Showing papers in "Journal of Helminthology in 1977"
TL;DR: The finding that inbred NIH and BALB/c mice acquire resistance to N. dubius offers possibilites for the systematic analysis of lymphoid cell activity in initiating and expressing immunity to this parasite.
Abstract: The development of immunity to Nematospiroides dubius was studied in three strains of inbred mice (BALB/c, C3H and NIH). Although a primary infection in NIH mice persisted for two months without evidence of a reduction in worm numbers, female mice of this strain readily developed resistance to reinfection. The degree of resistance was enhanced when an immunizing infection of 600 larvae was administered as 6 separate doses of 100 larvae given between days 0 and 11, and the worms removed by anthelmintic treatment given on days 15, 21, 28 and 35. Immunity in mice immunized in this way was manifest both as a reduction in worm recoveries on days 9–14 after challenge and also as an expulsion of established worms from the intestine. BALB/c mice were initially less resistant, but expelled most of the worms which became established; C3H mice showed no evidence of expulsion. The finding that inbred NIH and BALB/c mice acquire resistance to N. dubius offers possibilities for the systematic analysis of lymphoid cell activity in initiating and expressing immunity to this parasite.
81 citations
61 citations
TL;DR: The conclusion is that neither the temperatures encountered in the field nor the solar ultra-violet radiation penetrating turbid waters are likely to be harmful to miracidia and thus have no effect on the level of transmission.
Abstract: The influence of temperature and ultra-violet radiation on the degree of activity, survival and infectivity of schistosome miracidia is profound Miracidia of Schistosoma mansoni and S haematobium were affect eaually Only miracidia classified as "active" or "slow" were capable of penetration, a capacity they retained for about 17 hours at 19 degrees C Miracidia that were "lethargic" as a result of low temperature, old age or ultra-violet radiation lost their infective capacity The conclusion, however, is that neither the temperatures encountered in the field nor the solar ultra-violet radiation penetrating turbid waters are likely to be harmful to miracidia and thus have no effect on the level of transmission
57 citations
TL;DR: From the known species occurring in crocodilians, the genus Dujardinascaris is redefined and found to be a homogenous group of species, with dujardini Travassos, 1920 as the type species.
Abstract: From the known species occurring in crocodilians, the genus Dujardinascaris is redefined and found to be a homogenous group of species, with dujardini Travassos, 1920 as the type species. The following new species are described and added to the genus: gedoelsti, puylaerti, waltoni, mawsonae and taylorae. The following species are excluded from the genus: vandenbrandeni, australiensis, tasmani, alata and antipini. The distribution of the species in Dujardinascaris is as follows: in African crocodiles—dujardini, madagascariensis, gedoelsti, and puylaerti; in South American caimans—longispicula, paulista, and chabaudi (possibly a synonym of paulista); in North American alligator—waltoni; in Crocodylus acutus—helicina; in the Indian gavial—woodlandi; in crocodiles in Papua New Guinea and Australia—mawsonae and taylorae. These species are differentiated mainly by the relative length of the spicules and the form of the gubernaculums in the males and by the relative length of the vagina and the form of the vulva in the females.
45 citations
TL;DR: Adult Strongyloides ratti were expelled from the small intestine of rats starting 14-18 days after a primary infection and in a secondary infection very few adult worms developed and most of these were expelled before day 14.
Abstract: Adult Strongyloides ratti were expelled from the small intestine of rats starting 14-18 days after a primary infection. In a secondary infection very few adult worms developed and most of these were expelled before day 14. At the time of expulsion the worms migrated posteriorly in the intestine and their size decreased.
42 citations
TL;DR: Evidence supports the view that the gut acts as an important barrier to metacercariae of a challenge infection, and Protective mechanisms that may operate at the level of the gut are discussed.
