Myxobolus cuneusn. sp. (Myxosporea) infecting the connective tissue ofPiaractus mesopotamicus(Pisces: Characidae) in Brazil: histopathology and ultrastructure

The characteristics of Myxobolus cuneus n. sp. and its relationship to the host Piaractus mesopotamicus are described based on light and electron microscopy and histological observations. Polysporic plasmodia measuring 20 microm to 2.1 mm in size were found in 63.3 % of the P. mesopotamicus examined. The parasite was found in the gall bladder, urinary bladder, gills, spleen, fins, head surface, liver and heart. Generative cells and disporoblastic pansporoblasts occurred along the periphery of the plasmodia, and mature spores were found in the internal region. The mature spores had a pear shaped body in frontal view, with a total length of 10.0 +/- 0.6 microm and a width of 5.1 +/- 0.3 microm (mean +/- SD). The spore wall was smooth with sutural folds. The polar capsules were elongated, were pear shaped, and equal in size (length 5.7 +/- 03 microm; width 1.7 +/- 0.2 microm), with the anterior ends close to each other. The polar filaments were tightly coiled in 8-9 turns perpendicular to the axis of the capsule. The plasmodia were always found in connective tissue (wall of the arterioles of the gill filaments, serous capsule of the gall bladder, middle layer and subepithelial connective tissue of the urinary bladder, connective tissue between the rays of the fins, subcutaneous tissue of the head surface and fibrous capsule spleen). The parasite caused important damage in the gills, where development occurred in the wall of gill filament arterioles; a mild macrophage infiltrate was also observed. In advanced developmental stages, the plasmodia caused deformation of the arteriole structure, with a reduction and, in some cases, obstruction of the lumen. The parasite was found throughout the period studied and its prevalence was unaffected by host size, season or water properties.

Ancylostoma caninum MTP-1, an astacin-like metalloprotease secreted by infective hookworm larvae, is involved in tissue migration

Infective larvae (L3) of nematodes secrete macromolecules that are critical to infection and establishment of the parasite in the host. The dog hookworm Ancylostoma caninum secretes an astacin-like metalloprotease, Ac-MTP-1, upon activation in vitro with host serum. Recombinant Ac-MTP-1 was expressed in the baculovirus/insect cell system as a secreted protein and was purified from culture medium by two separate methods, cation-exchange fast-performance liquid chromatography and gelatin-affinity chromatography. Recombinant MTP-1 was catalytically active and digested a range of native and denatured connective tissue substrates, including gelatin, collagen, laminin, and fibronectin. A dog was immunized with recombinant Ac-MTP-1 formulated with AS03 adjuvant, and the antiserum was used to immunolocalize the anatomic sites of expression within A. caninum L3 to secretory granules in the glandular esophagus and the channels that connect the esophagus to the L3 surface and to the cuticle. Antiserum inhibited the ability of recombinant MTP-1 to digest collagen by 85% and inhibited larval migration through tissue in vitro by 70 to 75%, in contrast to just 5 to 10% inhibition obtained with preimmunization serum. The metalloprotease inhibitors EDTA and 1,10-phenanthroline also reduced the penetration of L3 through skin in vitro by 43 to 61%. The data strongly suggest that Ac-MTP-1 is critical for the invasion process of hookworm larvae, and moreover, that antibodies against the enzyme can neutralize its function and inhibit migration.

THE MYXOZOAN FAUNA OF FUNDULUS DIAPHANUS (CYPRINODONTIDAE) FROM FRESHWATER LOCALITIES IN EASTERN NORTH AMERICA: PREVALENCE, COMMUNITY STRUCTURE, AND GEOGRAPHIC DISTRIBUTION

Membership and richness of infracommunities and component communities of myxozoan fauna of the banded killifish (Fundulus diaphanus) from freshwater localities in Ontario, Quebec, New York State, New Brunswick, Nova Scotia, and Maryland were studied. Five species of parasites were found: Myxobolus diaphanus (Fantham, Porter, and Richardson, 1940) (connective tissue throughout the body and head), Myxobolus funduli (Kudo, 1918) (interlamellar), Myxobolus neurophilus (Guilford, 1963) (optic tectum of the brain), Myxobolus sp. (connective tissue, typically adjacent to vertebrae), and Sphaerospora sp. (kidney tubules). The most abundant species locally and regionally was M. diaphanus, occurring at prevalences of 14.2 to 93.3% at 6 of 9 localities. Myxobolus funduli and Myxobolus sp. were at 3 and 2 localities respectively, while M. neurophilus and Sphaerospora each occurred at single localities. Four of the 5 myxozoans appear to be specific to fundulids, the exception being M. neurophilus, which is typically a parasite of Perca flavescens. Mean infracommunity richness was 0-1.2. Component community richness was 0-3 species. The fauna is similar in composition to that described from the spottail shiner (Notropis hudsonius) in the Great Lakes in being dominated by histozoic myxobolids and in having maximum prevalence at any single locality correlate positively with geographical distribution. Moreover, mean infracommunity richness was correlated with percentage of hosts infected with any species at a locality, and maximum infracommunity richness was correlated with component community richness. Probably because fewer species of myxozoans of fundulids occur in the regional pool, myxozoan communities encountered in the present study are generally less rich than those described from N. hudsonius. It appears that dispersal of relatively resilient myxospores through such a mechanism as piscivory effectively distributes these parasites over the landscape, while the more delicate actinospores serve to ensure colonization by amplifying species' prevalence at a specific locality and thereby contributing to initial establishment. As such, these types of myxozoans, though they are autogenic, having their entire life cycle normally completed within the aquatic environment, behave more like allogenic parasites that rely on birds and mammals as definitive hosts.

