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At least 1,261 records · Page 70Linked to original sources
PubMed2002

The efficacy of formulations of triclabendazole and ivermectin in combination against liver fluke (Fasciola hepatica) and gastro-intestinal nematodes in cattle and sheep and sucking lice species in cattle.

OBJECTIVE: To assess the efficacy of two formulations of triclabendazole and ivermectin in combination against liver fluke (Fasciola hepatica), gastro-intestinal nematodes and sucking louse species in cattle and sheep. PROCEDURE: A study of 540 cattle and 428 sheep at 18 sites throughout Victoria and New South Wales was undertaken. At each site, one group of cattle or sheep was treated with a combined formulation (Fasimec Cattle or Fasimec Sheep), another received ivermectin and triclabendazole separately. In trials on lice infestation, an additional group remained untreated. Samples for faecal egg counts were collected on days -7, 0 (treatment day), +7, +14 and +21 after treatment. Lice assessments were carried out on days -7, 0, +7, +14, +28, +42 and +56. RESULTS: Both treatments were highly efficacious (> 98% efficacy) against liver fluke in cattle and sheep, against three sucking lice species of cattle and against gastro-intestinal nematodes in sheep. There was also no significant difference between treatments in efficacy. Against gastro-intestinal nematodes, Fasimec Cattle was significantly (P < 0.01) more effective than the separately applied ivermectin and triclabendazole treatment. Mean efficacy for the Fasimec Cattle and Ivomec/Fasinex 120 groups respectively, was 97.6% and 94.2% on Day +7, 98.9% and 91% on Day +14 and 98.5% and 92.6% on Day +21. CONCLUSION: The efficacy of Fasimec' Cattle and Fasimec Sheep was at least equal to that of currently registered products (with the same active ingredients) used to control these parasites.

Administration, Oral↗
PubMed1992

Efficacy of dapsone with pyrimethamine (Maloprim) for malaria prophylaxis in Maputo, Mozambique.

In a randomized controlled study of malaria prophylaxis, dapsone-pyrimethamine at a weekly dosage of dapsone 50-100 mg with pyrimethamine 6.25-12.5 mg or placebo was administered to 166 school children for 17 weeks. Fortnightly parasitological controls revealed 28 infections in the placebo group and none in the dapsone-pyrimethamine group. It is concluded that weekly dapsone-pyrimethamine is effective for the prophylaxis of falciparum malaria in Mozambique.

Child↗
PubMed2005

[Post-transfusion parasite transmission: do the present controls fit with the EU directive?].

Blood transfusion has become extremely safe regarding the transmission of infectious pathogens, some of them having been responsible for mostly severe complications and a certain loss of confidence from practitioners and patients over the last decades. This may result from the strict observance of ethical principles, of a better medical selection of donors, of technical steps for preparing and qualifying blood components for therapeutic use. The transfusion systems--which vary in their constitution and missions depending on the countries or even regions--have imposed themselves strict security rules and guidelines in industrialized countries. Further, governmental sanitary authorities have set up additional surveillance systems to make the transfusion systems the safest as possible. In addition, the Council of Europe has edicted directives to redefine guidelines to the preparation, use and quality assurance of blood products, that are mandatory in countries of the European Community. Regarding the infectious risks, most recommendations have focused more on the bacterial (immediate) and the viral (mostly delayed) risks than on the parasitic risks because these risks are not only less frequent in industrialized countries, but also far less well known and even much more complex. However, because travel habits and immigrations are increasing fast, most transfusion systems or blood banks must revisit their practices and controls towards hemoparasite transmission by blood transfusion. This review aims at discussing the present controls set up in most industrialized countries and particularly in Europe regarding the risk of post-transfusion transmission of hemoparasites, and the robustness of such controls as well as how these controls may be secured by the European Directive.

Bacterial Infections↗
PubMed2001

Rapidly fatal leishmaniasis in resistant C57BL/6 mice lacking TNF.

