London - AIDS death rates have fallen 80 per cent in Europe in the four years since the introduction of new multidrug cocktails to fight the disease, researchers report today. "The decline in mortality only occurred after the introduction of those new drugs. There is nothing else we could find that could explain it apart from the new drugs," Dr Amanda Mocroft said. Dr Mocroft and colleagues at the Royal Free Hospital and University College Medical School in London examined death rates from 17 countries across Europe among patients infected with the HIV virus.