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PubMed2001

Effect of iron deficiency on Trichuris suis and Ascaris suum infections in pigs.

The objective of this experiment was to detect a possible interaction between iron deficiency and intestinal nematode infections. We report on a 2 x 2 study where thirty-one 10-week-old pigs fed a low or a normal iron diet were infected with both Trichuris suis (4500 eggs) and Ascaris suum (1200 eggs). No significant difference was detected between diet groups with respect to parasitological parameters for A. suum or the total number of adult T. suis recovered at necropsy 10 weeks p.i. However, in the low iron group T. suis were located more proximally and the worms were increased in length. A higher proportion of pigs with initial faecal egg excretion at 6 weeks p.i. was observed in the low iron group, indicating a shortened pre-patency period. Worm fecundity and total faecal egg excretion were also highest in the low iron group. A significant correlation was found between female worm length and fecundity. The peripheral eosinophil counts were diminished in the low iron host groups. The infected low iron group experienced more severe pathophysiological changes in terms of hypoalbuminaemia and decreases in erythrocyte volumes. A significant inverse correlation existed between iron content in the bone-marrow and liver (body) store. In conclusion, iron deficiency increased the severity of T. suis infection in pigs.

Anemia, Iron-Deficiency↗
PubMed1999

A controlled evaluation of two school-based anthelminthic chemotherapy regimens on intensity of intestinal helminth infections.

BACKGROUND: School-based deworming programmes have been promoted as a cost-effective strategy for control of nematode infection in developing countries. While numerous efficacy studies have been conducted, there is little information on actual programme effectiveness in areas of intense transmission. METHODS: A randomized trial of a school-based deworming programme was conducted in 12 primary schools on Pemba Island, Zanzibar. Four schools each were randomized to control, twice a year deworming with single dose mebendazole or three times a year deworming. Baseline and 12-month follow-up data on helminth infection using the Kato-Katz technique, demographic information and nutritional status were collected on 3028 children from March 1994 to May 1995. RESULTS: Intensity of infection measured as eggs per gram of faeces (epg) declined significantly for Ascaris lumbricoides, Trichuris trichiura and hookworm infections in both treatment groups. A. lumbricoides infection intensity declined 63.1% and 96.7% in the twice and three times per year treatment groups compared to the controls. T. trichiura infection intensity declined 40.4% and 75.9% respectively and hookworm intensity declined 35.3% and 57.2% respectively compared to control schools. CONCLUSIONS: These results suggest that school-based programmes can be a cost-effective approach for controlling the intensity of intestinal helminth infection even in environments where transmission is high.

Animals↗
PubMed2005

The nematode Goezia sp. (Anisakidae) from Bagrus bayad (Osteichthyes) from Egypt.

The present study describes nematode infection in the freshwater fish Bagrus bayad (Osteichthyes) collected from the Red Sea at Suez Canal Zone. Of 32 examined fish, 21 (65%) were infected with Goezia sp. (Nematoda: Family: Anisakidae) with mean ntensity of 4.1 parasites. The nematode present here differs from Goezia braziliensis, G. breviaeca and G. intermedia, as well as from other species described. The main difference was in the greater number of pre-anal papillae in males compared to G. braziliensis. The present parasite also differs from G. braziliensis in spicule length and distance of vulva from the anterior extremity.

Animals↗
PubMed2005

The effect of dietary polyunsaturated fatty acids (PUFA) on infection with the nematodes Ostertagia ostertagi and Cooperia oncophora in calves.

Diet-induced changes in the polyunsaturated fatty acid (PUFA) content of immune cells influences the immune phenotype that develops following infection. The aim of this study was to examine the effect of manipulating dietary PUFA supply on tissue fatty acids composition and immunity to a mixed infection with an abomasal and an intestinal nematode parasite in calves. Calves (n=24) were allocated into two treatment groups and fed 25 g/day of either fish oil (n-3 group) or a binary mixture of palm/rapeseed oil (normal group) as a supplement in milk replacer. Within each treatment group eight calves were infected with 2000 L3 Ostertagia ostertagi and Cooperia oncophora, three times per week for 8 weeks, the remaining calves were pair-fed uninfected controls. Faecal egg counts (FEC) were carried out twice weekly. At slaughter, the whole gut was removed intact for worm counts and tissue samples were taken for fatty acid analysis. Samples of abomasum, duodenum and mid-gut were also collected for immunohistological analysis. FEC were not significantly influenced by oil supplement but tended to remain higher in the palm/rapeseed oil-fed group (normal infected). The number of intestinal immature worms was significantly (p<0.05) higher in the n-3 group. Mucosal mast cell (MMC) and eosinophil numbers were significantly increased (p<0.05) by infection and were significantly lower (p<0.05) in the intestinal tissue of the fish oil supplemented and infected group (n-3 infected group). These results suggest that feeding an n-3 PUFA-rich supplement (fish oil) can influence cellular mediators of immunity to nematode infection. This is the first report of the establishment of patency and the subsequent development of immunity to a mixed infection with O. ostertagi and C. oncophora in calves undergoing early rumen development. The trend in the FEC, MMC and eosinophil numbers in the n-3 group suggests that decreasing the dietary n-6/n-3 PUFA ratio may be a worthwhile immunonutritional strategy for potentiating the immune response to nematode parasite infection in the calf.

