A deadly fungus that wipes out honeybees has arrived in Northern Ireland for the first time.
Belfast-based scientists have warned beekeepers in the province to be vigilant against the disease that has killed huge numbers of the insect in Spain.
Nosema ceranae infects adult bees when they ingest its spores, which then germinate in the gut and impair the bee’s ability to absorb nutrition, particularly protein.
It has caused serious losses of honeybees in Spain linked to Marie Celeste Syndrome or Colony Collapse Disorder.
The disease was found in north Dublin in 2008 after it was first detected in six colonies in England and three in Wales in 2007.
Scientists at Belfast’s Agri-Food and Biosciences Institution (AFBI) laboratory confirmed fears that the parasite is here, although they believe it may have been present for some time as it was found in four colonies spread across Northern Ireland.
Another strain of the bee-killer, N. apis, was already present in Northern Ireland’s hives but N. ceranae is more aggressive, according to AFBI higher scientific officer Sam Clawson.
He said the scientists are monitoring the deadly fungus to prevent it affecting colonies here as seriously as those in Spain.
“In Spain the impact was very severe but in other countries it had no impact at all,” he said.
“It did cause problems there — it was seen as a cause of Colony Collapse Disorder. However, it has probably been here for some time.
“We are monitoring it and as far as beekeepers are concerned, it will just be another problem to watch out for.
“Bees travel from their hives and may contaminate each other — poor management of hives can play a part. It’s about making sure they are clean and well-managed — good husbandry in beekeeping. The message to beekeepers is to be vigilant and have good husbandry.”
One of the four samples in which the spores were detected came from attendant worker bees with a queen imported from the Republic.
The other three samples were taken from local colonies with no evidence of importation. The apiaries are in counties Antrim, Down and Londonderry.
The scientists examined the samples for the killer bug using light microscopy and the presence of N ceranae was confirmed by molecular techniques to detect species-specific DNA.
N. ceranae was originally described in 1996 as the Asian variant of N apis affecting the eastern honeybee.
An AFBI spokesman said: “Nosema ceranae is considered to produce a more virulent disease than N. apis, probably reflecting its more recent association with the western honeybee. Nosema ceranae symptoms differ from those produced by N. apis.
“The dysentery and crawling behaviour associated with the latter infection may not be displayed by bees infected with N. ceranae.
“Rather the symptoms of an infection are more nondescript and include colony dwindling and increased overwintering mortality.”
He said that approximately 20% of beekeepers in Northern Ireland use an antibiotic called fumagillin dicyclohexylammonium to fight the bee-killing parasite.
“Experimental studies have shown that this treatment is effective against N. ceranae, although work is ongoing.
“Antibiotics, though, will not kill spores in the hive, so comb changing and a hive scorch are recommended to clear an infection.
“As with all bee diseases, hygiene, good nutrition and vigilance are paramount,” he added.