You must complete the Quest https://vanillawowdb.com/?quest=969 Luck Be With You from Witch Doctor Mau'ari in Everlook, Winterspring so that you can get the https://vanillawowdb.com/?quest=975 Cache of Mau'ari quest that grants the item by the same name which will allow the E'Ko to drop in the first place!

Juju Chill gives +15 Frost Resist.

You MUST complete Luck Be With You before you can obtain the E'ko from any of the Winterspring mobs to turn back into the Witch Doctor.

You have to have the Cashe of Mau'ari, which is the reward from the Luck Be With You quest in your inventory for the E'ko to even have a chance to drop.

None of the E'ko quests give experience or rep. All you get are the Juju. So, unless you plan on running around killing Winterspring mobs for a long time, don't bother collecting the E'ko and turning it in. I was helping a Warlock kill the owlbeasts. We wiped that camp clean of owlbeasts at least 20 times total, and I only got 10 E'ko. So the drop rate is lame.