No if your eosinophils are that low you are usually not infected by bigger parasitic worms esp not roundworms (very common) as they tend to invade tissues in big numbers. If your eosinophils were that low during such infection that would literally have a lethal impact (few cases where they suppressed eosinophils using steroids thinking it was an allergy and ppl died because it was a large worm parasitic infection). Your body has no other means of defence left against such big parasites. Protozoa infections are not usually hunted by eosinophils that's the whole point. Only multicellular parasites are. Eosinophils don't have a very long life but your bone marrow will keep the constant supply of them during worm infection. Go and read articles on parasitology ppl.