Cancer in South America (updated)

Chávez announced in the middle of this year that he had cancer (sort of announced it). The former head of state of Brazil, Lula, announced in October that he had throat cancer. The president of Paraguay went to hospital the same month because he was diagnosed with non-Hodgkin's lymphoma. Now we hear the president of Argentina has thyroid cancer.

What is it? Coincidence?

Now I get the news, with delay, that Chávez hinted the United States of America is behind it all

Now we know what we are going to hear in the next 10 months.