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At least 1,063 records · Page 59Linked to original sources
PubMed1983

The fine structure of adult Onchocerca volvulus IV. The hypodermal chords of the female worm.

The morphology of the hypodermal chords in the anterior, midbody and posterior region and in worms of different ages are described and the amphids, the cephalic papillae and the nerve ring are demonstrated. At the anterior end, the hypodermal cap comprises the sensory organs. Close behind, the hypodermal chords are differentiated, and several cell margins are found in all of them. Four sublateral chords are differentiated, and several cell margins are found in all of them. Four sublateral chords are also found in the anterior region. A row of median cells is found between the dorsal and ventral syncytia further behind and at the posterior end. In the midbody region, the lateral chords are very large but without central cells. Various particles and inclusions such as bacteria, dense bodies and fibrils are found in the plasm of the hypodermal chords. A large multilayered inclusion was found in the degenerating chord of a female worm at least five years old.

Animals↗
PubMed1984

Studies on nodules and adult Onchocerca volvulus during a nodulectomy trial in hyperendemic villages in Liberia and Upper Volta. II. Comparison of the macrofilaria population in adult nodule carriers.

In the Liberian rain-forest and the savanna of Upper Volta 189 adult nodule carriers were operated on. From 2231 extirpated nodules 3327 male and 5713 female macrofilariae were isolated. About 98% of the male worms and 88% of the female worms were found alive. The sex ratio of the live male and female worms was 1:1.5 in Liberia and 1:1.6 in Upper Volta. Less than 1% of all live macrofilariae were immature in both countries. 22% of the live male worms in Liberia were regarded as old. The percentage of old male and female worms in Upper Volta and that of the old female worms in Liberia were similar (5-7%). The portion of old worms was independent of the age of the patients in Liberia. Dead worms were found in 66% of the Liberians and in 85% of the Voltaics. The percentage of patients with dead worms increased with the age. About 0.5% of all male and 8% of all female worms were calcified. In Liberia the percentage of calcified worms increased with the age of the patients. In both countries the highest number of live and dead worms were found on the pelvic girdle. On the thorax many more macrofilariae were found in Upper Volta than in Liberia. This may contribute to the severe eye lesions in this savanna area. The presented findings provide some basic information for the planning and performance of trials with macrofilaricidal drugs in hyperendemic areas of West Africa. However, the striking differences between individual worm burdens have to be considered.

Adolescent↗
PubMed1983

The fine structure of adult Onchocerca volvulus. V. The digestive tract and the reproductive system of the female worm.

The morphology of the oesophagus, the intestine, the ovary, the uterus, the vagina and some inclusions in the body cavity are described in worms of different ages. The oesophagus wall comprises mostly muscle fibrils and a few glandular regions located only in the posterior portion. In the lumen, some material was found. From the anterior to the posterior end, the lumen of the intestine is reduced. The plasm of the intestinal cells of older worms is filled with concentric spherules containing iron, which are absent in mature but not full-grown worms. The ovarial cells contain in their outer region some fibrils and in the inner region some dense bodies. The ring-muscles of the uterine wall run in clefts of the basal lamina. They usually have accumulated iron containing bodies. In the final portion of the uterus and in the vagina the muscles are very thick. A comparison of the general morphology of the midbody regions of young, not full-grown worms, one less than five years old worm and some worms at least five years old is given.

Aging↗
PubMed1978

Small-scale trials of six drugs against Onchocerca volvulus.

Six drugs in common use for the treatment of parasitic infections of man were given to 18 adult patients suffering from onchocerciasis. None of the six (metronidazole, tinidazole, mebendazole, trichlorophone, oxamniquine and pyrantel pamoate) showed any evidence of substantial activity against the microfilariae or adult worms of O. volvulus. The mean reduction in skin microfilarial counts a week after drug treatment (a measure of microfilaricidal action) was highest in patients treated with trichlorophone (47.0%) and mebendazole (40.0%). The rate of build-up of microfilariae over a follow-up period of 24 months after treatment with the drug under test followed by DEC (a measure of macrofilaricidal action) was slowest in the groups treated with metronidazole and trichlorophone (22.9% and 27.0% of the pre-treatment counts respectively). These results fall short of those expected of drugs with potential value in the treatment of onchocerciasis.

Adult↗
PubMed1983

The fine structure of adult Onchocerca volvulus. III. The cuticle, the interchordal hypodermis and the muscle cells of the female worm.

The morphology of the cuticle, the interchordal hypodermis and the muscle cells of three mature but not full-grown worms, one worm less than five years old, two worms at least five years old and seven worms of unknown age are described. The cuticle in the anterior region is very similar to that of the male worm, however, in the midbody region the cuticular structure is more simple. The length of the folds of the surface membrane and the thickness of the coat vary considerably. The outer surface of the hypodermis is increased by lamellae, the inner surface by a labyrinthine system of folds. The structure of the muscle cells is simpler than in the male worm: degenerative alterations are found frequently comprising reduction of the afibrillar portion, separation of the filaments from the septa, disintegration of the filaments, and separation of the plasma from the laminae and finally total disintegration of the cell, leaving the empty laminal coverings behind.