The resolution of infections with the protozoan parasite Leishmania major in mice requires a Th1 response that is closely associated with the expression of IL-12, IFN-gamma, and inducible NO synthase. Previous Ab neutralization studies or the use of mice deficient for both TNF receptors suggested that TNF plays only a limited role in the control of parasite replication in vivo. In this study we demonstrate that resistant C57BL/6 (B6.WT) mice locally infected with L. major rapidly succumb to progressive visceral leishmaniasis after deletion of the TNF gene by homologous recombination. A reduction of the parasite inoculum to 3000 promastigotes did not prevent the fatal outcome of the disease. An influence of the altered morphology of secondary lymphoid organs in C57BL/6-TNF(-/-) (B6.TNF(-/-)) mice on the course of disease could be excluded by the generation of reciprocal bone marrow chimeras. Although infected B6.TNF(-/-) mice mounted an L. major-specific IFN-gamma response and expressed IL-12, the onset of the immune reaction was delayed. After in vitro stimulation, B6.TNF(-/-) inflammatory macrophages released 10-fold less NO in response to IFN-gamma than B6.WT cells. However, in the presence of a costimulus, e.g., L. major infection or LPS, the production of NO by B6.WT and B6.TNF(-/-) macrophages was comparable. In vivo, inducible NO synthase protein was readily detectable in skin lesions and draining lymph nodes of B6.TNF(-/-) mice, but its expression was more disperse and less focal in the absence of TNF. These are the first data to demonstrate that TNF is essential for the in vivo control of L. major.

Animals↗
PubMed2006

[Apoptosis and programmed cell death. Host parasite relationship new paradigm].

Apoptosis and programmed cell death are amongst the most fascinating new concepts for understanding the host-parasite relationship. A growing body data is raising questions about the impact of the death of an individual parasite on the survival of the parasite population as a whole. Does the parasite induce the death of the host cell as an expression of virulence or does it inhibit that death as a factor for transmissibility? Current evidence that these effects are mediated through specific highly regulated mechanisms suggest that deciphering programmed cell death could provide new tools for control of parasitic diseases.

Animals↗
PubMedDate not supplied

The potential of ivermectin to control the malaria vector Anopheles farauti.

We investigated mortality in Anopheles farauti mosquitoes, a major coastal malaria vector in the south-west Pacific, fed on a volunteer who had taken a 250 micrograms/kg dose of ivermectin. High mortality was recorded in mosquitoes feeding during the first week after treatment of the volunteer, for instance 100-80% failed to survive 3 days. A long-term residual effect of ivermectin in the blood was indicated by a small but significantly higher mortality in mosquitoes fed 6 weeks after ivermectin was taken. These effects were included in malaria transmission models that incorporated host choice and host-induced mortality parameters. For the zoophilic An. farauti, ivermectin treatment of animals resulted in a greater reduction in malaria than ivermectin treatment of humans alone, whereas for an anthropophilic vector, treatment of humans was more important. This suggests that ivermectin treatment of animals could have an important role in malaria control where An. farauti is the vector. Improvement in the health of humans and domestic animals through control of parasitic worms and mites might encourage community participation in strategies involving ivermectin.

Animals↗
PubMed2002

Toxoplasma gondii microneme secretion involves intracellular Ca(2+) release from inositol 1,4,5-triphosphate (IP(3))/ryanodine-sensitive stores.

Calcium-mediated microneme secretion in Toxoplasma gondii is stimulated by contact with host cells, resulting in the discharge of adhesins that mediate attachment. The intracellular source of calcium and the signaling pathway(s) triggering release have not been characterized, prompting our search for mediators of calcium signaling and microneme secretion in T. gondii. We identified two stimuli of microneme secretion, ryanodine and caffeine, which enhanced release of calcium from parasite intracellular stores. Ethanol, a previously characterized trigger of microneme secretion, stimulated an increase in parasite inositol 1,4,5-triphosphate, implying that this second messenger may mediate intracellular calcium release. Consistent with this observation, xestospongin C, an inositol 1,4,5-triphosphate receptor antagonist, inhibited microneme secretion and blocked parasite attachment and invasion of host cells. Collectively, these results suggest that T. gondii possess an intracellular calcium release channel with properties of the inositol 1,4,5-triphosphate/ryanodine receptor superfamily. Intracellular calcium channels, previously studied almost exclusively in multicellular animals, appear to also be critical to the control of parasite calcium during the initial steps of host cell entry.

