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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Research Project #441382

Research Project: Molecular, Immune and Microbiome Approaches for Mitigating GI Nematode Infections of Livestock

Location: Animal Parasitic Diseases Laboratory

Project Number: 8042-32000-116-000-D
Project Type: In-House Appropriated

Start Date: Nov 10, 2021
End Date: Nov 9, 2026

Objective 1: Characterize host immune responses and identify vaccine candidates and therapeutics that mitigate the impact of parasite infections. Sub-objective 1A: Characterize truncated infection-induced host immune responses and identify T cell-stimulating antigens as vaccine candidates. Sub-Objective 1B. Test and optimize the efficacy of an enterically coated Cry5B formulation. Objective 2: Characterize and modulate the host microbiome to enhance resilience to parasitic infections. Objective 3. Identify genetic markers that discriminate between drug susceptible and resistant strains of nematodes. Objective 4. Use molecular epidemiology to investigate the role of wild ruminants as sources of nematode infections in domestic livestock. Sub-Objective 4A. Establish sampling procedures for population genetic analyses of GI nematodes of domestic and wild ungulates. Sub-Objective 4B: Survey the biodiversity of parasites in sympatric wild and domestic ruminants of the United States. Sub-Objective 4C. Population genetic structure of multiple GI nematode species across the United States.

Identify the most effective infection and drug treatment strategies that allow for maximized in-tissue immune stimulation by killed O. ostertagi, thereby increasing protection against challenge infection. Characterize the synergy between rumen protected methionine and probiotics on growth in parasite naïve goats. Test the synergistic effect of sequential exposure of parasites to two therapeutic treatments, the conventional anthelmintic drug Cydectin and Cry5B paraprobiotics, in reducing worm burden in sheep under natural infection on pasture. At necropsy, worm burden in the entire GI tract will be determined from actual counts of worms collected from the abomasum and small intestine. Parasite species, sex, and developmental stages will be recorded. Longitudinal repeat measure fecal egg count data will be transformed using the square root, log, or other means, and then be analyzed using a mixed model (linear or non-linear) in the R nlme package. Focus on Cooperia punctata, given that resistance is well documented and we possess two strains resistant to Ivermectin (IVM) or Doramectin (DM). fecal samples will be collected from 10 cattle from four locations that are separated by at least 50 miles and 10 white-tailed deer collected within 10 miles of the sampled farms. Fecal cultures will be prepared using a modified coproculture technique and DNA extracted. We will assess the abundance of various coinfecting species using the Nemabiome technique. use non-invasive techniques to assay wild and domestic parasite species in six regions of the United States based on the concentration of cattle production, natural geographic divisions, and wild ungulate species: the six regions refer to the Southeast, Northeast, Upper, Central, and Southern Midwest, and Southwest. Sequence individuals from these collections using RADseq technology and bioinformatic tools to examine population genetic structure for as many species as we have sufficient sampling (at least 30 individuals from multiple regions), taking advantage of the samples collected for the above discussed biodiversity assay.