Facioliasis: is the anemia caused by hematophagia?

Area of Science:

• Veterinary Parasitology
• Hematology
• Biochemistry

Background:

• Anemia is a known symptom of fascioliasis, but its cause remains debated.
• Theories include blood-feeding (hematophagia) by the fluke or a toxic substance it produces.

Purpose of the Study:

• To investigate the etiology of anemia in rats infected with Fasciola hepatica.
• To determine if Fasciola hepatica can cause anemia independently of hematophagia.

Main Methods:

• Hematological parameters (erythrocyte count, hemoglobin, reticulocyte count, mean corpuscular volume) were monitored in infected rats.
• Fasciola hepatica worms were implanted into uninfected rats within sacks to prevent blood-feeding.

Main Results:

• Infection led to decreased erythrocyte counts and hemoglobin, and increased reticulocyte counts and mean corpuscular volume.
• Rats with implanted worms (prevented hematophagia) developed anemia similar to naturally infected rats.
• Urobilinogen levels initially increased then normalized after worms reached the bile duct.

Conclusions:

• Fascioliasis-induced anemia in rats is caused by a substance released by Fasciola hepatica, not solely by blood-feeding.
• Proline released by the fluke is a potential candidate for inducing this anemia.