Table 2.

Potential and commercial infection-related markers for the diagnosis of GIN parasite infection.

Trait	Description	Advantages	Disadvantages	Application
Worm egg counts (WEC)	Phenotypic, WEC test where the amount of eggs in the faeces is an indicator of adult infection. Eggs counted by microscopy.	(i) Direct measure of infection (ii) On-farm readout (after training)	(i) Labour intensive and involves collection of faeces from the rectum (ii) High variability in counts (influenced by diet, age, degree of infection exposure, hypobiosis, and adult density)	Commercial; http://www.wormboss.com.au/tests-tools/tests/worm-egg-counting.php
	Genotypic, egg counts in faeces detected by DNA analysis.	(i) Direct measure of infection (ii) Quicker than phenotypic WEC (iii) Potentially cheaper as trained experts in worm egg counting are not required	(i) Qualitative only, can't determine infection level and hence resistance status (ii) Involves collection of faeces (iii) Off-farm	Research
	Phenotypic, lectin assay, use of antibodies to detect eggs in faeces.	(i) Direct measure of infection (ii) Can distinguish between species by egg morphology	(i) Involves collection of faeces (ii) Off-farm (iii) Currently only specific only for H. contortus	Commercial: http://archive.sheepcrc.org.au/management/worms-flies-lices/  rapid-laboratory-test-for-haemonchus-in-worm-egg-counts.php
Blood loss	Phenotypic, packed cell volume (PCV); involves calculating the percentage of red blood cells from a blood sample.	(i) Direct measurement of infection (ii) Earlier detection of infection compared to WEC	(i) Invasive (ii) Not specific to H. contortus infection-other causes of blood loss (iii) Off-farm	Research
	Phenotypic, haemonchus dipstick; blood loss measured by amount detected in faeces.	(i) Quick (ii) No need for highly trained laboratory technician (iii) On-farm	Blood loss is nonspecific therefore recommended to be used in conjunction with WEC	Commercial: http://archive.sheepcrc.org.au/management/  worms-flies-lices/haemonchus-dipstick-test.php
	Phenotypic, FAMACHAⒸ; involves matching eye lid colour with coloured chart indicating level of anaemia.	(i) Noninvasive (ii) Quick (iii) No need for highly trained laboratory technician (iv) On-farm	(i) Nonspecific (other disease induce anaemia) (ii) Subjective measurement	Commercial: http://www.acsrpc.org/Resources/famacha.html
Faecal odour	Phenotypic, infected and uninfected faeces have differential odours detectable by canines.	(i) Detects infection earlier than WEC (ii) Potential for on-farm testing	Can odour be used to determine infection levels? (i) Cost and time to train canines or development of artificial nose?	Research
Animal behaviour	Phenotypic, global positioning systems (GPS) to detect reduced movement found in resistant animals compared to susceptible.	(i) Potential for on-farm testing (ii) Noninvasive	(i) Cost of technology (ii) Indirect measure	Research
Weight loss	Phenotypic, performance based marker which involves calculation of body weight gain based on food efficiency rates.	(i) Potential for on-farm testing (ii) Non-invasive	(i) Cost of technology (ii) Indirect measure	Research HappyFactor
Worm burden	Phenotypic, measuring the number of GIN parasites in the stomach at post mortem.	(i) Distinguish nematode species (ii) Direct measurement of burden (includes exsheathed L3, L4 and adult GIN parasites)	(i) Measurement is terminal (ii) Time consuming (iii) Impractical	Research
Worm weight	Phenotypic, weight of the total amount of GIN parasites collected at post mortem.	Direct measurement of burden (less intensive than counting worm numbers)	(i) Measurement is terminal (ii) Time consuming (iii) Impractical	Research