"There has been a confirmed case of Kala Azar and the patient has been referred to the Thrissur Medical College Hospital," District Medical Officer Dr R Sushita K said today.
The patient hails from Muloorkara in the district and two others with similar symptoms have also been referred to the medical college, she told PTI.
Kala Azar cases are usually reported from states like Bihar and Uttar Pradesh.
Meanwhile, state Health minister, V S Sivakumar, said this was an isolated incident and there was no need to panic.
The symptoms include fever, weight loss, fatigue and anaemia, swelling of the lever and spleen.
According to World Health Organisation, the disease is highly endemic in the Indian subcontinent and in East Africa.