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In a sample of 23 breeding places of pacas (Agouti paca) in Costa Rica, the following parasites were found: Eimeria agoutii, Balantidium coli, Capillaria sp., Trichuris sp., Taenia sp., Strongyloides sp., and members of the superfamilies Strongyloidea and Ascaroidea.
The serum IgE levels of asthmatic subjects from Papua, New Guniea (PNG) were similar to those of corresponding control subjects but significantly higher than Caucasian asthmatics from Western Australia (AUS). Notwithstanding these differences in total IgE, the levels of IgE antibodies to D. pteronyssinus (RAST units) were similar in both asthmatic groups. The mite specific IgE antibody levels were independent of those to Ascaris and hookworm, suggesting that antigenic competition is not a factor of importance in sensitization to environmental allergens in the tropics. This study does not support the proposal that the low prevalence of allergic disease in tropical areas where parasitism is endemic is attributed to mast cell blockade through saturation of IgE receptors.
A study on Blastocystis hominis was undertaken for the purpose of clarifying the morphology of the organism using the following techniques; Giemsa, Heidenhain Iron Hematoxylin, and DAPI stains, phase-contrast microscopy, and transmission- and scanning-electron microscopy. Microscopic examinations of the lumen fluids aspirated at the endoscopical examination revealed the habitation of B. hominis in the lower ileum and cecum of a patient. When examined light-microscopically, organisms from stool materials, cultures, and aspirated intestinal lumen contents of a patient showed morphological resemblances to each other except for variations in size. Vacuolated cells, which were spherical in shape and characteristically had a large central vacuole and a narrow rim of cytoplasm containing nuclei and some inclusions, were the only form of the organism observed in this study, although the contents of the vacuole notably varied. DAPI stains clearly revealed the nucleus and the possible mitochondrion in the narrow rim of cytoplasm. Phase-contrast microscopy of fresh material prepared with physiological saline was recommended for diagnosis. When examined electron-microscopically, the organisms were coated with a capsule that was composed of fine filamentous materials. All the organisms contained a central vacuole although the contents of it varied considerably. The cytoplasm gave the organism a signet ring appearance and contained cristate mitochondria, a great number of ribosomes, Golgi's apparatuses, cytoplasmic microtubules, and nuclei with a nucleolus. Very few of the ultrastructures are those that would be expected of a yeast. Recent occurrences of B. hominis infection in Kyoto City, Japan, during a two-year period (June 1983 to August 1985) were also reported.
Oral vaccinations with Trichuris muris adult worm homogenate antigen with cholera toxin as the adjuvant were successful in both high-responder BALB/c and low-responder C57BL/10 mice, resulting in high levels of protection against subsequent infection, but were ineffective in the low-responder B10.BR mice. Subcutaneous vaccination with antigen in Freund's complete adjuvant resulted in protection of all of these strains but was most effective in high-responder BALB/c and least effective in B10.BR mice. Oral vaccination resulted in a T. muris-specific intestinal immunoglobulin A response only in the two protected strains. High levels of serum immunoglobulin G1 antibody were induced by Freund's complete adjuvant vaccination in all cases. A relationship between vaccine efficacy, expulsion phenotype, and induced T-helper subset-associated cytokines (interleukin-5 and gamma interferon) was noted. It was concluded that effective vaccination against T. muris requires the induction of Th2 responses and that this can be achieved by both oral and parenteral administration of antigens.
Podocotyle shawi is transferred to the genus Plagioporus. The miracidium develops and hatches in 11 to 14 days at 22 to 25 C. The operculate snail, Lithoglyphus virens, serves as first intermediate host. Mother and daughter sporocysts develop, the latter producing cotylomicrocercous cercariae within 90 to 130 days. Cercariae encyst in the amphipod, Hyalella azteca; stonefly nymphs of the genus Arcynopteryx; mayfly nymphs of the genera Heptagenia and Paraleptophlebia; chironomid larvae of the genera Chironomus, Polypedilum, Phaenopsectra, Ablabesmyia, and Psectrocladius and caddis larvae of the genera Brachycentrus, Limnephilus, and Hydropsyche. Metacercariae 60 to 100 days old were fed to young steelhead trout, Salmo gairdneri, and partially developed specimens of P. shawi were recovered 26 days later. Stonefly nymphs are believed to be the most important second intermediate host in the natural environment. The parasite seems to be restricted to the Pacific Northwest of the United States and has been reported from the silver salmon, Oncorhynchus kisutch; kokanee, O. nerka; cutthroat trout, Salmo clarki; steelhead trout, S. gairdneri; and the mountain whitefish, Prosopium williamsoni.
