To determine the role of interleukin-5 (IL-5) and eosinophils in protection against Strongyloides ratti, mice treated with anti-IL-5 monoclonal antibody (mAb) were infected with S. ratti larvae. Strongyloides ratti egg numbers in faeces (EPG) in mAb treated mice were higher than those in control mice on days 6 and 7 after inoculation. The numbers of migrating worms in mAb treated mice 36h after inoculation were higher than those observed in control mice. Intestinal worm numbers in mAb treated mice 5 days after inoculation were higher than those in control mice. These results show that eosinophils effectively protected the host against S. ratti infection by mainly the larval stage in primary infections. The involvement of eosinophils in protection against secondary infection was also examined. Before secondary infection, mice were treated with anti-IL-5 mAb and infected with S. ratti. Patent infections were not observed in either mAb treated or control Ab treated mice. The numbers of migrating worms in the head and lungs of mAb treated mice increased to 60% of that in primary infected mice. Intestinal worms were not found in mAb treated mice or in contcrol mice after oral implantation of adult worms. Eosinophils were therefore mainly involved in protection against tissue migrating worms in secondary infections.

1. Observations on faecal pellets, herbage and soil, under natural climatic conditions, indicate that the larvae of M. capillaris survive for several months. The majority of the surviving larvae remain in the faecal pellets, and do not pass on to the herbage.

2. In the laboratory, larvae survived for many weeks in dry faeces, but the longevity was less in wet faeces. They survived better at a low temperature range of 3–6°C, than at higher temperatures.

3. They exhibit a considerable degree of resistance to desiccation; some survived for a maximum of fourteen days at a relative humidity of 75%.

4. Bright sunlight rapidly kills off the larvae.

5. They can survive at temperatures below freezing point. All of the larvae were alive after three days' continuous freezing, but none were alive after being frozen for twelve days.

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°C. MAO of A. galli appeared to be thermolabile as nearly 80% of its activity was lost when the incubation temperature was increased 5° above optimum.

Parasites are often overlooked in the construction of food webs, despite their ubiquitous presence in almost every type of ecosystem. Researchers who do recognize their importance often struggle to include parasites using classical food-web theory, mainly due to the parasites' multiple hosts and life stages. A novel approach using compound-specific stable-isotope analysis promises to provide considerable insight into the energetic exchanges of parasite and host, which may solve some of the issues inherent in incorporating parasites using a classical approach. Understanding the role of parasites within food webs, and tracing the associated biomass transfers, are crucial to constructing new models that will expand our knowledge of food webs. This mini-review focuses on stable-isotope studies published in the past decade, and introduces compound-specific stable-isotope analysis as a powerful, but underutilized, newly developed tool that may answer many unresolved questions regarding the role of parasites in food webs.

The presence of Trichinella larvae was investigated in 247 samples taken from domestic, synanthropic and sylvatic animals, collected during 1996 to 2005 in 12 endemic provinces of Trichinella infection in Argentina. Muscle larvae of Trichinella from 65 infected animals were identified at the species level by single larva nested polymerase chain reaction (PCR) technique based on the variability within the expansion segment V (ESV) region of the ribosomal DNA. Trichinella infections were found in 97 of 164 pigs, 38 of 56 pork products, two domestic dogs, one domestic cat, 7 of 11 armadillos and 3 of 9 synanthropic rats. All Trichinella isolates were identified as Trichinella spiralis by nested PCR. These findings add new data on the epidemiology of trichinellosis and should be considered when implementing new strategies to control this zoonosis.

The incidence of aortic onchocerciasis was investigated by examining 167 aortas of adult cattle; of these 165 were positive for parasites and nodules.

Five young calves, aged between 3 and 6 months did not reveal any aortic infection, indicating that the infection is seen in adult animals mostly.

The affected aortas are invariably sclerosed, the degree of sclerosis being dependent on the degree of infestation; and the aortic nodules containing worms and microfilariae are seen on both sides but those on the outer wall mostly undergo degeneration and subsequent calcification while the nodules on the inner aspect permit the passage of microfilariae into the circulation.

Benzimidazole carbamates (mebendazole, albendazole and fenbendazole) are the most commonly used anthelmintic drugs for the treatment of larval toxocariasis (Toxocara canis) in paratenic hosts. However, the bioavailability of these drugs for tissues is very low due to their extremely low solubility, resulting in the administration of relatively high doses over a long period. To overcome this problem, neutral, negatively or positively charged and stabilized liposome drug carriers were examined in the chronic phase of T. canis infections in mice each orally inoculated with 1000 eggs. Moreover, liposomized albendazole and fenbendazole were co-administered with liposomized immunomodulator glucan. The highest efficacy of both drugs, evaluated 4 weeks after treatment, was recorded after their subcutaneous administration (ten doses of 25 mg kg-1) in stabilized liposomes and intramuscular co-administration of liposomized glucan (two doses of 5 mg kg-1). Fenbendazole was more effective in muscles (91.5%) whereas albendazole was more effective in the brain (92.2%). Liposomes with incorporated benzimidazole carbamate anthelmintics provide sustained drug-release reservoirs and can considerably enhance drug efficacy. Moreover, despite suppression by T. canis antigens, stimulation of the immune system by the immunomodulator glucan potentiates the effects of these antiparasitic drugs.