Animals↗
PubMed2004

Depletion of natural killer cells does not result in neurologic disease due to Sarcocystis neurona in mice with severe combined immunodeficiency.

Sarcocystis neurona is an apicomplexan parasite that is the primary etiologic agent of equine protozoal myeloencephalitis in horses. Protective immune responses in horses have not been determined, but interferon-gamma (IFN-gamma) is considered critical for protection from neurologic disease in mice. The role of adaptive and innate immune responses in control of parasites was explored by infecting BALB/c, IFN-gamma knockout (GKO), and severe combined immune deficient (SCID) mice with S. neurona (10(4) sporocysts/mouse). Immune competent BALB/c mice eliminated parasites within 30 days, with no sign of neurologic disease, whereas GKO mice developed fulminant neurologic disease. In contrast, SCID mice remained healthy throughout the experimental period despite the persistence of parasite at low levels in some mice. Treatment with anti-IFN-gamma antibody resulted in neurologic disease in infected SCID mice. Although SCID mice lack adaptive immune responses, they have natural killer (NK) cells capable of producing significant quantities of IFN-gamma. Therefore, SCID mice were infected with sporocysts of S. neurona and treated with anti-asialo GM1. Depletion of NK cells, confirmed by flow cytometry, did not result in neurologic disease in SCID mice. These results indicate that IFN-gamma mediates protection from neurologic disease in SCID mice. Protective levels of IFN-gamma may originate from a low number of nondepleted NK cells or from a non-T cell, non-NK cell population.

Animals↗
PubMed2000

Randomised trial of alternative malaria chemoprophylaxis strategies among pregnant women in Kigoma, Tanzania: I. Rationale and design.

OBJECTIVE: The objective of the study was to assess the effectiveness of alternative strategies of malaria chemoprophylaxis on the reduction of malaria episodes and prevalence of parasitaemia among pregnant women in Kigoma urban district in western Tanzania. DESIGN: Randomised antimalarial prophylactic trial. SETTING: The study was conducted in an urban maternal and child health (MCH) clinic in Kigoma town. SUBJECTS: All pregnant women attending antenatal care services at Kigoma urban MCH clinic were eligible. Informed consent was sought from each pregnant woman for participation in the study. INTERVENTION MEASURES: The intervention measures were intermittent and continuous malaria chemoprophylaxis using chloroquine and proguanil. MAIN OUTCOME MEASURES: Reduction of malaria episodes and parasitaemia and haemoglobin levels among participating pregnant women in Kigoma urban district. RESULTS: Baseline data indicates that the overall mean haemoglobin concentrations among the primigravidae and multigravidae women were similar within the intervention and comparison groups (F-test (df = 5, N = 701) = 1.27, P = 0.27). Similarly, no significant difference was observed in the prevalence of malaria parasitaemia within the primigravidae intervention and comparison groups (chi 2 test (df = 5, N = 701) = 5.4, P = 0.4). Hence, the process of randomisation produced comparable intervention and comparison groups with balanced characteristics. Specific results of the baseline studies are presented in the companion paper. CONCLUSION: We conclude that the process of randomisation resulted in comparable intervention and comparison groups. As malaria is a common cause of considerable morbidity and mortality among pregnant women in Tanzania, the present study provided useful data for improving reproductive health in Kigoma region, western Tanzania.

Adolescent↗
PubMed1980

Increased weight gains of Wisconsin dairy heifers following systematic deworming with fenbendazole.

Average daily weight gains (ADG) were compared among 26 dairy heifers on 11 farms. Half of the heifers were treated with fenbendazole (5 mg/kg) at 30- or 60-day intervals. Treatment every 60 days did not effectively control subclinical nematode parasitism, but did increase ADG by 0.05 kg, P less than 0.05. Treatment every days effectively controlled tha parasitisms and significantly improved ADG by 0.09 kg, P less than 0.01. Repeated treatment increased rate of gain on 10 of 11 farms. Cooperia, Ostertagia, and Nematodirus were the predominant genera found parasitizing the heifers. On several farms, the pattern of infection indicated that overwintering larvae were a source of infection.