Animals↗
PubMed1998

Purification and characterization of a high-molecular-weight insecticidal protein complex produced by the entomopathogenic bacterium photorhabdus luminescens

Photorhabdus luminescens is a gram-negative enteric bacterium that is found in association with entomopathogenic nematodes of the family Heterorhabditidae. The nematodes infect a variety of soil-dwelling insects. Upon entering an insect host, the nematode releases P. luminescens cells from its intestinal tract, and the bacteria quickly establish a lethal septicemia. When grown in peptone broth, in the absence of the nematodes, the bacteria produce a protein toxin complex that is lethal when fed to, or injected into the hemolymph of, Manduca sexta larvae and several other insect species. The toxin purified as a protein complex which has an estimated molecular weight of 1,000,000 and contains no protease, phospholipase, or hemolytic activity and only a trace of lipase activity. The purified toxin possesses insecticidal activity whether injected or given orally. Analyses of the denatured complex by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed it to be composed of several protein subunits ranging in size from 30 to 200 kDa. The complex was further separated by native gel electrophoresis into three components, two of which retained insecticidal activity. The purified native toxin complex was found to be active in nanogram concentrations against insects representing four orders of the class Insecta.

Journal Article↗
PubMed2003

Detection and quantification of Plectosphaerella cucumerina, a potential biological control agent of potato cyst nematodes, by using conventional PCR, real-time PCR, selective media, and baiting.

Potato cyst nematodes (PCN) are serious pests in commercial potato production, causing yield losses valued at approximately $300 million in the European Community. The nematophagous fungus Plectosphaerella cucumerina has demonstrated its potential as a biological control agent against PCN populations by reducing field populations by up to 60% in trials. The use of biological control agents in the field requires the development of specific techniques to monitor the release, population size, spread or decline, and pathogenicity against its host. A range of methods have therefore been developed to monitor P. cucumerina. A species-specific PCR primer set (PcCF1-PcCR1) was designed that was able to detect the presence of P. cucumerina in soil, root, and nematode samples. PCR was combined with a bait method to identify P. cucumerina from infected nematode eggs, confirming the parasitic ability of the fungus. A selective medium was adapted to isolate the fungus from root and soil samples and was used to quantify the fungus from field sites. A second P. cucumerina-specific primer set (PcRTF1-PcRTR1) and a Taqman probe (PcRTP1) were designed for real-time PCR quantification of the fungus and provided a very sensitive means of detecting the fungus from soil. PCR, bait, and culture methods were combined to investigate the presence and abundance of P. cucumerina from two field sites in the United Kingdom where PCN populations were naturally declining. All methods enabled differences in the activity of P. cucumerina to be detected, and the results demonstrated the importance of using a combination of methods to investigate population size and activity of fungi.

Animals↗
PubMed1996

Detection of Taenia saginata antigens in faeces by ELISA.

Stool samples were examined by capture ELISA for the presence of T. saginata antigens. The specimens were from 303 patients infected with T. saginata, 43 samples from individuals suffering from bacterial, fungal, protozoan and nematode infections and 36 ones deriving from uninfected persons. The samples were diluted 1:10 (w:v) in PBS + 0.35% Tween 20, centrifuged twice at 5000 g for 20 min at room temperature and resulting supernatant at 12,000 g for 30 min at 0 degree C. The capturing and detecting polyclonal antibodies were prepared in rabbits immunizing them with T. saginata surface antigens. The stool samples freshly obtained, stored at 4 degrees C not longer than 72 h, or kept at at -20 to -30 degrees C even for 24 months showed reliable results in ELISA. The samples kept for a long time at 4 degrees C, dried and covered with moult were negative in the test. All samples taken from patients infected with other than T. saginata parasites or uninfeced were negative.

Animals↗
PubMed1997

The effectiveness of a single treatment with doramectin or ivermectin in the control of gastrointestinal nematodes in grazing yearling stocker cattle.