Among 67 French patients presenting a toxocaral infection, various demographic, environmental, clinical and laboratory parameters (blood eosinophil count, eosinophil cationic protein (ECP), serum total IgE, specific IgE against common inhalant allergens, specific IgE and IgG4 against Toxocara excretory-secretory antigens) were investigated. Correlation studies and logistic regression analyses were conducted, testing elevated levels of ECP, specific anti-Toxocara IgE or IgG4 as outcome variables An elevated ECP level was significantly associated with both cough and rhinitis, a high level of specific anti-Toxocara IgE with itchy rashes and possible atopic status, and an increase of specific anti-Toxocara IgG4 with rural residence.

An experiment on six pairs of twin lambs earned out in 1946–6 was repeated in 1946–7, comparable results being obtained in the two years. One of each pair of twins was given 10,000, 15,000 or 20,000 infective larvae of Trichostrongylus axei when one month old; and four months later all the lambs were given 40 daily doses of 4,000 infective larvae of Trichostrongylus axei. Egg counts and weight gains were recorded weekly and when they were nine months old the surviving lambs were killed and examined post-mortem. The results show that the smaller doses of larvae given to lambs one month old increased their resistance to the second infestation but that the high doses (20,000 or more) decreased the resistance. There was an intermediate dosage level at which no effect, either of increased or decreased resistance, was observed.

The results of this experiment are discussed in relation to the work of other authors on resistance in animals to superinfection with parasites. It is suggested that the resistance to parasitic gastritis developed by sheep in the field may be partly a result of the intake of small numbers of larvae early in life and that it may actually be beneficial to expose young lambs to light infestations. It is, however, dangerous to expose them to a high level of infestation at an early age and because of the difficulty of assessing the dose of larvae necessary to stimulate resistance in a particular lamb, even by artificial infestation, it is impossible to make precise practical recommendations.

Evidence has been presented showing two kinds of acidic protease activities in adult Schistosoma mansoni, Dirofilaria immitis, Angiostrongylus cantonensis and Ascaris suum. A haemoglobinolytic activity without adding any SH-containing compounds was maximal at pH 3.5, 2.5, 30 and 3.5 in S. mansoni, D. immitis, Angiostrongylus cantonensis and Ascaris suum respectively. The inhibitor studies demonstrated that this activity is ascribable to carboxyl protease(s). In the presence of dithiothreitol, activity on Azocoll (azo-dye coupled hide powder) was maximal at pH 4.6, 4.6, 3.5 and 5.6 in S. mansoni, D. immitis, Angiostrongylus cantonensis and Ascaris suum respectively. The effects of inhibitors demonstrated that this activity belongs to the thiol protease class. The intraspecific distribution of the protease activities was studied in some of the nematodes from which the organs could be anatomically separated. The distribution patterns of the haemoglobinolytic and azocollytic activities were quite different in An. cantonensis and much the same in As. suum. Based on the present results, acidic haemoglobinolytic activities reported in adult S. mansoni by other authors are thought to be due to carboxyl and thiol protease(s) respectively.

Eosinophilia in human peripheral blood is caused by different agents, including toxocariasis. The present study aimed to evaluate the prevalence of toxocariasis in hypereosinophilic individuals in the city of Ahwaz, located in south-western Iran, using enzyme-linked immunosorbent assay and Western blot techniques. Serum samples were examined from 100 individuals with peripheral blood eosinophilia and also from another 100 individuals without eosinophilia as the control group. In hypereosinophilic individuals seroprevalence antibodies against Toxocara were found in 19 (19%), of whom 12 (63.15%) were female and 7 (36.85%) were male. Positive sera were subsequently confirmed by Western blot. All of the observed bands ranged from 24 to 100 kDa. Antibodies against Toxocara were found in 1% of the control group, but were not confirmed by Western blot. The results showed significant differences between the frequency of infection within age and gender (P < 0.05); the highest prevalence of infection was observed in adults. Differences between the hypereosinophilic and healthy individuals, in terms of Toxocara infection frequency, also proved significant (P < 0.05).The present study thus confirmed the significant prevalence of toxocariasis as a hygienic problem among hypereosinophilic individuals in this area. It is, therefore, necessary to examine these individuals for toxocariasis.

