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PubMed1994

IgE antibody production is associated with suppressed interferon-gamma levels in mesenteric lymph nodes of rats infected with the nematode Nippostrongylus brasiliensis.

IgE and IgG2a antibody production and interferon (IFN)-gamma secretion were studied in rats infected with the gut nematode Nippostrongylus brasiliensis by in vitro cultivation of mononuclear cells obtained from spleen (SPL), mesenteric lymph nodes (MLN) and pulmonary hilar lymph nodes (PLN). The highest levels of IgE were detected in the culture supernatants of MLN cells after infection: IgE levels were modest in PLN and negligible in SPL. In contrast, the highest levels of IgG2a were produced by PLN cells, followed by MLN and SPL cells. These results indicate that the MLN is the most significant site for IgE production in nematode infection, while IgG2a production is more marked in PLN. In naive rats, the spontaneous secretion of IFN-gamma was highest in PLN cells, followed by MLN and SPL cells. After the infection, IFN-gamma levels were significantly decreased in MLN and PLN. Suppression of IFN-gamma secretion was also observed in concanavalin A (ConA)-stimulated MLN and PLN cells from infected rats. In MLN, the ratio of CD4+ to CD8+ T cells was increased after the infection. Stimulation with an allergen-rich, excretory-secretory (ES) substance of the nematode enhanced ongoing IgE production, and suppressed IFN-gamma secretion by MLN and PLN cells. In contrast, an allergen-poor, adult worm extract potentiated IFN-gamma secretion. These results show that nematode-induced IgE antibody response is associated with the suppressed production and/or secretion of IFN-gamma, particularly in the MLN, and that some molecules in the ES substance may trigger these immune responses.

Animals↗
PubMed2003

Genetic resistance of Barbari and Jamunapari kids to natural infection with gastrointestinal nematodes.

An investigation was made in 252 Barbari and Jamunapari kids to assess their resistance to natural infection with gastrointestinal (GI) nematodes and to establish indicator traits for such resistance in Indian goats. The indicator traits, faecal egg counts (FEC) and packed cell volume (PCV) were affected by various genetic and non-genetic factors. There were no breed differences in the FEC or PCV at 3, 6 or 9 months of age. Jamunapari male kids had a higher FEC than the female kids at 6 months of age. However, Barbari female kids had a higher FEC than the respective male kids at 9 months of age. At 6 months of age in both breeds, the kids born in the spring (March-April) had a higher FEC than those born in the autumn (October-November). The FEC of kids at 9 months of age was higher than at 3 or 6 months of age. Sire had a significant effect on PCV at 6 and 9 months of age. The kids born in the autumn had a higher PCV than those born in the spring. The PCV of male Barbari kids differed significantly from that of female kids at all the ages. The correlation coefficient of FEC on both body weight and body weight gain was negative, and there was a loss of body weight in the individuals with a high FEC.

Age Factors↗
PubMed2002

Chemotherapeutic approaches to nematodes: current knowledge and outlook.

The situation in the chemotherapy of nematode infections. in both human and veterinary medicine, is currently satisfactory. There are different drugs available: the benzimidazoles, levamisole, pyrantel, and the different macrocyclic lactones (Tables 1. 2, 3, 4). In human medicine, mebendazole and albendazole are mainly used against the intestinal nematodes. while ivermectin and diethylcarbamazine are microfilaricidal drugs used in prophylaxis against onchocercosis and filarial infections. The situation in veterinary medicine is, however, governed by the great resistance problem in some animal hosts against all important anthelmintics. There are various reports of resistance against benzimidazoles, levamisole, pyrantel, and macrocyclic lactones in trichostrongylides in small ruminants (sheep, goats) and also Strongylides in horses. Resistance against ivermectin is now arising in cattle (Coles 2001; Sangster 2001). There are no reports of resistance problems in dogs and cats. Thus, there is always an urgent need in veterinary medicine for new anthelmintics with a new mode of action, which can easily break resistance against the existing anthelmintics. The situation in the chemotherapy of filarial infections in human medicine is not satisfactory. There is an urgent need for a new macrofilaricidal drug with only slight side-effects. Today, the only way is the prophylactic control of Onchocerca vovulus infections and treating lymphatic filariosis with ivermectin, diethylcarbamacine, ivermectin/diethylcarbamazine. or ivermectin/albendazole combinations.

