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At least 235 records · Page 13Linked to original sources
PubMed2006

The CC chemokine receptor 5 is important in control of parasite replication and acute cardiac inflammation following infection with Trypanosoma cruzi.

Infection of susceptible mice with the Colombiana strain of Trypanosoma cruzi results in an orchestrated expression of chemokines and chemokine receptors within the heart that coincides with parasite burden and cellular infiltration. CC chemokine receptor 5 (CCR5) is prominently expressed during both acute and chronic disease, suggesting a role in regulating leukocyte trafficking and accumulation within the heart following T. cruzi infection. To better understand the functional role of CCR5 and its ligands with regard to both host defense and/or disease, CCR5(-/-) mice were infected with T. cruzi, and the disease severity was evaluated. Infected CCR5(-/-) mice develop significantly higher levels of parasitemia (P < or = 0.05) and cardiac parasitism (P < or = 0.01) during acute infection that correlated with reduced survival. Further, we show that CCR5 is essential for directing the migration of macrophages and T cells to the heart early in acute infection with T. cruzi. In addition, data are provided demonstrating that CCR5 does not play an essential role in maintaining inflammation in the heart during chronic infection. Collectively, these studies clearly demonstrate that CCR5 contributes to the control of parasite replication and the development of a protective immune response during acute infection but does not ultimately participate in maintaining a chronic inflammatory response within the heart.

Acute Disease↗
PubMed1980

The control of parasites in antelope in small gama reserves.

The most important parasites of antelope in small game reserves are ixodid ticks, the larvae of oestrid flies and nematodes. Methods of control based on the seasonal prevalence of these parasites are suggested. Adult ticks can be controlled during summer by the introduction of cattle which are dipped or sprayed with an acaricide at 5-day intervals. The larvae of oestrid flies can be controlled by the capture during winter of all alcelaphine antelope and their oral treatment with a larvicide, while the addition of an anthelmintic to feed supplement blocks during winter can be used to control nematodes.

Animal Population Groups↗
PubMed1988

Field evaluation of an experimental albendazole pulse release bolus in the control of parasitic gastroenteritis in first-season grazing calves.

A field experiment is described which evaluates the use of an experimental albendazole pulse release bolus (E-bolus) on gastrointestinal parasitism. The bolus was administered at turnout to 9 first-season grazing calves and 9 animals were kept as controls on separate pasture. Dry summer months accounted for low infection levels in the calves; no cases of parasitic gastroenteritis were observed. The E-bolus introduced at the start of the grazing season provided moderate control of gastrointestinal parasitism. The beneficial effect of the treatment was demonstrated by lower strongyle egg counts and significant differences in ELISA extinctions for Ostertagia, Cooperia and Dictyocaulus. However pepsinogen values were elevated in the bolus-treated group, probably because of the long interval (31 days) between the pulsed treatments. Although not significant there was a trend for the bolus-treated group to gain more weight than the controls.

Albendazole↗
PubMed1987

Field evaluation of the oxfendazole pulse release bolus for the chemoprophylaxis of bovine parasitic gastroenteritis: a comparison with three other control strategies.

Three trials were conducted in southern England involving 120 autumn-born calves to evaluate the ability of an oxfendazole pulse-release intraruminal device (OPRB) to control parasitic gastroenteritis (PGE). Matched groups were set-stocked on adjacent paddocks. One group received an OPRB at turn-out; one was treated with an alternative chemoprophylactic programme; while the third acted as an untreated control. In each trial clinical PGE occurred in the latter group but not in OPRB or alternative strategy groups. The OPRB, the morantel sustained release bolus (MSRB) and fenbendazole administered at 3 and 6 weeks after turn-out gave similar weight-gain benefits when compared with untreated controls (P less than 0.01), but the growth rate of animals given regular levamisole treatments from July to housing was significantly poorer than the matching OPRB group (P less than 0.05) although better than controls. Faecal egg-output of OPRB calves was reduced by 97.0-99.9% compared with 95.5 and 58.9% for MSRB and fenbendazole treatments. Consequently, the late summer/autumn peaks in pasture larval counts were considerably reduced in all treatment groups other than the late-season levamisole strategy which reduced overall egg-output by only 37.6%. Serum pepsinogen and gastrin values confirmed a greater degree of abomasal disturbance in calves grazing on the more highly contaminated pastures. Incidental lungworm infections became clinically apparent in the control groups of two trials but not in any OPRB or alternative treatment group.

Animals↗
PubMed1986

Epidemiology and control of parasites in warm climates.