Histological and gross changes in the lymphatics of cats singly or repeatedly infected with Brugia pahangi were studied chronologically over a period of 5 years. Lymphatic dilatation occurred within 2 weeks of injection and an initial acute inflammatory reaction in the lymphatic wall and lumen was followed by chronic inflammation within 4 months. In some long-term repeatedly infected cats, the lymphatics became non-functional fibrous cords and conditions of oedema and early elephantiasis, similar to those seen in early human filariasis, were produced. The main points of contention in the study of filariasis which were cluciaated in this system were: (1) that living worms cause lymphatic damage, not exacerbated by their death; (2) that lymphatic damage is not progressive after a certain peak of reaction is reached, except in repeatedly challenged animals; (3) that microfilariae do not appear to cause lymphatic damage.

Brood capsules were obtained from freshly collected cysts of equine and ovine strains of Echinococcus granulosus. Protoscoleces were freed from brood capsules either by mechanical disruption or pepsin-HCl digestion. Preparations of protoscoleces studied included: mechanically released protoscoleces without further treatment, or incubated either in HCl pH 2·0 or in evaginating solution (containing Na taurocholate) for 24 h; pepsin-HCl released protoscoleces without further treatment or incubated in evaginating solution for 24 h or 7 days. Half of each preparation of ovine protoscoleces was fixed in absolute methanol.

All fresh preparations of protoscoleces lysed rapidly when incubated in normal human serum. Studies with a fluorescein isothiocyanate (FITC) labelled sheep anti-human C3 antiserum revealed the presence of C3 on the surface of lysing protoscoleces. Antibody could not be detected on the surface of any of the preparations of fresh or methanol-fixed protoscoleces using direct or indirect fluorescent antibody tests suggesting that the classical pathway of complement activation was not involved in the lytic process. Strong evidence for lysis by the alternate pathway of complement activation was the lysis of protoscoleces which had been treated with pepsin-HCl and lysis of protoscoleces in guinea-pig serum deficient in C4 component of complement.

Faecal samples of 250 horses from farms with a known history of tapeworm infection were examined comparatively for cestode eggs using a double centrifugation/combined sedimentation–floatation technique. From each faecal sample, three 5 g and three 15 g subsamples were processed, each using either saturated NaCl solution, specific gravity (sp. g.) 1.2 [NaCl]; concentrated sugar solution, sp. g. 1.26 [sugar]; or concentrated ZnSO4 solution, sp. g. 1.3 [ZnSO4] for floatation. In total, faeces from 187 horses ( = 74.8%) tested ‘positive’ for Anoplocephala eggs. Percentages of samples testing ‘positive’ for Anoplocephala ova were: 57.2% for 5 g faeces/NaCl, 66% for 15 g faeces/NaCl, 66% for 5 g faeces/sugar, 72.8% for 15 g faeces/sugar, 55.6% for 5 g faeces/ZnSO4, and 61.2% for 15 g faeces/ZnSO4, respectively. Processing of 15 g faecal samples resulted in a significant (P < 0.05; McNemar's χ2-test) increase in the percentage of Anoplocephala egg detection compared to processing of 5 g samples for all floatation solutions. By processing 15 g faecal samples using sugar solution for floatation, 97.3% of all samples that tested ‘positive’ for Anoplocephala eggs were identified; there was no significant difference between the rate of samples that tested ‘positive’ using 15 g faeces/sugar (72.8%) and the total rate of samples that tested ‘positive’ (74.8%). Conversely, percentages of ‘positive’ samples from other test combinations were significantly (P < 0.0001, McNemar's χ2-test) lower than the total rate of samples testing ‘positive’. Processing faecal samples using sugar solution for floatation gave significantly (P < 0.05, Wilcoxon test) higher Anoplocephala egg counts than using NaCl and ZnSO4 solutions, for both 5 g and 15 g faecal samples. The double centrifugation technique using 15 g faecal samples and concentrated sugar solution for floatation appeared to offer an advantage for the detection of Anoplocephala eggs in horse faeces compared to the other test combinations.

In order to determine the prevalence of intestinal parasites among labourers from Thailand in Taiwan, the stool samples from 1364 Thai labourers were examined by the formalin-ether concentration method and 18·0% were found to be infected with one or more parasites. The infection rates of hookworm, Opisthorchis viverrini, Strongyloides stercoralis, Enterobius vermicularis, Ascaris lumbricoides, Hymenolepis nana, Capillaria philippinensis, Schistosoma japonicum, Echinostoma sp., Entamoeba coli, Giardia lamblia, and Entamoeba histolytica, were 7·6%, 7·0%, 3·2%, 0·5%, 0·3%, 0·1%, 0·1%, 0·l%,0·l%, 0·4%, 0·2%, and 0·1% respectively. The prevalence was highest among the 21–25 age group (24·8%). Among the 245 infected persons, 91% were infected with one parasite, 8% with two parasites and 1% with three parasites. The finding that parasitic infections are prevalent among Thai labourers demonstrates the need for control measures in foreign labourers in Taiwan and further studies to determine the susceptibility of O. viverrini to the snail hosts of Clonorchis sinensis.

