The health unit is warning of a caterpillar that can cause a painful rash and even sickness.
The Hickory Tussock Moth Caterpillar, pictured above, is common in the area during this time of the year.
It is white and fluffy with black markings on its back. It has longer black hairs sticking out its front and back and measures about 4.5cm.
Officials say touching the caterpillar can cause a poison ivy-like rash. In some more serious cases, people get headaches, nausea or an allergic reaction.
If you accidentally touch one, the Middlesex London Health Unit recommends washing the exposed area and keeping an eye on it. If you experience any more serious symptoms you should see a doctor.
The caterpillars are found between July and September and feeds on the leaves of elm, oak, walnut, hickory and ash trees.
For more information click here. 11