Successive changes in tissue migration capacity of developing larvae of an intestinal nematode, Strongyloides venezuelensis

Infective larvae of an intestinal nematode, Strongyloides venezuelensis, enter rodent hosts percutaneously, and migrate through connective tissues and lungs. Then they arrive at the small intestine, where they reach maturity. It is not known how S. venezuelensis larvae develop during tissue migration. Here we demonstrate that tissue invasion ability of S. venezuelensis larvae changes drastically during tissue migration, and that the changes are associated with stage-specific protein expression. Infective larvae, connective tissue larvae, lung larvae, and mucosal larvae were used to infect mice by various infection methods, including percutaneous, subcutaneous, oral, and intraduodenal inoculation. Among different migration stages, only infective larvae penetrated mouse skin. Larvae, once inside the host, quickly lost skin penetration ability, which was associated with the disappearance of an infective larva-specific metalloprotease. Migrating larvae had connective tissue migration ability until in the lungs, where larvae became able to settle down in the intestinal mucosa. Lung larvae and mucosal larvae were capable of producing and secreting adhesion molecules.

The First Record of Dirofilaria immitis Infection in a Humboldt Penguin, Spheniscus humboldti

Dirofilaria immitis infection is an important parastic disease in many mammals, especially canids, but has not been reported in bird hosts. Filarial worms were isolated from the lumen of the right atrium of the heart and the connective tissue of the lung of a captive female Humboldt penguin, Spheniscus humboldti, that died at a zoo in Japan. One of these worms was observed morphologically and identified as D. immitis by features such as 4 pairs of cephalic papillae, 1 pair of cervical papillae, esophagus divided into 2 regions, 4 pairs of pre-anal papillae, 5 pairs of post-anal papillae, and unequal spicules. In addition, the partial DNA sequence (234 bp) of mitochondrial CO / gene of the filarial worm was identical to that of D. immitis. This is the first report of D. immitis infection in a bird.

Haemolymph parasite of the shore crab Carcinus maenas: pathology, ultrastructure and observations on crustacean haplosporidians

A protozoan parasite with some features of haplosporidians is described from the European shore crab Carcinus maenas. The parasite establishes a systemic infection through the haemal sinuses and connective tissues. Intracellular stages of the parasite were found within reserve inclusion, connective tissue, and muscle cells, while free forms were present in all haemal spaces. A uninucleate stage appeared to develop to a multinucleate plasmodial stage following multiple mitotic divisions of the nucleus. Histopathology also indicated that nuclear division may occur to form multinucleate plasmodia, in connective tissue, reserve inclusion and muscle cells, the multinucleate plasmodium being enclosed in the host-cell plasma membrane. It appears that the multinucleate plasmodium may then undergo internal cleavages which result in plasmodial fragmentation to form many uninucleate stages. Both stages, but particularly the uninucleate stage, contained cytoplasmic, large, ovoid, dense vesicles (DVs), some of which contained an internal membrane separating the medulla from the cortex, as in haplosporosomes. Golgi-like cisternae, closely associated with the nuclear membrane, formed DVs and haplosporosome-like bodies (HLBs), superficially resembling viruses. Infrequently, HLBs may condense to form haplosporosomes. The DVs, as in spores of some Haplosporidium spp. and paramyxeans, may give rise to, and are homologous with, haplosporosomes. Other features, such as the presence of an intranuclear mitotic spindle, lipid droplets, and attachment of DVs and haplosporosomes to the nuclear membrane, indicate that the C. maenas parasite is a haplosporidian. A similar organism reported from the haemolymph of spot prawns Pandalus spp., and haplosporidians reported from prawns Penaeus vannamei and crabs Callinectes sapidus may belong to this group. It is concluded that the well-characterised haplosporidians of molluscs and some other invertebrates may not be characteristic of the whole phylum, and that morphologically and developmentally similar organisms may also be haplosporidians, whether they have haplosporosomes or not.

[Rationale for removal of fibrous capsule in echinococcectomy from the liver]

Experience of radical surgical treatment in 253 patients with hepatic echinococcosis is presented. Twenty-six patients underwent hepatic resection; 218, pericystectomy, 9 patients, combined interventions. Based on comparative analysis of the results of surgical treatment in 109 patients from the study and control groups, it is concluded that radical operations have significant advantages and show fever postoperative complications and recurrences. Removal of fibrous capsule is a token of successful treatment for hepatic echinococcosis.

Hydatid cyst in soft tissues mimicking malignant tumors. Diagnosis by fine needle aspiration cytology

OBJECTIVE

To evaluate the role of fine needle aspiration cytology in the diagnosis of soft tissue hydatid cysts.

STUDY DESIGN

Five cases of soft tissue hydatid cyst were diagnosed primarily by fine needle aspiration cytology.

RESULTS

In all cases, large fragments of acellular material, finely lamellated, were found. There were no complications related to fine needle aspiration, and histologic studies confirmed the diagnosis of hydatid cyst.

