The death toll from contracting infection from tick bites in China's Henan province has climbed to 18.

According to provincial health authorities, the 18 victims were among 557 reported cases of suspected human granulocytic anaplasmosis (HGA) since May 2007.

"Most of the cases were found in Xinyang's Shangcheng and Guangshan counties and Shihe and Pingqiao districts," Xinhua news agency quoted provincial Public Health Department, as saying in a statement.

The officials said that disease is often reported from May to August, and most people infected are aged 40 to 70.

To investigate the cause of the disease, the Chinese Center for Disease Control and Prevention (CDC) has ordered Henan CDC to start monitoring the disease on May 31. (ANI)