Camelidae and Cervidae Multisystemic Internal Parasites – NAVLE Study Guide

Overview and Clinical Importance

Multisystemic internal parasites in camelids and cervids represent a critical category on the NAVLE. These parasites cause disease affecting multiple organ systems including the liver, GI tract, CNS, and cardiovascular system. Understanding host specificity, life cycles, and treatment is essential.

The concepts of definitive hosts, dead-end hosts, and aberrant hosts are particularly important for liver flukes and meningeal worms. Camelids often respond differently than domestic ruminants to the same parasites.

Section 1: Liver Flukes (Trematodes)

1.1 Fasciola hepatica (Common Liver Fluke)

Etiology and Life Cycle

Fasciola hepatica is a large trematode (up to 30mm x 13mm) parasitizing bile ducts. The indirect life cycle requires a lymnaeid freshwater snail intermediate host (Galba truncatula). Eggs pass in feces, embryonate in water, hatch as miracidia, penetrate snails, develop through sporocyst/rediae/cercariae stages, then encyst as metacercariae on aquatic vegetation. Hosts are infected by ingesting contaminated plants.