Showing papers in "Journal of Helminthology in 1983"
TL;DR: It is concluded that euphausiids in the North-East Atlantic and northern North Sea, and perhaps universally, are major intermediate hosts of A simplex and the status as hosts of squid and teleosts harbouring L3 is discussed.
Abstract: Larval Anisakis 7.7 to 23.6 mm long from euphausiids, and larvae 18.0 to 21.9 mm long from a teleost fish were morphologically and morphometrically alike and fitted the description by Beverley-Burton, Nyman & Pippy (1977) of A. simplex L3. Three small larvae, 4.2 to 5.9 mm long, from euphasiids resembled L3 in anterior but not in posterior morphology; their tails lacked a mucron but, in two of them, cuticular separation at the posterior extremity revealed clearly the mucron characteristic of L3 within. These small larvae are identified as L2 of A. simplex in the process of moulting to L3. Japanese reports of typical L3 from 6.9 to 32.7 mm long in euphausiids, the occurrence in teleosts of typical L3 from only 8.8 to over 30 mm long, and the present observations strongly suggest that the moult from L2 to L3 occurs in euphausiids and begins when the larvae are about 4-6 mm long. Although it appears, therefore, that only one moult occurs in the egg of A. simplex (i.e. ensheathed L2 hatches), two moults there have been reported for various terrestrial and certain aquatic ascaridoids (i.e. ensheathed L3 hatches). The morphology and homology of the lips and associated sense organs of A simplex L3 are discussed relative to that of a 'typical' adult ascaridoid. A main conclusion is that euphausiids in the North-East Atlantic and northern North Sea, and perhaps universally, are major intermediate hosts of A simplex. The status as hosts of squid and teleosts harbouring L3 is discussed. An extensive literature is reviewed in relation to the present observations.
132 citations
TL;DR: Over 26000 specimens representing five euphausiid species collected, mostly in 1969, in the North-East Atlantic and northern North Sea were examined for parasites, finding infection with larval Anisakis simplex was virtually restricted to Thysanoessa spp.
Abstract: Over 26000 specimens representing five euphausiid species collected, mostly in 1969, in the North-East Atlantic and northern North Sea were examined for parasites. Hysterothylacium sp. larvae were rare, occurring in only two euphausiid samples from inshore localities; the 9 larvae found (3.8 to 12.3 mm long) are described and illustrated. Infection with larval Anisakis simplex was virtually restricted to Thysanoessa spp. and appeared to be discontinuous. Infection was absent to the west of Scotland, and rare to the north of Scotland and at the Faroes. Larval A. simplex was not uncommon in offshore regions of the northern North Sea at depths between 100 and 200 m; the prevalence rate there for individual euphausiid species in individual samples was mostly 0 to 40% but an exceptionally high rate of 78.0% was recorded. Larvae in euphausiids do not become encapsulated but appear to remain active. Experimental observations on the sedimentation rate of A. simplex eggs and hatched larvae in sea water at 10°C are discussed in relation to embryonation and hatching at different temperatures, and depth of the sea. New host records are claimed for larval A. simplex in Nyctiplutnes couchii, and for larval Hysterothylacium sp. in Thysanoessa inermis. No individual euphausiid harboured more than one parasite, either larval nematode or ellobiopsid (see also SMITH, 1981). Morphological and morphometric observations on larval A. simplex from euphausiids are reported elsewhere (SMITH, 1983).
55 citations
TL;DR: Far more larvae were trapped in the liver after reinfection than after the primary infection but fewer were found in the livers of BALB/c-nu/nu than in BALB / c-nu/+ mice.
Abstract: Congenitally athymic nude mice (BALB/c-nu/nu) and BALB/c-nu/+ were infected with 500 embryonated Toxocara canis eggs. Six weeks later they were reinfected with the same number of eggs. The liver and other organs were examined for numbers of 2nd-stage larvae at 2, 4, and 6 weeks after reinfection. Far more larvae were trapped in the liver after reinfection than after the primary infection but fewer were found in the livers of BALB/c-nu/nu than in BALB/c-nu/+ mice.