Animals↗
PubMed1983

Non-specific suppression of antigen-induced lymphocyte blastogenesis in Onchocerca volvulus infection in man.

Lymphocyte blastogenic responses to O. volvulus antigen (Oncho Ag), SKSD, and the mitogen PHA were tested in three groups of persons: light to moderately infected persons (INF); previously exposed but uninfected persons (EXP) and normal controls (NC). The exposed group showed significant responsiveness to Oncho Ag (delta ct/min = 6,002 +/- 1,375), while the infected (delta ct/min = 943 +/- 418) and normal control (delta ct/min = 428 +/- 418) groups did not. The mean blastogenic response to SKSD were EXP, 8,644 +/- 5,249; NC 6,039 +/- 2,880; INF, 2,619 +/- 1,012. The reduced reactivity in the INF group to Oncho Ag showed a significant correlation with reactivity to SKSD (P less than 0.05). To elucidate the mechanism of hyporesponsiveness in the infected group rigorous adherent cell depletion, by adherence to plastic followed by a nylon wool column, was utilized. When 20% plastic adherent cells were added back to the T cells prepared in this fashion, the mean blastogenic response to SKSD was significantly augmented (P less than 0.01). In contrast, the responsiveness to Oncho Ag was not significantly altered. The addition of indomethacin (1 microgram/ml) or autologous plasma had no significant effect on reactivity to either SKSD or Oncho Ag. There were no significant differences in the mean reactivity of the three groups to PHA-M (delta ct/min EXP 78,514 +/- 12,564; INF 62,393 +/- 14,447; NC 61,423 +/- 4,465). These results suggest that O. volvulus infection is associated with decreased lymphocyte reactivity to both parasite related and unrelated antigens, and imply that the mechanism for the two types of hyporesponsiveness may be distinct. While a weakly adherent suppressor cell may account for non-specific hyporesponsiveness, the mechanism of parasite specific decreased reactivity remains unknown.

Adolescent↗
PubMed1983

[Occurrence of Onchocerca lienalis (Stiles, 1892) in cattle in Austria].

The prevalence of O. lienalis in 345 Austrian cattle was determined by detection of microfilariae in the skin. Though only one among 59 male animals yielded a positive result, 46.5% of the female cattle showed to be infected with the parasite. Comparing the presence of adult worms in the gastrosplenic ligament and that of larval stages in the skin a correlation of 87.5% could be obtained. Most of the microfilariae were concentrated in the umbilical region but with severely infested animals they also were found in the skin of the udder, head, ear and neck. Seasonal periodicity of microfilariae was not observed.

Animals↗
PubMed1982

Studies on the concentration of Onchocerca volvulus microfilariae in the skin in relation to the nodule.

The concentration of microfilariae in the skin over and at distance sup to 10 cm from the onchocercal nodule was studied in eight patients with established onchocerciasis. In spite of wide variations in microfilarial counts from snips taken from the same patient no significant differences were found in respect of distance or direction from the nodule. It is concluded that microfilariae are uniformly distributed in the skin around and onchocercal nodule in established infections.

Adult↗
PubMed1982

The fine structure of adult Onchocerca volvulus. I. The cuticle, the hypodermis and the muscle cell of the male worm.

The fine structure of the cuticle, the hypodermis and the muscle cells of five male worms from Liberia and of two male worms, at least five years old, from Upper Volta is described. The cuticle in the lateral regions is thicker and consists of more layers than in the dorsal and ventral regions. The innermost zone of the hypodermis contains a wide labyrinth of extracellular clefts. The muscle cells are of the shallow coelomyarian type. Bacteria were found in the hypodermis of worms from Liberia and Upper Volta. The hypodermis and the muscle cells contained various other inclusions and particles. Some of them were formed by aggregations of regularly arranged membranes and lamellae. Although all the worms had been alive at the moment of fixation, severe degenerative alterations of the hypodermis and the muscle cells could be observed. Only the cuticular morphology was more or less constant in all seven worms.

Animals↗
PubMed1982

The fine structure of adult Onchocerca volvulus. II. The intestine and the reproductive system of the male worm.

The morphology of the gut and the genital duct of five male worms from Liberia and two male worms at least five years old, from Upper Volta are described. The lumen of the intestine can be distended vesicularly or it can be reduced to a cleft which is filled with microvilli. The intestinal epithelium contains concentric spherules or dense bodies with piles of lamellae. In parts of the intestine of a live worm the cells can be completely disintegrated. The wall of the testis consists of a squamous epithelium which contains numerous dense bodies on the luminal side. The wall of the vas deferens is a squamous or cuboid epithelium which contains glycogen and various particles. In the ejaculatory duct the epithelial cells are linked together by desmosomes at their luminal side. The brownish appearance of some organs under the light microscope is related to the accumulation of iron containing particles.

Animals↗