a) saafremt arbejdstageren ikke efter den foerste udbetaling af ydelser har vaeret beskaeftiget i en anden medlemsstat ved et arbejde, der maa antages at kunne foraarsage eller forvaere den paagaeldende sygdom, paahviler det den kompetente institution i den foerstnaevnte stat at afholde de med ydelserne forbundne udgifter, under hensyntagen til den indtraadte forvaerring, efter den for denne institution gaeldende lovgivning;
(a) if the worker has not, while in receipt of benefits, been in employment under the legislation of another Member State likely to cause or aggravate the disease in question, the competent institution of the first Member State shall be bound to meet the cost of the benefits under the legislation which it administers taking into account the aggravation;