Schistosoma mansoni: female-dependent lipid secretion in males and corresponding changes in lipase activity.

Eight to 10-week old Schistosoma mansoni males from unisexual infections were examined histochemically for neutral lipids and lipase activity. In addition, in situ fixed pairs were examined for lipase activity. Neutral lipid content of males from unisexual infections was variable and lipase activity was minimal. Following 1 h incubation at 37 degrees C in Earle's balanced salt solution (EBSS) in which females had previously been maintained for 1 h, males showed moderate increase in lipid content and diminished lipase activity. In contrast, unisexually developed males incubated for 1 h with females from bisexual infections showed increased lipid accumulation and lipase activity. Unisexually developed males incubated for 1 h in EBSS showed both lipid accumulation and release from the dorsal surface. Worm-pairs fixed in situ showed greater lipase activity in females than in males. These observations suggest that a factor(s) released by females affects the physiology of males.

Laboratory diagnosis of autoinfection in strongyloidiasis.

Among 10,072 examinations of concentrated stools, Strongyloides stercoralis rhabditiform larvae were found in 93, and filariform larvae in four. In two of the four cases harboring filariform larvae, subsequent stools revealed only rhabditiform larvae, but filariform larvae continued to be found in the stools and sputum of the other two cases. It was concluded that only two of the cases were true autoinfections, and the other two apparent cases resulted from prolonged storage of unrefrigerated stools in the hospital ward. The importance of distinguishing true autoinfections from a free-living Strongyloides life cycle in stools is stressed.

Two cases of enteric myiasis in man. Pseudomyiasis and true intestinal myiasis.

Dipterous larvae were found in the appendices from two postmortem examinations. The single maggot in the first case was not immediately identified in the sections. However, when the posterior end of the larva was recovered from the unsectioned portion of the appendix, it was identified as a maggot of the genus Sarcophaga. The first case was believed to be a case of "pseudomyiasis,+ i.e., the accidental entrapment of a swallowed larva passing through the digestive tract. In the second case, the appendix contained numerous larvae with great variation in sizes and stages of development of the mouth hooks, pharyngeal sclerites, and spiracular breathing plates. Such development was considered to have occurred within the intestinal tract, which indicated that this was a case of true intestinal myiasis.

A case of Rictularia infection of man in New York.

A gravid female nematode was found in histopathologic sections of an appendix in a postmortem examination. This parasite was identified as Rictularia, a genus of small intestinal parasites in numerous mammals. The parasites of this genus have not previously been identified in man.

Schistosoma mansoni: characterization of clones maintained by the microsurgical transplantation of sporocysts.

Five male and 5 female clones of Schistosoma mansoni were established and maintained for 3 yr by the serial microsurgical transplantation of sporocysts from infected to uninfected Biomphalaria glabrata snails. The clones were initially derived from 10 randomly selected snails with monomiracidial infections. Clones were characterized by several criteria, including their infectivities for mice and snails, their cercarial outputs, and their ability to produce immunity in mice. The mean infectivities of individual clones in mice ranged from 26 to 44%, and were highly consistent within each clone. The infectivities of cloned sporocysts in snails ranged from 44 to 100% and were also highly consistent within clones. Mean cercarial outputs from individual clones ranged from 450 to 4,300 per snail. In mice, clones differed significantly from each other in their ability to immunize and in their susceptibility to immunity. Each clone was unique and did not appear to differ with time or subpassaging through snails, suggesting that the differences had a genetic basis.

Cytologic detection of Wuchereria bancrofti microfilariae in urine collected during a routine workup for hematuria.

A 23-year-old Guyanese man experienced intermittent, total, painless, gross hematuria for a month for which he sought medical attention at the Kings County Hospital Center in Brooklyn. Hematuria was accompanied by weakness but not by frequency of urination or burning on urination. Catheterized urine at the time of cystoscopy and each of two subsequent voided specimens examined cytologically contained sheathed microfilariae. Distinguishing features of the microfilariae were well demonstrated with the Papanicolaou stain. The well-stained nuclei, which did not extend into the clear zone, and the distinct, pale-stained sheath led to the positive identification of the microfilariae as Wuchereria bancrofti. The Papanicolaou stain may well be the stain of choice for the identification of microfilariae in the blood. The excellent detail obtained with this routine cytologic stain is as good as that with Giemsa, which does not stain the sheath.

Schistosoma mansoni: chemoreception through n-acetyl-d-galactosamine-containing receptors in females offers insight into increased severity of schistosomiasis in individuals with blood group A.

The role of exposed surface carbohydrates in chemoreception in Schistosoma mansoni females was investigated in vitro. Sexually mature females were treated with peanut (PNA), soybean (SBA) or wheat germ (WGA) agglutinin, and their migration in response to excretory-secretory (ES) products of males was measured in a bioassay system. Random distribution of untreated and lectin-treated females was similar (p=>0.05). PNA-treated females were unresponsive for 1.0 h, after which they exhibited slight repulsion to ES products. SBA-treated females did not respond to ES products for 3.0 h. WGA-treated females were unresponsive for 1.5h, after which they exhibited slight attraction to male ES products. Attempts were made to restore chemoattraction by using specific sugar inhibitors of lectin-binding; chemoattraction was best restored in n-acetyl-d-galactosamine (GalNAc)-treated females. These data suggest that GalNAc-containing receptors, possibly GP50, the major SBA-binding schistosome glycan, mediate chemoreception in schistosome females. These findings may explain the observed differences in morbidity between individuals with different blood groups. Individuals with blood group B or O may afford partial protection because of their natural anti-A or by mounting a more efficient antibody response directed against GalNAc-containing structures shared by blood group A red blood cells.

Pellioditis pellio: Substituted phenolic compounds as chemoattractants.

Vanillin, vanillic acid, and other related compounds are chemoattractants either for nematodes or arthropods. We tested vanillin, vanillic acid, and 2,4-dihydroxybenzaldehyde in an in vitro bioassay system for their ability to attractPellioditis pellio males and females. Females were not attracted to any of the three compounds tested. Males responded to vanillin and vanillic acid, but not to 2,4-dihydroxybenzaldehyde. Males responded to vanillin and vanillic acid when these compounds were present at 10(-5) M concentration. Vanillin at 10(-3) and 10(-7) M concentrations was not attractive.

Schistosoma mansoni: a chemoattractive factor released by males and its receptor in females.

Chemoattraction between developing (23- to 28-day-old) and adult (10- to 12-week-old) Schistosoma mansoni males and females has been described previously. We report here on in vitro attraction of mature worms to released products of worms of the opposite sex. In the absence of a stimulus worms migrated randomly and did not show any preference in their orientation. Males were not significantly attracted to released products of females. Females exhibited greatest attraction to released products of males, and some attraction to the lipid fraction of released products of males. The aqueous fraction of male-released products slightly repelled females. Prior exposure to released products of males rendered females unresponsive to subsequent exposure, suggesting receptor saturation. These findings have important potential implications for the control of schistosomiasis by intercepting attraction and mating between males and females.