Security firm F-Secure has spotted 58 separate threats targeting OS X in the past nine months.

F-Secure has published a report looking at Mac threats between April and December 2011 which showed June and October as being particularly busy months for Mac malware while only one threat was spotted in August.

Of the 58 threats spotted in total, 15 were classified as 'backdoor' threats, seven were Trojans, 29 were Trojan downloaders and the other seven were classified simply as 'rogue'.

"Mac malware has not scaled continuously due to market share, but rather, is more the result of opportunist 'bubble economies' that have produced new threats in fits and starts. We expect more of the same for 2012," F-Secure said.

The company notes that while the number of threats is minute when compared to the number seen targeting the Windows platform, it is a significant increase on previous years.