Identification of Haemonchus species in domestic ruminants based on morphometrics of spicules.

An easy and rapid tool for the individual identification of Haemonchus species in domestic ruminants might be very useful in the study of natural populations, especially when two (or three) species are sympatric. Techniques based on cytology, cuticular-ridge patterns, sublateral hypodermic chords, or molecular biology allow species identification but are either expensive or time-consuming. Therefore, a discriminant function combining three measures of male spicules was established from experimental infections with H. contortus in both sheep and goats and with H. placei in zebu. The discriminant function was evaluated on individual worms and on average values obtained in natural and experimental populations throughout the world. It was compared with a previously established function. The use of our function permitted better species identification for all Haemonchus species of ruminants, including H. longistipes from camels and H. similis from cattle.