Showing papers in "Journal of Helminthology in 1984"
TL;DR: A consistent and reproducible method is described for isolating pure populations of microfilariae of Litomosoides carinii, Brugia pahangi, B. malayi and Dipetalonema viteae from blood by density gradient centrifugation on Percoll in 0.25 M sucrose.
Abstract: A consistent and reproducible method is described for isolating pure populations of microfilariae of Litomosoides carinii, Brugia pahangi, B. malayi and Dipetalonema viteae, free of cells, from blood, by density gradient centrifugation on Percoll in 0.25 M sucrose. The recovery of the microfilariae was 85 to 97%.
58 citations
TL;DR: The findings imply that adult dogs may not always be immune to toxocaral infection and may therefore contribute significantly to the problem of environmental contamination with T. canis ova.
Abstract: Three adult male greyhounds have been repeatedly infected with Toxocara canis by oral administration of 100 to 200 infective ova. Each infection has become patent as shown by the presence of eggs in faeces. Anthelmintic treatment between 7 and 14 weeks after infection yielded an average of 25% of the inoculum as adult worms. These dogs have continued to be fully susceptible to infection despite repeated exposure to this parasite, and despite the presence of serum antibody to both parasite surface and secreted antigens. These findings imply that adult dogs may not always be immune to toxocaral infection and may therefore contribute significantly to the problem of environmental contamination with T. canis ova.
44 citations
TL;DR: The utility of the IgG fraction of human filarial serum immunoglobulin in detecting circulating antigen by sandwich enzyme linked immunosorbent assay (ELISA) was studied and those sera from persons with microfilaraemia that showed the presence of circulating antigen showed an apparent positive correlation between the microfilippial density and the antigen titre.
Abstract: The utility of the IgG fraction of human filarial serum immunoglobulin in detecting circulating antigen by sandwich enzyme linked immunosorbent assay (ELISA) was studied. 27 of 33 sera from persons with microfilaraemia, 19 of 30 sera from clinical cases of filariasis, 4 of 30 sera from normal persons from a region endemic for filariasis showed the presence of circulating filarial antigen. All the 20 normal sera from the area where filariasis was not endemic gave negative reaction for filarial antigen. Those sera from persons with microfilaraemia that showed the presence of circulating antigen also showed an apparent positive correlation between the microfilarial density and the antigen titre.
41 citations
TL;DR: Histological examination of the small intestine of mice infected with Heligmosomoides polygyrus indicates that the final site of the larvae is in the circular muscle layer of the muscularis externa of the anterior small intestine.
Abstract: Histological examination of the small intestine of mice infected with Heligmosomoides polygyrus indicates that the final site of the larvae is in the circular muscle layer of the muscularis externa of the anterior small intestine. The larvae become embedded in the muscle between the first and third days after infection and are subsequently sequestered by a localized leucocytic response. There is no evidence of a true cyst. Histological evidence suggests that the larvae actively feed on the tissues of the host during their development.
34 citations
TL;DR: It is concluded that in vitro screening tests employing the free-living stages of these five genera of nematodes afford simple yet effective means for selecting relevant compounds for further evaluation as possible leads to new broad spectrum anthelmintics for use in ruminants.
Abstract: The response of the free-living stages of Nippostrongylus brasiliensis, Nematospiroides dubius, Haemonchus contortus, Trichostrongylus colubriformis and Ostertagia ostertagi to a wide variety of antiparasitic agents in vitro was investigated. All the major broad spectrum veterinary anthelmintics showed good activity against each of these worms with EC50 values varying from about 0.0002 mg/l for certain benzimidazoles and ivermectin to about 6.5 mg/l for febantel. Of 22 known narrow spectrum anthelmintics useful only against H. contortus and/or helminths other than trichostrongyles, only 10% showed good activity at concentrations equal to or less than 10.0 mg/l. Further, only one of 15 antiprotozoal agents showed good activity in these tests at the 10.0 mg/l level. The screening test employing free-living Nippostrongylus brasiliensis was selected for an extended trial where the evaluation of 1400 miscellaneous organic chemicals was undertaken. Approximately 10% of these showed activity at concentrations equal to or less than 10.0 mg/l. It is concluded that in vitro screening tests employing the free-living stages of these five genera of nematodes afford simple yet effective means for selecting relevant compounds for further evaluation as possible leads to new broad spectrum anthelmintics for use in ruminants. However, tests using the free-living stages of these worms, including H. contortus, are unsuitable for detecting narrow spectrum 'specifics', e.g., for the treatment of haemonchiasis.