Abstract: Groups of rats, infected 7 weeks previously with Fasciola hepatica, together with appropriate control groups, were challenged either orally or intraperitoneally with 30 metacercariae. The mean worm recovery from the previously infected, orally challenged rats was significantly lower than from their respective controls (2.2 +/- 1.1 worms as opposed to 9.0 +/- 2.6). There was no significant difference in mean worm recovery from the previously infected, intraperitoneally challenged rats and their respective controls (5.3 +/- 3.2 worms as opposed to 6.2 +/- 1.9). Livers of the orally challenged group appeared to be largely free from secondary damage but considerable damage was evident in rats which received an intraperitioneal challenge. This evidence supports the view that the gut acts as an important barrier to metacercariae of a challenge infection. In a further experiment, young flukes were recovered from the gut, abdominal cavity and liver of immune and control rats 9, 18, 27, 36 and 45 h after oral challenge. It was found that fewer flukes successfully penetrated the guts of immune rats (3%) than those of uninfected controls (13%), again pointing to the gut as a barrier to metacercariae of a challenge infection. Protective mechanisms that may operate at the level of the gut are discussed.
31 citations
TL;DR: A key to cercariae of British strigeoids for which life-cycles are known has been compiled and the value of various characters of systematic importance is discussed.
Abstract: From original observations and from data in the literature, a key to cercariae of British strigeoids for which life-cycles are known has been compiled. The value of various characters of systematic importance is discussed.
28 citations
TL;DR: Antibody could not be detected on the surface of any of the preparations of fresh or methanol-fixed protoscoleces using direct or indirect fluorescent antibody tests suggesting that the classical pathway of complement activation was not involved in the lytic process.
Abstract: Brood capsules were obtained from freshly collected cysts of equine and ovine strains of Echinococcus granulosus. Protoscoleces were freed from brood capsules either by mechanical disruption or pepsin-HCI digestion. Preparations of protoscoleces studied included: mechanically released protoscoleces without further treatment, or incubated either in HCI pH 2.0 or in evaginating solution (containing Na taurocholate) for 24 h; pepsin-HCI released protoscoleces without further treatment or incubated in evaginating solution for 24 h or 7 days. Half of each preparation of ovine protoscoleces was fixed in absolute methanol. All fresh preparations of protoscoleces lysed rapidly when incubated in normal human serum. Studies with a fluorescein isothiocyanate (FITC) labelled sheep anti-human C3 antiserum revealed the presence of C3 on the surface of lysing protoscoleces. Antibody could not be detected on the surface of any of the preparations of fresh or methanol-fixed protoscoleces using direct or indirect fluorescent antibody tests suggesting that the classical pathway of complement activation was not involved in the lytic process. Strong evidence for lysis by the alternate pathway of complement activation was the lysis of protoscoleces which had been treated with pepsin-HCI and lysis of protoscoleces in guinea-pig serum deficient in C4 component of complement.
28 citations
TL;DR: It is concluded from comparative studies, based on measurements, sections and electron scanning micrographs, that fourth stage larvae of S. sulcata collected from the stomach of turtles are identical with fourth stage ascaridoid larvae found in the adductor muscle of scallops and that turtles become infected with this species by eating bivalves.
Abstract: The genus Sulcascaris is upheld and redefined. Sulcascaris sulcata from Chelonia mydas and Caretta caretta is redescribed, from Rudolphi's type material and material from the Mediterranean and Western Pacific, demonstrating that the excretory pore opens between the subventral lips and that the excretory cell is bilateral, comprising a short filamentar right component and a more capacious ribbon-like left component containing the nucleus. The phylogenetic significance of this form of excretory system occurring in an ascaridoid of a marine reptile is discussed. It is concluded from comparative studies, based on measurements, sections and electron scanning micrographs, that fourth stage larvae of S. sulcata collected from the stomach of turtles are identical with fourth stage ascaridoid larvae found in the adductor muscle of scallops (Amusium balloti and Chlamys sp.) and that turtles become infected with this species by eating bivalves. Adult S. sulcata were obtained from tank-reared C. caretta fed with encapsulated larvae from scallops.
28 citations
26 citations
TL;DR: Clinical trials with Praziquantel against human diphyllobothriasis show great promise, all of ten patients treated with 25-0 mg/kg of the drug being cured.
Abstract: Praziquantel (Droncit) is a new anthelminthic agent with a strikingly wide therapeutic index. The efficiency of the drug against Diphyllobothrium latum was tested in vivo and in vitro. With a drug dose of 50 mg/kg, artificially infected hamsters were completely cured. The threshold value of the active dose was between 2·5 and 10·0 mg/kg. Clinical trials with Praziquantel against human diphyllobothriasis show great promise, all of ten patients treated with 25·0 mg/kg of the drug being cured. Praziquantel had little effect on larval or adult diphyllobothriids in vitro.
