Two people with cholera symptoms were admitted to Kinango hospital on Wednesday, Kwale Health CEC Francis Gwama has said.
Gwama said the patients were from Mkongani in Matuga sub-county where the health team carried out contact tracing.
"We detected cholera symptoms in two people but they are now under medication," Gwama said.
He noted sensitisation, preventive drugs, water treatment and improved sanitation measures would keep the disease from spreading.
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Health chief officer Kishindo Mwaleso said it was confirmed that one of the patients had cholera but noted they were both in a good state.
But Emmaculate Awino, Matuga sub-county public health officer, said on Thursday that she was not aware of reports about the disease in the area.
"I have not heard of any cholera cases in Matuga. I will get in touch if I do," she said.
She added: "We are sensitising locals on sanitation but if the situation get out of control, we will order immediate closure of roadside food stalls."
Previous reports indicated the county had been cholera-free for about 10 years.
Health officials attributed this to the high number of officers employed at ward level and volunteers who helped distribute information about the disease and reported possible outbreaks.