Two women smoke cannabis vape pens at a party in Los Angeles. Picture: Richard Vogel/AP.

NEW YORK (AP) — Health officials say their investigation into a recent outbreak of severe vaping-related illnesses is increasingly focused on products that contain THC.

The Centers for Disease Control and Prevention said Friday most people who got sick vaped THC, the ingredient that produces a high in marijuana.

A new study published by CDC found two-thirds who got sick in Illinois and Wisconsin said they vaped prefilled THC cartridges from one brand.

The investigation is ongoing. No single device, ingredient or additive has been identified.

The ailment has sickened at least 805 people, from 46 states and one U.S. territory. Thirteen deaths have been reported, from 10 states.

In South Africa, calls are mounting for a ban on e-cigarettes after several deaths in the US were attributed to vaping, and after India banning the selling, producing, importing, or advertising of e-cigarettes.

The national government’s proposed Control of Tobacco Products and Electronic Nicotine Delivery Systems Bill seeks to regulate e-cigarettes in the same way as traditional cigarettes.