[IRON DEFICIENCY IN TROPICAL HELMINTHIASIS. I. NEMATODE INFECTIONS].
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Cross-sectional serological survey on gastrointestinal and lung nematode infections in first and second-year replacement stock in the netherlands: relation with management practices and use of anthelmintics.
A cross-sectional survey was carried out on 86 farms randomly distributed in The Netherlands. After housing following the first and the second grazing season (FGS and SGS) serum samples were collected to determine IgG levels against Cooperia oncophora and Dictyocaulus viviparus, and the pepsinogen content. A questionnaire was used to inquire on grazing management practices and the use of anthelmintic drugs. On 80.7 and 60.2% of the farms FGS and SGS animals, respectively, were treated at least once with an anthelmintic drug. The percentage for the SGS animals indicates that the use of anthelmintic drugs in those animals has increased enormously over the last 10-15 years. Generally, parasitic nematode control in the FGS is good on most farms, but it can be characterised as being overprotective. There is a tendency that if anthelmintic drugs are used in the FGS they also are used more often in the SGS. On 12 farms (14%), no anthelmintic drugs were given in the FGS and the SGS. These farms did not differ from the others with respect to management practices in any obvious way. The serological results were in general very low, indicating low levels of exposure to gastrointestinal nematode infection in both FGS and SGS animals. This was not surprising in view of the good to high level of nematode control practices reported by the farmers. Although not statistically significant, a consistent result was that serological results for the SGS animals were more often positive or on average higher on those farms where FGS parasite control tended to be excessive. For D. viviparus, a prevalence rate of 41% positive farms was found. Following comparison with previous data, it is speculated that lungworm (sero-)prevalence in replacement stock may be declining as a result of continuing high levels of parasite control in replacement stock. It is concluded that the results confirm previous surveys, lending support to the conclusion that parasitic nematode control on Dutch dairy farms, certainly in FGS calves, is good but tends to be overprotective.
Animal Husbandry↗
Basophil leucocytes in cutaneous hypersensitivity reactions in nematode-infected guinea-pigs.
Cutaneous hypersensitivity reactions were elicited in guinea-pigs infected with the parasitic nematode Trichostrongylus colubriformis by injecting them with a crude extract of T. colubriformis fourth-stage larvae. The reaction was characterized by early oedema and pronounced cellular infiltration, initially with neutrophils but later with mononuclear cells, basophils and variable numbers of eosinophils. Because basophils have been implicated as effector cells in the protective immune response of guinea-pigs to this nematode, the capacity to elicit a basophil-rich cellular infiltrate in infected animals might be a useful assay for T. colubriformis protective antigen(s).
Animals↗
[Effect of treatment on gastrointestinal nematode infection of heifers and their weight gain in southern Poland].
The level of infection with gastro-intestinal nematodes in heifers of 3 farms (668 head) was studied by coproscopic methods and the efficacy of treatment was evaluated. Extensiveness of infection reached 80% and intensity (EPG) - 120. Comparative studies of weight gains of heifers treated and untreated revealed that the best results were obtained in heifers treated twice a year in May and August. The efficacy was estimated at 93% with respect to extensiveness of infection and at 97% for EPG. Mean final weight gains of the treated heifers were 8,0-16,8 kg higher compared to those of untreated heifers. The mating time for treated heifers was about 30 days earlier than that for untreated ones.
Animals↗
[The effect of dehelminthizations performed during the year on the seasonal dynamics of natural nematode infections in sheep].
In four sheep flocks of two age categories dynamics of natural infections by pulmonary and gastrointestinal nematodes was studied; sheep were kept on a farm in Western Bohemia. Dehelminthizations were performed in different intervals during the grazing period on the basis of the results of quantitative coprologic examinations. Total effectiveness of 80--100% intenseffectiveness (IE) was obtained as a result of single peroral or intraruminal dehelminthization with the following preparations: pyrantel hydrochloricum (Spofa), helmatac (SKF) and nilverm (ICI); the effectiveness concerned gastrointestinal nematodes of the genus Haemonchus, Cooperia, Ostertagia, Trichostrongylus, Bunostomum, Chabertia, Nematodirus, Strongyloides, Oesophagostomum and Trichocephalus. The effectiveness of nilverm on lungworms of D. filaria and P. kochi reached 100%; the preparation was less effective and ineffective on M. capillaris. Dehelminthization practices during three years were more successful as to lowering of incidence of lungworm infections of D. filaria and P. kochi than in gastrointestinal nematodes. If sping dehelminthizations had been postponed till the second half of May or June, the climax of the elimination of ova from summer re-infection was put off till November, with an initial significant increase in September. The third dehelminthization, applied in August, did not result in the increased elimination of ova in autumn, while there was no usual autumnal climax following September dehelminthization. Effective dehelminthization performed at the end of November in all three years maintained low levels of infections during winter housing and significantly influenced the health conditions of ewes before lambing. Dynamics of the elimination of ova after dehelminthization was affected by nematodes with the migration phase in organs and tissues -- S. papillosus, Oesophagostomum sp. and Ostertagia sp.; the same effect was observed, during pasture, in nematodes with relatively short exogenous development of the genus Haemonchus, Ostertagia, Trichostrongylus and Nematodirus. In spite of these dehelminthization practices, the elimination of ova and larvae corresponded to the course of temperatures and rainfall in spring and autumn climaxes every year.
