November 21, 2018

The Veterinarian's Role in Beekeeping

In this billion-dollar industry, veterinarians are a major asset in maintaining the health of bee colonies.
By Nicola M. Parry, BVSc, MRCVS, MSc, DACVP, ELS
The bee represents not just an important pollinator but also an economic superpower, according to Jörg Mayer, DVM, MS, DABVP (ECM), DECZM, DACZM, an associate professor of zoological and exotic animal medicine at the University of Georgia College of Veterinary Medicine in Athens. “There were an estimated 120,000 beekeepers in the United States in 2017, operating within a billion-dollar industry,” he said.

“Bees are insects, but few veterinarians realize they are also classified as food animals,” Dr. Mayer said. “They are the only managed animal species whose food cannot be provided or controlled by the farmer.” During a presentation at the Indiana Veterinary Medical Association’s 2018 annual meeting in Indianapolis, Dr. Mayer highlighted the important role of veterinarians in bee health.

Bee diseases are important from an economic standpoint, Dr. Mayer said, with some designated as reportable. (Box 1)1 Recent regulatory changes aiming to combat the development of antibiotic-resistant bacteria also now mean that beekeepers can no longer purchase over-the-counter antibiotics to treat their bees. As of January 1, 2017, FDA rules require beekeepers to obtain antibiotics from a veterinarian, through either a prescription or a written order known as a veterinary feed directive. This gives veterinarians a new and important reason to become involved in bee health.

Although veterinary students have traditionally received broad training in disease diagnosis and management across a variety of species, until recently, bee medicine was rarely taught at US veterinary schools. In contrast, Dr. Mayer noted, bees have been part of the veterinary curriculum in Mexico and Europe, as well as in other countries outside the United States, for some time.

Veterinarians are a major asset in beekeeping, he said. Just as is the case when caring for other animal species, the role of the veterinarian in beekeeping focuses on prophylaxis and managing colony health disorders. “Think ‘herd health,’” Dr. Mayer said: The unit is the hive or the bee colony, not the individual bee.

Veterinarians may become involved in different aspects of beekeeping, Dr. Mayer said, including:
  • When the beekeeper sees clinical signs
  • At the request of insurance companies
  • To prevent diseases
  • In epidemiologic studies
  • During removal of wild colonies in residential settings
Veterinary involvement is essential at all sector levels, he added. To help maintain bee colony health, the local veterinarian may inspect the beekeeper’s hive and assess the property. State veterinarians play an important role in public health and managing notifiable bee diseases. Because of the economic importance global level, such as by implementing regulations to control bee diseases.

COMMUNICATING WITH THE BEEKEEPER
Veterinarians must participate as a team with beekeepers and apiary technicians, Dr. Mayer said. “Be respectful and listen carefully to them,” he advised, “but don’t automatically assume they are experts because they have been keeping bees for 20 years.” When inspecting a bee colony, veterinarians should ask pertinent questions (Box 2) that will provide infor- mation to help them assess the colony. Veterinarians should also encourage beekeepers to maintain good records, he noted, including a log of dates of all veterinary inspections and interventions.

INVESTIGATING THE COLONY
A bee colony should be examined during the day—“not too early, and not too late,” Dr. Mayer advised. Bees are most active and collecting pollen and nectar during the day. “At this time, when the bees are warm and full of nectar, they are quite tame to handle,” he explained. Also, most pests that attack the hive, such as skunks and racoons, are active at night.
When examining the colony, it is important to take a systematic approach that will minimize colony stress and disruption, Dr. Mayer said.

First, examine the external hive, documenting its type and placement (eg, off ground or leveled, proximity to other hives). Also, inspect the front for obvious signs of problems (eg, dead bees, bee feces). Note any important environmental factors, too, he said, such as the outside humidity level, whether the hive is exposed to direct sunlight or full shade, and whether it is in a high-traffic area. Take multiple photographs of the hive’s external appearance and environment, as well as any important findings.

Next, open the hive. “But just before opening it, use your stethoscope on the hive, listening as you tap on it,” Dr. Mayer said. “After tapping, you should hear the bees react by making a revving noise.” This will provide a good idea about the strength of the colony. After opening the hive, check for the presence or absence of propolis. “This is the resinous material that bees use to glue their hive together,” Dr. Mayer said. Note whether the bees are aggressive, whether other insects are present, and what the hive smells like: “Is it sweet, or is there a rotting smell?” To minimize stress on the bees, Dr. Mayer advised keeping the hive open for no more than 15 minutes. Again, take lots of photographs to document findings, he said.

