There is a rapidly spreading viral disease in Britain that is killing bees. It is raising alarm with researchers, who are studying whether it is a new strain of the chronic bee paralysis virus that was recorded only in Lincolnshire in 2007.

It seems that bees raised by beekeepers and professionals are most commonly affected by the disease. Many dead bees are found lying outside hives with entire colonies frequently wiped out by it.

Chronic bee paralysis virus (CBPV) is a viral disease with such symptoms as severe abnormal trembling, inability to fly, and shiny, hairless abdomens followed by death. Honeybees suffer from it for about a week before they die.

A decade after it was found in Lincolnshire, it was found to be in 39 of the 47 English counties and 6 of the 8 Welsh counties, according to data collected from over 24,000 beekeepers.

This 2:23-minute long video shows bees infected with CBPV virus:

Professor Giles Budge of Newcastle University’s School of Natural and Environmental Sciences led the team of scientists that identified clusters of the disease. The most concentrated number of cases were in apiaries of professional beekeepers as compared to amateurs, where management practices differ significantly.

Their study, published in Nature Communications, was based on data from 130,000 honeybee imports from 25 countries. For the first time it was supported that CBPV was twice as likely to be found in apiaries owned by beekeepers who imported honeybees. Professional beekeepers import honeybee queens every few years to replenish their hives.

This is not a new virus; it has been around since the time of Aristotle, who described the symptoms. Modern researchers are concerned that a new and more virulent strain could be behind this global surge.

Infected bees carry the virus for up to 6 days before showing symptoms and can spread it to other colonies via food foraging areas where other bees come in contact and bring it back to their colonies. The virus appears to be rapidly transmitted in densely populated hives, and hive size is larger in commercial beekeeping.

According to Budge, British professional beekeepers may run into problems in spring, when the bee colonies they successfully brought through winter seek out early flowers like oilseed rape. But if the weather grows wet, these large colonies will be confined in their hives where no social distancing is possible, so space would need to be increased.

Another problem is that a quarter of beekeepers have multiple bee sites, which could help spread the disease since significant clusters of the disease were found up to 40 km apart, but honeybees only forage up to 10 km away from home.  

Budge indicated it was “unfair” to conclude that the disease is caused by industrial beekeeping and that is it as yet unclear whether the disease was imported by queens. He said compared to Germany and the USA, where beekeeping operations may have up to 10,000 colonies, bee farmers in Britain are small-scale, with 100-200 colonies.

Even in the United States there is a substantial increase in CBPV. In 2010 prevalence was at 0.7% but by 2014 it had reached 16%. In Italy, it doubled from 5% to 10% between 2009 and 2010 alone. And in China, it grew in prevalence from 9% to 38%.

This disease “burns out” in Britain and does not recur in hotspots between seasons, it returns to other locations in the country over time. It has also bee found in wild bumblebee and ant populations, but the direction of transmission is unclear.

Research continues on the genetics of the disease to determine if this is a new strain, the susceptibility of different honeybee races, whether imported queens bring the disease into Britain, or if those queens are more susceptible to the virus that is already there. Hopefully this work will reduce or mitigate the damage this disease can do to honeybees.

The project is a collaboration between Newcastle and St. Andrews Universities, the Bee Farmers’ Association and the National Bee Unity of the Animal and Plant Health Agency with funding by the BBSRC.

Rob Nickless, chairman of the Bee Farmers’ Association, said that this is the sort of research that brings practical benefits at a grassroots level to bee farmers and to the industry, helping to improve honeybee health and increase UK honey production.

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