1. A new species of Wuchereria is described, from the lymphatic systems of dogs, cats and Genet Cats (Genetta tigrina) on Pate Island off the Kenya coast. It is named W. patei after the island on which it was first discovered.

2. The new species belongs to the “W. malayi” group which are characterized in the microfilarial stage by the presence of one terminal and one sub-terminal nucleus in the tail; and in the adults by the presence of only 5 pairs of adanal papillae in the male and by the well-developed centre section in the left spicule.

The present study was based on assessments of the molluscicidal and antiparasitic activities of Solanum nigrum villosum. This plant has been collected in Tozeur's traditional oases (south-western Tunisia). Molluscicidal activities of leaves, ripe fruit and unripe fruit extracts of S. n. villosum have been assessed in experimental and semi-field conditions on uninfected Galba truncatula. Antiparasitic activities have also been assessed on larval stages (rediae, intraredial germinal masses and cercariae) of the parasite Fasciola hepatica infecting G. truncatula naturally. The unripe fruit extract (LC50 = 41.2 mg l− 1) was more toxic than the leaf (LC50 = 132.5 mg l− 1) and the ripe fruit (LC50 = 172.8 mg l− 1) extracts on the snail after 48 h of treatment. One mg l− 1 of cupric chloride produced the death of 97% of G. truncatula after 25 days of treatment. Solanum n. villosum extracts used at the lethal laboratory concentration in semi-field conditions were also toxic to G. truncatula. The unripe fruit extract was more toxic than the leaf and the ripe fruit extracts on larval stages of F. hepatica. Maximum deterioration rates were obtained with the unripe fruit extract: 65.6% for rediae, 77.8% for cercariae and 27.6% for intraredial germinal masses after 48 h of treating the snails. The possibility of the unripe fruit extract application for the control of G. truncatula and F. hepatica larval stages should be considered.

The validity and reliability of haematuria when used as screening criteria in community diagnosis of urinary schistosomiasis is presented. Between May and July, 1998, 1173 persons were screened for haematuria and examined for the presence of eggs of Schistosoma haematobium in their urine from all participating households in the Ozitem area of Bende Local Government Area, Abia State, Nigeria. Haematuria showed a sensitivity rate of 41.0% and specificity of 82.0% when used to identify cases of urinary schistosomiasis. Some factors that influenced the validity of haematuria as a diagnostic criterion are discussed. The use of haematuria amongst subjects in the first twenty years of their life is recommended.

The nematode has been known as a serious parasite of potatoes for a number of years. The disease produced by it was first described in Germany by Kühn (1888) under the name of Wurmfäule. Shortly after this Ritzema Bos (1892) confirmed and amplified Kühn's account and carried out an experimental investigation on the disease. The present writer Goodey (1923) gave a short résumé of this earlier work and an account of the occurrence of the disease on potatoes in the Holbeach area of Lincolnshire. Buckhurst (1925) also reported the results of certain successful pot experiments in which potatoes were infected by growing in soil containing diseased tuber material. Finally, an important paper by Quanjer (1927) has appeared in which he deals with the occurrence of the disease on potatoes at Wageningen, Holland, and shows that the physiological race of worms attacking potatoes there occurs naturally on certain wild plants in the pastures and is capable of attacking a wide range of host plants both cultivated and wild. He also discusses the mode of entry of the parasite into the host and the nature of its action on the plant tissues.

During the past decade, parasites have been considered important components of their ecosystems since they can modify food-web structures and functioning. One constraint to the inclusion of parasites in food-web models is the scarcity of available information on their feeding habits and host–parasite relationships. The stable isotope approach is suggested as a useful methodology to determine the trophic position and feeding habits of parasites. However, the isotopic approach is limited by the lack of information on the isotopic discrimination (ID) values of parasites, which is pivotal to avoiding the biased interpretation of isotopic results. In the present study we aimed to provide the first ID values of δ15N and δ13C between the gyrocotylidean tapeworm Gyrocotyle urna and its definitive host, the holocephalan Chimaera monstrosa. We also test the effect of host body size (body length and body mass) and sex of the host on the ID values. Finally, we illustrate how the trophic relationships of the fish host C. monstrosa and the tapeworm G. urna could vary relative to ID values. Similar to other studies with parasites, the ID values of the parasite–host system were negative for both isotopic values of N (Δδ15N = − 3.33 ± 0.63‰) and C (Δδ13C = − 1.32 ± 0.65‰), independent of the sex and size of the host. By comparing the specific ID obtained here with ID from other studies, we illustrate the importance of using specific ID in parasite–host systems to avoid potential errors in the interpretation of the results when surrogate values from similar systems or organisms are used.