Hyderabad, Nov 29 : As many as 42 students and one teacher of a government-run residential school for girls in Telangana's Sangareddy district have tested positive for Covid-19. The cases have come to light at Mahatma Jyotiba Phule Gurukul school at Muthangi village in Sangareddy district, about 50 km from Hyderabad. Of the 491 students at the school, Covid test was conducted on Sunday on 261 students. A total of 42 students were found infected. Health authorities were conducting tests on remaining students on Monday. A health official said all 27 teachers and staff members were screened and one teacher was found positive. The samples of the students who tested positive were sent to Hyderabad for genome sequencing. The official said the infected students were kept in isolation at the hostel in school premises and they were all stable. A student had taken ill three days ago. Since she was showing suspected symptoms of Covid, the school authorities decided to conduct tests on all students. This is the third incident of students testing positive in large numbers at any educational institution in Telangana during the last 10 days. Last week, Mahindra University near Hyderabad was shut down after 25 students and five staff members tested positive for the virus. The authorities conducted Covid tests for 1,700 students and staff members. A total of 25 students, one faculty member and four support staff were tested positive. The university declared a holiday for 15 days and began online classes from Monday. Earlier, 29 students of a government-run residential school and junior college for girls in Khammam district had tested positive for the Coronavirus. The cases were reported at the school and junior college in Wyra town. The school authorities conducted tests for all 550 students after a couple of students showed suspected symptoms. This was the first time since reopening of residential schools in the state last month that such a large number of students were found positive. Educational institutions in Telangana reopened from September 1. However, the High Court allowed reopening of residential schools in the last week of October after the education department gave an assurance that all preventive measures will be taken. /IANS