Fatal Haemonchosis in a Llama
Erin Edwards, DVM, MS, DACVP and Mindy Borst, LVT
Haemonchosis refers to parasitic infection with Haemonchus contortus, a blood-sucking parasite that lives in the abomasum. This parasite is also known as the barber pole worm due to the macroscopic appearance of the worms. Heavy loads of H. contortus can cause anemia, hypoproteinemia, weight loss, and death. Infection is best described in small ruminants (sheep and goats). Camelids (llamas and alpacas) are also known to be highly susceptible to haemonchosis.
Recently, a deceased, 2-year-old llama from the Brazos Valley was submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for necropsy. This llama had a history of parasitic resistance and severe anemia that required blood transfusion. Postmortem examination revealed a thin body condition, severe pallor of the ocular and oral mucus membranes, subcutaneous edema, tricavitary effusions, and pallor of the internal organs. The third gastric compartment (C3), which is equivalent to the abomasum in ruminants, contained tremendous amounts of parasites that were identified as H. contortus (Figure 1). The parasite burden in this llama was responsible for the other noted necropsy findings and was determined to be the primary cause of death.
H. contortus thrives in warm, humid environments such as Texas. Haemonchosis is a major problem in small ruminants and camelids in tropical environments, including other parts of the southeastern United States. This parasite has become increasingly more resistant to anthelmintics and infections are often hard to clear, as demonstrated in this case. For more information on developing strategies to reduce resistance and manage this disease, visit the Texas A&M AgriLife Extension website.
For more information about this case, contact Dr. Erin Edwards, assistant anatomic pathology section head, or Mindy Borst, clinical pathology laboratory supervisor. To learn more about TVMDL’s test offerings, visit tvmdl.tamu.edu or call 1.888.646.5623.
Figure 1: Haemonchus contortus nematodes that were recovered from the third gastric compartment of a 2-year-old llama. Note the twisted appearance of some, which is why this parasite is also known as the barber pole worm.
Reference:
Edwards EE, Garner BC, Williamson LH, Storey BE, and Sakamoto K. Pathology of Haemonchus contortus in New World camelids in the southeastern United States: a retrospective review. J Vet Diagn Invest. 2016.