31 citations
TL;DR: Serum from reindeer infected with Elaphostrongylus rangiferi is demonstrated to contain antibodies directed against antigen(s) on the cuticle of the parasites first-stage larvae (L1), and a relationship between stress, immunity and larval output is suggested.
Abstract: The use of an indirect immunofluorescence technique demonstrated that serum from reindeer, Rangifer tarandus tarandus, infected with Elaphostrongylus rangiferi (Nematoda, Metastrongyloidea) contained antibodies directed against antigen(s) on the cuticle of the parasites first-stage larvae (L1). Output of L1 from the male reindeer was low in the period June to August, but increased to a higher level during the rutting season (September to October). The titre of specific antibody showed an inverse pattern. In the female reindeer, larval output remained high throughout the sampling period from January to July. During this period antibody titre was low. A relationship between stress (rutting season or calving period), immunity and larval output is suggested.
30 citations
TL;DR: Third-stage larvae (L3) of Anisakis simplex of a known minimum age of 60 to 61 weeks, the oldest of which may have spent at least three years in herring, were artificially excapsulated in saline and appeared healthy.
Abstract: Third-stage larvae (L3) of Anisakis simplex of a known minimum age of 60 to 61 weeks, the oldest of which may have spent at least three years in herring, were artificially excapsulated in saline and appeared healthy. A small proportion succccded in penetrating the gut wall of rats. The length distribution of L3 of minimum age 18 to 23 weeks did not differ significantly from that of larvae of minimum age 60 to 61 weeks.
30 citations
TL;DR: The proteolytic enzyme has trypsin-like properties and evidence is presented for its continuous synthesis during in vitro storage and the “excretory” system, previously suggested as a source of invasive enzymes, does not seem to be involved.
Abstract: Indirect fluorescent antibody techniques and incubation of sectioned and ligatured larvae have been used to locate the source of azocoll-positivc secretions within the oesophagcal glands of third-stage Anisakis simplex larvae. The “excretory” system, previously suggested as a source of invasive enzymes, docs not seem to be involved. The proteolytic enzyme has trypsin-like properties and evidence is presented for its continuous synthesis during in vitro storage.
29 citations
TL;DR: In this article, a detailed study of the surface topography of the echinostomes Echinostoma revolution and Isthmiophora melis has been carried out using SEM.
Abstract: A detailed study of the surface topography of the echinostomes Echinostoma revolution and Isthmiophora melis has been carried out using SEM. The tegument of the body surface has a cobblestone-like appearance with interspersed pits. The presence of possible secretory granules is noted. Observations of the anterior end reveal that the collar spines are retractable. An unusual structure is described from the ventral gap of the spiny collar of E. revolutum. The origins of this structure and the possible functions of the spiny collar are discussed. The shape and distribution of body spines is described. Differences in cirrus morphology for the two species are described. The taxonomic position of, I. melis and the significance of cirrus morphology as a useful taxonomic character are discussed. Four types of presumed sensory or secretory structures occur—ciliated, domed, button and bilobed papillae. Their distribution is described and possible functions discussed.
22 citations
TL;DR: A considerable increase in the production of lactic acid over that of ether-soluble and volatile acids under the influence of these drugs, suggests a change in the catabolism of sugar towards homolactate fermentation.
