The use of nemabiome metabarcoding to explore gastro-intestinal nematode species diversity and anthelmintic treatment effectiveness in beef calves.

Next-generation deep amplicon sequencing, or metabarcoding, has revolutionized the study of microbial communities in humans, animals and the environment. However, such approaches have yet to be applied to parasitic helminth communities. We recently described the first example of such a method - nemabiome sequencing - based on deep-amplicon sequencing of internal transcribed spacer 2 (ITS-2) rDNA, and validated its ability to quantitatively assess the species composition of cattle gastro-intestinal nematode (GIN) communities.

Exploring the Gastrointestinal "Nemabiome": Deep Amplicon Sequencing to Quantify the Species Composition of Parasitic Nematode Communities.

Parasitic helminth infections have a considerable impact on global human health as well as animal welfare and production. Although co-infection with multiple parasite species within a host is common, there is a dearth of tools with which to study the composition of these complex parasite communities. Helminth species vary in their pathogenicity, epidemiology and drug sensitivity and the interactions that occur between co-infecting species and their hosts are poorly understood.

Current Status of Parasite Control at the Feed Yard.

Fly and louse infestations are readily discerned and remedied in feedlot cattle. Tapeworm and fluke infections are accepted as probable but, given the lack of anthelmintics with realistic efficacy against these infections, these helminths are allowed to persist without treatment. Nematode infections are considered ubiquitous with cattle coming from pasture and are targeted with a macrocyclic lactone, usually in combination with a benzimidazole.

A sampling of factors relative to the epidemiology of gastrointestinal nematode parasites of cattle in the United States.

Gastrointestinal nematodosis of cattle is a parasitic condition resulting from an immense and seemingly forever-expanding array of factors. Countless determinants influence the incidence and severity of the species-specific infections that occur in cattle, determinants that affect the free-living or environmental stages of the parasites and the parasitic stages. The vast majority of animals have a subclinical or economic level of parasitism undetectable to the eye but quantified more accurately by treatment-induced improved performance (e.