22 citations
TL;DR: In this paper, a modified quick-Kato technique and the Stoll dilution method for the diagnosis of Opisthorchis viverrini infection were compared from the standpoints of both replicability and sensitivity.
Abstract: A modified quick-Kato technique and the Stoll dilution method for the diagnosis of Opisthorchis viverrini infection were compared from the standpoints of both replicability and sensitivity. One Stoll dilution preparation and two modified quick-Kato smears were prepared from single stool specimens collected from 221 persons in a village in north-eastern Thailand. Stool examinations were made in duplicate for each technique by two examiners, and the averages of the raw egg counts were used to estimate the intensity of infection. Statistical analyses revealed that the modified quick-Kato technique was slightly more sensitive, and thus would detect more positives, but was lacking in replicability and hence less suitable for measurement of individual intensity of infection. We therefore recommend the Stoll dilution technique for field surveys and measurement of individual intensity of O. viverrini infection.
19 citations
TL;DR: MAO was present in mitochondria and deaminated noradrenaline at the maximal rate, although serotonin, adrenaline, tyramine and dopamine were also degraded but more slowly, while of the organs studied, the body wall, female reproductive organ and intestine showed highest MAO activity.
Abstract: Monoamine oxidase (MAO), catalysing oxidative deamination of biogenic monoamines, has been detected in adult Ascaridia galli. MAO was present in mitochondria and deaminated noradrenaline at the maximal rate, although serotonin, adrenaline, tyramine and dopamine were also degraded but more slowly. Of the organs studied, the body wall, female reproductive organ and intestine, the body wall (containing neuronal structures) showed highest MAO activity. Km value for chick ascarid mitochondrial MAO using tyramine as substrate was 1.66 X 10(-3) M and it was most active at 2.5 mM tyramine concentration, pH 7.5 and 40 degrees C. MAO of A. galli appeared to be thermolabile as nearly 80% of its activity was lost when the incubation temperature was increased 5 degrees above optimum.
19 citations
TL;DR: Electron microscopic observations were made on unhatched eggs of Taenia crassiceps in utero, finding that the 'oncospheral membrane' is distinct, darkly stained and relatively thick.
Abstract: Electron microscopic observations were made on unhatched eggs of Taenia crassiceps in utero . The outermost envelope consists of a thin, relatively smooth capsule over a highly convoluted outer envelope which contains a highly granulated cytoplasm and numerous mitochrondria. The inner envelope, consisting of a thick embryophore and the cytoplasmic component of the embryophore cell, resembles that found in most other taeniids. Three epithelial layers separate the oncosphere from the embryophore. While these layers are narrow and difficult to distinguish, the ‘oncospheral membrane’ is distinct, darkly stained and relatively thick. The oncospheral hook lies within the oncoblast with its blade portion held by cytoplasmic folds within a modified ‘sheath’ in the ‘basal epithelial layer’. Round, dense bodies are concentrated at the epithelial membranes around the ‘sheaths’. Hook muscles insert on the basal lamina at the ‘collar’ region of the hooks. Penetration gland cells are packed with numerous dense disc-shaped secretory bodies.
17 citations
TL;DR: Mice infected with Nematospiroides dubius were incapable of responding normally to i.p. or i.v. challenge with SRBC, and mice given low-level and long-standing infections also showed reduced responses toSRBC, although these animals were not severely depressed.
Abstract: Mice infected with Nematospiroides dubius were incapable of responding normally to ip or iv challenge with SRBC The HA and PFC response to SRBC in infected animals was characterized by a severe depression of antibody to SRBC on day 4 and a reduced HA peak titre during the following week The greatest depression of the response to SRBC was associated with an interval of 14 days between infection and the administration of antigen, suggesting that a particular stage of the parasite contributed significantly to immunodepression during this critical period It was proposed that a combination of parasite induced damage to the intestine, release of parasite secretory/excretory products and loss of appetite by the host produced trauma during which the host was incapable of responding normally However, mice given low-level and long-standing infections also showed reduced responses to SRBC, although these animals were not severely depressed It is possible that this generalized weakening of host immunocompetence is the inevitable consequence of a parasite mechanism which operates more specifically to suppress the expression of homologous immunity at the intestinal level
16 citations
TL;DR: Four little-known ascaridoid species occurring in crocodilians are discussed and a key to eight genera of Heterocheilinae in crocodILians is provided.