TL;DR: Dietary feeding of drugs for 5 days to mice infected with Nematospiroides dubius and Hymenolepis nana detected all modern anthelmintics examined except stilbazium, reported by a simple test using eggs of Nematodirus spathiger and adult Nippostrongylus brasillensis.
Abstract: Dietary feeding of drugs for 5 days to mice infected with Nematospiroides dubius and Hymenolepis nana detected all modern anthelmintics examined except stilbazium. A simple test using eggs of Nematodirus spathiger and adult Nippostrongylus brasillensis to detect anthelmintics in vitro is reported.
TL;DR: It is suggested that differences in the diffusion of these antigens through the laminated membranes of hydatid cysts in the same or different host species may account for variable serological responses during infection.
Abstract: Cyst wall, brood capsules and evaginated protoscoleces of E. granulosus (ovine and equine) and E. multilocularis were fixed in 10% formol-saline, embedded in paraffin and cut at 8 micrometer. Specific rabbit antisera to antigen 5 and antigen B of hydatid cyst fluid were used with immunoperoxidase methods to localise the antigens in the histological sections. Antigen 5 was found in all parasites and was associated with cells of the subtegumental area of the protoscolex, the brood capsule wall and the germinal membrane. The labelled antigen appeared as distinct granules in all areas. It is suggested that antigen 5 may be synthesised in all of these sites and that a source of the antigen in cyst fluid may be the germinal and brood capsule membranes. The laminated membranes of E. granulosus (ovine and equine) were, except for the superficial layers, free from antigen 5. Antigen B was present in all parasites. It was distributed diffusely throughout the laminated membrane, germinal membrane and brood capsule wall. There were areas of densely labelled antigen B on the surface of the distal cytoplasm of the protoscolex tegument and the surface of calcareous corpuscles. The distribution of antigen B in relation to PAS positive material and possible complement activating substances is discussed. The laminated membrane of E. granulosus was apparently more permeable to antigen B than to antigen 5. It is suggested that differences in the diffusion of these antigens through the laminated membranes of hydatid cysts in the same or different host species may account for variable serological responses during infection.
TL;DR: Five cestode, one monogenean, and two nematode species comprised the "normal" intestinal helminth fauna of Raja naevus in British waters and no numbers showed any significant variation associated with host sex.
Abstract: Five cestode, one monogenean, and two nematode species comprised the "normal" intestinal helminth fauna of Raja naevus in British waters. An additional two nematodes, a digenean, an acanthocephalan and a crustacean recorded are considered to be accidental infections. Geographical differences in the species composition and level of infection are noted and discussed. Short descriptions of the tetraphyllidean cestode Echeneibothrium sp. and the nematode Capillaria sp. are given, but the species, although probably both new, are left unnamed. The intensity of cestode infections show two patterns associated with host length and these are discussed in relation to variations in host diet. Speculations are made on the cestode life cycles. Only Echeneibothrium sp. numbers showed any significant variation associated with host sex.
TL;DR: An in vitro larval precipitate test using second-stage ToxocaraCanis larvae and an indirect fluorescent antibody (IFA) test employing cuticles of T. canis larvae as antigen were evaluated and the latter test was considered unsuitable because of cross-reactions that occurred when sera from pigs infected with other ascarids were tested.
Abstract: An in vitro larval precipitate test using second-stage Toxocara canis larvae and an indirect fluorescent antibody (IFA) test employing cuticles of T. canis larvae as antigen were evaluated using antisera produced in pigs experimentally infected with T. canis, T. cati, Ascaris suum, Toxascaris leonina and Parascaris equorum. The former test was both specific and sensitive and is suggested as a reliable and simple method of detecting Toxocara antibodies in pigs. The latter test was considered unsuitable because of cross-reactions that occurred when sera from pigs infected with other ascarids were tested. An IFA test for Ascaris antibodies, employing cuticles of A. suum larvae as antigen, is described. The degree of specificity of this test suggests that it may be of value in the detection of antibodies to Ascaris in pigs under natural conditions.
