Mwiva is the "closest" word in Swahili I could find -- a kind of fish :
http://research.yale.edu/cgi-bin/swahili/main.cgi?right_frame_src=http%3A//research.yale.edu/cgi-bin/swahili/lookup.cgi%3FWord%3Dmwiva%26EngP%3D0%26SUBMIT2%3DLook+UpI seriously doubt there is any relation, however.
How about calling the Embassy of Tanzania in
Washington DC ? The number is (202) 9396125