Animals↗
PubMed2005

Evaluating the effectiveness of a Mexican strain of Duddingtonia flagrans as a biological control agent against gastrointestinal nematodes in goat faeces.

The use of Duddingtonia flagrans in the control of goat nematodes was investigated. Initially, the time of passage of chlamydospores through the digestive tract of goats was evaluated. Two groups of seven parasite-free kids were formed. Group A received a single dose of 3.5x10(6) D. flagrans chlamydospores (FTHO-8 strain) per kg of live weight. Group B did not receive any chlamydospores. Faeces were obtained from each kid daily from day 4 prior to inoculation until day 5 post-inoculation (PI) and were placed in Petri dishes containing water agar. Gastrointestinal nematode infective larvae were added to each Petri dish and incubated at 25 degrees C for 7 days. Petri dishes were examined to detect the fungus and trapped nematodes. A second trial evaluated the effect of D. flagrans on the number of gastrointestinal nematode larvae harvested from goat faecal cultures in naturally infected goats. Two groups of seven goats were formed. The treated group received a single dose of 3.5x10(6) D. flagrans chlamydospores per kg of liveweight. The control group did not receive any chlamydospores. Faeces were obtained twice daily from each kid. Two faecal cultures were made for each kid. One was incubated for 7 days and the other for 14 days. Gastrointestinal nematode larvae were recovered from each culture and counted. Percentage of larval development reduction was determined using a ratio of larvae/eggs deposited in the control and treated groups. Duddingtonia flagrans survived the digestive process of goats, and maintained its predatory activity, being observed from 21 to 81 h PI (3 to 4 days). A reduction in the infective larvae population in the treated group compared to the non-treated group was observed in both incubation periods (7 days: 5.3-36.0%; 14 days: 0-52.8%, P>0.05). Although a single inoculation of D. flagrans can induce a reduction of infective larvae collected from faeces, a different scheme of dosing may be needed to enhance the efficacy of D. flagrans in goats.

Animals↗
PubMed1995

Transretinal membrane formation in diffuse unilateral subacute neuroretinitis.

BACKGROUND: Diffuse unilateral subacute neuroretinitis (DUSN) is characterized by unilateral visual loss with vitreous inflammation, optic disc swelling, and the presence of gray-white lesions in the deep retina, and can be associated with intraocular nematode infection. To date, no cases of transretinal membrane formation in DUSN have been reported. METHODS: A 22-year-old woman was examined for a 2-week history of unilateral decreased vision and neuroretinitis. A subretinal nematode was identified and a diagnosis of DUSN was made. The nematode was destroyed with laser photocoagulation. An epiretinal membrane and traction retinal detachment persisted and the membrane was removed surgically, at which time it was noted to be transretinal, passing through a full-thickness retinal defect into the subretinal space. Laser photocoagulation was performed with the argon green laser (400 mW, 400 microns, 100 msec). Subsequent removal of the epiretinal portion of the transretinal membrane was performed via a pars plana approach. The membrane was studied by transmission electron microscopy (TEM). RESULTS: The laser photocoagulation was successful in destroying the nematode. Partial resolution of the neurosensory detachment resulted in marked improvement in visual acuity. The membrane consisted of a pauicellular collagenous stroma with scattered fibroblasts and mononuclear inflammatory cells. CONCLUSION: Removal of membranes affecting the macula may be of benefit in selected patients with DUSN.

Acute Disease↗
PubMed1994

Comparative efficacy of moxidectin and mebendazole against gastrointestinal nematodes in experimentally infected lambs.