Animals↗
[Nematode infection: clinical evaluation of trichlorophenol-diethylenediamine].
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Chlorophenols↗
Disruption of CD40-CD40 ligand pathway inhibits the development of intestinal muscle hypercontractility and protective immunity in nematode infection.
In our previous studies, we demonstrated that during Trichinella spiralis infection, T helper (Th) 2 cells contribute to the development of intestinal muscle hypercontractility and worm expulsion from the gut via STAT6. In addition, we have linked the altered muscle contractility to the eviction of the parasite and thereby to the host defense. However, the initial events linking infection to the development of muscle hypercontractility are poorly understood. In this study, we examined the contribution of CD40-CD40 ligand (CD40L) interaction in the development of intestinal muscle hypercontractility, in monocyte chemoattractant protein-1 (MCP-1) production, and in the Th2 response in CD40 ligand-deficient (CD40L -/-) mice infected with T. spiralis. Expulsion of intestinal worms was substantially delayed in CD40L -/- mice compared with the wild-type mice after T. spiralis infection. Consistent with delayed worm expulsion, there was a significant attenuation of intestinal muscle contractility in CD40L -/- mice. Infected CD40L -/- mice also exhibited marked impairment in the production of MCP-1, IL-4, IL-13, IgG1, IgE, and mouse mucosal MCP 1 (MMCP-1), and in goblet cell response. These results demonstrate that CD40-CD40 ligand interaction plays an important role in MCP-1 production, Th2 response, intestinal muscle hypercontractility, and worm expulsion in nematode infection. The present data suggest that the early events leading to the generation of Th2 response include CD40-CD40 ligand interaction, which subsequently influences the production of Th2 cytokines, most likely via upregulation of MCP-1.
Animals↗
Chronic intestinal nematode infection induces Stat6-independent interleukin-5 production and causes eosinophilic inflammatory responses in mice.
The role of Stat6 (signal transducers and activators of transcription) in the recruitment and activation of eosinophils has been studied in detail in asthma and other allergic diseases. In this study, we demonstrated that eosinophil responses occur in a Stat6-independent manner in mice infected with the intestinal nematode, Nippostrongylus brasiliensis. Stat6-deficient (Stat6(-/-)) mice cannot expel N. brasiliensis and establish chronic infections. Prominent blood and intestinal eosinophilia were induced after day 14 postinfection (p.i.) and maintained at this level in Stat6(-/-) mice, whereas in wild-type mice eosinophil responses reached a peak on day 10 p.i. and declined thereafter. The introduction of a secondary infection of N. brasiliensis into wild-type mice induced rapid and exaggerated eosinophilia, whereas secondary infection in Stat6(-/-) mice resulted in almost the same eosinophil responses as those of the primary infection, suggesting a lack of memory responses. Blood eosinophilia was also induced in Stat6(-/-) mice implanted with N. brasiliensis in the small intestine, suggesting that intestinal exposure to parasitic antigen is sufficient to induce eosinophil responses. Furthermore, this prominent eosinophil response of Stat6(-/-) mice after day 14 was closely associated with an increase of interleukin (IL)-5 production in serum and intestine. Neither IL-4 nor eotaxin were significantly induced in Stat6(-/-) mice after infection with N. brasiliensis. We also found that mRNA for IL-5, GATA-3 and eosinophil peroxidase (EPO) are induced in the intestine of Stat6(-/-) mice on day 14 p.i. Taken together, these results provide evidence for Stat6-independent IL-5 production and subsequent eosinophil responses after chronic infection with N. brasiliensis.
Animals↗
Patterns of parasitic nematode infection and immunity in dairy heifers treated with ivermectin in a sustained-release bolus formulation either at turnout or in the middle of the grazing season.