Abstract: Four little-known ascaridoid species occurring in crocodilians are discussed Typhlophorus lamellaris Linstow, 1906 and Hartwichia rousseloti Chabaud & Bain, 1966 are considered to be closely related to Heterocheilus tunicatus Diesing, 1839; Porrocaecum assymmetricum Ortlepp, 1932 is transferred to Trispiculascaris together with T trispiculascaris Skrjabin, 1916 These three genera are placed in the subfamily Heterocheilinae sensu Sprent (1980) on account of the structure of the oesophago-intestinal junction, the labial pulp and, where known, the male tail A key to eight genera of Heterocheilinae in crocodilians is provided
14 citations
TL;DR: Microfilariae of Dirofilaria immitis retained their infectivity for susceptible mosquitoes after cooling to -196 degrees C in the presence of 5% dimethylsulphoxide using a two-step cooling sequence.
Abstract: Microfilariae of Dirofilaria immitis retained their infectivity for susceptible mosquitoes after cooling to −196°C in the presence of 5% dimethylsulphoxide (Me2SO) using a two-step cooling sequence. Motility and in vitro development of cryopreserved microfilariae also compared favourably with unfrozen controls. Third-stage larvae frozen by the same cooling sequence in the presence of either 5% Me2SO or 16% hydroxyethyl starch were motile upon thawing. Thawed larvae completed the third- to fourth-stage moult in vitro at a frequency approximately 5 to 10% of that seen in unfrozen controls.
14 citations
TL;DR: Female Gallus gallus L. are more susceptible to Heterakis pusilla than are male hosts, and the worm burden decreased with increase in size and weight of domestic fowls.
Abstract: Female Gallus gallus L. are more susceptible to Heterakis pusilla than are male hosts. The worm burden decreased with increase in size and weight of domestic fowls. The frequency distribution of H. pusilla in the two sexes, and by host's size and weight classes was log-normal.
11 citations
TL;DR: A new genus is proposed for Orneoascaris alata, which differs in the unique form of the lips and in the more extensive U-shaped enlargement of the nucleus of the dorsal oesophageal gland.
Abstract: A new genus is proposed for Orneoascaris [= Amplicaecum] alata (Baylis, 1947) Le Van Hoa, 1960. The new genus is defined and differentiated from Orneoascaris by the posterior position of the vulva and by the wide cervical alae. It is differentiated from Ophidascaris by fewer postcloacal papillae and spicules less than half the length of the ejaculatory duct. From both genera alata differs in the unique form of the lips and in the more extensive U-shaped enlargement of the nucleus of the dorsal oesophageal gland. It is suggested that this species is a specialized form, possibly of neotropical origin.
TL;DR: The transmission of Hyostrongylus rubidus and Oesophagostomum spp.
Abstract: The transmission of Hyostrongylus rubidus and Oesophagostomum spp. following anthelmintic treatment was studied over a period of two years in a herd of sows kept out-of-doors on a commercial farm in south-eastern England. The sows were moved on to a clean pasture each autumn and at the same time were treated with an anthelmintic. The treatment was repeated six months later when the faecal worm egg count was rising. Contamination of the pasture with worm eggs was both light and intermittent. The pasture herbage remained free of infective larvae until the early summer; subsequently the herbage became lightly infected with larvae so that transmission of the parasites was possible, but limited. The level of infection on the herbage was much lower than was seen in earlier observations when the more commonly used system of treating groups of sows at different times of the year, in between farrowings, was used.
TL;DR: It is suggested that collagenase is active in the adult females at the time of migration in the intestinal mucosa during oviposition in Strongyloides ratti.
