Complex sentence: Since 1999, Clodoveo Ferri investigated the pathogenetic role of parvovirus B19 and cytomegalovirus (CMV) in systemic sclerosis (scleroderma): a significantly higher prevalence of parvovirus B19 infection was firstly demonstrated in both bone marrow and skin of scleroderma patients compared to controls.
Split into simpler sentences: Since 1999, Ferri investigated the pathogenetic role of parvovirus B19 and cytomegalovirus (CMV) in systemic sclerosis (scleroderma). A significantly higher prevalence of parvovirus B19 infection was originally demonstrated in both bone marrow and skin of scleroderma patients compared to controls.