The detection of anthelmintic resistance in nematodes of veterinary importance.

Direct anthelmintic effects of condensed tannins towards different gastrointestinal nematodes of sheep: in vitro and in vivo studies

Summary: Infection of humans with the nematode worm parasite Anisakis simplex was first described in the 1960s in association with the consumption of raw or undercooked fish During the 1990s it was realized that even the ingestion of dead worms in food fish can cause severe hypersensitivity reactions, that these may be more prevalent than infection itself, and that this outcome could be associated with food preparations previously considered safe Not only may allergic symptoms arise from infection by the parasites (“gastroallergic anisakiasis”), but true anaphylactic reactions can also occur following exposure to allergens from dead worms by food-borne, airborne, or skin contact routes This review discusses A simplex pathogenesis in humans, covering immune hypersensitivity reactions both in the context of a living infection and in terms of exposure to its allergens by other routes Over the last 20 years, several studies have concentrated on A simplex antigen characterization and innate as well as adaptive immune response to this parasite Molecular characterization of Anisakis allergens and isolation of their encoding cDNAs is now an active field of research that should provide improved diagnostic tools in addition to tools with which to enhance our understanding of pathogenesis and controversial aspects of A simplex allergy We also discuss the potential relevance of parasite products such as allergens, proteinases, and proteinase inhibitors and the activation of basophils, eosinophils, and mast cells in the induction of A simplex-related immune hypersensitivity states induced by exposure to the parasite, dead or alive

Anisakis simplex: from Obscure Infectious Worm to Inducer of Immune Hypersensitivity

Anthelmintic resistance in human and animal pathogenic helminths has been spreading in prevalence and severity to a point where multidrug resistance against the three major classes of anthelmintics--the benzimidazoles, imidazothiazoles and macrocyclic lactones--has become a global phenomenon in gastrointestinal nematodes of farm animals. Hence, there is an urgent need for an anthelmintic with a new mode of action. Here we report the discovery of the amino-acetonitrile derivatives (AADs) as a new chemical class of synthetic anthelmintics and describe the development of drug candidates that are efficacious against various species of livestock-pathogenic nematodes. These drug candidates seem to have a novel mode of action involving a unique, nematode-specific clade of acetylcholine receptor subunits. The AADs are well tolerated and of low toxicity to mammals, and overcome existing resistances to the currently available anthelmintics.

http://jpkc.fudan.edu.cn/picture/article/84/6b37ad7f-5a34-40fe-9608-573fbaae51e0/926caa05-ccd1-4f93-815b-ab47a8a17456.pdf

A new class of anthelmintics effective against drug-resistant nematodes

Anthelmintic resistance now poses problems to sheep farmers throughout the world. In some Southern hemisphere countries multiple resistance has reached levels which make sheep farming non-sustainable. Evidence from studies in the UK and Europe suggests (a) that the selection process occurs over a longer time frame than in Southern tropical/temperate regions and (b) that for some of the key ovine species little or no reversion to susceptibility may occur for many years after the withdrawal of the selecting agent. The dynamics of the selection process are influenced by a number of host, parasite, drug, management and environment-dependent factors. Recent mechanistic studies on resistance against avermectins and milbemycins (AM) suggest that there may be a number of mechanisms associated with resistance at the different target sites for these drugs. Within Europe endectocides within the AM drug group have now become the crucial element in strategies aimed at controlling important diseases such as sheep scab and nematodoses. Given that there is little likelihood of a series of novel action compounds emerging in the immediate future to replace this family the conservation of efficacy of the AM group should be accorded the highest priority for research in this area.

The development of anthelmintic resistance in sheep nematodes.

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) second edition of guidelines for evaluating the efficacy of anthelmintics in ruminants (bovine, ovine, caprine).

T. Kassai

Papers

World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) second edition of guidelines for evaluating the efficacy of anthelmintics in ruminants (bovine, ovine, caprine).

Standardized nomenclature of animal parasitic diseases (SNOAPAD)

Is there a relationship between haemoglobin genotype and the innate resistance to experimental Haemonchus contortus infection in Merino lambs

WAAVP second edition of guidelines for evaluating the efficacy of anthelmintics in ruminants ( bovine and ovine)