Abstract: Larvae and adults of Strongyloides ratti were examined for collagenolytic activity on 14C proline-labelled, native, guinea-pig skin collagen substrate. The activity was measured by determining either the amount of hydroxyproline released or the amount of radioactivity in the solubilized fraction of the collagen substrate. Bacterial collagenase was used for enzyme control and trypsin served as substrate control. No collagenolytic activity was found in living larvae, their extracts or metabolites. The collagenolytic activity of the metabolites of adult worms appeared weak, whereas that of the extracts of the adults was pronounced. It is suggested that collagenase is active in the adult females at the time of migration in the intestinal mucosa during oviposition.
TL;DR: It is suggested that rejection of H. diminuta from mice is associated with the activities of gut-associated, tapeworm antigen-sensitized immune cells localized in the mesenteric lymph nodes.
Abstract: The development of lymphoid cells reactive to tapeworm-associated antigens during the course of Hymenolepis diminuta rejection from mice was studied using an in vitro tapeworm extract (TWE)-induced cell proliferation culture system. Mice infected with three cysticercoids on day 0 developed three adult worms by day 7 but worms were rejected by day 21 post-infection. Concomitant with worm rejection was the development of TWE-sensitized lymphoid cells which responded by proliferation when stimulated in vitro with TWE. Sensitized cells were detected in gut-associated mesenteric lymph nodes but were not detected in spleen, axillary lymph nodes, or Peyer's patches of infected mice, or in lymphoid organs of non-infected mice. These studies suggest that rejection of H. diminuta from mice is associated with the activities of gut-associated, tapeworm antigen-sensitized immune cells localized in the mesenteric lymph nodes.
TL;DR: The anterior end of the miracidium of Fasciola hepatica contains a large flask-shaped apical gland and four unicellular lateral glands, all of which have ducts which pass to the tip of the apical papilla.
Abstract: The anterior end of the miracidium of Fasciola hepatica contains a large flask-shaped apical gland and four unicellular lateral glands, all of which have ducts which pass to the tip of the apical papilla. These glands appear to be involved in penetration of the larva into the snail host. The apical gland secretes as the miracidium proves the epidermis of the host before attachment. It seems likely that its secretion is a chemical which lyses the epidermal cells. The lateral glands are PAS-positive and may contain a neutral mucopolysaccharide. They also secrete as the miracidium probes the snail and a layer of PAS-positive material may be seen at the leading edge of the apical papilla as the larva penetrates into the host. Both the apical gland and the lateral glands may be visible in the sporocyst for several days after penetration.
TL;DR: It is concluded that the parasite is well adapted to its natural hosts and that it has potential as a rodent model for human onchocerciasis because of the localization of microfilariae in the skin.
Abstract: Monanema globulosa (Nematoda: Filarioidea) was recovered from four species of rodents in Kenya, with a prevalence of up to 94% in the striped mouse, Lemniscomys striatus. The adult worms are site-specific to the pulmonary arteries and release sheathed microfilariae that travel via the blood to the skin. Densities of microfilariea in the ears (mf/mg) were five to eight times greater than in any other region of the body and were directly proportional to the number of adult worms present. Highest concentrations of microfilariae in the skin were reached after 100 to 200 days and low numbers persisted in most animals for approximately 500 days. Third-stage larvae from ticks ( Haemaphysalis leachii ) injected subcutaneously into jirds migrated widely through the body during early development. Moults occurred twice, after 5 to 10 days and 25 days, and the mean prepatent period was 75 (range 69 to 88) days. A mild eosinophilia developed which peaked after 29 days. Adults in the lungs provoked widespread and intense perivascular cuffing and more localized hypertrophy and fibrosis of the intima in arterioles. Dead adults caused granulomata which obliterated smaller vessels. Microfilariae in the skin elicited no local tissue reaction, but some which invaded the eyes caused a monocyte infiltration of the cornea. It is concluded that the parasite is well adapted to its natural hosts and that it has potential as a rodent model for human onchocerciasis because of the localization of microfilariae in the skin.
