DDT is still used in the Third World, and mosquitoes are becoming resistant:

https://www.sciencemag.org/news/2016/10/after-40-years-most-...

https://mosquitoreviews.com/insecticides/ddt-resistant-mosqu...

> Several serious human health problems, including diabetes and hormonal disruptions, have been linked to DDT, and it is suspected to be carcinogenic.

So, no, it wasn't just the eagles.