A controlled trial was conducted to determine the anthelmintic efficacies of moxidectin and mebendazole. The compounds were administered orally at doses of 0.2 mg/kg bodyweight and 15.0 mg/kg bodyweight, respectively, to lambs infected experimentally with large numbers of gastrointestinal nematode larvae including a benzimidazole-resistant strain of Haemonchus contortus. Moxidectin was 100 per cent effective against adult H contortus, Ostertagia species, Trichostrongylus colubriformis, Cooperia curticei and fifth stage larvae of Oesophagostomum species and Chabertia ovina, but was only 76 per cent effective against adult Strongyloides papillosus. Mebendazole was 100 per cent effective against adult Ostertagia species and T colubriformis, but reduced the numbers of adult C curticei by only 39 per cent, S papillosus by 58 per cent, H contortus by 76 per cent, and fifth stage larvae of Oesophagostomum species by 79 per cent and C ovina by 72 per cent.

Administration, Oral↗
PubMed2006

Microcapsules formulated in the enteric coating copolymer Eudragit L100 as delivery systems for oral vaccination against infections by gastrointestinal nematode parasites.

Microcapsules using the copolymer of methacrylic acid (Eudragit L100) were formulated for oral delivery of vaccines against the enteral/parenteral nematode parasite Trichinella spiralis. Antigenic preparations from first stage larvae (L1) of T. spiralis were microencapsulated in Eudragit L100. The microcapsules prepared by the spray drying method were resistant to acid pH, although the antigen was rapidly released under neutral and basic environmental conditions. The native protein conformation and biological activity was preserved in the microcapsules, as assessed by SDS-PAGE and ELISA. When administered to NIH mice, the antigen loaded microcapsules protected against infection by T. spiralis at both the intestinal and muscular levels, the worm burden diminishing by 45.58 and 53.33%, respectively. Furthermore, following administration of the microparticles an increase of the serum IgG1 response, a marker for the Th2 type response, was evident. These results indicate that microcapsules formulated with anionic biocompatible polymers such as Eudragit may be useful for oral vaccination against nematode infections.

Administration, Oral↗
PubMed1992

The interaction of Trypanosoma congolense and Haemonchus contortus infections in trypanotolerant N'Dama cattle.

The interactions between Trypanosoma congolense and Haemonchus contortus infections were studied in N'Dama calves. A total of 38 N'Dama bulls was divided into four groups and each group infected either with H. contortus 1 week after infection with T. congolense or with T. congolense 4 weeks after infection with H. contortus, or with either infection singly. Parasitological (faecal egg counts, parasitaemia), haematological (packed cell volume, white blood cell counts, albumin) and clinical parameters (body weight change, mortality rate) were compared among the various groups. The results showed a reduced prepatent period and a markedly increased pathogenicity of H. contortus infections in animals with a concurrent T. congolense infection. The most harmful combination was a H. contortus infection 1 week after the T. congolense infection which resulted in a progressive and severe anaemia, accompanied by hypoalbuminaemia, increased weight loss and high mortality. The anaemia induced by dual infections showed a low responsiveness to chemotherapy and in several cases supportive treatment did not help recovery. The results also showed that animals with a concurrent T. congolense and H. contortus infection ran a higher risk of succumbing during the infection, and also during 10 weeks following treatment. Although infections with T. congolense alone produced no clinical signs, they were found to significantly reduce the ability of infected animals to mount a normal response to a subsequent H. contortus infection. It was concluded that the increased H. contortus egg excretion observed in animals infected with both parasites might significantly increase the risk of nematode infections and that the reduced prepatent period might necessitate more frequent anthelmintic treatments. These interactions should, therefore, be considered wherever attempts are made to control these two diseases.

Animals↗
PubMed1998

Lactic dehydrogenase virus infection enhances parasite egg production and inhibits eosinophil and mast cell responses in mice infected with the nematode Nippostrongylus brasiliensis.