CONCLUSION

When acellular, laminated fragments suggestive of a laminated layer are identified on smears, hydatid cyst should be considered in the differential diagnosis, even in atypical locations and in the absence of hooklets, protoscolices or both.

Quantitative analysis of cardiac lesions in chronic canine chagasic cardiomyopathy

Lesions observed in chronic chagasic cardiopathy frequently produce electrocardiographic alterations and affect cardiac function. Through a computerized morphometrical analysis we quantified the areas occupied by cardiac muscle, connective and adipose tissues in the right atrium of dogs experimentally infected with Trypanosoma cruzi. All of the infected dogs showed chronic myocarditis with variable reduction levels of cardiac muscle, fibrosis and adipose tissue replacement. In the atrial myocardium of dogs infected with Be78 and Be62 cardiac muscle represented 34 and 50%, fibrosis 28 and 32% and adipose tissue 38 and 18%, respectively. The fibrosis observed was both diffuse and focal and mostly intrafascicular, either partially or completely interrupting the path of muscle bundles. Such histological alterations probably contributed to the appearance of electrocardiographic disturbances verified in 10 out 11 dogs which are also common in human chronic chagasic cardiopathy. Fibrosis was the most important microscopic occurrence found since it produces rearrangements of collagen fibers in relation to myocardiocytes which causes changes in anatomical physiognomy and mechanical behavior of the myocardium. These abnormalities can contribute to the appearance of cardiac malfunction, arrythmias and congestive cardiac insufficiency as observed in two of the analyzed dogs. Strain Be78 caused destruction of atrial cardiac muscle higher than that induced by strain Be62.

Mouse model for Chagas disease: immunohistochemical distribution of different stages of Trypanosoma cruzi in tissues throughout infection

Different stages of Trypanosoma cruzi are seen during mammalian infection. Histologic sections of infected hearts have shown amastigotes and, when using immunohistochemistry (IHC), parasite antigens; however, demonstration of trypomastigotes in these tissues has proven elusive. Using a mouse strain that develops chagasic cardiomyopathy (histologically similar to human infection) 70 days after injecting T. cruzi-Brazil strain, we studied the distribution of parasite stages and the extent of inflammation. All organs had varying amounts of mononuclear inflammation by day 10, which peaked between day 20 and day 30, and decreased by day 50. Amastigotes were detected in myocytes, histiocytes, acinar pancreatic cells, astrocytes and ependymal cells by day 10, and the number of amastigotes peaked on day 30. Immunohistochemistry demonstrated trypomastigotes in sinusoids, vessels and interstitial tissues of several organs between day 15 and 50. Abundant parasite antigens (granular staining) were detected in connective tissues throughout the infection. The burden of amastigotes and trypomastigotes during the acute phase seems to correlate with the degree of inflammation and granular staining in the chronic stage.

Strigea falconispalumbi in Eurasian buzzards from Germany

Eighty-three free-living Eurasian buzzards (Buteo buteo) from three different areas in Germany were examined for adult stages and the metacercaria of the trematode Strigea falconispalumbi. Prevalences of adult parasites in the small intestine was 36% (Berlin/Brandenburg), 28% (Lower Saxony) and 3% (Baden-Württemberg). Metacercaria in the connective tissue of the neck were found in 58%, 55%, and 10% of birds from the respective areas. Significant differences in the prevalence of S. falconispalumbi adults and metacercaria between the areas were attributed to the different abundance of freshwater which is the key habitat for two intermediate hosts.

MRI evaluation of soft tissue hydatid disease

Infestation in soft tissue by Echinococcus granulosus is not a common disease, and its diagnosis is based on clinical, laboratory data and radiological findings. The aim of our retrospective study is to give an overview of the different signs and patterns shown by MRI that can be useful in characterizing soft tissue hydatid disease. The MRI images obtained in seven patients with soft tissue and subcutaneous hydatidosis were reviewed. Typical signs of hydatidosis were multivesicular lesions with or without hypointense peripheral ring ("rim sign"). Related to the presence and absence, respectively,of viable scolices in the microscopic exam, daughter cysts were presented either as high signal intensity or low signal intensity on T2-weighted images. Low-intensity detached layers within the cyst and peripheral enhancement with gadolinium-DTPA were also presented. Atypical signs were presented in an infected muscular cyst, a subcutaneous unilocular cyst and several unilocular cysts. Knowledge of the different patterns in MRI of soft tissue hydatid disease can be useful in diagnosing this entity. We observed that the "rim sign" is not as common as in other locations, and in addition, MRI seems to be of assistance when evaluating the vitality of the cysts.

Distribution of mast cells and their correlation with inflammatory cells around Onchocerca gutturosa, O. tarsicola, O. ochengi, and O. flexuosa

In recent years, bovine Onchocerca species have been used as models for human onchocerciasis in drug screens. They have been suggested for immunology studies and evaluation of vaccine candidates. Therefore, mast cells and their association with other inflammatory cells were studied in five onchocercal species of cattle and deer using immunohistology. Intact mast cells occurred in large numbers in the capsule and septae of nodules, in fibrous tissue adjacent to nonnodular worms, and perivascularly. Inactive and, more frequency, activated and degranulating mast cells were observed within infiltrates in the nodule center or around nonnodular filariae. They were not detected in direct contact with the cuticle of adult worms or of microfilariae or among the macrophages, giant cells, and neutrophils forming the innermost layer around the worms. Eosinophils, but not mast cells, were obviously associated with microfilariae-producing females. The distribution, frequency, and activity of mast cells were similar for all five species and O. volvulus.