Animals↗
PubMed2006

Efficacy of eprinomectin pour-on in naturally Oestrus ovis infested merino sheep in Extremadura, South-West Spain.

The aim of this study is to evaluate the efficacy of the eprinomectin pour-on in naturally Oestrus ovis-infested sheep. To carry out this trial, 14 naturally infected sheep from the same flock were used. The animals were randomly distributed in three groups: group 1 (non-treated sheep), group 2 treated with 0.5 mg/kg bodyweight and group 3 treated with 1 mg/kg bodyweight of eprinomectin. The sheep were slaughtered 15 days after treatment and their heads were sectioned to count and identify larvae instar. The following results were obtained: Group 1: the average was 34 live and 0.75 dead larvae per sheep. Group 2: the efficacy of the eprinomectin was 83.5% against O. ovis group 3: the efficacy of the eprinomectin pour-on was 100%. Drug analysis was made to determine plasma eprinomectin concentration 9 days after treatment and the average concentrations in groups 2 and 3 were 1.23 and 3.04 ng/ml, respectively. The statistical study showed a significant difference between the efficacy and the dose used, and there was correlation between the plasma concentration of eprinomectin and the dose. The efficacy and easy application allow us to take into account this endectocide as an alternative method in the integral control of parasites in sheep.

Animals↗
PubMed1992

Sex-related susceptibility of bulls to gastrointestinal parasites.

The effects of sex and anabolic implants on fecal egg counts and pasture contamination were examined in 77 naturally infected yearling bulls, steers, and heifers of mixed beef breeds grazing the same contaminated pasture in southern Ohio in the spring of 1990. Fecal egg counts were compared in seven groups of 10-14 animals each, twice before anabolic implants and twice after implants. Comparisons were made between untreated bulls, steers, and heifers, between steers with and without implants, and between heifers with and without implants. Bulls had significantly (P < 0.01) higher fecal egg counts than steers, and counts from steers were not significantly different to those from heifers. There were no significant differences between counts from implanted and control steers or heifers. The results have important practical implications both for parasite control and for bovine parasite research. There is a need to pay special attention to young bulls when designing parasite control programs, and to distribute the sexes equally between groups when doing research trials with cattle of mixed sexes. Some previous studies on worm population dynamics and anthelmintic evaluation may need to be re-examined in the light of sex differences.

Anabolic Agents↗
PubMed2000

Vaccination against cysticercosis and hydatid disease.

Infections with the larval stages of taeniid cestode parasites cause substantial human morbidity as well as economic losses in domestic livestock species. Despite ongoing efforts around the world, few countries have been able substantially to reduce or eradicate these infections through the use of anthelmintics and lifestyle changes. Vaccines offer an additional potential tool to assist with the control of parasite transmission. Here, Marshall Lightowlers and colleagues review the substantial progress that has been made towards developing practical vaccines against hydatid disease in sheep and cysticercosis in sheep and cattle. Recombinant antigens have been used to induce more than 90% protection against challenge infections. Such success in animals encourages investigation of the potential use of vaccines in humans to prevent hydatid disease arising from infection with Echinococcus granulosus and cysticercosis from infection with Taenia solium.

Amino Acid Sequence↗
PubMed1992

Risk of contamination of human and agricultural environment with parasites through reuse of treated municipal wastewater in Riyadh, Saudi Arabia.