The effects of lactic dehydrogenase virus (LDV) infection on the protective immune responses to the nematode Nippostrongylus brasiliensis were studied. Mice with chronic LDV infection showed significantly higher levels of parasite egg production than non-LDV-infected (control) mice after N. brasiliensis infection. Concurrent LDV infection also suppressed peripheral blood eosinophilia and the lung mastocytosis induced by this nematode. LDV infection showed higher expression levels of the interferon-gamma (IFN-gamma) mRNA in lymph nodes compared with control mice before N. brasiliensis infection. In addition, the IgG2a production in LDV-infected mice was higher than that in control mice before and after N. brasiliensis infection. These results suggest that LDV infection modulates protective immune responses against N. brasiliensis infection by the activation of T-helper type 1 cells.

Animals↗
PubMed1984

Isolation and characteristics of small intestinal lamina propria cells from normal and nematode (Nippostrongylus brasiliensis)-infected rats.

Intestinal lamina propria (LP) cells were isolated from normal or nematode (Nippostrongylus brasiliensis)-infected rats. At certain times after infection (days 11-17), viable cell recoveries from infected rats were lower, whereas at other times (days 20-50), they were significantly greater than those from normal rats. The frequencies of lymphocytes, plasma cells, eosinophils, mast cells and macrophages from LP differed between normal and infected rats, and the histamine content did also. However, spontaneous 3H-uridine and 3H-thymidine incorporation and the number of cells with cytoplasmic immunoglobulin were similar. LP cells from normal rats were unresponsive to the mitogens phytohemagglutinin, concanavalin A and pokeweed. 125I-deoxyuridine-radiolabeled LP lymphoblasts from normal rats were widely distributed in recipients 22-24 h after transfer and showed no selective predilection to return to the intestine. The isolation procedure can be used to study intestinal LP cells from normal or diseased animals.

Animals↗
PubMed1997

Safety of milbemycin as an oral or bath treatment for the tropical freshwater angelfish Pterophyllum scalare.

Technical grade milbemycin (A3-A4 oxime) was formulated in propylene glycol to produce a stock concentration of 5.0 mg/ml. Groups of six pond-reared freshwater angelfish (Pterophyllum scalare) randomly housed in 32-L aquaria were exposed to milbemycin by prolonged bath at 63, 125, and 188 PPB or by its incorporation into their gelatinized food at 2.5 mg or 5.0 mg/100 g food, which they were fed ad lib. for 1 day. Control fish were exposed to a prolonged bath (24 hr without charcoal filtration) of 0.8 ml propylene glycol/32 L water, were given gelatinized food incorporating 1 ml propylene glycol/100 g food ad lib. for 1 day, or were untreated (no propylene glycol exposure). All fish treated at 188 PPB and the smallest individuals from the 63- and 125-PPB aquaria died. Other fish at 125 PPB exhibited transient lethargy and increased opercular movement but recovered within 24 hr. No deleterious effects were noted in the fish given milbemycin orally. Pretreatment parasitic nematode infection rate, evaluated by gut dissection of 16 randomly selected fish, was 68.75%. Identification of nematodes to species was not performed. No significant differences in infection rates between treated and untreated groups were detected.

Administration, Oral↗
PubMed1992

Radiolabelling of the excretory-secretory and somatic antigens of Anisakis simplex larvae.

Anisakis simplex larvae were cultured in vitro in medium containing 35S-methionine for ten days. The medium and the larval tissues were analysed for biosynthetically labelled polypeptide by sodium dodecyl sulphate polyacrylamide gel electrophoresis and autoradiography. Immunoprecipitates with positive and negative human antisera were similarly analysed, using Staphylococcus aureus to absorb immuno-complexes. ES products of Anisakis larvae contained many polypeptides with molecular weights of less than 200 K. 180 KDa and 40 KDa polypeptides in ES products reacted with IgG in Anisakis-infected human sera. Somatic extracts also contained many polypeptides with molecular weights of less than 200 K. One of these polypeptides with a molecular weight of 130 K reacted with IgG in Anisakis-infected human sera. These polypeptides did not react with other nematode-infected human sera.

Animals↗
PubMed2000

Nematode parasites of adult dairy cattle in the Netherlands.

