How does the author’s discussion of the shared virus between the pigs and the bats help us understand animals’ role in human disease?

Around 75% of new diseases are spread by animals and the animals play an important role in human disease.

Explanation:

The germs that are causing this disease is known as pathogen. The sources from which these disease spread are the animals such as pigs and bats. The disease is being transmitted from animals to human being through various media such as air, from the the saliva of the animals, from their bites.

As the human beings' immune system has not encountered the virus previously hence when the human being is being affected by the disease transmitted by the animal , they fall sick due to the disease as their immune system is unable to fight with the virus.

describe a little more.

england is crowded cold and polluted while north america was like the opposite