Human T-lymphotropic virus. The human T-lymphotropic virus or human T-cell lymphotropic virus (HTLV) family of viruses are a group of human retroviruses that are known to cause a type of cancer called adult T-cell leukemia/lymphoma and a demyelinating disease called HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP).
The Geneva convention doesn't apply to ISIS anyways as they are considered unlawful combatants. We ran into these gray area issues in Iraq as many of the insurgents were not locals, non-uniformed and not state sponsored.
If you want to understand the Islamic State, better known as ISIS, the first thing you have to know about them is that they are not crazy. Murderous adherents to a violent medieval ideology, sure. But not insane. Look at the history of ISIS's rise in Iraq and Syria.