Abomasa, blood samples and faecal samples for examination of nematode infections were collected from 125 dairy cows during the period November 1997-October 1998. Of these, 12 had no grazing history and were, therefore, excluded from this study. From the remaining 113, 88.5% had nematode eggs in the faeces. Larval identification of the positive cultures showed that Ostertagia spp. larvae were most frequent (97%), followed by Trichostrongylus spp. (29%), Oesophagostomum spp. (23%), Cooperia punctata (20%), Cooperia oncophora (4%), Haemonchus contortus (2%) and Bunostomum phlebotomum (1%). The geometric mean EPG was 2.4. Two cows excreted larvae of Dictyocaulus viviparus (0.1 and 0.6 LPG resp.). Worms were found in the abomasa of 108 cows (96%). In all these abomasa Ostertagia spp. was present (100%). Trichostrongylus axei was found in 47 abomasa (43.5%) and two cows (2%) were infected with Capillaria bovis. The geometric mean of the total abomasal worm counts was 1743 and of Ostertagia spp. alone 1615. Almost all male worms were Ostertagia ostertagi, only occasionally Skrjabinagia lyrata10,000) total worm burden. Ostertagia specific antibodies were highest in late summer and autumn and lowest in spring and early summer. The same pattern, although not so pronounced, was observed for the serum pepsinogen values. No clear seasonal pattern was found for the Cooperia specific antibodies. Antibodies against D. viviparus were detected in seven cows (6%).

Animals↗
PubMed1999

Changes in the morphology and the distribution of rat intestinal eosinophils during infection with the nematode Nippostrongylus brasiliensis.

Increases in the numbers of eosinophil leukocytes present in the lamina propria of intestines infected with nematodes is a well described phenomenon, yet the role of these leukocytes and their actions in this situation are not yet fully understood. Morphologic changes in these cells occur with the course of the infection, as do alterations in their location within the gut; these findings may give important clues to the function of this prominent cell. We observed changes in intestinal eosinophils in the August rat during infection with the nematode Nippostrongylus brasiliensis and found, together with the well known increases in number infiltrating the lamina propria at Day 20 (three times the levels in normal animals), a distinct change in the morphology of individual cells which included increase of the cell's overall size and changes in shape, as well as a dissemination of cytoplasmic granules in relationship to the cell's nucleus. No ultrastructural evidence of extracellular degranulation or intact eosinophil cytoplasmic granules outside the bounds of cell cytoplasmic membranes was seen. This finding is important considering the light microscopic appearance of individual eosinophil granules apparently distributed extracellularly, and lying in the connective tissue of the lamina propria, a common histopathologic observation in eosinophilic conditions. Eosinophils within the lamina propria changed their location as the infection progressed, tending to move to line up along the subepithelial zones. In addition, eosinophils were observed both at the light and electron microscopic levels to be passing through the basement membrane and into the epithelial layer. This latter phenomenon was confirmed using confocal optical slicing where eosinophils were commonly observed on the luminal side of the nuclei of the gut epithelium. These observations strongly suggest that morphologic alterations occur in eosinophils in the lamina propria and these changes may be associated with functional alterations in these cells akin to the putative phenomenon of "activation." Our findings indicate that eosinophils have the capacity to enlarge and extend their cytoplasmic processes between various components of the lamina propria and move toward the basement membrane during an active infection, as well as into, and possibly through, the intestinal epithelium. These findings emphasize the need for careful consideration of the changing morphologic status of eosinophils when investigating biologic changes associated with the activation of these cells in tissue inflammatory responses.

Animals↗
PubMed1992

Sequential in vivo measurements of body composition of calves exposed to natural infection with gastrointestinal nematodes.

Sequential in vivo measurements of total body water, exchangeable sodium and exchangeable potassium, made by radioisotopic dilution techniques, were used to determine changes in body composition in calves exposed to natural infections with gastrointestinal nematodes during their first grazing season. Two groups of calves were studied, one of which received a sustained release anthelmintic bolus at turn out. Over the grazing season the bolus-treated calves showed a significantly improved pattern of bodyweight gain, compared with the untreated control calves. There were also significant increases in both total body water and exchangeable potassium, as a percentage of the bodyweight, in the bolus calves compared with the controls. These findings indicated that body protein as a percentage of bodyweight was increased in the bolus animals. The bolus-treated calves also had significantly lower serum pepsinogen concentrations, faecal egg counts and worm burdens.

