W. Va. Code § 56-4-47
Where plaintiffs or defendants sue or are sued as partners, and their names are set forth in the declaration or bill, or where a plaintiff or defendant sues or is sued as a corporation, it shall not be necessary to prove the fact of such partnership or the existence of such corporation, unless the pleading which puts the matter in issue be verified, or there be an affidavit filed therewith denying such partnership or the existence of such corporation. A plea putting in issue the existence of a corporation shall be sufficient if it be in form or effect as follows:
"And the said defendant for plea says that the plaintiff (or defendant, as the case may be) is not a corporation, as in the plaintiff's declaration is alleged."
W. Va. Code § 56-4-47