TL;DR: The species of the genera Longistrongylus, Kobusinema and Bigalkenema are redescribed and their hosts and geographical localities are listed.
Abstract: The species of the genera Longistrongylus, Kobusinema and Bigalkenema are redescribed Kobusinema and Bigalkenema are considered synonyms of Longistrongylus and their species are transferred as new combinations Bigalkenema neveulemairei (Gutteres, 1947) Jansen, 1958 and Longistrongylus muraschkinzevi (Shulz and Kadenatsii, 1950), Jansen, 1958 are considered species inquirendae A key to the species of the genus Longistrongylus is given and their hosts and geographical localities are listed
TL;DR: To test this theory experiments were set up to compare the infectivity of male and female cercariae, and it was found that the male parasite seems to be more successful than the female in reaching maturity.
Abstract: Over 90% of Schistosoma haematobium and S. mansoni infections show a dominance of male worms in experimental animals. Male: female ratios as high as 5: 1 are common in S. haematobium (Ghana) infections and 1·5: 1 is a typical ratio in S. mansoni infections. The male parasite seems to be more successful than the female in reaching maturity. To test this theory experiments were set up to compare the infectivity of male and female cercariae.
TL;DR: Metacercariae of the trematode Microphalloides japonicus were cultivated in various media to gravid adults, and the results were compared with those in vivo.
Abstract: Metacercariae of the trematode Microphalloides japonicus (Osborn, 1919) were cultivated in various media to gravid adults, and the results were compared with those in vivo. A few eggs were produced in the uterus even in balanced salt solution, although cultivation in Eagle's MEM and NCTC 109 media was much better. Addition of heat-inactivated serum resulted in even better development. Encysted metacercariae also produced eggs in some media, but most of them were incomplete and without shells.
TL;DR: Histopathological observations and faecal egg counts both indicated an inability of hamster strain eggs to penetrate the intestinal lumen; this was probably important in reducing the pathogenicity of theHamster strain.
Abstract: Border Leicester X Suffolk sheep infected with a strain of S. mattheei maintained in hamsters do not develop the same pathological changes as Romney Marsh sheep infected with the same strain of parasite before hamster passage. To determine the cause of this reduced pathogenicity, five Romney Marsh sheep were each infected with 10 000 cercariae of the hamster-passaged parasite and five with 10 000 cercariae of a S. mattheei strain from Onderstepoort, South Africa, passaged exclusively through sheep. Striking pathological and parasitological differences were found between the two strains. Infection with the "sheep" strain was lethal, whereas infection with the "hamster" strain produced little evidence of clinical disease. By 13 weeks post-infection the mean body weight of the sheep infected with the sheep strain had declined by 15% compared with both the uninfected controls and the sheep infected with the hamster strain, and the mean PCV was lowered to 20% in the sheep strain infected animals. Egg production began at seven weeks with the sheep strain, faecal counts rising to more than 300 e.p.g., whereas only two of the sheep infected with the hamster strain passed eggs in the faeces (at nine weeks) and the maximum egg count was 50 e.p.g. Twice as many adult worms of the sheep strain were recovered, and, although the number of eggs found in the tissues "per worm pair" was not significantly different, overall egg production was higher for the sheep strain; also more of the sheep strain eggs were deposited in the intestines. Similar parasite differences were seen in a supplementary study in mice and it seemed that "attenuation" of the parasite had occurred, presumably due to its maintenance in hamsters. Histopathological observations and faecal egg counts both indicated an inability of hamster strain eggs to penetrate the intestinal lumen; this was probably important in reducing the pathogenicity of the hamster strain.
TL;DR: Infection with single miracidial doses of Schistosoma intercalatum from Cameroun in Bulinus forskalii and from Zaire in B.globosus resulted in an equal number of male and female infections, and the cercarial production of both sexes started at the same time.