TL;DR: The prevalence of Schistosomiasis and the distribution of the snail intermediate hosts on three adjoining irrigated estates in the lowveld of Swaziland was investigated and there was a marked difference between the prevalence rates of S. mansoni between estates.
Abstract: The prevalence of schistosomiasis and the distribution of the snail intermediate hosts on three adjoining irrigated estates in the lowveld of Swaziland was investigated. The prevalence rates of Schistosoma haematobium and S. mansoni among estate employees was lower than anticipated and there was a marked difference between the prevalence rates of S. mansoni between estates. The reasons for this and the influence of water supplies and agricultural practice on the prevalence of schistosomiasis are discussed.
TL;DR: The macroscopical similarity between spargana of Spirometra and tetrathyridia of some Mesocestoides species has been pointed out earlier and has, in previous years, lead to some confusion and misidentification.
Abstract: About two years ago our laboratory received for identification a sparganum of Spirometra sp. (about 10 cm long) removed from a nodule in the knee of a Tanzanian negro by Doctor Knut Saug. About the same time we received for identification two tetrathyridia of Mesocestoides sp. (about 8 cm long) found in the peritoneum of a Norwegian cat. The latter was the first record of tetrathyridia found in domestic animals in Norway (BERG & ANDERSEN, 1982). Macroscopically these two larval types were extremely similar and impossible to separate. Both larval types have an anterior end, a bit broader than the rest of the larval body, where the invaginated scolex is situated. In transverse sections of the region, the sparganum showed bothrial slits (Fig. 1), while the tetrathyridia showed typical suckers (Fig. 2). Transverse sections of the larval body also showed very distinct differences in the musculature between these two larval types (Figs. 3 & 4). In spargana of Spirometra spp. (this was also verified by sectioning S. mansonoides larvae from experimentally infected white mice) the parenchymal longitudinal musculature is arranged in distinct bundles scattered more or less randomly throughout the parenchyma (Fig. 3), while in tetrathyridia of Mesocestoides the parenchymal longitudinal musculature forms an elliptic band. On the dorsal and ventral side of the larval body of Mesocestoides there are muscle bundles consisting of several muscle fibres; moving laterally, these bundles decrease in size until only single muscle fibres are seen (Fig. 4). The macroscopical similarity between spargana of Spirometra and tetrathyridia of some Mesocestoides species has been pointed out earlier and has, in previous years, lead to some confusion and misidentification (see NELSON et al., 1965). In their paper on the significance of wild animals in the transmission of cestodes of medical importance in Kenya, NELSON et al. (1965) state that the identification and separation of tetrathyridia and spargana, without histological sectioning of the scolex end of the larvae, is unreliable. They further state that all \"spargana\" so far collected from animals in Kenya on sectioning of the scolex end of the larvae proved to be tetrathyridia, the larval stage of Mesocestoides. The musculature has not, to my knowledge, previously been properly described for either of these larval types, although TAYLOR (1976) shows a picture of a musculature very similar to that illustrated in this paper from a human case of sparganosis in the U.S.A. In the past, there has been some argument about the value or otherwise of deepseated and less variable systems of organs, such as the genitalia or muscles, in identification of tapeworms. SOUTHWELL (1929) argued strongly in favour of the major value of external metromorphic characters, while WOODLAND (1925 and 1927) was of
TL;DR: The caecal epithelium of the two amphistomes has been found to be syncytial bearing regularly arranged numerous, long but equal-sized and closely packed cylindrical microvilli.
Abstract: Histochemical techniques have been used to study the chemical composition of the oesophageal gland secretions of Orthocoelium scoliocoelium and Paramphistomum cervi. Results suggest that the secretions contain numerous enzymes, e.g., non-specific alkaline and acid phosphatases, ATPase, TPPase, esterase (Cathepsin C like), beta-galactosidase, beta-glucuronidase and N-acetyl-beta-glucosaminidase. The role of these enzymes in the digestion of food in these amphistomes is discussed. On the basis of histological and histochemical studies the caecal epithelium of the two amphistomes has been found to be syncytial bearing regularly arranged numerous, long but equal-sized and closely packed cylindrical microvilli. The role of various hydrolytic enzymes in well fed and starved flukes in relation to their gastrodermis and microvilli has also been discussed.
