New research from the U.S. Department of Agriculture (USDA) shows that diseases in honey bees aren’t just limited to the spring. This article from USDA says information from Ryan Schwarz and Jay Evans, entomologists with the Agricultural Research Service (ARS) in Maryland, shows that two pathogens causing mysterious honey bee ailments might pose a threat year-round.

Schwarz and Evans, based at the ARS Bee Research Laboratory in Beltsville, and their colleagues at the Brazilian Honey Bee Laboratory in São Paulo analyzed the DNA of bees in Beltsville and Brazil between 2011 and 2013. Bees were collected from 11 states in Brazil and 2 areas in Beltsville. Schwarz had recently developed genetic markers that allow researchers to distinguish S. apis from other bacteria in bees. They used those markers and another recently developed set of S. melliferum markers to determine the year-round prevalence of the two pathogens.

As expected, the researchers found that both pathogens were prevalent in the spring. But they also found that they were common at other times of the year as well and that their prevalence rates varied depending on the location. In Beltsville, the pathogens were more prevalent in the spring, while in Brazil they were more prevalent in the fall. The results also showed that S. melliferum was the more prevalent of the two and that the presence of one pathogen made bees more susceptible to the other.

The researchers say this information should help beekeepers and scientists monitor the health of honey bees by raising awareness about the year-round nature of the threat the pathogens might pose.