In 1979, the very first cases of AIDS appeared in New York. Cases of the disease that had never been seen prior to 1979, but is now considered more deadly than the bubonic plague, continued to surface in California and New York, almost exclusively in homosexual men.
Monkeys are the cause of AIDS.
The statement does not state where or who the cause of AIDS is so monkeys may or may not have caused it.
( z1 cause :ARG0 ( z2 monkey ) :ARG1 ( z3 disease :name ( z4 name :op "AIDS" ) ) )