The gene encoding an immunodominant Eimeria acervulina merozoite surface antigen (EAMZ250) was expressed in bacteria as a fusion peptide with the galactose-binding protein (GBP) of Escherichia coli. Recombinant and control antigens were administered to 1-wk-old chickens by peroral inoculation with live nonpathogenic bacteria that were expressing GBP-EAMZ250 or GBP protein. The immunization elicited antigen-specific humoral and cellular immune responses as measured by ELISA and T-cell blastogenesis assay. In addition, chickens immunized with recombinant GBP-EAMZ250 exhibited significant protection against weight loss and intestinal lesions after E. acervulina challenge. Bacterial transformants were recoverable from the upper and middle intestine of inoculated chickens for various times after immunization. These data indicate that oral administration of live E. coli expressing a recombinant E. acervulina antigen is an effective means of inducing resistance to coccidiosis.
In a blind comparison, 465 randomly collected clinical fecal specimens were examined. Hemo-De was found to be an excellent replacement for ethyl acetate in the concentration procedure and for carbol-xylene and xylene in the trichrome staining procedure. Elimination of toxic reagents, combined with its lower cost, makes Hemo-De the preferred choice in routine parasitology examinations.
We describe for the first time the ultrastructure of spermiogenesis of a representative of the family Dipylidiidae, Dipylidium caninum. Spermiogenesis begins with the formation of a differentiation zone. This conical area presents two centrioles with associated striated roots. One of the centrioles develops a flagellum and posteriorly a proximodistal fusion is produced between the axoneme and a median cytoplasmic process. In a final stage of spermiogenesis a condensation of electron-dense material between cortical microtubules is observed in the anterior part of the differentiation zone. This is the origin of the crest-like body that appears at the end of spermiogenesis. The presence of striated roots associated with centrioles constitutes the first report of these structures in the spermiogenesis of a cyclophyllidean cestode.
The major pepsin inhibitor from Ascaris suum was isolated by affinity chromatography and chromatofocusing. Its amino acid sequence was determined by automated Edman degradation of peptide fragments. Peptides were produced by chemical and enzymatic cleavage of pyridylethylated protein and were purified by reverse-phase high-performance liquid chromatography. The inhibitor consists of 149 residues with the following sequence: QFLFSMSTGP10FICTVKDNQV20FVANLPWTML30EGDDIQVGKE40 FAARVEDCTN50VKHDMAPTCT60KPPPFCGPQD70MKMFNFVGCS80VLGNKLFIDQ90KYVRDLTAK D100 HAEVQTFREK110IAAFEEQQEN120QPPSSGMPHG130AVPAGGLSPP140PPPSFCTVQ149. It has a molecular weight of 16,396. All cysteines are engaged as disulfide bonds: Cys(13)-Cys(59), Cys(48)-Cys(66), and Cys(79)-Cys(146). The protein is probably composed of two domains connected by a short hydrophobic region. This is the first aspartyl protease inhibitor of animal origin that has been sequenced. The sequence has no significant homology with any other known protein.
The ultrastructure of spermiogenesis and the mature spermatozoon in Catenotaenia pusilla (Cestoda: Catenotaeniidae) is described. Spermiogenesis is characterized by the presence of a single axoneme which grows on the outside of a cytoplasmic extension at an angle of 45 degrees. Flagellar rotation and proximodistal fusion are produced in this process. The centrioles lack striated roots and an intercentriolar body. In the mature spermatozoon four different regions are described. The anterior extremity is capped by an apical cone and presents two helical crest-like bodies of unequal length. The axoneme, of the 9 + '1' pattern of the Trepaxonemata, presents a periaxonemal sheath. The cortical microtubules form a spiral pattern at an angle of about 40 degrees to the hypothetical spermatozoon axis. The nucleus is kidney- to horseshoe-shaped in cross section. Granules and proteinaceus walls are not observed in the spermatozoon of C. pusilla.
The parasitic worm Ascaris suum contains the opiate alkaloid morphine as determined by HPLC coupled to electrochemical detection and by gas chromatography/mass spectrometry. The level of this material is 1168 +/- 278 ng/g worm wet weight. Furthermore, Ascaris maintained for 5 days contained a significant amount of morphine, as did their medium, demonstrating their ability to synthesize the opiate alkaloid. To determine whether the morphine was active, we exposed human monocytes to the material, and they immediately released nitric oxide in a naloxone-reversible manner. The anatomic distribution of morphine immunoreactivity reveals that the material is in the subcuticle layers and in the animals' nerve chords. Furthermore, as determined by RT-PCR, Ascaris does not express the transcript of the neuronal mu receptor. Failure to demonstrate the expression of this opioid receptor, as well as the morphine-like tissue localization in Ascaris, suggests that the endogenous morphine is intended for secretion into the microenvironment.