Two selected sites in the Riyadh metropolitan area were surveyed for the presence of human pathogenic parasites in treated municipal wastewater (TMWW). A total of 100 samples were collected from both sites at two different seasons, the winter and summer reason. The most common parasites seen were the larvae and adult of Strongyloides sp. There were few Ascaris lumbricoides ova, some of which were embryonated and possibly infective, while the highest frequency of Ascaris ova (100 +/litre) was found at site 2 h, the highest frequency of Strongyloides sp. larvae (36-72/litre) and Strongyloides sp. adult (100 +/litre) were found at sites 2 W and 1 W respectively. The variation between sites and seasonal fluctuations showed a significant difference in parasite per litre. High atmospheric temperatures in the Riyadh area seem to be lethal to most intestinal pathogens similarly the absence of protozoal cysts in the TMWW could be attributed to certain treatment processes and other environmental factors. Data obtained from this study will be valuable in planning for the control of parasitic diseases in particular and public health pathogens in general.

Animals↗
PubMed1980

[Studies of the Pedix Pe 50 excretion dynamics in milk].

Reported in this paper are studies which had been conducted in to excretion through the milk of butonate, trichlorophone, DDVP, and vinylbutonate, following Pedix PE 50 treatment of lactating cattle. Pedix PE 50 with butonate as its active principle, is going to be used on lactating cattle for the control of parasites, after it had been applied with good success to other animal species. The amounts of organophosphorus insecticide detectable in the above experiments and related to one kilogram of milk were 0.079 mg in the first milked portion, 0.03 mg in the second, and 0.02 mg in the third. Hence, control of the first two milked portions appears to meet all demands emanating in terms of food hygiene, toxicology, and economy, provided that in applying Pedix PE 50 to lactating cattle due consideration is given to the concentration specified in the manufacturers' instructions for use as well as to the necessary time interval between treatment and first milking.

Animals↗
PubMed1996

Cutaneous leishmaniasis: a model for analysis of the immunoregulation by accessory cells.

In the mammalian host, Leishmania are obligate intracellular parasites and invade macrophages and Langerhans cells. The accessory functions of both types of host cells are important for regulation of the specific cellular immune response and involve the following activities: infiltration into the site of infection, initiation of a T cell response, maintenance of immunity and the effector mechanisms that control intracellular parasite replication.

Animals↗
PubMed2001

Topographic specificity of Diplozoon paradoxum nordmann, 1832 (Monogenea: Diplozoidae) in the bream, Abramis brama (Linnaeus, 1758) in the Vistula Lagoon, Poland.

Location of the monogenean Diplozoon paradoxum on the branchial arches of the Vistula Lagoon bream is described. The highest number of parasites was found on the first gill arch, followed by the numbers recordedon the second and third arches; the lowest numbers of the monogenean were typical of the fourtharch. About 70% of the monogeneas were found to dwell on the dorsal part of the branchial arch. It is concluded that the distribution of parasites is controlled by the direction of water flow through the gills as well as the size of the gill arch occupied by the helminths.

Animals↗
PubMed1993

Thrombospondin related anonymous protein (TRAP) of Plasmodium falciparum in parasite-host cell interactions.

Thrombospondin related anonymous protein (TRAP) of Plasmodium falciparum is characterized by the presence of an amino acid motif based on the sequence Trp-Ser-Pro-Cys-Ser-Val-Thr-Cys-Gly (WSPCSVTCG) that is found in a growing family of proteins. The sequence WSPCSVTCG is considered to confer sulpho-galactosyl-cerebroside (sulphatide) binding properties to antistasin, TSP, CS protein and properdin. The observation that TRAP is localized both on the micronemes and on the surface of P. falciparum sporozoites would suggest a role played by TRAP, and its putative sulphated glycoconjugates binding motif, in the recognition and/or entry of hepatocytes by the sporozoite. Our results indicated that TRAP constructs, expressed in E. coli, bind to sulpho-galactosyl-cerebrosides (sulphatides) and to the surface of HepG2 cells using the conserved amino acid motif WSPCSVTCG. Antisera raised against TRAP constructs inhibited sporozoite invasion of HepG2 cells thus suggesting, thus, that TRAP may be one of the parasite-encoded molecules implicated in the sporozoite invasion of hepatocytes. Moreover, the possibility that TRAP antibodies may be relevant in malaria immunity is supported by the results obtained in a prospective study conducted in a malaria endemic area. In adolescents, the presence of TRAP antibodies, before malaria transmission, correlated positively with the control of parasite density.

Adolescent↗