Abstract: Cotugnia digonopora consumes, in 24 hours, glucose equivalent to 38% of its body-weight and converts it into metabolites. The Krebs' cycle is insignificant in the breakdown of glucose because very little CO2 is formed. Ether-extractable acids account for most of the consumed sugar, confirming that metabolism is predominantly anaerobic. Glucose is assimilated as glycogen rather than as nucleic acids, lipids and proteins. Niclosamide, praziquantel and mebendazole strongly inhibit uptake of glucose by the parasite. A considerable increase in the production of lactic acid over that of ether-soluble and volatile acids under the influence of these drugs, suggests a change in the catabolism of sugar towards homolactate fermentation.
21 citations
TL;DR: The results suggest that Fr.
Abstract: Medium in which T. canis larvae had been cultured was applied to a Sephadex G-25 gel column and four fractions (Fr. 1-Fr. 4) were isolated. Each fraction was administered to mice by implanting a mini-osmotic pump into the peritoneal cavity and the subsequent peripheral blood eosinophilic counts were recorded. Mice given Fr. 1 showed a markedly greater eosinophilic response than did those given the other fractions. Complement activation by each fraction was investigated using normal human serum. Fr. 1 and Fr. 3 had a capacity to activate complement. The results suggest that Fr. 1 may be not only antigenetic and allergenic but also could induce eosinophilia and activate complement.
TL;DR: During a survey in 1980-81, 125 of 478 camels in Saudi Arabia were found infected with onchocerciasis, a disease characterized by hard nodules in the connective tissue around the nuchal ligaments and in the subcutis.
Abstract: During a survey in 1980–81, 125 of 478 (26·2%) camels in Saudi Arabia were found infected with onchoccrciasis. The prevalence rates in local and imported camels were 93/272 (34·2%) and 32/206 (15·5%), respectively. The disease was characterized by hard nodules in the connective tissue around the nuchal ligaments and in the subcutis. The nodules consisted of cavities containing live, degenerate or dead Onchocercafasciata , inflammatory cells, fibrosis and calcification. The microfilariac were concentrated in the skin over the head and neck regions and often caused mild non-suppurativc dermatitis.
TL;DR: Eggs of Trichostrongylus vitrinus in faecal pellets deposited on grass plots each month from April 1981 to March 1982 developed into infective larvae, which survived for up to 16 months on the herbage of grass plots; some survived during very cold weather in the winter of 1981/82.
Abstract: Eggs of Trichostrongylus vitrinus in faecal pellets deposited on grass plots each month from April 1981 to March 1982 developed into infective larvae. From October to March development was slow and mortality of the pre-infective stages was very high. From April to September development was more rapid. The weather was generally dry and mortality of the pre-infective stages was high on plots with short herbage but was lower on most of the plots with long herbage, especially in July and August. In the laboratory, development of eggs into infective larvae was completed at temperatures ranging from 4 degrees C to 27 degrees C in faecal pellets which were either kept moist or dried out slowly, but not in faecal pellets which dried out rapidly. The rate of development increased as the temperature rose. Infective larvae survived for up to 16 months on the herbage of grass plots; some survived during very cold weather in the winter of 1981/82. In the laboratory, infective larvae suspended in tap water survived even longer at 4 degrees C and 10 degrees C but not at higher temperatures. They were rapidly killed by continuous freezing. They survived for up to 8 weeks when subjected to desiccation. The relationship between climatic conditions and the development and survival of the free-living stages is discussed.
TL;DR: Wild rats and molluscs were examined for Angiostrongylus cantonensis infection on Viti Levu, Fiji, and larvae developed to adult A. cantonense in the pulmonary arteries of laboratory rats 40 to 42 days after ingestion, the first record of A. Cantonensis in Fiji.
Abstract: Wild rats and molluscs were examined for Angiostrongylus cantonensis infection on Viti Levu, Fiji. A. cantonensis were recovered from 29–6% (16/54) of Rattus rattus and 59–5% (25/42) of R. exulans. A. cantonensis like larval nematodes were found in all of four slugs, Laevicaulis alte, and ten of 20 unidentified land snails. The larvae developed to adult A. cantonensis in the pulmonary arteries of laboratory rats 40 to 42 days after ingestion. This is the first record of A. cantonensis in Fiji.
