For every new Mac malware discovered we write lots of articles, because of the usual resistance against computer viruses. On Android, the picture is roughly comparable to Windows PCs. According to the GData Security blog, in the first quarter of 2017 750,000 new Android malware were discovered: it means more or less to 8,400 new malware per day.
The root of this dangerous situation is unfortunately only one: the poor updating process for Android users. iOS has a rather simple and efficient upgrading system, to the point that the vast majority of iPhone and iPad in circulation are up to date (as long as the hardware holds on). But Android has a more cumbersome update process, which depends on various smartphone makers and in some countries even telephone carriers.
The advice we can give you is to download apps only from the Google Play Store, where the chance to cross malicious software is considerably lower. Moreover, several antiviruses include a mobile version for Android: we suggest installing and checking regularly your smartphone (or tablet).