The Toxocara Life Cycle

What is a lifecycle? Which life cycles are we already familiar with? What differences can you see between these life cycles? Can you suggest any more? What do we mean by ‘life cycle?’ How does each life cycle help each creature adapt to it’s habitat?

Toxocara is a worm Speedy Challenge: In pairs can you try to draw the lifecycle for a worm? Perhaps try to think about an earthworm… Do you think it lays eggs or has live young?

Toxocara Life Cycle

These are Toxocara eggs These are Toxocara eggs. They can be found in soil where dogs and cats have pooed. Larvae (tiny worms) develop inside the eggs. Look carefully, what can you see? How is the worm different to the larvae?

Toxocara Dogs can pick up the eggs, which are sticky, on their paws. They eat the eggs without knowing it. Cats can also do this, and even people (not with their paws!). The eggs are microscopic and can only be seen with a microscope so you wouldn’t even know!

Can we create some definitions for the tricky language? When an infected dog poos, thousands of Toxocara eggs are in the poo. If no one picks the poo up, the eggs end up in the soil and the cycle starts again. Definitions: Infected: Life cycle: Larvae: Worm: Microscopic: Can we create some definitions for the tricky language?

Some symptoms of Toxocara: When dogs have worms inside them, it does not usually harm them, but Toxocara larvae can make people very sick, affecting different parts of the body. Some symptoms of Toxocara: Sleeplessness Blurred vision Tummy ache Asthma Itchy rash Epilepsy Which parts of the body show these symptoms? Further information on the life cycle and disease: https://www.cdc.gov/parasites/toxocariasis/

The Life Cycle of a Toxocara Worm Group challenge: Can you use the images on your sheet to create your own life cycle of a Toxocara worm? Aim for the life cycle to form a circular shape which goes round and round. Extension: Using the glossary we created together earlier, choose some of these words to add detail to your lifecycle.