Abstract: Infection with single miracidial doses of Schistosoma intercalatum from Cameroun in Bulinus forskalii and from Zaire in B.globosus resulted in an equal number of male and female infections. The cercarial production of both sexes started at the same time. The male infected snails produced a greater number of cercariae, because of the longer duration of infection. The recovery of schistosomes from infection with male and female cercariae was for S. intercalatum, Zaire, 38.8 +/- 10.6 and 18.7 +/- 14.0 respectively. For S. intercalatum from Cameroun, with single sex cercariae from two different populations of intermediate hosts from Zaire and Cameroun were 38.3 +/- 7.3 (male); 20.3 +/- 9.3 (female) and 35.0 +/- 8.7 (male); 12.2 +/- 4.5 (female), respectively.
TL;DR: An early rise in serum IgE levels was observed in five of seven patients with acute primary trichinosis, and elevated levels persisted long after the clinical recovery of the patients.
Abstract: An early rise in serum IgE levels was observed in five of seven patients with acute primary trichinosis. Parallel increases in the total IgG, IgM and IgA levels, as well as specific IgG and IgM antibody titres to Trichinella spiralis larval antigen, were detected in two. The elevated levels persisted long after the clinical recovery of the patients.
TL;DR: The efficiency of five different methods of infection of mice with Schistosoma mansoni or S. intercalatum cercariae was compared; of these the ring method, the tail immersion technique, and the paddling method were found to be the most effective.
Abstract: The efficiency of five different methods of infection of mice with Schistosoma mansoni or S. intercalatum cercariae was compared; of these the ring method, the tail immersion technique, and the paddling method were found to be the most effective. A new radioisotope assay system for cercarial host-finding capacity is described. This employs the tail immersion technique with radiolabelled S. mansoni cercariae. The amount of tail-bound radioactivity retained after exposure to radiolabelled cercariae was used to measure the host-finding capacity of the cercariae under various experimental conditions. A direct proportionality was found to exist between the number of penetrating radiolabelled cercariae and the subsequent tail-bound radioactivity. Also, a direct proportionality was demonstrated between the number of labelled larvae available in the suspension and the subsequent tail-bound radioactivity. The influence of light and of length of exposure period on cercarial host-finding was analysed. After an exposure period of 30 minutes the amount of radioactivity confined to tails in the light greatly exceeded that of tails exposed in total darkness. However, after 60 minutes comparable radioactivity levels were achieved in the tails exposed in the light or in total darkness, respectively. In the light, maximum tail-bound radioactivity was achieved after 20 minutes exposure and no further change was observed in the radioactivity level at 40 and 60 minutes.
TL;DR: The digeneans Asymphylodora k Kubanicum and Sphaerostoma bramae showed distinct and different site preferences in the roach intestine, the majority of A. kubanicum being found in the first limb and the majority in the second and third limbs, which is considered to be the basis of the observed distribution of the parasite in the host's intestine.
Abstract: The digeneans Asymphylodora kubanicum and Sphaerostoma bramae showed distinct and different site preferences in the roach intestine, the majority of A. kubanicum being found in the first limb and the majority of S. bramae occurring in the second and third limbs. A. kubanicum excysts and establishes itself in the first limb and this is considered to be the basis of the observed distribution of the parasite in the host's intestine. The site preference of S. bramae is discussed in relation to the physiology of the parasite and the host and to possible competitive interactions with A. kubanicum.
TL;DR: The extract prepared from the metacestodes removed from the peritoneal cavity of rats tested against rabbit anti-normal rat serum and contained an antigen common to both the host and the parasite.
Abstract: Laboratory rats were infected by intra-peritoneal injection with the metacestodes of Taenia crassiceps. A soluble extract was prepared from the metacestodes removed from the peritoneal cavity of the rats. Double-diffusion, immuno-electrophoresis and fluorescent labelled antibody staining techniques were used. The extract tested against rabbit anti-normal rat serum was found to contain an antigen common to both the host and the parasite.
TL;DR: Ethyl-6-ethoxybenzothiazole-2-carbamate was evaluated for efficacy against natural helminth infections in ponies, pigs, lambs and chickens and recorded against Heterakis gallinarum at the 1000 ppm dietary drug level.
