U.S. Department of Agriculture scientists at the Bee Research Laboratory in Beltsville, Maryland, have sequenced the genome of a parasite called Nosema ceranae that can kill honeybees and is suspected of playing a role in colony collapse disorder. They have also almost finished sequencing the genome of a related parasite, Nosema apis.

Nosema is a fungus-related microbe that produces spores that the bees consume when they forage. Infection spreads from the bees’ digestive tract to other tissues. Colonies can be wiped out within weeks. N. apis was the leading cause of microsporidia infections in domestic bee colonies until recently, when N. ceranae jumped from Asian honeybees to the European honeybees used commercially in the United States.

Sequencing the genome should help scientists figure out how N. ceranae became dominant, how the microbes spread infection, and how diagnostic tests and treatments can be developed, according to information from the ARS.