BENGALURU: Karnataka , which has been reporting a record number of positive Covid-19 cases each passing day has another concern looming. The number of asymptomatic patients testing positive has overtaken the number of symptomatic ones, a district-wise analysis of data up to April 16 shows.Asymptomatic patients turning positive account for nearly 60% of the total 315 cases as on Thursday, according to government data accessed by TOI. Of the 315 positives, 186 were asymptomatic, while 129 people had symptoms.The state has reported more cases since Thursday, and the government on Saturday said that as of Friday 208 of the 359 positive cases (58%) were asymptomatic. But district-wise breakup for Friday’s figures was not immediately available.Experts TOI spoke with said this trend will add additional stress on the state machinery, which is already struggling to cope with the increasing samples it has to test daily. “If there are more asymptomatic cases than those patients with symptoms, the authorities will not be able to neglect a large section of the population, which means an added burden on testing labs,” one of them said.Chief minister BS Yeddyurappa said on Friday that the state will increase the number of samples it will test daily, but the number of daily tests as of Friday still stood at 2,000, while the number of samples available for testing is way more. This has prompted the government to fix rates for testing of samples in private labs to augment capacity.Of the 20 districts that had reported Covid-19 cases as on Thursday, six (30%) reported more than 80% asymptomatic cases, including 16 of 17 (94%) cases in Vijayapura , while in Bengaluru Rural has all four cases reported have seen patients without symptoms turn positive.Three districts reported more than 60% of their cases as asymptomatic, while another three had zero per cent of cases without symptoms (see graphic).A paper published by Chinese researchers and doctors on April 4 reads “...In the period of initial success for Covid-19 control and prevention, one bottleneck has been screening out asymptomatic carriers for reducing new infections. As frontline doctors, we believe that there have been asymptomatic carriers of who can infect their close contacts.”In a specific article on asymptomatic carriers, Nature, a leading scientific journal notes that most people with mild infections would not be ill enough to seek medical help, and would probably slip past screening methods such as temperature checks, so the extent of the phenomenon and its role in virus transmission remains elusive.So far tests have been conducted on people who have arrived from other countries and primary and secondary contacts of those who have tested positive, which experts say may not be enough given the increasing number of asymptomatic cases.Dr CN Manjunath, member, a government task force on Covid-19, said: “In the coming days we will have to start conducting random tests. To begin with, random samples in hotspot areas and containment zones will be tested. This is the way forward, and also, like in any viral infection, with more time we will develop herd immunity.”