What parasite is primarily responsible for anemia in small ruminants?

Haemonchus contortus, commonly known as the barber pole worm, is recognized as a primary cause of anemia in small ruminants such as sheep and goats. This nematode is particularly notorious for its ability to cause significant blood loss, as adult female worms feed on the host's blood in the gastrointestinal tract. The consequences of such feeding can lead to severe anemia, characterized by a reduction in red blood cell count and hemoglobin levels, which can be fatal if not addressed.

The life cycle of Haemonchus contortus is particularly adapted to warm climates, leading to high levels of infection under suitable environmental conditions. The presence of this parasite can be exacerbated by poor management practices or inadequate deworming protocols, leading to an increase in infection rates and subsequent anemia.

While other parasites such as Bunostomum spp. and Trichostrongylus spp. can impact the health of small ruminants and may contribute to various gastrointestinal issues, they are not as directly associated with causing anemia. Similarly, Ostertagia spp. primarily affects the gastric mucosa, leading to different clinical signs rather than anemia. Thus, Haemonchus contortus is distinctly recognized for its role in inducing anemia in these animals