Thiruvananthapuram, June 23 (IANS): Three migrant labourers in the state have been identified with kala azar or 'black fever', said Kerala health authorities.

A top state health officer on condition of anonymity said that one case has been detected in Thrissur and two in Malappuram district.

Kala azar or black fever in medical lexicon is known as Visceral leishmaniasis (VL), and is prevalent in central India and parts of north India, but not in Southern India.

One of the patients currently being monitored for the disease is from Jharkhand.

Fever outbreak at the onset of monsoon is very common in Kerala. But the nodal officer for H1N1 in the state Amar S. Fettle said that at the moment things are under control and all precautionary activities are being undertaken.

"I am in touch with health officials in all the districts through video conferencing and all the necessary inputs for them are given on a day-to-day basis," said Fettle.

Meanwhile, cases of various other diseases like dengue, malaria and rat fever have been reported from central districts of the state and also from Kasargod and Kozhikode.