Vipera berus and V. ammodytes (Serpentes:Viperidae) represent new host for Caryospora simplex (Apicomplexa:Eimeriidae) in Europe

During a survey of the coccidian parasites of reptiles, caryosporan oocysts wee found in the faeces of wild and captive European viperid snakes Vipera berus (L.) and V. ammodytes (L.). Thirty two of 37 examined V. berus (86%) and 9 of 17 examined V. ammodytes (53%) specimens were found to be passing caryosporan oocysts. Morphological characters of all caryosporan isolates were identical and fitted well with the description of Caryospora simplex Léger, 1904. Experimental inoculation of severe combined immunodeficient (SCID) mice with seven isolates of C. simplex from V. berus or V. ammodytes confirmed the heteroxenous life cycle pattern, for the first time for isolates of evidently European origin. Caryosporan developmental stages were observed in the connective tissues of the nose, cheeks, ear and scrotum in all inoculated SCID mice. V. berus and V. ammodytes represent new hosts for C. simplex. The present paper represents the first widely based report on coccidian parasites of the genus Caryospora Léger in European viperids. Our findings indicate a wide distribution of C. simplex throughout the range of distribution of snakes of the genus Vipera.

Evaluation of colchicine with or without praziquantel therapy in the control of hepatic fibrosis in murine schistosomiasis

Colchicine alone or following praziquantel was given to mice infected with Schistosoma mansoni either 6 or 10 weeks post infection. Praziquantel increased body weight gain, histologically reduced number, diameter and cellularity of granuloma and improved liver function parameters. Early praziquantel therapy decreased hepatic collagen content as detected by the colorimetric method and the serum procollagen propeptide (PIIIP), while later treatment at the 10th week of infection increased hepatic collagen content and serum PIIIP. Colchicine therapy significantly decreased body weight gain with significant weight loss after early treatment. Colchicine did not change the histologic picture of schistosomal liver fibrosis; it induced a detectable hepatocytic injury recorded ultrastructurally and histologically with excitation of the inflammatory reaction in the granuloma and in portal tracts after early treatment. Excess pigmentation in macrophages and Kupffer cells, binucleation and large sized hepatocytic nuclei were evident after colchicine therapy. Colchicine increased hepatic collagen content microgram/mg protein, raised globulin and total serum protein and normalized the raised serum PIIIP of infected mice, but had no effect on PIIIP of normal mice. Early cessation of schistosomal infection evidently minimized the adverse effects of colchicine.

Parenteral strobilar development of Echinococcus multilocularis in scid mice

Parenteral strobilation of Echinococcus multilocularis was observed in acid (severe combined immuno-deficient) mice after intracerebral, subcutaneous and intraperitoneal inoculation with protoscoleces. Evaginated protoscoleces and segmented worms were obtained at the inoculated sites. Most worms recovered from peritoneal cavity of scid mice were encapsulated by connective tissue and granulocytes but showed a maximum of 3 proglottids, elongation of genital primordia and vesiculation. Viability of worms recovered from the subcutaneous tissue and peritoneal cavity of scid mice were higher (69.1-91.4%) than those from the immunologically normal C.B-17 (4.0-48.0%) control mice. However, viabilities of worms from the cerebrum of both scid and C.B-17 were almost the same (87.7-94.4%). Worms recovered from scid mice showed further development of reproductive organs when transplanted into the small intestine of prednisolone treated golden hamster. These findings suggest that the parenteral milieu of scid mice allows adult development of E. multilocularis protoscoleces.

Corneal virulence, cytopathic effect on human keratocytes and genetic characterization of Acanthamoeba

Acanthamoeba keratitis is a sight-threatening complication of corneal trauma or contact lens wear. Although the majority of corneal isolates of Acanthamoeba belong to Group II in the Pussard-Pons classification based on cyst morphology, they have been placed in at least six species and their genetic relatedness is uncertain. The aim of this study was to determine the virulence of, and the relationship among, strains derived from the cornea, the nasal mucosa, and other environmental sources. To assess virulence, 10(4) trophozoites of each strain were incubated with monolayers of human corneal fibroblasts. By day 7, 12 of 29 strains tested had induced significant cytopathic changes. In addition, inocula of 10(4) cysts or trophozoites with 10(6) Corynebacterium xerosis were injected into the corneas of Porton rats; 11 amoebic strains induced infection within 7 days. The correlation between the virulence of trophozoites in vitro and in vivo was 86%. Using allozyme electrophoresis, 23 Acanthamoeba strains clustered into 5 major phylogenic divisions. Three divisions contained one or more strains that were virulent in the rat cornea. Virulent Pussard-Pons Group II strains clustered tightly to a fixed allelic difference of 13.6%. The eight corneal isolates clustered to 33%, dividing into three lineages. Five avirulent nasal isolates were strongly differentiated from other Group II strains. The results were not in accord with species designations based primarily on morphological criteria. These data suggest that particular subsets of Acanthamoeba strains are virulent in the human cornea.

