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Parasite Control (parasite + control)

Distribution by Scientific Domains

Medical Sciences	66%
Life Sciences	33%

Selected Abstracts

An evidence-based approach to equine parasite control: It ain't the 60s anymore

EQUINE VETERINARY EDUCATION, Issue 6 2010
R. M. Kaplan
Summary Most veterinarians continue to recommend anthelmintic treatment programmes for horses that derive from knowledge and concepts more than 40 years old. However, much has changed since these recommendations were first introduced and current approaches routinely fail to provide optimal or even adequate levels of parasite control. There are many reasons for this. Recent studies demonstrate that anthelmintic resistance in equine parasites is highly prevalent and multiple-drug resistance is common in some countries, but few veterinarians take this into account when making treatment decisions or when recommending rotation of anthelmintics. Furthermore, the current approach of treating all horses at frequent intervals was designed specifically to control the highly pathogenic large strongyle, Strongylus vulgaris. But this parasite is now quite uncommon in managed horses in most of the world. Presently, the cyathostomins (small strongyles) are the principal parasitic pathogens of mature horses. The biology and pathogenesis of cyathostomins and S. vulgaris are very different and therefore require an entirely different approach. Furthermore, it is known that parasites are highly over-dispersed in hosts, such that a small percentage of hosts harbour most of the parasites. The common practices of recommending the same treatment programme for all horses despite great differences in parasite burdens, recommending prophylactic treatment of all horses without indication of parasitic disease or knowing what species of parasites are infecting the horses, recommending use of drugs without knowledge of their efficacy and failing to perform diagnostic (faecal egg count) surveillance for estimating parasite burdens and determining treatment efficacy, are all incompatible with current standards of veterinary practice. Consequently, it is necessary that attitudes and approaches to parasite control in horses undergo a complete overhaul. This is best achieved by following an evidence-based approach that takes into account all of these issues and is based on science, not tradition. [source]

Transmission dynamics of lymphatic filariasis: vector-specific density dependence in the development of Wuchereria bancrofti infective larvae in mosquitoes

MEDICAL AND VETERINARY ENTOMOLOGY, Issue 3 2006
L. C. SNOW
Abstract The principles of meta-analysis developed in a previous study were extended to investigate the process of Wuchereria bancrofti (Cobbold) (Filarioidea: Onchocercidae) infection in mosquito (Diptera: Culicidae) hosts, focusing specifically on the functional forms and strength of density dependence in the development of ingested microfilariae (mf) to infective (third instar) larvae (L3). Mathematical models describing observed mf,L3 functional responses for each of the major three parasite-transmitting vector genera, Aedes, Culex and Anopheles mosquitoes, were fitted to paired mf,L3 data collated from all available studies in the published literature. Model parameters were estimated and compared by deriving and applying a data synthetic framework, based on applying a non-linear weighted regression model for fitting mathematical models to multistudy data. The results confirm previous findings of the existence of significant between-genera differences in the mf,L3 development relationship, particularly with regard to the occurrence of limitation in Culex mosquitoes and facilitation in Aedes and Anopheles mosquitoes. New and unexpected findings regarding L3 development from ingested mf were discovered as follows: (1) for Culex, overcompensation in L3 development at higher intensities of mf (or a peaked mf,L3 functional response) was detected; (2) for Aedes mosquitoes, facilitation (with an apparent asymptotic constraint on L3 development at high mf densities) was shown to be the major process governing L3 development, and (3) for Anopheles, a stronger facilitation type of response with no apparent saturation in L3 development appears to govern L3 output from ingested mf. These results yield major new insights regarding filarial vector infection dynamics and their potential impacts on parasite control, and demonstrate the efficacy of employing a data synthetic approach to reveal and estimate parasitic infection processes in host populations. [source]

The immunology of susceptibility and resistance to scabies

PARASITE IMMUNOLOGY, Issue 8 2010
S. F. WALTON
Summary The transmission of scabies occurs with the burrowing of Sarcoptes scabiei var. hominis mites into the skin. Infestation invariably leads to the development of localized cutaneous inflammation, pruritis and skin lesions. Classical transmission studies document an initial increase in S. scabiei numbers subsequent to primary infestation with a gradual reduction as host immunity develops. However, certain individuals fail to control infection and develop severe crusting of the skin, accompanied with extremely high mite burdens, elevated antibody levels and eosinophilia. These individuals have the nonhealing form of the human disease known as crusted scabies. The genetic predisposition for susceptibility or resistance to S. scabiei infection in humans is hypothesized to correlate with the dominance of an IgE-driven Th2 response in severe disease or an interferon-,-dominated Th1 response that promotes parasite control. However, recent data reveals complexities in cytokine regulation in the skin and the mechanisms of acquired resistance and immune escape. In this review, we consider the recent immunological and biomolecular advances in understanding the human host immune response to S. scabiei infestations in the context of earlier studies and attempt to reconcile apparent differences and emphasize those aspects of the Th1/Th2 model that are supported or refined. [source]

Manipulating host immunity to improve nematode parasite control ,Quo vadit

PARASITE IMMUNOLOGY, Issue 2 2008
A. R. SYKES
First page of article [source]

Genome Sequencing and Comparative Genomics of Tropical Disease Pathogens

CELLULAR MICROBIOLOGY, Issue 12 2003
Jane M. Carlton
Summary The sequencing of eukaryotic genomes has lagged behind sequencing of organisms in the other domains of life, archae and bacteria, primarily due to their greater size and complexity. With recent advances in ,high-throughput ,technologies ,such ,as ,robotics and improved computational resources, the number of eukaryotic genome sequencing projects has in-creased significantly. Among these are a number of sequencing projects of tropical pathogens of medical and veterinary importance, many of which are responsible for causing widespread morbidity and mortality in peoples of developing countries. Uncovering the complete gene complement of these organisms is proving to be of immense value in the develop-ment of novel methods of parasite control, such as antiparasitic drugs and vaccines, as well as the development of new diagnostic tools. Combining pathogen genome sequences with the host and vector genome sequences is promising to be a robust method for the identification of host,pathogen interactions. Finally, comparative sequencing of related species, especially of organisms used as model systems in the study of the disease, is beginning to realize its potential in the identification of genes, and the evolutionary forces that shape the genes, that are involved in evasion of the host immune response. [source]