Mariyamman – the disease mother – is a ‘fever goddess’ of southern India. She is said to cause, prevent or alleviate (depending on her moods) fevers or diseases (particularly of the eyes).
Temples & shrines to Mariyamman can be found in rural regions of southern India & Sri Lanka, and there are local variations in her name, such as Karumariyamman, Bhadramariyamman or Kaliyamman (in Tamil Nadu Mariyamman is sometimes said to be either a form of Kali, or her sister).
Mariyamman is variously described as a widow, a woman who has been expelled from her home, a mistreated young girl, a deified witch (and a devourer of children). She has some similarities to Sitala. Her origin stories sometimes portray her as a high-caste woman who, due to misfortune or defilement, loses her status and becomes low-caste. In one variant, the goddess is originally a wife of one of the nine Rishis, famed for her beauty and virtue. Such is her renown that Shiva, Brahma and Vishnu visit her one day. Not recognising the gods, and resenting their intrusion, she changes them into small children, after which they curse her so that she becomes a deformed creature, covered with sores. Mariyamman is sometimes said to have the head of a Brahmin woman but the body of an untouchable. In other origin stories, she is tricked into marriage with a low-caste man, and her rage, when this is discovered, reduces her husband to ash.
An etymological suggestion for Mariyamman is that it is derived from Muttu – meaning “pearl” – suggesting (in this context) “the disfiguring pustules contracted during an onset of chicken pox or smallpox.” Mariyamman is sometimes depicted showering humans with these ‘pearls’ using a flywhisk or feather. Another suggestion is that the word mari which in Tamil can mean ‘to change’ – suggestive of her unpredictable temperament and her capacity for anger. It has also been proposed that mari can mean ‘rain’ as Mariyamman is sometimes referred to as a ‘cool goddess’ – or a goddess who can be propitiated by her image being cooled with water (she is said to be most active in the hot season, when contagious fevers are particularly dangerous). The term amman means ‘mother’ – in this context, an honorific.
See Taming the Fever Goddess: Transforming a Tradition in Southern India by William Harman, 2003