Changes in the tegumental surface of Schistosoma haematobium during development in the mammalian host.

The development of surface of Schistosoma haematobium in the mammalian host was studied by scanning electron microscopy, beginning with lung stages obtained at 7 days, and at various intervals thereafter to completion of development. The major changes observed were similar to those previously seen in Schistosoma mansoni.

Strongyloides fulleborni-like infections in man in Papua New Guinea.

During the course of a survey of intestinal parasites among the inhabitants of villages along the Fly River in the Kiunga region of Papua New Guinea, eggs of a Strongyloides species were found in the feces of several persons. In subsequent studies, 93 (17.8%) of 520 persons examined from five villages were found to be infected with this parasite. The examination of parasitic and free-living stages of the worm revealed that it is very similar to S. fulleborni, a parasite of monkeys, baboons and apes in Africa and Asia, although a definitive identification could not be made with the material available. Since non-human primates have apparently never inhabited New Guinea, the origin of these S. fulleborni-like infections is unknown.

Cysticercosis. A modern day plague.

The authors describe the magnitude of the cysticercosis problem and describe the organism, the clinical features of the disease, the propensity of the organism for development in the central nervous system, pathologic considerations, clinical diagnosis, and treatment.

Secretory/excretory antigens produced by tetrathyridia of Mesocestoides corti defined by SDS--PAGE and HPLC.

Antigens derived from culture medium in which metacestodes of Mesocestoides corti Hoeppli, 1925, had been maintained were studied by sodium-dodecyl-sulfate--polyacrylamide gel electrophoresis (SDS--PAGE) and high performance liquid chromatography (HPLC). By SDS--PAGE a minimum of 18 Coomassie-staining bands were discerned, of which 4 major bands and 4 major peaks by HPLC of similar molecular weights were observed. The HPLC eluate peaks were analyzed for antigenic activity in vitro by double diffusion in two dimensions, and in vivo in a rabbit. The rabbit had been artificially sensitized with a dialyzable leukocyte extract, showing transfer-factor-like activity, from peritoneal exudate cells removed from mice infected with tetrathyridia. All of the HPLC fractions reacted with rabbit antibody prepared against secretory/excretory antigens, but the sensitized rabbit responded only to two fractions. It is now possible by HPLC to fractionate complex antigens without denaturing them and to elucidate further the role they play during infection.

Axenic growth of oncospheres of Hymenolepis citelli (Cestoda) to fully developed cysticerocoids.

Cysticercoids of the cestode Hymenolepis citelli were grown axenically in vitro from the oncosphere to stages infective for the mammalian host. Reducing agents were an essential component of the culture medium. Of several reducing agents tested, L-cysteine was the most effective. Concentration of reducing agent was critical in that excessive amounts induced abnormal growth.

Fine structure of a racemose cysticercus from human brain.

The surface of a racemose cysticercus from the human brain was studied by scanning electron microscopy and the tegument of the cyst by transmission electron microscopy. The surface of the larva is covered by microvilli of uniform shape and size. The glycocalyx of the microvilli bears knotlike areas positive for acid mucopolysaccharides. Microvilli are interconnected by a fine, electron-dense network. The tegumental and subtegumental tissues vary in thickness from one region to the next, and the tissues below the vesicular layer are scattered irregularly, in a seemingly disordered manner.

Immunoglobulins on the surfaces of tetrathyridia of Mesocestoides corti Hoeppli 1925 (Cestoda), from laboratory infections of ICR mice.

7Sgamma2b antibody was detected, by fluorescein labeled antibodies, on the body surfaces and wall of excretory bladder of tetrathyridia of M. corti removed from the peritoneums of 5--24-week laboratory infections of ICR/TIMCO mice. 7Sgamma1, 7Sgamma2a, 7Sgamma3, IgM, IgA, and C3 were not found by use of the same techniques. Tetrathyridia maintained in culture medium to which pooled normal mouse, infected mouse, and horse (control) serums containing all known classes and subclasses of immunoglobulins had been added showed only mouse 7Sgamma2b on their surfaces and wall of the excretory bladder, and then only when incubated in pooled serum from infected mice. No other mouse immunoglobulin classes or subclasses were found attached to the worms, nor was any reaction obtained from tetrathyridia incubated in culture medium alone, normal mouse serum, or horse serum. This suggests a highly selective nonspecific absorption of 7Sgamma2b, or more likely demonstrates the specificity of the antibody for the parasite surfaces and wall of the excretory bladder. The possibility that 7Sgamma2b may be acting in an enhanceing mode is discussed.

Axenic development of cysticercoids of Hymenolepis nana.

Cysticercoids of the tapeworm Hymenolepis nana were grown axenically in vitro, from oncospheres hatched in vitro to fully developed organisms infective to mice. A gas phase of 95 N2--5 CO2 was essential for normal development.

Fine structure of the tegument of Mesocestoides tetrathyridia by scanning and transmission electron microscopy.

The tegumental surface of tetrathyridial stages of the tapeworm, Mesocestoides corti, was studied by scanning and transmission electron microscopy. Two structural types of microvilli were observed--blade-shaped or conical ones, and elongated, slender microvilli. The distribution and relative frequency of the two types of microvilli differs in different areas of the body surface. Host peritoneal cells were observed attached to the blade-shaped microvilli by slender cytoplasmic projections.

Schistosoma mekongi sp. n. from man and animals, compared with four geographic strains of Schistosoma japonicum.

Schistosoma mekongi sp. n. is described from man and animals in Cambodia. It is compared to 4 geographic strains of Schistosoma japonicum. It differs from S. japonicum in the size of embryonated eggs, in the length of the prepatent peroid in the mammalian host, and in its utilization of a different snail host. The relative usefulness of conventional morphologic criteria in the differentiation of Asian schistosomes is discussed.

Changes in tegumental surface during development of Schistosoma mansoni.

The tegumental surface of immature Schistosoma mansoni was studied with the scanning electron microscope. The surfaces of immature males and females bear no resemblance to that of adult worms and are characterized by having many tegumental folds. The tegumental surfaces of immature males and females are similar, and the dorsal and ventral surfaces of the male are similar before formation of the gynecophoral canal. Transition of the tegumental surface from the juvenile to the adult form begins after worms are in copula and have grown to several millimeters in length.

Synergistic growth promoting action of L-cysteine and nitrogen upon Hymenolepis diminuta cysticercoids in vitro.

Development in vitro of cysticercoids of the cestode Hymenolepis diminuta in the presence of L-cysteine proceeded twice as rapidly under 100% nitrogen as it did with air as the gas phase. No growth was obtained with the following: D-cysteine, L-cysteine methyl ester, S-aminoethyl cysteine, L-cystine, glutathione (reduced), L-methionine, D-pantothenic acid, taurine, or thioglycolic acid; limited growth only was obtained with ascorbic acid and dithiothreitol. Homocysteine or coenzyme A was as effective as L-cysteine in stimulating the complete development of oncospheres to cysticercoids. Experiments with 14C-L-cysteine indicated that L-cysteine was perhaps incorporated into the organisms.