Answer:
A negative effect of the Columbian exchange on Europe was the sand fleas arrival to the old world.
Explanation:
The majority of the negative effects were caused to the Americas, nevertheless, the Europeans also had their portion of negative effects. One of them was the sand fleas that inserted their eggs under the skin of the carrier and propitiated unknown infections as well as breakouts in different species. The Europeans carried them in themselves, in animals and even in the inventories of crops and organic tissue they transported to Europe. They also faced rural changes due to the introduction of new world plants to the old world and the modification of the fields lead them to ruin it for profit.
