Letters 'BWG' in the name of this parasite mean, that it was created with the help of BWG creation utility and doesn't strive to mail itself to different addresses (as lots of viruses do; their extension is BWG@mm). This description means, that BAT.BGW.a is a trojan horse, which concentrates on damaging one specific machine. This trojan usually deals with BAT-files, infects them and, finally, causes a potent threat to the stability and performance of the infected system.