See:
Greenhouse Plants, Ornamental - Impatiens Necrotic Spot
Symptoms The most common symptom of impatiens necrotic spot virus on cyclamen is necrotic ringspots. They may be concentric, or tissue within the ringspot may become yellow. The petiole end of the leaf may brown, but infection by bacterial soft rot and Fusarium wilt also have this symptom. Early symptoms can include a silvery speckling that resembles thrips damage. Colored flowers may develop light streaks that run the length of the flower. Necrosis in the vascular bundles of the corms also has been observed as well as brown, zigzag line patterns. Symptoms may not occur for several months after exposure to western flower thrips.
Reference Elmer, W.H, and Daughtrey, M.L. 2018. Diseases of Cyclamen. In McGovern, R.J. and Elmer, W.H. (eds.) Handbook of Florists' Crops Diseases. Springer Int.