Which type of WBC increases during allergenic reactions and parasitic worm infection?

The type of WBC that increases during allergenic reactions and parasitic worm infections is eosinophils.

Here's why:

* Allergic reactions: Eosinophils play a crucial role in the allergic response by releasing histamine and other inflammatory mediators. They also help in the destruction of parasitic worms.

* Parasitic worm infections: Eosinophils are essential for fighting off parasitic worms. They release cytotoxic substances that damage the worms and help in their expulsion from the body.

So, an elevated eosinophil count in a blood test can indicate an allergic reaction or a parasitic worm infection.