TL;DR: The effects of different dosage levels and dosage times on the autophagous activity in the colon of Schistosoma mansoni were evaluated in vivo as mentioned in this paper, and the results showed that the most dramatic ultrastructural changes were observed after high doses and over several days of treatment.
Abstract: The effects of Astiban, Lucanthone, Hycanthone and Niridazole on autophagic activities in the gastrodermis of Schistosoma mansoni were determined in vivo, using different dosage levels and dosage times. With Astiban, high levels of autophagy were observed in the gastrodermis 2 hours after an injection of the drug into the mouse, and this response had declined by 20 hours, marking a recovery by the parasite from the drug. Hycanthone and Lucanthone produced an autophagic response several days after the onset of treatment, and no recovery was observed in the morphology of the gastrodermis after the drug was discontinued. The effects of Niridazole on the gastrodermis were to produce the most dramatic ultrastructural changes after high doses and over several days of treatment. With all the drugs examined, gastrodermal autophagy was characterized by the formation of vacuoles containing cell components, lipid droplets and sometimes hydrolytic enzyme reaction product. The autophagic vacuoles appeared to be formed by the sequestration of cytoplasmic material by the basal membrane infoldings, and the transfer of enzymes into the vacuole from within the limiting membrane. The residues from intracellular digestion appeared to be emptied into the caecal lumen.
TL;DR: It is suggested that differences in habitat microclimate could not account entirely for the observed differences in redial burden and the role of multiple miracidial infection is discussed.
Abstract: Of the 2,652 Lymnaea truncatula collected from sites in Cumbria and Gwynedd during 1973-75, when the prevalence of fascioliasis in the primary host was low and declining, only 123 were infected with Fasciola hepatica. Dissection of these snails revealed that the proportion infected, the mean redial burden and the proportion of mature rediae in each snail increased with shell length. The results are compared with a similar data set acquired when the prevalence of infection in both the primary and intermediate hosts was uncharacteristically high. Although the results are qualitatively similar, there are important quantitative differences. The mean redial burden of infected snails at times of high disease prevalence was generally twice as high as that reported in the present study. It is suggested that differences in habitat microclimate could not account entirely for the observed differences in redial burden and the role of multiple miracidial infection is discussed.
TL;DR: Infectivity, growth and development were studied in 23 one-day-old domestic chicks each fed 25 pre-selected metacercarial cysts of Echinostoma revolutum, finding that as worms aged in the chick, the body length increased relative to the width, the acetabulum shifted more anteriad and the size of the excretory bladder increased.
Abstract: Infectivity, growth and development were studied in 23 one-day-old domestic chicks each fed 25 pre-selected metacercarial cysts of Echinostoma revolutum. All chicks were infected at necropsy one to 44 days post-exposure with one to 18 flukes/chick. From the 575 cysts fed to chicks, 145 (25%) flukes were recovered from the ileum, caeca, rectum-cloaca and bursa of Fabricius. Length measurements on 113 uncurled flukes fixed in hot alcohol-formalin-acetic acid showed that worms grew slowly to 1.0 mm by day 3, rapidly to 6 mm by day 14, and less rapidly to 9 mm by day 36. Worms became ovigerous by day 9. As worms aged in the chick, the body length increased relative to the width, the acetabulum shifted more anteriad and the size of the excretory bladder increased.
TL;DR: A new fasciolicide, triclabendazole, tested at single oral dose rates of 5 and 10 mg/kg body-weight, proved to be highly effective against chronic field infections of Fasciola hepatica and F. gigantica in sheep.
Abstract: A new fasciolicide, triclabendazole, tested at single oral dose rates of 5 and 10 mg/kg body-weight, proved to be highly effective (greater than 99%) against chronic field infections of Fasciola hepatica and F. gigantica in sheep. The performance of the new drug compared favourably with niclofolan at the recommended dose. Neither product was effective against Dicrocoelium dendriticum and Paramphistomum spp.