The kind of parasites a horse acquires depends upon its environment. Because patterns of transmission vary greatly with climate and management, no one worming program has universal applications. This article discusses epidemiology and control of equine parasites in the southern United States, where climates vary from warm temperate to subtropical and from humid in the southeast to arid in the southwest.

Animals↗
PubMedDate not supplied

The treatment and control of parasitic diseases.

In many parts of world, transmission of malaria due to Plasmodium falciparum can no longer be controlled by insecticides. Furthermore, this species has developed an amazing capacity for resistance to polyvalent drugs. The advent of new drugs and the possibility of developing a vaccine offer some hope for control of falciparum malaria. The fact that the spread of many parasitic diseases is promoted by contaminated water supplies resulting from inadequate waste disposal raises important questions about the relevance of current research. The control of some endemic infections, like Chagas' disease, would be better served by delivery of available technology than by improved science education. Discovery of means to promote self-help programs in rural communities will be an important aspect of research in disease control in the future.

Africa↗
PubMed1993

The role of nematophagous fungi in the biological control of nematode parasites of livestock.

The control of nematode parasites of livestock is presently based entirely on anthelmintic treatment and grazing management. On their own, these methods are not sustainable because parasites invariably develop resistance to anthelmintics and because of increasing public concern about chemical residues in livestock products and the environment. Although alternative, non-chemotherapeutic control strategies, such as vaccines and genetic selection for resistance are the focus of considerable research activity worldwide, biological control of nematode parasites has been virtually ignored. The little work that has been done is restricted largely to western Europe and involves virtually just one fungal species, namely Arthrobotrys oligospora. More recent studies indicate other known nematophagous fungal species are more efficient predators of infective larvae in sheep faeces than A. oligospora, and others have a greater capacity to survive passage through the gastrointestinal tract of ruminants. These findings plus the relatively sparse numbers of microbial competitors in the fresh faecal environment, compared with the plant rhizosphere where biological control of plant parasites is proving a particularly intractable problem, engenders optimism that the biological control of animal parasitic nematodes may become a practical reality. Such control will never be a substitute for chemotherapy, where the primary purpose is worm removal from the host, but should be incorporated together with other options into integrated pest management systems to provide sustainable nematode control of livestock into the twenty-first century.

Animals↗
PubMed1997

Sustainable helminth control of ruminants in developing countries.

Widespread anthelmintic resistance, at least amongst the important nematode parasites of small ruminants, threatens the sustainability of these livestock industries throughout both the developed and developing world. The exacerbation of this problem over the last decade or so, has provided the impetus for research into non-chemotherapeutic parasite control alternatives, such as host genetic resistance, grazing management, worm vaccines and biological control. Although some of these options provide practical benefits if currently adopted, or exciting prospects for the future, collectively they are unlikely to dispense with the need for the timely intervention of effective anthelmintic treatment. The issue of sustainability of helminth control practices therefore rests with the preservation of anthelmintic effectiveness through the implementation of principles of integrated pest management. Herein lies the difficulty-putting the principles into practice. Much of the research into sustainable nematode parasite control of ruminants has been done in the developed rather than the developing world, and the efforts to transfer this information to livestock owners has also been commensurately greater in the former. However the need for research and technology transfer is much more urgent in the developing world because of the lack of scientific and financial resources, the greater dependence on livestock industries and the much greater severity of the problem of anthelmintic resistance. This will require a major philosophical change in the affluent western world to the funding of national and international aid organisations who are largely responsible for these activities.

Animals↗
PubMed1997

The role of drugs in the control of parasitic nematode infections: must we do without?

Parasitic helminths (worms) cause serious infectious diseases in humans and domestic animals. Control of these infections relies mostly on chemotherapeutics (the anthelmintics), but resistance has developed against most of these broad-spectrum drugs in many parasite species. These resistant parasites are being used to elucidate the molecular mechanisms of drug resistance and drug action. This has led to the development of sensitive assays to detect resistant parasites, but this has not delayed the emergence of additional drug resistant parasite populations. Therefore, as development of new drugs by pharmaceutical companies is slow, we may have to be prepared for a time when broad-spectrum drugs are no longer effective, especially against worms of sheep.

Animals↗
PubMed2002

A survey of helminth control practices in equine establishments in Ireland.

