Toxascaris leonina

Toxascaris leonina	Contents	Rev 10/25/2025
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Toxascaris Menu		Ecosystem Functions and Services
	Distribution	Management
Return to Ascarididae Menu	Feeding	References
	Go to Nemaplex Main Menu	Go to Dictionary of Terminology

Classification:

Class: Chromadorea

Subclass: Chromadoria

Order: Rhabditida
Suborder: Spirurina: Superfamily: Ascaridoidea; Family: Ascarididae

Toxascaris leonina (von Linstow, 1902) Leiper, 1907

Synonym:

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Morphology and Anatomy:

Adults are cream to pinkish color
Dorsal curvature of the anterior with long, narrow, lanceolate (spear shaped) cervical alae that taper gradually into the body
Tail that gradually tapering to a point.

Males:

Length 2- cm; widthe 1.5-2 mm
Spicules 0.7-1.5 mm long.

Females:

Length 2-10 cm; widthe 1.8-2.4 mm
Tail 170-210 um long.
Eggs ellipsoidal with a smooth shell; 75-85 x 60-75 Âµm with a single cell when laid.

Ref: Cruthers et al., 2020

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

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Distribution:

Worldwide, especially in cooler climates. Intestinal parasite of dogs and cats,

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Economic Importance:

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Hosts:

Dogs and cats

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Feeding:

Intestinal parasite of dogs and cats,

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Life Cycle:

Differs from species of Toxocara in that the larvae do not migrate through the lungs; rather, the entire developmental cycle occurs in the intestine.

Eggs of T. leonina develop to the L2 in 4-7 days, depending temperature conditions
Eggs are ingested by a dog or cat by consuming fecal material. After ingestion, the L2 hatches in the stomach and penetrates the mucosa of the small intestine.
The L3 development occurs in the intestinal wall and the larva returns to the lumen, molts to the L4 which develops into an adult. The development takes place entirely in the wall and lumen of the intestine with no somatic migration phase.
Alternatively, if infective eggs are ingested by paratenic hosts, infective L2 larvae encyst in their tissues. Ingestion of the infected paratenic host by a suitable definitive host leads to infection in the small intestine.
The prepatent period is as early as 4-11 weeks.

Ref Cruthers et al., 2020.

Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click	If species level data are not available, click for genus level parameters

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Damage:

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Management:

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References:

Cruthers, L.R., Reinemeyer, C.R., Yazwinski, T.A., Marchiondo, A.A. 2020. Nematoda, Ascaridida. Chapter 2 in Marchiondo, Cruthers and Fourie (eds) Parasiticide Screening Vol 2. Academic Press