TL;DR: Counter current immunoelectrophoresis was used to detect porcine cysticercosis and water soluble extracts of scolex and of scoles with cyst wall were used as antigens and the test was rapid and sensitive.
Abstract: Counter current immunoelectrophoresis was used to detect porcine cysticercosis and water soluble extracts of scolex and of scolex with cyst wall were used as antigens. Serum samples from 40 pigs infected with Cysticercus cellulosae, five infected with C. tenuicollis and five with hydatid cysts, and 15 healthy pigs were tested. A sharp and thick concave precipitin band was observed at the point of interaction of antigen and antibody within 90 min in 39 sera from infected pigs (97.5%). The precipitin reaction was better in barbitone buffer of pH 8.6 with the well distance at 6 mm. No false or cross reaction were found and the test was rapid and sensitive.
TL;DR: The host-parasite interaction at the site of attachment of the adult hookworm, Ancylostoma ceylanicum, to the small bowel mucosa of the dog has been examined by transmission electron microscopy.
Abstract: The host-parasite interaction at the site of attachment of the adult hookworm, Ancylostoma ceylanicum, to the small bowel mucosa of the dog has been examined by transmission electron microscopy. The lamina propria around the heads of the worms showed intense infiltration with neutrophilic and eosinophilic leucocytes, and plasma cells were also prominent. Erythrocytes were extravasated within the lamina propria while the portions of mucosa engulfed into the buccal cavities of the worms were necrotic and included aggregates of collagen fibres. Within the lumina of the worms were erythrocytes in varying stages of lysis together with other necrotic debris. The mucous membrane adjacent to the heads of the worms was ulcerated while more distant enterocytes were small, distorted and displayed various degrees of microvillar loss. Many mucosal blood vessels had platelet aggregates within their lumina but no fibrin deposition was observed. Vessels were often seen in the bases of the ulcers and were prone to rupture. Erythrocytes and leucocytes were seen in the dog intestinal lumen in close proximity to the bodies of the worms.
TL;DR: The in vitro release of eggs in a 24-hour period by one female nematode peaked from day 25 to day 39, a second rise occurred in day 70 after infection and thereafter gradually declined.
Abstract: Ancylostoma ceylanicum is a new introduction as an experimental hookworm model. Information on the biology of this parasite in its laboratory host--the golden hamster, is meagre. Its infectivity, longevity and fecundity were studied to obtain relevant information especially on vulnerable points in the maintenance and continuation of the infection. 100% infectivity was obtained with an inoculum of 60 larvae per animal. Maximum numbers of parasites were harboured from day 15 to day 18 after infection and thereafter gradually declined. Approximately 10% of the worms were still present at the end of the third month of infection. The in vitro release of eggs in a 24-hour period by one female nematode peaked from day 25 to day 39, a second rise occurred in day 70 after infection.
TL;DR: Treatment with praziquantel at the beginning of the lumen phase of Hymenolepis nana in mice showed conclusively that the mouse given eggs of H. nana produces two separate immune responses against reinfection.
Abstract: Treatment with praziquantel at the beginning of the lumen phase of Hymenolepis nana in mice showed conclusively that: (i) the mouse given eggs of H. nana produces two separate immune responses against reinfection, one directed exclusively against the tissue phase of egg challenge (early response), the other against the lumen phase of cysticercoid challenge (late response); (ii) a tissue phase of egg inoculation is not necessary for initiating the late response but is necessary to provoke the early response; and (iii) H. nana expresses several stage-specific immunogens through its development in the mouse host.
TL;DR: In the desert city of Beersheba, Israel, a survey was made of the infection rate of Toxocara canis in dogs, and 7% of faecal samples gathered from day care centres throughout the city were shown to contain T. canis eggs.