Four studies were conducted to a similar experimental design in the U.S. to evaluate the effectiveness of doramectin injectable administered to yearling stocker cattle in the control of gastrointestinal nematodiasis over the subsequent grazing period. Studies were conducted in Wisconsin (WI) and Arkansas (AR) during the summer season. The other two studies were conducted in Georgia (GA) and Mississippi (MS) during the winter/spring season. Doramectin was compared with both ivermectin injectable and ivermectin pour-on in the WI study, with ivermectin injectable alone in the GA study and with ivermectin pour-on alone in the other two studies. At each study site, an area of permanent pasture previously grazed by parasitized animals was subdivided by fencing into equal pasture units each with its own water supply. A treatment designation (non-medicated control, doramectin injectable, ivermectin injectable or ivermectin pour-on) was randomly assigned to each pasture unit. Weaned beef calves with confirmed gastrointestinal nematode infections were randomly allotted to a pasture unit and corresponding treatment group. Each treatment group consisted of three replicates of seven animals per pasture unit (total 21 animals) in the WI study, three replicates of four or six animals per pasture unit (total 16 animals) in the AR study, five replicates of six animals per pasture unit (total 30 animals) in the GA study and three replicates of 12 animals per pasture unit (total 36 animals) in the MS study. Treatments were 1% doramectin injectable solution, 1% ivermectin injectable solution, 0.5% ivermectin pour-on solution or non-medicated controls. The injectables were administered at a dose of 1 ml/50 kg body weight (200 micrograms doramectin or ivermectin/kg) by subcutaneous injection in the neck. Ivermectin pour-on solution was administered topically at a dose of 1 ml/10 kg body weight (500 micrograms ivermectin/kg). After receiving their prescribed treatment, animals were placed on their designated pasture unit where they remained for the entire grazing period (84-140 days). Fecal nematode egg counts and body weights were monitored at predetermined intervals throughout each study. Doramectin treatment reduced pretreatment egg counts by between 95 and 100% by 21 days post-treatment. Subsequent rises in egg output from exposure to infective pastures were delayed by two to four weeks resulting in substantial reductions in total egg deposition over the grazing period and, therefore, potential pasture recontamination. Doramectin treatment resulted in substantial average daily weight gain advantages (0.152-0.272 kg) over the grazing season compared to non-medicated controls. Advantages were statistically significant (P < 0.05) in three of the four studies. There were no significant differences (P > 0.05) in average daily gain between the doramectin and ivermectin injectable or ivermectin pour-on treated groups.

Animal Feed↗
PubMed1995

IgE regulation by nematodes: the body fluid of Ascaris contains a B-cell mitogen.

Nematode infection of human beings or laboratory animals leads to markedly increased levels of circulating IgE, most of which is not specific to worm antigens. This phenomenon is known to be interleukin-4-dependent, but little is known about the mechanism of activation of the response. In an attempt to elucidate this mechanism, we have used a reductive approach with worm products rather than infections. In a previous article we showed that injection of the body fluid of the nematode Ascaris yields a marked increase in circulating IgE. In this study we demonstrate that the body fluid contains a B-cell mitogen. Incubation with purified splenic B cells with 50 micrograms/ml body fluid yields marked proliferation of B cells, as measured by tritiated thymidine uptake. Similarly, Ascaris body fluid stimulates G0 B cells to enter the cell cycle. T cells are unaffected by the mitogen, and the response is dependent on viable accessory cells. Contamination of Ascaris body fluid or reagents by bacterial lipopolysaccharide has been ruled out as a source of artefactual data. A model is proposed, which suggests that the B-cell mitogen in Ascaris body fluid stimulates polyclonal B-cell activity and that other nematode factors either stimulate the release of interleukin-4 or act in an interleukin-4-like manner to cause class switch to IgE.

Animals↗
PubMed2005

Survey of nematophagous fungi in South Africa.

Three hundred and eighty-four samples of leaf litter, soil, faeces from domestic and game animals, compost and aqueous cultures of infective nematode larvae contaminated with unidentified fungi were plated out on water agar, baited with pure infective larvae of Haemonchus contortus, incubated and examined for the presence of nematophagous fungi. Duddingtonia flagrans was isolated from five samples, and 73 samples were positive for other nematophagous fungi.

Animals↗
PubMed1978

A parasitological study on the chacma baboon (Papio ursinus) from the Northern Transvaal.

Baboons imported into Rhodesia from the Northern Transvaal proved to be heavily infected with intestinal protozoa and helminths. In fact, six protozoan species, one cestode and eight nematode species were recorded. A new concept in "identification graphs" is included in the paper which allows one to read off directly the species of strongyle eggs being passed by baboons in Southern Africa based upon length and breadth measurements of the eggs. Treatment of Balantidium coli and nematode infections of baboons is discussed as is the implication of some of these intestinal parasite infections in terms of potential human infection under natural conditions.

