Diagnosis of Plasmodium falciparum malaria using rapid diagnostic tests and treatment with artemisinin derivatives, the main component of the malaria treatments recommended by the World Health Organization (WHO), are under threat in the Horn of Africa. Scientists have detected the emergence and spread in Eritrea of parasites with both artemisinin resistance and genome modifications that prevent their detection with rapid diagnostic tests, thereby jeopardizing malaria control and elimination campaigns in the region and potentially elsewhere in Africa.