Animals↗
PubMed1986

The epidemiology and control of intestinal helminths in the Pulicat Lake region of Southern India. I. Study design and pre- and post-treatment observations on Ascaris lumbricoides infection.

The study design of a project to investigate the epidemiology, population dynamics and control of intestinal nematode infections in fishing village communities in Southern India is described. The paper focuses on Ascaris lumbricoides infection and describes changes in prevalence and intensity (worm burdens) with host age, the aggregated frequency distributions of parasite numbers per person, a density-dependent relationship between parasite fecundity and worm burden and rates of reinfection following chemotherapeutic treatment. The age-intensity of infection profile is convex in form, where maximum worm burdens are attained in children in the age range five to nine years. On the basis of juvenile to adult worm ratioos, the life expectancy of Ascaris in man is estimated to be of the order of one year. Rates of reacquisition of worms after chemotherapy are shown to be dependent on host age. Wormy individuals with heavy infections are shown to be predisposed to this state such that they reacquire heavier than average worm burdens following treatment.

Adolescent↗
PubMed2001

Neural change in Trichinella-infected mice is MHC II independent and involves M-CSF-derived macrophages.

Intestinal inflammation due to nematode infection impairs enteric cholinergic nerve function and induces hypercontractility of intestinal muscle. Macrophages have been implicated in the neural changes, but the subpopulation and mechanism involved are unknown. We examined whether macrophages alter nerves by virtue of their ability to activate lymphocytes via major histocompatibility complex (MHC) II-restricted antigen presentation. We also attempted to evaluate the role of macrophage subsets using op/op mice deficient in macrophage colony-stimulating factor (M-CSF). ACh release from the myenteric plexus was measured in MHC II- and M-CSF-deficient (op/op) mice infected with Trichinella spiralis. F4/80-positive macrophages and interleukin-1 beta were constitutively present in op/op and op/? mice but increased only in op/? mice postinfection. After infection, a marked suppression of ACh release occurred only in infected MHC II-deficient and op/? mice. Muscle hypercontractility remained evident in infected op/? mice. Treatment with M-CSF restored macrophage number, and this was accompanied by suppression of cholinergic nerve function during infection. Thus M-CSF plays a critical role in this model by recruiting a subset of macrophages that selectively suppresses enteric neural function.

Acetylcholine↗
PubMed2006

F4/80+ alternatively activated macrophages control CD4+ T cell hyporesponsiveness at sites peripheral to filarial infection.

Both T cells and APC have been strongly implicated in the immune suppression observed during filarial nematode infections, but their relative roles are poorly understood, particularly in regard to timing and locality of action. Using Litomosoides sigmodontis infection of susceptible BALB/c mice, we have studied the progression of filarial immunosuppression leading to patent infection with blood microfilaremia. Patent infection is associated with decreased immune responsiveness in the draining thoracic lymph nodes (tLN) and intrinsically hyporesponsive CD4+ T cells at the infection site. We now show that we are able to separate, both in time and space, different suppressive mechanisms and cell populations that contribute to filarial hyporesponsiveness. L. sigmodontis infection recruited a F4/80+ population of alternatively activated macrophages that potently inhibited Ag-specific CD4+ T cell proliferative responses even in the presence of competent naive APC. T cell responsiveness was partially restored by neutralizing TGF-beta, but not by blocking IL-10 or CTLA-4 signaling. During prepatent infection, the macrophage population was restricted to the infection site. However, once infection became patent with systemic release of microfilariae, the suppressive macrophage activity extended peripherally into the tLN. In contrast, the hyporesponsive CD4+ T cell phenotype remained localized at the infection site, and the tLN CD4+ T cell population recovered full Ag responsiveness in the absence of suppressive macrophages. Filarial immunosuppression, therefore, evolves over time at sites increasingly distal to infection, and the mechanisms of filarial down-regulation are dependent on proximity to the infection site.

Amino Acid Sequence↗