The Ministry of Education loses between four to six of the 235,000 teachers daily through HIV/Aids. Permanent Secretary Prof Karega Mutahi said there was a large number of teachers already infected and that many others are bed-ridden. This has affected teaching and student performance in both primary and secondary schools, he added. "Sick teachers have to be on the payroll which means that the already stressed education system must carry a large proportion of unproductive persons. That means that work is piled up on those not sick," he said.