Filariasis (Pelecitus sp.) in the cervical subcutaneous tissue of a pigeon with trichomoniasis

Filariasis due to Pelecitus was found in the subcutaneous tissue of the neck of a domestic pigeon from Spain that died from trichomoniasis. Macroscopically, filariae were observed in the congested and hemorrhagic cervical connective tissue. Microscopically, a particular distribution of parasites with no inflammatory infiltrates was observed. Adult nematodes were located in peritracheal connective tissue and in the deep zone of the subcutaneous tissue. Microfilariae were mainly located in the superficial zone of the subcutaneous tissue. The only other changes observed were a moderate catarrhal tracheitis and congestion of the viscera.

On the pathology and localisation of Cysticercus ovis in the skin of sheep

Histological studies were conducted with experimentally and spontaneously infected lambs on the localisation of T. ovis larvae in the subcutaneous connective tissue and in the skin. In the first few days following infection an inflammatory process in the papillar and reticular skin layers was found, causing skin defects which appeared on tanning. Forty days after infection the mature cysticerci caused atrophic changes. Openings of 6-8 mm in diameter, evident on the tanning of the skin, appeared. These injuries reduced significantly the quality and the economic value of the skins.

Neutral lipid synthesis and accumulation during in vitro induction of the lipocyte phenotype in hepatic connective tissue cells

Connective tissue cells of liver parenchyma are known as hepatic myofibroblasts and lipocytes (fat-storing cells, Ito-cells). They are considered to belong to a single cell lineage, that may switch between these two phenotypes. We have studied cellular and molecular parameters and controls of this switch in the murine GRX cell line, established from liver fibro-granulomatous lesions induced by schistosomal infection. Accumulation of neutral lipids (triacylglycerols, monoalkyl-diacylglycerol, cholesterol) was monitored. It was dependent upon induction with indomethacin. Insulin alone did not induce lipid accumulation in GRX cells, but in cells induced by indomethacin it increased the quantity of stored lipids. We propose that hepatic lipocytes are not cells directly involved in energy storage, but that they represent a particular cell population specialized in storage and in controls of the homoeostasis of lipid-soluble substances at the systemic level.

Metalloproteases of infective Ancylostoma hookworm larvae and their possible functions in tissue invasion and ecdysis

To infect their hosts, hookworm larvae must exsheath and migrate through connective tissue. A modified in vitro skin chamber was used to show that the human hookworm Ancylostoma duodenale and the zoonotic canine hookworm Ancylostoma caninum penetrate epidermis, basement membrane, and dermis in similar ways. These similarities in tissue invasion properties reflect the observed biochemical similarities in parasite protease composition. The larvae of both species contain protease activity that is inhibited by o-phenanthroline; this identifies the proteases as metalloproteases. The enzyme activities exhibit an alkaline pH optimum between pH 9 and 10. During modified sodium dodecyl sulfate-polyacrylamide gel electrophoresis in which a protein substrate (either casein or gelatin) was used, the protease activities resolved into a major band at an Mr of 68,000 and a minor band at an Mr of 38,000. Proteases were released by living A. caninum larvae in vitro and degraded purified and radiolabeled casein to smaller peptides. Motile hookworm larvae were also incubated with purified and radiolabeled connective tissue macromolecules in vitro. Both Ancylostoma species degraded human fibronectin to a 60,000-Mr polypeptide intermediate, but could not degrade solubilized bovine elastin or human laminin. In contrast, the obligate skin-penetrating nematode Strongyloides stercoralis degraded all three substrates. This biochemical difference may explain some observed differences in invasiveness.

Isolation of Onchocerca gibsoni tissue from frozen nodules for biochemical use

A new procedure is described which enables gram quantities of adult Onchocerca tissue to be isolated from frozen connective tissue nodules, thus minimizing the risk of enzymatic degradation. Bovine connective tissue nodules containing adult Onchocerca gibsoni worms were obtained from Australia frozen at -70 degrees C and sectioned while still frozen into 3 mm thick slabs. The sections were thawed immediately before use, worm segments removed, rinsed, pelleted, and flash frozen in liquid nitrogen. Quality of the isolated material was demonstrated by the presence of an intact adult epicuticle as determined by electron microscopy, and by the presence of viable uterine larvae and cells. This procedure is applicable to other nodule-forming worms such as Onchocerca volvulus and is suitable for investigations which require the isolation of labile molecules or those present in minute quantities.

Gravid adult female worms of Wuchereria bancrofti in fine needle aspirates of soft tissue swellings. Report of three cases

Gravid adult female worms of Wuchereria bancrofti were observed in fine needle aspirates of soft tissue swellings from three patients. An inguinal lymph node was aspirated in two cases, and a breast nodule was the site of aspiration in the third case. In one of the inguinal lymph node aspirates, two adult gravid female worms were identified.

Mast cell heterogeneity in the small intestine of normal, gnotobiotic and parasitized pigs

A formalin fixative and a formalin-free fixative were used to study mast cells in the small intestine of conventional, gnotobiotic and parasitized pigs. Many more mast cells were identified after basic lead acetate fixation ('mucosal mast cells', MMC) than after routine formalin fixation ('connective tissue mast cells'). The MMC were preferentially localized in the lamina propria. There were no differences between conventional and gnotobiotic pigs. However, in parasitized animals, the number of mast cells was several times higher, mainly because there were more MMC. The heterogeneity of intestinal mast cells in the pig indicates that this might be an interesting model for functional studies on mast cell subsets.

