yeah, the spread of TB among the local citizenry through TB infected foreigners who are now swamping the island like flies. Zika is only a bite and curable; TB is more serious, a long term ailment if not detected and cured early.
So, LKY did not have helicopter vision after all which his porlumpars wanted people to believe him. LKY spoke highly about welcoming foreigners to sinkie land but he was too blind to foresee the foreigners would also bring prostitution, AIDs, TB, scam, theft, etc with them.