Twenty-eight Holstein-Friesian heifers, born the previous year and weighing between 130 and 310 kg, were allocated to one of two treatment groups by restricted randomisation, based on their initial weight. The heifers in group 1 were each treated with ivermectin in a sustained-release bolus formulation at turnout in April, and those in group 2 were each given an ivermectin bolus on July 10, 84 days after turnout. On that day the mean geometric worm egg counts of groups 1 and 2 were 0.4/g and 38.8/g, respectively, and they both had a mean plasma pepsinogen concentration of 0.59 iu/litre; in group 1, two of 14 faecal samples were positive for Dictyocaulus viviparus larvae, and in group 2 all 13 samples were positive; in group 1 eight calves were positive and three inconclusive for the presence of antibodies to D viviparus, and in group 2 the corresponding figures were 10 positive and two inconclusive; the mean liveweights of groups 1 and 2 were 274.4 kg and 262.8 kg, respectively. By December 4,231 days after turnout, the corresponding results were: mean geometric worm egg counts of 2.2/g and 0.5/g; one of 13 and none of 14 faecal samples positive for D viviparus larvae; 12 positive and two inconclusive and none positive and 10 inconclusive for the presence of antibodies to D viviparus; 214 days after turnout their mean liveweights were 361.1 kg and 358.3 kg. Although the patterns of parasitic nematode infection were different in the two groups during the grazing season, by the time they were housed both groups had achieved similar liveweights and showed evidence of an immune response to both D viviparus and gastrointestinal nematodes.
Animals↗
Genetic control of the immune repertoire in nematode infections.
Mammals vary considerably, both within and between species, in the way in which their innate and adaptive immune systems respond to infections. An understanding of the processes involved in such variability will not only contribute to explaining heterogeneity in susceptibility and pathology, but will also be relevant to vaccination. This will be particularly important for the new generation of vaccines that are likely to be composed of one or a few cloned or synthesized antigens. For helminth infections, this could have particular relevance to hypersensitivity responses. The adaptive immune response is fundamentally constrained by the genetic constitution of an individual, and the need to avoid reactivity to self. This will have important implications for the dynamic relationship between host defences and parasite evasion mechanisms at both physiological and evolutionary levels. In this review, Malcolm Kennedy examines the genetic control of the specificity of the immune response to nematode infections, and in particular, the role of the major histocompatibility complex.
Journal Article↗
Larval nematodes infecting Amphiporeia virginiana (Amphipoda: Pontoporeioidea) on Sable Island, Nova Scotia.
Three species of larval nematodes were found infecting the nearshore subtidal amphipod Amphiporeia virginiana collected from beaches on Sable Island, Nova Scotia. Five and 2 sealworms, Pseudoterranova decipiens s.l., were found in 2,020 and 2,044 amphipods, respectively, collected in 1991 and 1992, dissected, and examined microscopically. Two sealworms, 1 Paracuaria adunca and 1 Ascarophis sp., were found in 5,157 amphipods collected in 1992 and enzymatically digested. Infection with each species constitutes a new host record. These 3 nematodes possess the capability to infect a wide variety of invertebrate intermediate hosts. The shoreline niche of A. virginiana places it in close proximity to the sealworm's definitive host, the grey seal, which hauls out on Sable Island in abundance. The amphipod's distribution also places it in the vicinity of both the definitive hosts of Ascarophis sp. (marine fish) and P. adunca (piscivorous birds).
Animals↗
Gastrointestinal and pulmonary nematode infections decrease goat productivity in Moroccan semi-arid conditions.
A herd of goats naturally infected with lungworm and gastrointestinal nematodes was divided into three groups and treated with either morantel tartrate or fenbendazole at strategic periods, i.e. in June (at pre-mating), in November (at pre-kidding) and in January (at early lactation) or left untreated. Morantel tartrate treatment (8 mg kg-1) was efficient in reducing the gastrointestinal nematode egg output and fenbendazole treatment (15 mg kg-1) was efficient in reducing the gastrointestinal nematode egg and small lungworm larvae faecal output. Reductions in mortality of adult goats and their progeny and improvement of rearing percentages were recorded in both treated groups, with fenbendazole showing a greater response than morantel tartrate. A relative risk analysis showed that mortality in goats and kids was significantly reduced in treated kids and goats. Reduction of 6.6% in kidding rates, 0.21 in prolificacy, and an increase of 1.3 in abortion rates, 8.3% in kid and 2.2% in goat mortalities, could be attributable to the small lungworm infection. Small lungworm infections seem therefore to be one of the main causes of indirect kid mortality and inadequate breeding performance of goats in the semi-arid Middle Atlas region of Morocco.
