Shitala is the Hindu Goddess of smallpox, both the disease and the cure. When Shitala first arose from a sacrificial fire, Brahma told her that humans would always worship her, as long as she carried the seeds of a particular lentil. Along with her companion, Jvarasura, the demon of fever, she traveled to visit the other Gods. Somewhere along the way, her lentils turned into smallpox germs, and anyone who they visited came down with a fever and smallpox. The Gods asked Shitala for mercy, and asked her to take her load of germs and go to the earth. She agreed, and she and Jvarasura went down to the earth. Their first stop was to the court of King Birat, who worshipped Shiva. King Birat would not give Shitala supremacy over Shiva, so she threatened to infect his people. He was not swayed, and Shitala called down 75 different kinds of pox on his people. The disease spread far and wide, and there were many deaths. Finally, King Birat relented, and Shitala healed him and his people.
Shitala rides on a donkey, and she has four arms. In her hands she carries a silver broom, a fan, a small bowl, and a pot of water. She uses these items to rid a house of disease–she sweeps up the germs with her broom, uses the fan to collect them, and dumps them into the bowl. She then sprinkles water from the pot (which is water from the river Ganges) to purify the house. Shitala’s name means “the cooling one”, and is also seen as Shitala Mata, Sheetla Mata, Shitala Devi, and Sheetala Devi.
Sheetlastami is celebrated in the dark half of Chaitra Masa. People worship Sheetla mata this day.