We report the results of a survey to assess the attitudes of horse owners and managers of equine businesses in Ireland to the control of helminth parasites, and the extent to which veterinary practitioners are involved in providing advice on parasite control of horses. Replies to our questionnaire indicated that there is a high level of awareness on the need for helminth control, typically leading to several doses of anthelmintic being administered to each animal every year. While a majority of respondents (61%) were concerned about the issue of anthelmintic resistance, only a few were of the opinion that it was a problem on their establishment. Measures to minimise the development of resistance, such as decreasing the frequency of dosing, optimising non-drug-based control strategies and assessing the need for dosing by faecal egg counts (FECs), were not widely employed in a strategic manner. Just over half (54%) of respondents indicated that they devised worming control programmes based on veterinary advice, and a large majority did not perceive any need for modification of their current worm control programmes. We concluded that there is considerable scope for increased veterinary involvement in the design and implementation of control programmes for helminths in horses, and that veterinarians do not always provide advice in accordance with "best practice" in helminth control.

Animal Husbandry↗
PubMed2005

Development and regulation of cell-mediated immune responses to the blood stages of malaria: implications for vaccine research.

The immune response to the malaria parasite is complex and poorly understood. Although antibodies and T cells can control parasite growth in model systems, natural immunity to malaria in regions of high endemicity takes several years to develop. Variation and polymorphism of antibody target antigens are known to impede immune responses, but these factors alone cannot account for the slow acquisition of immunity. In human and animal model systems, cell-mediated responses can control parasite growth effectively, but such responses are regulated by parasite load via direct effects on dendritic cells and possibly on T and B cells as well. Furthermore, high parasite load is associated with pathology, and cell-mediated responses may also harm the host. Inflammatory cytokines have been implicated in the pathogenesis of cerebral malaria, anemia, weight loss, and respiratory distress in malaria. Immunity without pathology requires rapid parasite clearance, effective regulation of the inflammatory anti-parasite effects of cellular responses, and the eventual development of a repertoire of antibodies effective against multiple strains. Data suggest that this may be hastened by exposure to malaria antigens in low dose, leading to augmented cellular immunity and rapid parasite clearance.

Animals↗
PubMed2005

NKT cells mediate organ-specific resistance against Leishmania major infection.

Whereas the acquired T cell-mediated protection against intracellular pathogens such as Leishmania major has been well studied in the past, the cells and mechanisms involved in their innate control are still poorly understood. Here, we investigated the role of natural killer T (NKT) cells in a high dose L. major mouse infection model. In vitro, L. major only weakly stimulated NKT cells and antagonized their response to the prototypic NKT cell ligand alpha-galactosylceramide, indicating that L. major partially escapes the activation of NKT cells. NKT cell deficiency as analyzed by subcutaneous infection of Jalpha281-/- mice (lacking invariant CD1d-restricted NKT cells) and CD1-/- mice (lacking all CD1d-restricted NKT cells) led to a transient increase in skin lesions, but did not impair the clinical cure of the infection, NK cell cytotoxicity, the production of IFN-gamma, the expression of inducible nitric oxide synthase, and the control of the parasites in the lymph node. In the spleen, however, NKT cells were required for NK cell cytotoxicity and early IFN-gamma production, they lowered the parasite burden, and exerted bystander effects on Leishmania antigen-specific T cell responses, most notably after systemic infection. Thus, NKT cells fulfill organ-specific protective functions during infection with L. major, but are not essential for parasite control.

Animals↗
PubMed2002

Vaccinology for control of apicomplexan parasites: a simplified language of immune programming and its use in vaccine design.

Most mammalian immune systems and parasites have co-evolved over the millennia, interacting within a common environment and communicating through a common language. This language is comprised of copious dialects in which a variety of host innate and acquired immune pathways actively interact with a multitude of parasite-specific survival strategies. Nonetheless, a simplified language is likely present since the same basic molecular and cellular mechanisms are associated with resistance or susceptibility to parasite infection. Protective immunity against protozoa within the phylum Apicomplexa (e.g. Cryptosporidia, Eimeria, Neospora, Plasmodia and Toxoplasma) is generally CD4+ T cell-dependent and elicited along the IL-12/IFN-gamma/iNOS effector axis. This simplified language can be decoded in part by significant advances in understanding naïve T cell activation, differentiation and generation of immunologic memory. Vaccine adjuvants and new immunisation strategies for generation of more potent immunity can also be viewed through this common language lens. The aim of this paper is to summarise recently published fundamental immunology studies, their relevance through examples in specific coccidian-host immune dialects, and how this simplified language can be used for the more rationale design of parasite vaccine control strategies.

Adjuvants, Immunologic↗