TL;DR: The metacercariae identified as those of the heterophyid trematode, Galactosomum ussuriense were collected from 3 species of brackish water fishes from Bheemunipatnam and are described in detail.
Abstract: Metacercariae identified as those of the heterophyid trematode, Galactosomum ussuriense were collected from 3 species of brackish water fishes from Bheemunipatnam. The organization of the the larva is described in detail. This is the first record of the metacercaria of this species although the adult has not so far been recorded from India.
TL;DR: Another species in the genus Heterocheilus Diesing, 1839, collected from Trichechus senegalensis, is described, which differs from H. tunicatus in possessing elongate cuticular plaques on the body surface in the oesophageal region, a cuticle-lined vestibule between mouth and oESophagus, and triangular interlabial structures.
Abstract: Another species in the genus Heterocheilus Diesing, 1839, collected from Trichechus senegalensis, is described. It differs from H. tunicatus in possessing elongate cuticular plaques on the body surface in the oesophageal region, a cuticle-lined vestibule between mouth and oesophagus, and triangular interlabial structures. A comparison is made between specimens of H. tunicatus from T. manatus and the specimens from T. inunguis described in a previous paper (sprent, 1980).
TL;DR: The nature of complement binding to the surface to infective larvae of Trichinella spiralis and Nippostrongylus brasiliensis differs and the outer structure of the cuticle of the T. spiralis larvae was shown not to contain ATP-ase, thus differing from many cell membranes.
Abstract: The nature of complement binding to the surface to infective larvae of Trichinella spiralis and Nippostronaylus brasiliensis differs. When worms were incubated in serum from uninfected hosts, washed and incubated in fluorescent reagent the whole surface of T. spiralis fluoresced but in N. Brasiliensis fluorescence was confined to the anterior end and some internal organs. The outer structure of the cuticle of the T. spiralis larvae was shown not to contain ATP-ase, thus differing from many cell membranes.
TL;DR: By means of scanning electron microscopy, aspects of the attachment of Moniliformis dubius (Acanthocephala) to the intestinal wall of the rat are described together with various changes in the structure and form of the mucosa.
Abstract: By means of scanning electron microscopy, aspects of the attachment of Moniliformis dubius (Acanthocephala) to the intestinal wall of the rat are described together with various changes in the structure and form of the mucosa. Attachment of the parasite results in the formation of a distinct pit around the everted proboscis and a crater around the neck. Contact between the anterior region of the trunk of the worm and the intestine of the host appears to lead to villous fusion so that characteristic grooves are formed in the mucosal tissue. Evidence was also obtained to suggest that host goblet cells may become exhausted during the course of an infection with Moniliformis.
TL;DR: The possibility of cryopreserving the eggs of Angiostrongylus cantonensis collected from the uterus of female worms was investigated, and the highest level of survival could be obtained with 32-cell eggs cooled at a rate of 0.3 degrees C min-1, and survival was influenced more by cooling rate than by warming rate.
Abstract: The possibility of cryopreserving the eggs of Angiostrongylus cantonensis collected from the uterus of female worms was investigated. Eggs were cultured in NCTC 109 medium containing 50% rat serum, and various growth stages, from one-cell eggs to embryonated eggs, were used in this study. As a cryoprotective agent, dimethylsulphoxide (Me2SO) was added to the medium at a final concentration of 1 M. Eggs suspended in 0.2 ml of the medium at 37 degrees C were cooled to 0 degrees C at a rate of 1 degree C min-1, then an equal volume of 2M-Me2SO solution was added. After equilibration for 15 min, the freezing procedures were started. In the freezing procedures, the effectiveness of (i) a seeding process, (ii) different cooling and warming rates and (iii) the relationship between the growth stages of the eggs and their tolerance to freezing at -20 degrees C were investigated. It was found the highest level of survival could be obtained with 32-cell eggs cooled at a rate of 0.3 degrees C min-1 or more slowly with seeding at -4 degrees C and warming at a rate of 5 degrees C min-1. Survival was influenced more by cooling rate than by warming rate. Using these optimum conditions, the survival of eggs was then investigated following cooling to various temperatures. While more than 50% of eggs were found to survive cooling to -30 degrees C, extremely low survival was noted from lower temperatures.
