Thiruvananthapuram, Nov 4 : The mystery sickness that engulfed Thalassery court near Kerala's Kannur district has now been identified to that of Zika virus after one of the 22 samples sent for test to the Alappuzha Virology Institute tested positive. Authorities in and around Thalassery were baffled for a while, after judges, advocates and staff working in the district court fell ill in quick succession. Most of them reported fever, red eyes, swollen body and pain. Despite the best efforts, the real cause was not known until it was decided to conduct a medical check-up. Blood samples were taken and sent for testing, and the results showed that one of them has tested positive for Zika virus. Zika virus is transmitted primarily by Aedes mosquitoes, which bites mostly during the day. Authorities have now announced that on November 6, another medical check-up of all the staff will be done during the office hours. The public health authorities have started an anti-mosquito drive in and around the court premises. /IANS