Implantation of adult Onchocerca gutturosa into laboratory rodents

Adult males and females of Onchocerca gutturosa were implanted into the peritoneal cavity of mice, and their survival was determined at intervals thereafter by post-mortem examination. Ten of 17 animals receiving males dissected free of bovine host tissues contained live parasites at necropsy up to 4 months later. Female worms digested free from connective tissue by collagenase did not survive well, even though they appeared motile and intact before implantation; only 2 were alive 10 days later in 2 of 16 recipients. When males and females still contained within connective tissue capsules were implanted they survived for up to 2 months, and microfilariae were detected transiently in the skin of 2 recipient mice. The results suggest the feasibility of maintaining adult O. gutturosa in rodents by this means, provided exposure of worms to enzymes used to free them from host tissue is avoided.

The Wellcome Trust lecture. Inflammatory responses to filarial connective tissue parasites

The inflammatory responses to lymphatic filariae and to Onchocerca volvulus are reviewed with particular attention to evolutionary biology; inflammatory host spectrum; non-specific components; immunoregulation; immune evasion versus immunomodulation; chronic tissue damage and scarring and disease models. Basic principles of pathogenesis are emphasized, comparisons drawn with schistosome infection, and critical items of missing information are highlighted.

Pathological changes and immunity associated with experimental Eimeria vermiformis infections in Mus musculus

Pathological changes and immunity induced by Eimeria vermiformis (Ernst, Chobotar & Hammond, 1971) were studied in outbred Swiss mice inoculated with 5000, 10,000, 20,000, or 40,000 oocysts. Cross immunity to E. ferrisi was also studied. In the case of E. vermiformis, mortality was dose dependent; most deaths were observed in the intermediate-dose groups. Most deaths also correlated with peak oocyst output. Histopathologic changes consisted of an early neutrophil and mononuclear cell infiltration in the small intestine. Later, villus atrophy and crypt hyperplasia caused a decrease in the villus-crypt ratio. During the acute phase (8-10 days after inoculation), villus tips were eroded and parasites with necrotic debris filled the cryptal and intestinal lumina. Vacuolar changes were observed in epithelial cells of the small intestine. Neither parasites nor significant pathological changes were observed in extra-intestinal organs. Mice were totally immune to reinfection with E. vermiformis 30 and 105 days after inoculation. Cross immunity was not observed between E. vermiformis and E. ferrisi.

Parelaphostrongylus andersoni (Nematoda: Protostrongylidae) and P. odocoilei in two cervid definitive hosts

Infectivity (as percentage of initial dose), location, orientation, and productivity (as maximum weekly larval output) of adult Parelaphostrongylus andersoni Prestwood, 1972 and P. odocoilei (Hobmaier and Hobmaier, 1934) were compared in white-tailed deer (Odocoileus virginianus) (WTD) and mule deer (Odocoileus hemionus) (MD). Fourteen WTD and 10 MD were exposed to third-stage larvae of P. andersoni or P. odocoilei. Infectivity was 20% and 31%, respectively, in 7 WTD and 4 MD exposed to P. andersoni and 45% in 6 MD exposed to P. odocoilei. No nematodes were recovered from 7 WTD exposed to P. odocoilei. Nematodes were usually found in pairs, although the sex ratio was 3 females: 2 males in all deer. Most adults (greater than 90%) were located in connective tissue within skeletal muscles of the host. Distribution among muscles varied with total number recovered and, perhaps, time after exposure. Productivity was 1,834 larvae/gram and 2,630 larvae/gram, respectively, in 8 WTD and 3 MD exposed to P. andersoni and 0.9 larvae/gram and 15,103 larvae/gram, respectively, in 7 WTD and 5 MD exposed to P. odocoilei. The data were similar for P. andersoni infections in the 2 deer species but markedly different for P. odocoilei in these hosts. These results represent the first experimental demonstration of infection of mule deer with P. andersoni, and illustrate its potential occurrence in these hosts in wild populations.

Extraintestinal development of Caryospora simplex (Apicomplexa: Eimeriidae) in experimentally infected mice, Mus musculus

Developmental stages of Caryospora simplex were found in connective tissue of the cheek, tongue, and nose of Swiss-Webster and C57 BL/6 mice (Mus musculus) from 8 through 70 days after oral inoculation with 50,000 or 250,000 oocysts, or 60,000 free sporocysts of the same species obtained from an Ottoman viper, Vipera xanthina xanthina. The earliest developmental stages were seen on day 8 post-inoculation (PI) and consisted of two types of meronts and gamonts (undifferentiated sexual stages). Gamonts, microgametocytes, macrogametes, and unsporulated oocysts were found on days 10 and 12 PI. Fully sporulated, thin-walled oocysts containing eight sporozoites surrounded by a thin sporocyst membrane were first seen 12 days PI. Monozoic cysts (caryocysts) were first seen 12 days PI and appeared fully viable throughout the duration of the study, 70 days PI. Four mice injected intra-peritoneally with 150,000 free sporozoites and killed 12 days PI contained unsporulated and sporulated oocysts in connective tissues of the cheek, tongue, and nose, suggesting that sporozoites may be carried to the site of infection via the lymphatic/circulatory system. Four cotton rats, Sigmodon hispidus, inoculated orally with 250,000 oocysts all had unsporulated and sporulated oocysts of C. simplex in connective tissue of the cheek, tongue, and nose when killed on day 12 PI, indicating extraintestinal development in the secondary host is not species specific. This is the first report of a heteroxenous coccidium with both asexual and sexual development in the primary (predator) and secondary (prey) hosts.