Abstract: In the desert city of Beersheba, Israel, a survey was made of the infection rate of Toxocara canis in dogs. 3.0% of dogs destroyed at the municipal dog pound had intestinal T. canis. 7% of faecal samples gathered from day care centres throughout the city were shown to contain T. canis eggs. This low rate of infection could possibly be explained by the hot, arid climatic conditions which may render eggs non-infective or by the sandy soil in the area that may cover faeces containing T. canis ova and make the eggs unavailable to other dogs.
TL;DR: The intestinal morphology of rats given one, 10 or 100 cysticercoids of hymenolepis diminuta was examined by scanning electron microscopy and the presence of one large H. diminuta resulted in more severe pathological damage than caused by several smaller worms.
Abstract: The intestinal morphology of rats given one, 10 or 100 cysticercoids of hymenolepis diminuta was examined by scanning electron microscopy. The presence of this tapeworm causes extensive villous atrophy and fusion. The most extreme changes in mucosal architecture were observed adjacent to the mature proglottides of the worm and in these areas the villi were reduced either to flattened plate-like structures or to low irregularly shaped undulations. The presence of one large H. diminuta resulted in more severe pathological damage than caused by several smaller worms. Colonization of the upper region of the ileum by long filamentous bacteria was also observed in rats infected with H. diminuta.
TL;DR: An approach to the identification of parasite proteins which are immunogenic in natural infections is described, using the infection with the larval stage of Echinococcus multilocularis as a parasite model.
Abstract: An approach to the identification of parasite proteins which are immunogenic in natural infections is described, using the infection with the larval stage of Echinococcus multilocularis as a parasite model. Metacestode proteins were separated by SDS-polyacrylamide gel electrophoresis, and transferred electrophoretically to nitrocellulose sheets (Western blotting). Subsequently, immune recognition of the proteins was performed with various host sera and antigen-antibody complexes were detected enzymatically. Using homologous antisera, different patterns of immunogenic bands were revealed by sera of different host species. Cross-reactions with sera from individuals infected with unrelated helminths were analysed. Four proteins of E. multilocularis which failed to show any cross-reaction were identified.
TL;DR: Jirds were given a chemoprophylactic inoculation of flubendazole and then five injections of infective larvae of Brugia pahangi whilst still protected by the FMBZ but worms numbers were not significantly reduced as compared with untreated controls.
Abstract: Jirds were given a chemoprophylactic inoculation of flubendazole (FMBZ) and then five injections of infective larvae of Brugia pahangi whilst still protected by the FMBZ. When the drug was thought to be non-effective the jirds (and controls) were given a challenge infection of B. pahangi larvae. By comparison with control jirds the treated-infected-challenged jirds had 40% fewer adult worms. The control treated-challenged jirds contained mostly sterile female worms showing that they were still partially protected by FMBZ but worms numbers were not significantly reduced as compared with untreated controls.
TL;DR: Extracts of Dirofilaria immitis adults and microfilariae cause the degranulation of mast cells in rat mesentery when applied in vitro and also cause increased vascular permeability in guinea-pigs and rabbits.
Abstract: Extracts of Dirofilaria immitis adults and microfilariae cause the degranulation of mast cells in rat mesentery when applied in vitro and also cause increased vascular permeability in guinea-pigs and rabbits. Adult worms but not microfilariae are able to activate complement in vitro and both stages contain a plasminogen activator. No proteolytic activity or haemolysins could be detected in either stage. The possibility that these factors may be important in the pathogenesis of dirofilariasis and in the adverse drug reactions that may follow treatment of microfilaraemic animals with diethylcarbamazine is discussed.
TL;DR: It is concluded that the hypersecretion of gastric acid induced by insulin is responsible for the posteriad migration of H. diminuta in rats.
Abstract: The effects of insulin on worm (Hymenolepis diminuta) migration was studied. Insulin injection (20 U/kg, s.c.) significantly increased gastric acid output but did not affect the serotonin content of blood, intestinal lumen or worms. The drug produced, dose-dependently, posteriad migration of the worms in rats without pylorus-ligation but ligation of the pylorus prevented this migration. It is concluded that the hypersecretion of gastric acid induced by insulin is responsible for the posteriad migration of H. diminuta in rats.