“To our knowledge it is the first time such a doubly armed organism appears in nature,” said researcher Manu Vanaerschot, who obtained a PhD for his detective work at ITG and Antwerp University. “It certainly makes you think.”

Vanaerschot studies the Leishmania parasite, a unicellular organism that has amazed scientists before. Leishmania is an expert in adaptation to different environments, and the only known organism in nature disregarding a basic rule of biology: that chromosomes ought to come in pairs. (The latter was also discovered by ITG-scientists recently.) The parasite causes leishmaniasis, one of the most important parasitic diseases after malaria. It hits some two million people, in 88 countries—including European ones—and annually kills fifty thousand of them. The parasite is transmitted by the bite of a sand fly. The combined resistance against a medicine and the human immune system emerged in Leishmania donovani, the species causing the deadly form of the disease.