Origine: Bemba, Southern Africa
Source: Bemba (Zambia) proverb (UMUNWE UMO TAUSALA NDA); translation ("One finger does not pick lice") and explanation from "Bemba Proverbs And Their Role In Society," The Zambian Observer (zambianobserver.com). Earlier recorded here as also in Laur Mwepu Luiza, "A Collection of 100 Bemba Proverbs" (afriprov.tangaza.ac.ke); that collection was not re-read.
La source l’explique: This proverb encourages cooperation among people
. La formulation du sens est de nous.