The Euro Did It!
Shoppers in Italy stage nationwide strike against merchants, who many consumers say have exploited transition to common European currency by marking up price of everything; consumer groups in Greece call on shoppers there to refrain from buying fruit and vegetables next week; these are latest ripples in wave of anger that has swept across Continent since euro notes and coins became legal tender in 12 European countries in January; European Central Bank bank president Wim Duisenberg says effects of changeover are over and that inflation is not problem; photo (M)