Current Status for Gastrointestinal Nematode Diagnosis in Small Ruminants: Where Are We and Where Are We Going?

Table 3

Potential and commercialised immune-related markers of GIN parasite resistance.

Trait	Description	Advantages	Disadvantages	Application
Serum antibodies	Phenotypic, enzyme-linked immunosorbent assay (ELISA).	Routine laboratory procedure	(i) Invasive sampling; (ii) Off-farm; (iii) Not sensitive to infection level; (iv) Transient up regulation	Research
Salivary antibodies		(i) Relatively easy collection; (ii) Routine laboratory procedure	(i) Off-farm; (ii) Requires certain level of infection for detection	Commercialised; http://www.kelso.co.nz/partners/; carla%c2%ae-saliva-test-measuring-; parasite-immunity-in-sheep/
Faecal antibodies		(i) Relatively easy collection; (ii) Routine laboratory procedure	(i) Off-farm; (ii) Involves faecal collection; (iii) Low accuracy	Research
Blood eosinophilia	Phenotypic, morphological cell differentiation after staining.	Routine laboratory procedure	(i) Invasive sampling; (ii) Off-farm; (iii) Trained technician required to count eosinophils; (iv) Transient up regulation	Research
Ghrelin levels in blood	Phenotypic, ELISA platform. Higher levels in susceptible sheep following infection.	Routine laboratory procedure	(i) Invasive collection; (ii) Off-farm; (iii) Transient up regulation; (iv) Only tested in resistant and susceptible lines	Research
Cutaneous hypersensitivity reactions	Phenotypic, cutaneous injection of sensitised antigen to measure immune function.	(i) Tests responds to a range of diseases; (ii) Noninvasive readouts; (iii) Potential for on-farm development	(i) Involves injection of antigens into animals; (ii) 2–24 hr time delay for readout	Research