The Pentagon has been urged to investigate whether ticks were developed as 'biological weapons' amid a rise in Lyme disease cases in the US.
A bill passed in the House of Representatives by a vote last week has demanded a thorough investigation into the source of the illness.
Pentagon officials will determine whether ticks and other insects were 'weaponised' and used in experiments by the Department of Defense between 1950 and 1975.
Politicians also demanded they reveal whether any ticks or insects used in such experiments were released outside of any laboratory either by accident or on purpose.
The number of reported cases of Lyme disease in the US has more than doubled since the mid-1990s, according to official figures.
Lyme disease is uncommon but can have crippling and even deadly effects – it's most often spread by the bites of ticks.