Researchers in Japan say they’ve discovered “super” resistant mosquitoes in Asia. In a study published this week, they detail finding populations of Aedes aegypti mosquitoes—a common disease vector—in Vietnam and Cambodia carrying several mutations believed to confer strong protection against the most widely used insecticides. The discovery should merit urgent action to prevent these mutations from spreading globally, they argue.

A. aegypti mosquitoes are one of the most prolific sources of human misery in the world, thanks in part to the wide assortment of germs they can transmit to us. These mosquito-borne diseases include yellow fever, dengue, Zika, and chikungunya, to name a few. The global presence of A. aegypti (along with a related species, A. albopictus) and the diseases they spread has expanded in recent years. Many experts expect their range to only grow wider over the coming decades as the climate continues to warm, including throughout the southern and eastern parts of the United States. So these new findings, published Wednesday in Science Advances, might add yet another concern to an already serious problem.