Nasu (Zoroastrianism)

Directly after death, as soon as the soul has left a corpse, “the druj Nasu rushes upon” the body, “in the shape of a raging fly, with knees and tail sticking out, droning without end” (Vd. 7:2). As soon as Nasu takes hold of a corpse, the body instantly becomes contaminated. If one comes into contact with a corpse, Nasu will emerge from the body and infect them, rendering them “unclean … for ever and ever” (Vd. 3:14). Nasu continues to inhabit the corpse until the sagdīd ritual is performed, during which a dog must look at the corpse, or until a carrion-eating bird or dog consumes the body, which causes her to return to her home in the north (Vd. 7:3).

Besides contaminating corpses upon death, Nasu also contaminates those who interact with corpse-matter in specific ways. In Vendidad 3:14, Ahura Mazda explains to the prophet Zoroaster that one must never carry a corpse on their own, lest Nasu’s infection transfers to them. If one carries a corpse alone, Nasu emerges “from the nose … , the eye, the tongue, the sexual organs, and the hinder parts” of the deceased, and “rushes upon [the corpse bearer] … [and stains him] even to the end of the nails, and he is unclean, thenceforth, forever and ever” (Vd. 3:14). In this case, there is no way to purify the infected individual. In order to avoid the spread of contamination, he must live in an enclosure where “the ground is the cleanest and the dryest and the least passed through by flocks and herds, by the fire of Ahura Mazda, by the consecrated bundles of Baresma,[lower-alpha 1] and by the faithful” (Vd. 3:15). There, other Zoroastrians must provide him with “the coarsest food” and “the most worn-out clothes,” until he ages into an old man (hana) (Vd. 3:18-19). Once he is elderly, the infected must be beheaded, and his corpse is offered to the vultures. At this point, “he is absolved by his repentance” (Vd. 3:20-21).

Nasu also attacks humans who consume the corpse of a dog or human, or those who put a corpse in water or fire. These individuals are considered unclean forever, with no option of repentance (Vd. 7:23-26). Nasu will also attack humans and dogs who are nearby a person at the time of their death (Vd. 5:27).

In some cases, a living individual who has been defiled by Nasu has a chance at regaining purity, if the proper purification rites are performed (Vd. 9:42). However, if the ritual is performed by an unqualified purifier, Nasu will grow stronger, and the contamination will heighten (Vd. 9:48).

In fargard 10 of the Vendidad, Ahura Mazda recommends recitation of certain verses from the Gathas to “fight against” Nasu and purify a contaminated individual (Vd. 10:1-12). Some verses must be recited twice (Yasna. 28:2, 35:2, 35:8, 39:4, 41:3, 41:5, 43:1, 47:1, 51:1, 53:1), thrice (Y. 27:14, 33:11, 35:5, 53:9), or four times (Y. 27:13, 34:15, 54:1).

The Sros baj, or “utterance against pollution,” an important daily recitation in honor of Sraosha, “is a powerful prophylactic prayer that protects one against decay and death.”[1]

In fargard 18 of the Vendidad, Sraosha has a dialogue with Nasu. While striking Nasu, he asks her if she bears offspring without copulating with a man (Vd. 18:30). To this, Nasu responds that she is impregnated whenever practitioners of Zoroastrianism are greedy (Vd. 18:34), “emit seed” during sleep (Vd. 18:46), spill water (Vd. 18:40), or if they “[walk] without wearing the sacred girdle and the sacred shirt” (Vd. 18:54). Conversely, “the fruit of [her] womb” is destroyed every time one is generous to another Zoroastrian, or recites the Ahuna Vairya after emitting seed or spilling water.