Click for map of Australian distribution. Haemonchus thrive in subtropical conditions where temperatures exceed 10 o C and rainfall exceeds 50mm per month. Endemic areas are those where disease occurs annually. In sporadic areas unseasonal wet weather can lead to parasitism. L3 are vulnerable to drying and freezing.
Worms suck blood and cause anaemia in sheep.
Severe to fatal, rapidly developing disease or longer term anaemia causing production loss. Eggs in faeces are similar to those of other nematodes.