One theory is that this is because so many Africans take ivermictin and/or hydroxychloroquine (for reasons other than COVID).

Ivermectin is also given to livestock for parasites.

It is given to chickens either as a topical liquid, paste, or as an injection. It is recommended not to eat the eggs for two weeks after the birds are medicated as ivermectin shows up in the egg yolks.

Aw gee whiz, discard the eggs unless you want to get a dose of ivermectin .

If my hens were laying ivermectin laced eggs I'll bet I could get good money for them .

You can search out the Ivermectin/COVID/Africa sites. Unfortunately most of the pro-ivermectin sites are also rabid anti-vax sites.

Here is an ivermectin site for backyard chicken keepers:
https://sandcreekfarm.net/ivermectin-for-chickens/

Amazon sells ivermectin for livestock.