Eicar is a special harmless byte pattern. It is not a real virus and it cannot harm.

This byte pattern is detected by all antivirus products as "test virus" (EICAR-test). It is used for test purpose only. That is why you must not worry about real virus (real danger). Therefore, it cannot be removed and should not be removed.

x-Wall series (c-Wall, e-Wall and s-Wall) includes the byte pattern for test
purpose too. As the products are able to check viruses with several external antivirus
processors, there is a need to verify the antivirus selection propriety and
the selected antivirus efficiency.

After an antivirus is selected (x-Wall Settings tab) you can check it by
pressing "Test" button. x-Wall produces three temporary files with Eicar byte pattern and calls selected antivirus. After that, x-Wall interprets the antivirus respond and informs you about the results. Finally, temporary files are deleted. Three temporary files are needed for checking three most important antivirus options - virus checking ability in raw files, archive files (zip) and e-mail.

See details at http://www.eicar.org/anti_virus_test_file.htm