Besnoitia sp. from goats in Kenya

The eyelids of goats in Kenya contained several, conspicuous white cysts which were up to 1.5 mm in size. By histological and electron microscopical studies it was confirmed that these cysts belong to the genus Besnoitia.

[Behavior of a Trypanosoma brucei strain (STIB 348C) in mice. 3. Histopathological findings in the terminal stage of infection]

Histopathological findings in the terminal stage of the infection of mice and rats with different variants of the Trypanosoma brucei brucei stock are described. Mice infected with mild variants showed after 12-149 days intense trypanosome colonization of the interstitial connective tissue, especially of the heart muscle, pancreas and choroid plexus, with severe tissue destructions, especially in the pancreas. With longer duration of the infection, round cell infiltrations of the leptomeninx and around intracerebral vessels developed. The alterations were the same in animals dying with high and low parasitemias. Some animals died with continuous bleeding from the tip of the tail, with serious effusions and massive edema or with generalized bacterial infection. The lymphatic organs showed intense reactive alterations, trypanosomes were only rarely found in lymph nodes. In the liver large fields of lymphatic and myeloid cells were seen, sometimes necroses developed. The kidneys showed marked deposition of eosinophilic material in the glomeruli and precipitation of proteinaceous material in dilated tubules. - Rats infected with mild trypanosomes exhibited intense colonization of the heart by trypanosomes, in some places many trypanosomes in lymph nodes, few trypanosomes in the pancreas. They died after a long phase of high parasitemia.--After infection with virulent parasites which killed the animals with high parasitemia in a few days, mice and rats had single small foci of trypanosome colonization of the interstitial connective tissue of heart, pancreas and choroid plexus as well as of the loose connective tissue in the hilum of the kidney and around lymph nodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Degradation of extracellular matrix by larvae of Schistosoma mansoni. I. Degradation by cercariae as a model for initial parasite invasion of host

We have examined the ability of cercariae of Schistosoma mansoni to degrade a model extracellular connective tissue matrix produced by rat vascular smooth muscle cells in culture. In this model, connective tissue macromolecules are present in the interactive framework that characterizes their structure in vivo. Cercariae were stimulated to degrade the matrix by skin lipid or linoleic acid. At the maximally stimulating concentration of linoleic acid (25 micrograms/cm2), 68% of the total matrix was degraded, including 57% of the glycoprotein, 79% of the elastin, and 8% of the collagen. Degradation of the matrix and transformation of cercariae to schistosomula began within minutes of exposure to maximally stimulating concentrations of linoleic acid. Degradation continued for 24 hours and was dependent on the number of cercariae. Some degradation occurred without exogenous stimulants but at a slower rate than with skin lipid or linoleic acid. Degradation of matrix was inhibited by alpha 1-proteinase inhibitor and soybean trypsin inhibitor. Ethylenediaminetetraacetic acid inhibited degradation by unstimulated but not linoleic acid-stimulated cercariae. Preacetabular gland secretions collected from cercariae also degraded the matrix with an activity 86% of that of live cercariae. Preacetabular gland proteolytic activity was also inhibited by alpha 1-proteinase inhibitor, soybean trypsin inhibitor, and ethylenediaminetetraacetic acid. The similar characteristics of matrix degradation by both live cercariae and cercarial preacetabular gland secretions support the idea that a proteinase secreted from cercarial preacetabular glands facilitates invasion of skin and connective tissue by these larvae. Degradation of elastin and glycoprotein constituents of extracellular matrix is probably essential for skin penetration.

Degradation of extracellular matrix by larvae of Schistosoma mansoni. II. Degradation by newly transformed and developing schistosomula

We have studied the ability of schistosomula of Schistosoma mansoni to degrade an extracellular connective tissue matrix synthesized by rat vascular smooth muscle cells in culture. Six to 12% of the total matrix was degraded by schistosomula from the time of transformation from cercariae to adult development in vitro. Most matrix degradation occurred during the first 24 hours of incubation and was dependent on the number of schistosomula and the type of medium in which they were incubated. The use of proteinase inhibitors indicated that schistosomula activity was distinctly different from that of cercariae. Newly transformed schistosomula expressed one activity that was similar in inhibition characteristics to that of cercarial preacetabular gland secretions and another activity that was unique to schistosomula. From 1 day after transformation to adulthood, the schistosomula-derived activity was the predominant activity detected. Schistosomula degraded a smaller percentage of the total matrix than did cercariae and showed a different substrate profile. Schistosomula degraded glycoprotein components of extracellular matrix but showed little or no activity against elastin or collagen. Matrix-degrading activity was also detected in schistosomula-conditioned medium. Sedimentation of the activity and lack of permeability through filter barriers suggest that the enzyme may be initially associated with membrane and then sloughed with membrane fragments. Since the schistosomula-derived activity initially overlaps with cercarial preacetabular gland proteolytic activity, the two activities may act in concert to facilitate skin penetration by newly transformed schistosomula. However, schistosomula activity probably serves some, as yet undetermined, function later in development.

