Ornithobilharzia (Orientobilharzia)

Ornithobilharzia (Orientobilharzia): Taxonomy, Morphology, Life Cycle & Pathogenesis

Ornithobilharzia (Orientobilharzia) is a genus of schistosome blood flukes belonging to the family Schistosomatidae. These parasites inhabit the mesenteric veins of various domestic mammals, including ruminants and equines, and have a life cycle involving freshwater snails as intermediate hosts.

Ornithobilharzia resembles Schistosoma but differs in possessing numerous testes (about 60 or more). The intestinal caeca tend to anastomose anterior to the median posterior intestinal caecum. The ovary forms a spiral in the anterior region of the body, and the uterus is short, containing only one egg at a time.

Taxonomical Classification

• Kingdom: Animalia
• Phylum: Platyhelminthes
• Class: Trematoda
• Subclass: Digenea
• Order: Strigeidida
• Family: Schistosomatidae
• Genus: Ornithobilharzia (Orientobilharzia)

Ornithobilharzia turkestanicum

• Host: Sheep, goats, camels, cats, cattle, buffaloes, and equines
• Distribution: Turkestan region, Kazakhstan, Mongolia, Iraq, and France
• Location: Mesenteric veins
• Intermediate Host: Lymnaea euphratica

Morphology

• They are very small. Males are about 4.2–8 mm long, while females are about 3.4–8 mm long.
• There are 70–80 testes.
• The ovary is spirally coiled.
• The uterus contains one egg at a time.
• The egg measures about 72–74 × 22–26 μm, is oval in shape with a terminal spine, and has a short appendage at the opposite end.

Pathogenesis

Ornithobilharzia turkestanicum is of little significance in large animals but causes debility in sheep and goats, leading to marked hepatic cirrhosis and nodules in the intestinal wall, accompanied by loss of body weight in small ruminants.

Ornithobilharzia bomfordi

• Host: Zebu cattle (Bos indicus)
• Location: Mesenteric veins
• Intermediate Host: Lymnaea acuminata

Morphology

• Males are about 6–9 mm long, while females are about 3–7.3 mm long.
• There are about 60 testes in males.
• The female has a long posterior caecum.
• The egg measures about 100–136 × 44–60 μm, is oval in shape with a posterior spine, and is found in the feces of the host.

Treatment

Praziquantel is effective against Ornithobilharzia bomfordi.