From the article you posted:
“The impact of Chagas disease is not limited to the rural areas in Latin America in which vectorborne transmission occurs. Large-scale population movements from rural to urban areas of Latin America and to other regions of the world have increased the geographic distribution and changed the epidemiology of Chagas disease.”
So, looks like letting in unlimited numbers of unvetted southern 3rd world peasants brings in their 3rd world bugs and diseases with them.
Yup...no doubt a piece of information known and ignored by those in power.