The spread of chikungunya continued to cause serious concern in many parts of Kerala [Images] with the toll mounting to 71 with six more deaths reported from the worst affected Alappuzha district on Wednesday.

A nine-member team of experts, including those from World Hospital Organisation, arrived in the state to make an on-the-spot assessment of the situation and help health authorities tackle the spread of the disease.

While more cases of chikungunya were reported from Palakkad, Ernakulam, Kottayam and Kollam districts, four casualties were reported due to rat fever (Weil's disease) from Thrissur, official sources said.

The experts, three of them from WHO and others from the National Institute of Virology and National Institute of Communicable Diseases, visited Cherthala area of Alappuzha district, from where most of the casualities have been reported and thousands of patients are still in hospitals.

The issue also rocked the state Assembly with the opposition United Democratic Front forcing an adjournment of the house for an hour, charging the government with having totally failed to tackle the situation.

The opposition, during the reply of Health Minister P K Sreemathy during the debate on the demand for grants of her ministry, walked out of the house, alleging that she was not taking the situation seriously and was trying to 'cover up' the magnitude of the problem.

After boycotting the proceedings, opposition members led by their leader Oommen Chandy, held a sit-in in the assembly complex.