Animals↗
PubMed2003

The cytoskeleton in nematode feeding sites.

Sedentary edoparasitic nematodes induce specialised feeding cells in plant roots. Giant cells induced by root knot nematodes and syncytia generated by cyst nematodes in plant roots are large multinucleated cells containing a dense cytoplasm. To examine the plant cytoskeleton during feeding cell development, transcriptional activity of actin and tubulin genes and organization of the actin filaments and of the microtubules were analyzed in situ. Immunolocalizations of actins and tubulins and in vivo observation of green fluorescent protein decorated actin filaments and microtubules in nematode infected root cells revealed that major rearrangements of the cytoskeleton occur during the formation of nematode induced feeding cells.

Actins↗
PubMed2001

Coordinated Muc2 and Muc3 mucin gene expression in Trichinella spiralis infection in wild-type and cytokine-deficient mice.

Mucin hypersecretion is an important component of the immune response to gastrointestinal nematode infection. Two discrete types of mucin proteins exist in the mouse intestine, secretory Muc2 and membrane-bound Muc3. We examined Muc2 and Muc3 expression in wild-type mice and mice lacking gamma interferon receptor (IFNgammaR-/-), tumor necrosis factor receptor 1 (TNFR1-/-) and interleukin 4 (IL4-/-) infected with Trichinella spiralis. Infected wild-type mice demonstrated significant goblet cell hyperplasia and increased mucin glycoprotein. In situ hybridization showed this was accompanied by increases in Muc2 and Muc3 mRNA. Total intestinal mucin protein and Muc2 and Muc3 mRNA levels were also significantly increased in cytokine-deficient mice. These data demonstrate the coordinated up-regulation of two types of mucin genes in response to T. spiralis infection and may form the basis of an innate mucosal response independent of IFN-gamma, TNF, and IL-4.

Animals↗
PubMed1997

Anthelmintics. A comparative review of their clinical pharmacology.

Virtually all the important helminth infections in humans can be treated with one of 5 anthelmintics currently in use: albendazole, mebendazole, diethylcarbamazine, ivermectin and praziquantel. These drugs are vital not only for the treatment of individual infections, but also useful in controlling transmission of the more common infections. This article reviews briefly the pharmacology of these 5 drugs, and then discusses current issues in the use of anthelmintics in the treatment and/or control of soil-transmitted nematode infections, filariasis, onchocerciasis, schistosomiasis (and other trematode infections), neurocysticercosis and hydatidosis. Mebendazole and albendazole are most effective against intestinal nematodes, but are contraindicated during the first trimester of pregnancy. The efficacy of prolonged therapy with these 2 drugs for treatment of larval cestode infections has not yet been established. Diethylcarbamazine is widely used to treat and control lymphatic filariasis, but adverse effects related to death of microfilariae or damage to adult worms may be marked. While ivermectin has been used in the treatment of patients with onchocerciasis, it is also undergoing investigation against lymphatic filariae. Praziquantel, used to treat schistosome infections, is also effective in other trematode infections and adult cestode infections.

Anthelmintics↗
PubMed2005

Systemic dissemination and persistence of Th2 and type 2 cells in response to infection with a strictly enteric nematode parasite.

Oral infection with the nematode parasite Heligmosomoides polygyrus H. polygyrus is entirely restricted to the small intestine. Although the evoked Th2 response has been extensively studied in secondary lymphoid organs, little is known about the systemic dissemination of Th2 cells or type 2 associated eosinophils and basophils. In this study we use bicistronic 4get IL-4 reporter mice to directly visualize the type 2 response to H. polygyrus infection. We observed that CD4(+)/GFP(+) Th2 cells spread systemically and found that these cells accumulated in nonlymphoid "hot spots" in the liver, the lung airways, and the peritoneal cavity. Interestingly, the total number of Th2 cells in the peritoneal cavity was comparable to those found in the draining mesenteric lymph node or the spleen. Peritoneal Th2 cells were distinguished by an exceptionally low apoptotic potential and high expression of the intestinal homing receptor alpha(4)beta(7) integrin. CD4(+)/GFP(+) Th2 cells from these peripheral sites were fully functional as indicated by rapid IL-4 production upon polyclonal or Ag-specific restimulation. Th2 cells persisted in the intestinal tissue and the peritoneal cavity of drug-cured mice for weeks. The presence of peripheral memory Th2 cells in the intestine might be crucial for immunity to recall infections. These findings have important implications for the design of vaccination strategies because it may be necessary to establish and maintain memory CD4(+) T cells at the potential future site of infection.

Animals↗