Tetrapetalonema (T.) colombiensis sp. n. (Nematoda: Filarioidea) from Colombian primates

Tetrapetalonema (T.) colombiensis sp. n., a filarial nematode from the subcutaneous and intermuscular connective tissues of squirrel monkeys (Saimiri sciureus) and tufted ringtail monkeys (Cebus apella) from central Colombia is described. Tetrapetalonema colombiensis is a very small species (male 8 mm, females 11-21 mm), and within the subgenus most closely resembles T. panamensis and T. saimiri in dimensions and in general appearance. It can be distinguished from these species by the following major features: smoothly rounded profile of the anterior extremity; single pair of lateral caudal petals in the male; vagina vera directed immediately posteriad in the female; and a large (295-335 by 4.3-6.7 micron) microfilaria that assumes a gently curved attitude in 2% aqueous formalin preparations (Knott's technique), and which has a conspicuous inner body.

Dipetalonema (Cercopithifilaria) kenyensis subgen. et sp. n. (Nematoda: Filarioidea) from African baboons, Papio anubis

Dipetalonema (Cercopithifilaria) kenyensis subgen. et sp. n. is described from the subcutaneous connective tissues of Papio anubis, from Kenya, Africa. Of the six recognized subgenera of the genus Dipetalonema, Cercopithifilaria most closely resembles Loxodontofilaria and Chenofilaria in having an undividied esophagus. The appearance of the female tail and the number and arrangement of the caudal papillae in the male distinguish it from these two subgenera. The species kenyensis is distinct from all other species by its body size, its microfilaria, and the size and shape of the spicules. This is the first species of Dipetalonema to be described from an African primate.

Observations on Ichthyosporidium giganteum (Microsporida) with particular reference to the host-parasite relations during merogony

Connective tissue cells, particularly fibroblasts, of the fish Leiostomus xanthurus Lacépède respond to the invading microsporidian parasite Ichthyosporidium sp. [assumed to be identical with Ichthyosporidium giganteum (Thélohan)] by proliferating themselves, coalescing into a syncytium, synthesizing copious amounts of cytoplasm around the parasites, and walling off the parasitized islands of cytoplasm with fibrous capsules. The resulting cysts are xenoparasitic complexes of the syncytial xenoma type, clearly different from the cell hypertrophy tumor (xenoma sensu Weissenberg) exemplified by the Glugea cyst. These findings involve a new concept of the structure and host-parasite relations of Ichthyosporidium. Formerly, the parasitized masses of cytoplasm were interpreted as extracellular plasmodial stages of the parasite (stages uncharacteristic of the microsporidia), while the parasites themselves were interpreted as nuclei of the "plasmodia." Actually, the parasite undergoes merogony in parasitophorous vacuoles which coalesce before sporogony begins. The nuclei of the mermonts are very small chromatin granules, becoming transformed into large basophilic diplokarya of the sporonts. Sporulation is diplokaryotic throughout, the diplokarya becoming reduced in size through 2 steps during sporogony.

[A fourth species of Onchocerca, O. garmsi n.sp. from the European deer (author's transl)]

Description of O. garmsi n.sp. in the connective subcutaneous tissue of Cervus elaphus; furhter information on the description of O. tubingensis Bain and Schulz-Key, 1974, in subcutaneous nodules of the same host.

On two filarioid worms, Setaria labiatopapillosa and Pseudofilaria giraffae n. sp., from the East African giraffe

A single, however gravid, female filarioid worm collected from the peritoneal cavity of a giraffe in East Africa was identified as Setaria labiatopapillosa. Further filarioid worms recovered from the subcutaneous tissue and the Ligamentum nuchae of the same giraffe were recognized a new species and were described as Pseudofilaria giraffae.

[Investigations on the filariidae of the cervidae in Southern Germany. 3. The filariidae of roe deer (Capreolus capreolus) and fallow deer (Dama dama) (author's transl)]

Roe deer in southern Germany are frequently infected with W. rugosicauda. The adult worms are found subcutaneously in the connective tissues of the back of the host. The microfilariae concentrate in a considerable distance near the nose, in smaller numbers also in the ears and in the skin of the legs. The vector is probably Ixodes ricinus. In fallow deer C. wenki are found intradermally and subcutaneously. The microfilariae remain in the skin near the site of the adult worms. Skin inhabiting microfilariae of another filariid worm are found which cannot be associated with the described species of Cervidae. The host specificity of the filariid forms of roe deer, fallow deer and red deer is indicated, the development of the microfilarial distribution patterns is discussed.

[Course of Trypanosoma musculi infections in Plasmodium berghi-infected mice (author's transl)]

Trypanosoma musculi brought into Plasmodium berghei-infected mice in the later stages of the malaria infection shows rapid, approximately logarithmic multiplication in the peripheral blood. The trypanosome number increases by a factor of 2-9 per day, multiplication of the parasites kills most mice in a few days. Many multiplicative forms of the trypanosomes and a few trypanosomes without nuclei are seen in blood smears. Histologically and in touch preparations, masses of multiplicative forms of the trypanosomes are seen in the sinusoids of the liver. Aggregates of trypanosomes are found, too, in the kidney medulla and, inconstantly, in venous sinuses of the spleen and postcapillary venules of lymph nodes. Occasionally, trypanosomes may be found extravascularly in the interstitial connective tissue especially of the pancreas, in lymph vessels and lymph node sinuses. - Mice infected in earlier stages of the Plasmodium berghei infection achieve stabilization of trypanosome numbers.