TL;DR: Rats acquired a degree of protective immunity to reinfection with Angiostrongylus cantonensis after a single infection with 50 infective larvae, and Worms surviving from the primary infection showed enhanced growth after each reinfections but their fecundity was impaired.
Abstract: Rats acquired a degree of protective immunity to reinfection with Angiostrongylus cantonensis after a single infection with 50 infective larvae. Infected rats resisted the establishment of most challenging larvae and protective immunity increased with subsequent reinfections. Part of the primary infection was lost after a superimposed second and also following a superimposed third infection, but the total size of the concurrent adult worm populations remained the same as that from a primary infection. Worms surviving from the primary infection showed enhanced growth after each reinfection but their fecundity was impaired.
TL;DR: Six dogs infected with Dirofilaria immitis and known to develop shock-like reactions after administration of diethylcarbamazine (DEC) were given ivermectin 50 micrograms/kg orally and subsequently all reacted to DEC 20 mg/ kg orally.
Abstract: Six dogs infected with Dirofilaria immitis and known to develop shock-like reactions after administration of diethylcarbamazine (DEC) were given ivermectin 50 μg/kg orally. None of the dogs showed any adverse reaction and subsequently all reacted to DEC 20 mg/kg orally.
TL;DR: The morphological features of both uterine and skin microfilariae were determined and it was found that skin microFilariae are shorter than uterine ones and tend to accumulate in the regions of Linea alba and withers of infected donkeys.
Abstract: Onchocerca raillieti is the only Onchocerca species infecting Sudanese donkeys; it occurs only in the ligamentum nuchae, especially in the lamellar part of the ligament. The morphological features of both uterine and skin microfilariae were determined. Skin microrilariae are shorter than uterine ones and tend to accumulate in the regions of Linea alba and withers of infected donkeys. The possible identity of the vector of this worm in the Sudan is discussed.
TL;DR: Experimental investigations of the subcutaneous infection of third-stage larvae of Nippostrongylus brasiliensis reveal discrepancies between the actual and intended inoculum, and also variability between replicate inocula.
Abstract: Experimental investigations of the subcutaneous infection of third-stage larvae of Nippostrongylus brasiliensis reveal discrepancies between the actual and intended inoculum, and also variability between replicate inocula. Emphasis is thus placed on the importance of obtaining accurate estimates of the level of confidence associated with inoculum size. Under specified laboratory conditions, the retention of infectivity of N. brasiliensis larvae was found to be age-dependent, with a maximum of between 120 and 156 days. The motility of the larvae was not found to be indicative of their ability to complete migration and to become established in the small intestine of the host following subcutaneous inoculation.
TL;DR: It is suggested that the acetylcholinesterase secreted by M. expansa performs a metabolic role at the worm's surface.
Abstract: Acetylcholinesterase (EC 3:1:1:7) and alkaline phosphatase (EC 3:1:3:1) were detected in secretions of Moniezia expansa maintained in vitro. Ultrastructural cytochemical studies demonstrated acetylcholinesterase activity on the surface of the microtriches at the base of the interproglittidal glands and in the gland lumen but not in the distal tegument or the gland cells. Alkaline phosphatase activity was demonstrated in the cytoplasm of the gland cells and especially in their protoplasmic connections with the distal tegument. Activity was also found in the distal tegument and the microtriches. It is suggested that the acetylcholinesterase secreted by M. expansa performs a metabolic role at the worm's surface.