Many immigrant families in South America moved about between countries due
to commercial, educational, professional, political and family reasons.
You can view an example of this by checking out the Brazilian immigration
cards for Molly Arost Staub's Jarast family which can be found on the
familysearch.org site. You can see by the dates of immigration and whether
the individuals were adults or children what their reason for moving might
Members of the Jarast family moved >from Argentina to Brazil as follows:
1950 - Adolfo Lifschitz, a doctor, and his sister Mina Lifschitz, a
pharmacist, the children of Abraham Lifschitz and Luisa Jarast.
1961 - Uscher Jarast, a doctor, son of Osias Jarast and Rosa Rapaport.
1963 - Albeto Daniel Jarast, a student, and Ricardo Ernesto Jarast, a
student, the children of Enrique Jarast and Marta Elena Kaplan.
1963 - Adrian Horacio Jarast, a student, the son of Elias Jarast and Sara
I did not look at the Sao Paolo, Brazil immigration cards which may also
contain additional Jarast family members.
As you can see, the immigration cards have lots of genealogically relevant
information and there was additional data such as their address, birth