Abstract: Ethyl-6-ethoxybenzothiazole-2-carbamate (Sch 18099) was evaluated for efficacy against natural helminth infections in ponies, pigs, lambs and chickens. Sixteen critical trials were conducted in ponies at dosages of 15 to 150 mg/kg. At 15 mg/kg, efficacy against adult and larval Oxyuris equi was 100% and 91% and against small strongyles it was 98%. Efficacy levels were 95% against Strongylus vulgaris and S. edentatus at the 20 mg/kg dosage. In two trials at 100 mg/kg efficacy against Parascaris equorum was 77%. No efficacy was observed against Gastrophilus spp. or Anoplocephala spp. In swine single oral doses of 10 to 100 mg/kg were not effective. 500 ppm Sch 18099 in the diet for seven days resulted in 100% efficacy against Ascaris suum and Trichuris suis but had no effect on Stongyloides ransomi. Efficacy at 250 ppm against A. suum was 77%. Efficacy at 200 mg/kg in lambs was greater than 90% for Haemonchus contortus, Trichostrongylus axei, Marshallagia marshalli, Bunostomum trignocephalum, Oesophagostomum columbianum, Trichuris ovis, and Chabertia spp. Efficacy was less than 80% for Trichostrongylus vitrinus, Nematodirus filicollis, Ostertagia circumcinta and Cooperia curticei. Except for O. circumcinta and C. curticei, drug efficacy was reduced for these worms in lambs treated at 100 mg/kg. Efficacies of 14.3-89% against Ascaridia galli were obtained with dietary levels of 125-1000 ppm Sch 18099 fed for 7 days. Efficacy of 100% was recorded against Heterakis gallinarum at the 1000 ppm dietary drug level.
TL;DR: The annual cycle of occurrence and maturation of Sphaerostoma bramae is discussed in relation to fluctuating environmental variables and the feeding behavior of the roach.
Abstract: Two hundred roach (Rutilus rutilus) were examined over a twelve-month period to provide information concerning the occurrence of Sphaerostoma bramae. Infection levels were high during the autumn and winter and at this time of year the parasite population was composed almost exclusively of immature parasites. Maturation was rapid in the spring but was accompanied by a decrease in the infection level. In late summer, after egg-laying, losses due to the death of spent parasites began to be replaced by the recruitment of immature parasites and this recruitment reached its peak in the autumn and winter. The annual cycle of occurrence and maturation is discussed in relation to fluctuating environmental variables and the feeding behavior of the roach.
TL;DR: A further survey in East Caprivi, Chobe National Park, Okavango swamps and Kavango was undertaken in June 1976, confirming the hypotheses that cattle and goats are poor hosts of the lechwe schistosomes and S. mansoni has increased alarmingly over the past 20 years.
Abstract: A further survey in East Caprivi, Chobe National Park, Okavango swamps and Kavango was undertaken in June 1976. No evidence of lechwe schistosomes was found in droppings of African buffalo (Syncerus caffer) nor baboons (Papio ursinus) living in lechwe habitats. It was thought that they were not capable of spreading or maintaining these parasites outside the confines of the known distribution of Kobus sp. The role of goats was equivocal but probably they too are poor hosts. Kavango, an endemic area of S. haematobium and S. mansoni, was thought to be free of all animal schistosomes, thus confirming the hypotheses that (1) cattle and goats are poor hosts of the lechwe schistosomes and (2) S. mattheei was blocked from entering the territory by the presence of lechwe schistosomes in the surrounding areas. Evidence of schistosomes was not found in cattle and goats at Maun for the same reasons. The prevalence of S. mansoni at Maun has increased alarmingly over the past 20 years with a simultaneous disappearance of lechwe from the area. S. margrebowiei and S. leiperi eggs were found in lechwe and tsessebe droppings some 80 km north of Maun. A high proportion of children with negative excreta from "non-endemic" areas in East Caprivi had positive CFT and/or skin tests, suggestive of exposure to lechwe schistosomes resulting in a possible immunity to S. mansoni and S. haematobium.
TL;DR: Monanema nilotica n.sp.
Abstract: Monanema nilotica n.sp. (Nematoda: Onchocercidae) is described from the right auricle and pulmonary artery of the Nile rat, Arvicanthis niloticus testicularis (Sundevall, 1842), trapped in Khartoum-North, Sudan. It differs from other species principally in length of adults and microfilariae, in the shape of the buccal capsule and in the structure of the spicules of the males.