Nematode Parasite Resistance in Small Ruminants

Gastrointestinal nematodes represent a pervasive challenge to sheep and goat production worldwide, with species such as Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis causing anaemia, reduced weight gain and impaired nutrient absorption. Traditional control has depended heavily on broad-spectrum anthelmintics, but the rise of drug resistance has undermined their long-term efficacy and driven interest in alternative strategies. Host genetic resistance offers a sustainable complement to chemical control by exploiting naturally varying immune responses; resistant animals often mount stronger type 2 (Th2) responses characterised by elevated IgA, eosinophils and mucosal mast cells. Concurrently, vaccine research has sought to identify protective antigens capable of inducing durable immunity, while integrated approaches combine improved grazing management, selective breeding and vaccination to manipulate host–parasite equilibrium. Advances in molecular tools have deepened understanding of resistance mechanisms, revealing key genes, pathways and the influence of the gastrointestinal microbiota. The global significance of nematode resistance research lies in its potential to safeguard animal welfare, ensure food security and reduce reliance on dwindling anthelmintic resources.

Research from Nature Portfolio

Recent studies have demonstrated that recombinant vaccine antigens can achieve partial protection when expressed in plant systems that recapitulate native glycosylation patterns. By producing Ostertagia ostertagi activation-associated secreted proteins in Nicotiana benthamiana with authentic N-glycan structures, researchers achieved a significant reduction in faecal egg output comparable to native antigens, offering a template for next-generation vaccines against a broad range of abomasal nematodes. In a foundational comparative transcriptomic analysis of sheep breeds with contrasting resistance phenotypes, abomasal mucosal RNA sequencing revealed that resistant animals rapidly induce acute inflammatory responses, complement activation and accelerated tissue repair. These mechanisms, coupled with immunity directed against parasite fecundity, underpin the durable resistance observed in certain indigenous breeds and highlight molecular targets for breeding programmes.

Nematode Parasite Resistance in Small Ruminants publication trend

The graph below shows the total number of articles in nematode parasite resistance in small ruminants across all publications each year (not limited to Nature Index journals).

Technical terms

Anthelmintic resistance: Reduced sensitivity of parasitic nematodes to chemical dewormers, leading to treatment failure.

Fecal egg count (FEC): Quantitative measure of parasite burden based on eggs per gram of faeces.

Single-cell RNA sequencing: High-throughput profiling of gene expression in individual cells.

Quantitative trait locus (QTL): Genomic region statistically associated with variation in a heritable trait.

Glycosylation: Enzymatic attachment of sugar moieties to proteins, critical for antigen structure and immunogenicity.

Microbiota: Community of microorganisms residing in the host gastrointestinal tract, influencing immunity and metabolism.

References

1. Plant-based production of a protective vaccine antigen against the bovine parasitic nematode Ostertagia ostertagi. Scientific Reports (2023).
2. Single-Cell Transcriptomic Profiling Unveils Dynamic Immune Cell Responses during Haemonchus contortus Infection. Cells (2024).
3. Multi-omics data elucidate parasite-host-microbiota interactions and resistance to Haemonchus contortus in sheep. Parasites & Vectors (2024).