A world-first human trial has used live hookworms to combat diseases such as Type 2 diabetes. 

Dr Doris Pierce from JCU’s Australian Institute of Tropical Health and Medicine (AITHM) says infecting people with microscopic hookworm larvae is safe and has had a beneficial impact on their glucose metabolism, inducing a significant reduction in insulin resistance levels in most trial participants.

Dr Pierce recruited 40 people - all with early warning signs of future metabolic diseases such as type 2 diabetes - to take part in the two-year clinical trial.

“Participants were inoculated with either 20 or 40 infectious larvae of the human hookworm species Necator americanus or a placebo,” said Dr Pierce.

“Metabolic diseases are characterised by inflammatory immune responses and previous studies have suggested that hookworms release proteins into their host to control the immune system and safeguard their survival,” said Dr Pierce.

Successful efforts to eradicate parasitic worms in developed countries are now linked to increases in human inflammatory and metabolic diseases, including type 2 diabetes.

Dr Pierce said all participants in the JCU trial received regular clinical health checks for safety purposes.

“All trial participants had risk factors for developing cardiovascular disease and Type 2 diabetes. The trial delivered some considerable metabolic benefits to the hookworm-treated recipients, particularly those infected with 20 larvae,” said Dr Pierce.

She said it was striking that participants infected with 20 hookworms experienced a median Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) level drop from a pre-trial level of 3.0 units to just 1.8 units within 12 months, restoring their level of insulin resistance to a normal, healthy range.

Worm recipients tended to report feeling better, mood-wise, than those in the placebo group.

“That was an interesting observation as well, given that much of the trial took place during the first waves of the COVID-19 pandemic. I think to see any improvement in mood was remarkable in itself,” said Dr Pierce.

After two years, participants were offered a deworming medication or could elect to stay in the trial for a further 12 months. 

All but one of the infected participants decided to keep their worms.

The full study is accessible here.