University of Maryland scientists have genetically modified a fungus to produce a toxin fatal to mosquitoes, in order to reduce the malaria death toll they currently cause. An out-of-lab trial destroyed a mosquito population almost entirely within 45 days, leading some to criticise the work as “too dangerous” for the real world.

The study, published in Science journal, took a fungus that naturally kills mosquitoes and engineered it to produce a toxin from the Australian Blue Mountains funnel-web spider instead, resulting in a swifter demise for mosquitoes. When tested in a screen-enclosed village in Africa, the fungus almost wiped out the mosquito population in under 45 days.

A member of environmental group Friends of the Earth had concerns, however: “Genetic engineering of fungus could have problematic negative public health impacts and unpredictable ripple effects on ecosystems, affecting pollinators, bats, and bees. Like with all genetic engineering, this needs to be addressed with great caution.”