Now inspect the inside. “You should remove a frame from the hive and look closely at it,” Dr. Mayer said. “A typical covered frame has approximately 1400 bees on it if it is well populated.” Make sure no parasites are present on the frame, he added. Next, check to see if any of the bees have physical abnormalities, such as crippled wings. Examine their behavior for any abnormalities—for example, are they neurologically appropriate? Because the queen bee is central to a strong and productive colony, be sure to locate her and verify her health status. “Some beekeepers mark the queen,” Dr. Mayer said, “but, if not, she is often easy to locate, because she is typi- cally much larger than the worker bees and is always surrounded by a few worker bees, too.”

Also, examine the brood, including cell shape and distribution. “There should be approximately 800 cells per square decimeter,” Dr. Mayer noted. Examine the cells and record the color and consistency of the wax: “New wax should be white to yellow, and old wax is pigmented.” Check for the presence of pollen and honey. “Examining the brood is the equivalent of cardiac auscultation in the mammal. This is what keeps the colony alive. Without the brood, the hive will soon die,” Dr. Mayer said.

Considering all findings of the hive examination will provide a good idea of the colony’s health status.

IMPORTANT CAUSES OF COLONY LOSS
Bee diseases can be caused by biological hazards (eg, bacteria, viruses, parasites) or chemical hazards (eg, toxins), Dr. Mayer said. However, the categories should not be separated.

Mites
Varroa destructor mites, a particularly common problem, are a significant cause of colony loss. This type of mite presents as a red moving spot on either the bee or the hive’s bottom board, according to Dr. Mayer.2 Infested bees can experience a shortened life span, weight loss, wing and limb deformity, and reduced natural resistance to infections. Varroa infestation contributes to significant losses in apiaries, predominantly because the mite transmits serious bee viruses, including acute bee paralysis virus, black queen cell virus, chronic bee paralysis virus, deformed wing virus, Kashmir bee virus, and sacbrood virus.

The mite can also play a role in transmitting spores of the bacterium Paenibacillus larvae subsp larvae, the cause of American foulbrood, which is one of the few bee diseases capable of killing a colony.

Varroa detection should be part of the veterinarian’s hive inspection routine, Dr. Mayer emphasized. One way to do this is to examine the bottom board, he noted, because Varroa mites frequently fall off the bees and land there.

Strategies to help control Varroa infestations range from natural control of the mite to chemical control. Pesticides can also be used, Dr. Mayer said. These can be added to the bee’s feedstuff, applied topically on adult bees, or used as a fumigant on a contact strip that hangs in the hive. However, the mites are developing drug resistance, a significant and growing problem,3 he emphasized. Additionally, because the residue can be found in honey, pesticide misuse can lead to problems.

Hive Beetles
The small hive beetle, an invasive bee pest from Africa, is an emerging health concern in the United States and can be a serious problem for beekeepers. “Maintaining a strong colony will keep this beetle in check,” Dr. Mayer said. Beekeepers can use strategies such as manually removing the beetle from the bees and hive or using pesticide strips. Severe infestation can lead to swarming of the bee colony, he noted, and veterinarians should investigate why the colony was not strong enough to combat the problem.

CONCLUSIONS
In an interview with American Veterinarian®, Dr. Mayer explained that inspecting the hive may not always be enough to identify the cause of colony losses. “Postmortem examination may be required to reach a diagnosis in some cases,” he said, “and the veterinarian may need to sacrifice some bees for this purpose.” Because no specific clinical practice guidelines exist for bee euthanasia, he recommends selecting a method that induces death as quickly and humanely as possible. “These include techniques such as rapid decapitation using a scalpel blade or simply placing the bee in a jar of formalin,” he said.

For veterinarians interested in learning about beekeeping, Dr. Mayer advised: Get a bee and get a book. “I recommend getting 2 hives, so you can compare bee behavior between them,” he said. “Knowledge is power.”

Veterinarians are a major asset to the beekeeping sector, and the One Health concept provides a basis for cooperation among all current and future stakeholders in this sector, Dr. Mayer concluded.

References

1. 2017 U.S. National List of Reportable Animal Diseases (NLRAD) – National Animal Health Reporting System (NAHRS) reportable disease list. aphis.usda.gov/animal_health/nahrs/downloads/2017_nahrs_dz_list.pdf. Published 2017. Accessed August 22, 2018.
2. Mayer J. Red specks on honeybees (Apis mellifera). Lab Anim (NY). 2005;34(7):19-21. doi: 10.1038/laban0705-19.
3. Pettis JS. A scientific note on Varroa destructor resistance to coumaphos in the United States. Adipologie. 2004;35(2): doi: 91-92.

                                                                                                                                                                                                    
Dr. Parry, a board-certified veterinary pathologist, graduated from the University of Liverpool in 1997. After 13 years in academia, she founded Midwest Veterinary Pathology, LLC, where she now works as a private consultant. Dr. Parry writes regularly for veterinary organizations and publications.




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