The government of Anambra, a state in southeeastern Nigeria, has banned the drinking of raw garri, which it says can lead to Lassa fever.
The disease is transmitted to humans via food and objects contaminated with rodent urine or faeces, according to the World Health Organisation.
Garri is a popular Nigerian food made from cassava that can be eaten or drunk. If it is cooked thoroughly, the Lassa fever virus will die.
But many Nigerians consume it raw.
“The garri you see spread along the highway while you’re travelling is very risky to consume, especially when you drink it,” said Anambra’s State Commissioner for Health, Dr Joe Akabuike.
He added that much of this garri has been has been exposed to contamination.
Cases of Lassa fever have been recorded across Nigeria.
On Sunday, a doctor died in Edo State after contracting the disease from an infected child.