The protozoan parasite Entamoeba histolytica is the cause of amoebic dysentery and liver abscess. It is therefore responsible for significant morbidity and mortality in a number of countries. Infections with E. histolytica are treated with nitroimidazoles, primarily with metronidazole. At this time, there is a lack of useful alternative classes of substances for the treatment of invasive amoebiasis. Alkylphosphocholines (alkyl-PCs) such as hexadecyl-PC (miltefosine) were originally developed as antitumor agents, but recently they have been successfully used for the treatment of visceral leishmaniasis in humans. We examined hexadecyl-PC and several other alkyl-PCs with longer alkyl chains, with and without double bond(s), for their activity against two strains of E. histolytica. The compounds with the highest activity were oleyl-PC, octadecyl-PC, and nonadecenyl-PC, with 50% effective concentrations for 48 h of treatment between 15 and 21 microM for strain SFL-3 and between 73 and 98 microM for strain HM-1:IMSS. We also tested liposomal formulations of these alkyl-PCs and miltefosine. The alkyl-PC liposomes showed slightly lower activity, but are expected to be well tolerated. Liposomal formulations of oleyl-PC or closely related alkyl-PCs could be promising candidates for testing as broad-spectrum antiprotozoal and antitumor agents in humans.
Intestinal parasites are Giardia lamblia, Cryptosporidium parvum, Entamoeba histolytica, hookworms, ascaris, tape worms and others. As to organ parasites, their life-threatening courses are pointed out: amebiasis in the intestine, liver, lung and brain, toxoplasmosis in the brain, lung and heart muscle, including the danger for the child of a pregnant woman with an acute infection, West African sleeping sickness with encephalitis, the East African form with polyserositis, South American Chagas' disease with intestinal and myocardial involvement, visceral leishmaniasis Kala Azar, the filariasis Onchocerca volvulus with threatening blindness, the dog tapeworm with cysts and Echinococcus multilocularis with carcinoma-like infiltration of the liver and other organs, cysticercosis of the brain, eye and muscle tissue; partly generalizing parasitoses in immuno-suppressed including AIDS patients, finally skin parasites as causes of disease (e.g. scabies), and as potential carriers of pathogens.
Spermiogenesis in Vampirolepis microstoma begins with the formation of a nuclear cone and a differentiation zone. This is delimited at the front by arched membranes, bordered by cortical microtubules, and contains two parallel centrioles linked together at their bases by electron-dense, amorphous material. The nuclear cone elongates, becomes filiform, and migrates into the spermatid body. Later, one of the centrioles gives rise to a flagellum that grows at the same pace as the cortical microtubules. Subsequently, 6 crested bodies form and the old spermatid separates from the residual cytoplasm. The mature V. microstoma spermatozoon is filiform and lacks mitochondria. Its anterior end exhibits six crested bodies 100 to 200 nm thick of unequal lengths. The axoneme is of the 9+"1" pattern. The cortical microtubules are spiralized and make an angle of about 20 to 30 degrees to the spermatozoon axis, except at their posterior extremity where they become parallel to this axis. The nucleus is an electron-dense cord coiled in a spiral around the axoneme. The cytoplasm is slightly dense but contains many electron-dense granules in regions III, IV, and V of the spermatozoon. The presence of centrioles linked together at their bases by electron-dense material has never, to our knowledge, been reported in a Platyhelminth. Likewise, a nuclear migration, right from the beginning to the end of spermiogenesis, has never been described in a cestode. In addition, we observe for the first time the existence of six crested bodies in a cestode from a Mammal.
Genetic and environmental factors both influence autoimmune disease occurrence, but the identity and mechanism of action of environmental factors are poorly understood. Here we show that pinworm-infected neonatal but not adult mice, injected with an ovarian self peptide of the zona pellucida protein 3 (pZP3) in water and without adjuvant, develop Th2 responses and severe eosinophilic autoimmune ovarian disease. A strong Th2 memory response is recalled when, as adults, the mice are challenged with a regimen that elicits a strong Th1 response in naive adults. The strong Th2 autoimmune response included high levels of IL-4 and IL-5 production by pZP3-specific T cells, and an IgG1-biased autoantibody response. The Th2 response ended promptly upon pinworm eradication, and partially resurfaced upon re-infection. We conclude that the rodent pinworm is an environmental agent that modifies the neonatal response to a self peptide, resulting in termination of the tolerance state and induction of a strong Th2-associated autoimmune disease and T cell memory.
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