Help with identifying disease

I have this shrub which every year gets brown and mottled some years is worse than others and sometimes it pulls through and it gets healthier green leaves.  This year it looks completely disease ridden the leaves look like they have been eaten by something very tiny and the leaves are brown and mottled there are the one or two healthy leaves.  Can anyone identify the disease as I am a 'doesn't have a clue gardener'.  I love the shape and position of the shrub and wondered if I couldeif I  bring it back to,life.  I have enclosed some pictures and any info would be much appreciated.