Animals↗
[Persistent intestinal motility disorder after transient intestinal nematode infection in rats].
OBJECTIVE: To investigate the intestinal motor function (distal colonic manometry and gastrointestinal transit time) after T. spiralis infection in rats. METHODS: Sprague-Dawley rats were infected by administering T. spiralis larvae. Rats were studied on 14, 42, and 56 days post-infection (PI). Age matched non-infected animals served as controls. All rats underwent colonic manometry and gastrointestinal transit time test. RESULTS: (1) The small intestinal inflammation became the most severe on day 14 PI, and returned to normal on day 56. (2) The distal colonic manometry showed significantly active motility in acute infected rats either at rest or upon balloon stimulating. (3) Rat colonic motility parameters were not different from those of the control rats either at rest or upon small volume (1mL) balloon stimulating on day 42 and day 56 PI. But when the balloon was inflated with 2 mL of air, the colonic activity increased significantly compared with that of the control. (4) Gastrointestinal transit time was slower in acute and PI rats than that in the control group. CONCLUSION: Intestinal motility function was abnormal persistently after transient intestinal nematode infection in rats either in distal colonic manometry or in gastrointestinal transit time.
Animals↗
A critical role for IL-13 in resistance to intestinal nematode infection.
Mice in which either the IL-4 or the IL-13 gene has been disrupted (IL-4 KO and IL-13 KO) were susceptible to infection with the intestinal nematode Trichuris muris, whereas their wild-type littermates were highly resistant and expelled the parasite. IL-4 KO mice showed diminished Th2-type responses with T. muris infection and also failed to produce parasite-specific IgG1 Abs. Although IL-13 KO mice made reduced Th2-type responses early in infection, they were capable of generating strong Th2-type responses at later time points and were unable to regulate the magnitude of their Ab isotype response. These results confirm the importance of IL-4 in resistance to T. muris and provide the first demonstration of an important role for IL-13 in resistance to helminth infection. The IL-13 KO mouse had a separate phenotype to that of the IL-4 KO mouse, suggesting that both IL-4 and IL-13 play important yet different roles in mediating immunity to intestinal helminths.
Animals↗
Leucocyte recruitment during enteric nematode infection.
Resolution of infection with the intestinal nematode Trichinella spiralis depends on the host mounting a T helper 2 (Th2) response. It is known that both mast cells and T cells play a crucial role. We have previously shown that efficient migration of mast cells to the gut during infection depends on their expression of the integrin beta 7. beta 7 forms a heterodimer complex with either alpha E or alpha 4 integrin chains, alpha E beta 7 binding to E-cadherin expressed by epithelial cells and alpha 4 beta 7 binding to mucosal addressin cell adhesion molecule (MAdCAM-1) on the endothelium. We were interested to know whether dysfunctional mast cell localization to the gut in the absence of beta 7 was due to the failure of alpha 4 beta 7 to bind to MAdCAM-1 or the failure of alpha E beta 7 to bind to E-cadherin. We used blocking monoclonal antibodies against alpha E (M290) or alpha 4 (PS2) or beta 7 (HB293) during T. spiralis infection of C57BL/6 mice and found that all antibody treatments reduced mastocytosis. In contrast, none of the antibody treatments prevented the migration of CD3(+) T cells into the intestine. These results indicate that during inflammation (a) there is integrin redundancy for lymphocytes but not for mast cells and (b) both alpha E beta 7 and alpha 4 beta 7 are crucial either for the entry of mast cells into the gut or for their maturation once they have entered.
Animals↗
A survey of parasitic nematode infections of chickens in rural Zimbabwe.
A survey to determine the nematode species in rural chickens reared extensively was carried out in six districts of Zimbabwe. Two-hundred-and-seventy chickens were randomly collected from the districts and processed for helminth recovery. One genus and 10 species were identified from the gastrointestinal tract but no parasites were found in the respiratory tract and eyes. Skrjabinocerca sp., Capillaria obsignata, Capillaria contorta and Trichostrongylus tenuis are new records in Zimbabwe. Allodapa brumpti and Tetrameres americana were the most common species with a prevalence of 64.8% and 64.1%, respectively.
Animals↗
HOST-PARASITE INTERACTION IN ROOT-KNOT NEMATODE-INFECTED CARROT TISSUE.
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Animals↗
Tetramisole in the treatment of nematode infections in man.
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Adolescent↗