Thirty-two per cent of the COVID-19patients treated at hospitals in Ernakulam district in Kerala were asymptomatic, official statistics showed on Monday with doctors voicing concern over the trend, saying such silent infections can lead to spread of the contagion.The statistics were released by the District Surveillance Team here on Monday, days after Ernakulam was declared "Green Zone" by the central government.According to the team, eight out of 25 people who were treated for COVID-19 in Ernakulam district were asymptomatic.Doctors warned that undiagnosed asymptomatic infection was dangerous as it may cause spread of virus and complicate efforts to bring it under control.Ernakulam Government Medical College Hospital Resident Medical Officer Dr Ganesh Mohan said the ability of the novel coronavirus to be transmitted by persons with no symptoms was a major factor for the its spread.The last patient under treatment for novel coronavirus in Ernakulam was discharged last week, making the district COVID-19 free.Seven British nationals were treated at the hospital here for novel coronavirus but only one among was symptomatic to COVID-19, officials said."Asymptomatic carrier state is dangerous because no one doubts about such persons' health conditions. If there is an asymptomatic carrier, the patient himself will not suspect that he is sick and he will go on with his daily activities and he will spread the disease", Dr Mohan told PTI.He said asymptomatic carriers should be a focus for disease prevention.