Senegalese authorities are still trying to explain a mysterious skin disease that has affected a thousand fishermen since its appearance a week ago in the Dakar region, the Health Minister said Tuesday.

A viral and contagious risk has been ruled out as all reported cases have progressed favorably without complications.

Only one infected person out of a total of 1,004 according to a new assessment has been hospitalized, while there were much more cases a few days ago, Abdoulaye Diouf Sarr told a press conference.

‘’There is no contamination. It is not a contagious disease, there is no risk in relation to the consumption of fish," he said.

His colleague Environment minister, Abdou Karim Sall, raised the possibility that an algae was involved.

Samples analyzed by a laboratory did not reveal any chemical or toxic infection of the water or fish, the environment minister said. "The results of the biological tests did not reveal an infectious cause, but further investigations are underway," he said.

The analysis carried out by the anti-poison center of the Cheikh Anta Diop University of Dakar are scheduled for Tuesday or Wednesday, he added.

Many fishermen have complained about the poor sales of their products after messages on social networks advising them not to eat fish for a while.

In this West African nation, fishing generates more than 53,000 direct and 540,000 indirect jobs, according to the United Nations.