). These events might be explained by a muscular passivity of the microfilariae treated with ivermectin. Transmission of the two filarioid species is restored normally about D25-40 post ivermectin because a new population of microfilariae has appeared. These ivermectin experiments emphasize the diversity and complexity of two important phases of the filarial cycle in the vector: the ingestion of microfilariae and the passage through the stomach wall.

Histo-pathological analysis of the eyes, ears, skin and associated skeletal muscles of the back of 14 animals infected with a filarioid worm with dermal microfilariae, Cercopithifilaria johnstoni: seven Rattus fuscipes, of which four were naturally infected, two marsupials, Perameles nasuta and Isodon macrourus, and five R. norvegicus. This filarioid nematode induces skin and eye lesions in all the infected animals. These lesions are similar to those described earlier with other filarioid species with dermal microfilariae, such as Monanema martini and Onchocerca volvulus; the pathogeny is similar: microfilariae live inside the lymphatic vessels and their accidental exit gives rise to a localized inflammatory reaction leading to fibrosis. C. johnstoni is particularly interesting because it may be adapted to the laboratory rat, and because the ocular lesions are severe.

Ultrastructure of white blood cells (WBC) were studied in peripheral venous blood from Saudi patients with acute falciparum malaria (AFM) and compared with their counterparts in same patients 2 weeks after chloroquine treatment and full recovery. A counting system was incorporated to determine the rate of abnormal to normal cell type in plastic thick sections during the course of the disease. Neutrophilia, monocytosis, eosinopenia and lymphocytosis were associated with various ultrastructural abnormalities including: (1) Knobby phagocytic polymorphonuclear neutrophils (PMN) and promyelocytes, and PMN with highly vacuolated cytoplasm. (2) Irregularly outlined electron-dense nuclei in non-functional monocytes. (3) Unusual distribution of nuclear chromatin in resting B-lymphocytes, while others possess highly vacuolated cytoplasm and knobby surfaces. (4) Absence of granules in granular lymphocytes containing the known diagnostic paratubular crystalline arrays. (5) Plasmablasts containing electron-dense granules and swollen mitochondria. These abnormalities were suggested to be due to the high level of parasitaemia producing some toxic soluble products. They may also be attributed to alteration of bone marrow macrophages as a sequence of their interaction with soluble parasite products or their phagocytic parasitized red cells and debris released during the rupture of schizonts. This study showed that the number of abnormal WBC increases in patients with high level of parasitaemia; plasmablasts have the lowest rate of abnormalities, while monocytes have the highest; old patients present with lower degree of parasitaemia than young patients due to a less mature immune system; and the AFM may have independent effects on the structure of human WBC.

The authors describe and illustrate the morphology of the adult stage of Maritrema feliui n. sp. (Trematoda Microphallidae) obtained from the intestine of the shrew Crocidura russula (Hermann, 1780), definitive host of the fluke present in the estuary of the river Llobregat (Catalonia, Spain). The larval stages are found in two hosts obtained from the area: 1) Mercuria confusa (Frauenfeld) [= Pseudamnicola similis (Draparnaud)] (Mollusca: Hydrobiidae), and 2) Gammarus aequicauda (Martynov) (Crustacea: Amphipoda). The adult stage is anatomically related to the Maritrema with a mean size of the body, two equal suckers, a short oesophagus and long caeca, and a short and transversal cirrus pouch with a smooth and filiform cirrus. According to morphological and geographical affinities, the authors propose the synonymies of 1) Maritrema "opisthometra" sensu Bridgman et al., 1972 with M. chiriacae Deblock, 1975; 2) Maritrema longiforme Kifune et al., 1972, with Maritrema laricola Ching, 1963. Besides Maritreminoides congjiangensis Chiu et Gu, 1981 is transferred into the genus Quasimaritrema Deblock, 1973 according to Maritreminoides Rankin is invalidated.