A Good Time To Check For Anaplasmosis
As winter approaches, active cases of bovine anaplasmosis typically drop off. But now isn’t the time for veterinarians and producers to let down their guard. Instead, because there aren’t as many vectors around in winter, this is a good time to evaluate the disease status in cattle herds, according to Hans Coetzee, DVM, PhD and Head of the Department of Anatomy and Physiology at Kansas State University.
“One of the control strategies that we’re very enthusiastic about is for producers to work with their veterinarians to take blood samples from animals that they consider to be at risk, and to do diagnostic testing so that they can understand how many animals in the herd are truly infected with the disease,” Coetzee says.
He notes that when entire herds are blood sampled, veterinarians typically find that only one-third to one-half of the herd is actually positive for the disease.
“So, for a producer to spend a lot of money to control a disease on a herd-wide basis, when only a subset of the animals are infected, may not make the most economic sense,” he says.
The vaccine costs up to $20 per head for the initial shot and booster, whereas, the diagnostic test costs between $6 and $8 per animal, on average.
“Assuming that the current, conditionally-licensed vaccine is effective, vaccinating only the seronegative animals is likely more cost effective than herd-wide vaccination,” Coetzee says.
Also, he encourages veterinarians to remind producers to change needles between animals when vaccinating, as needles are one of the most significant risk factors for transmission.
Kansas State University veterinarian Gregg Hanzlicek, referencing one research project, says six out of 10 animals became infected just from moving the needle from a positive animal to a negative animal.
Anaplasmosis, which is caused by a blood parasite, is also transmitted from animal to animal by ticks and biting flies. Infected animals might not show clinical signs, but once infected the animal will be a carrier of the disease for life.
Anaplasma marginale is the most common pathogen of cattle, but researchers have found over 100 strains and suspect there are many more.
Earlier this year, researchers at the K-State College of Veterinary Medicine, in collaboration with Iowa State University, announced the development of a new vaccine delivery platform to protect cattle from anaplasmosis infections. The single-dose vaccine is administered in the back of the animal’s ear. The vaccine has been shown to protect against clinical anaplasmosis for up to two years.
Iowa State University currently holds a patent for the implant platform. The K-State/Manhattan Innovation Center is exploring a partnership with Iowa State to further develop the technology. One of the first steps to commercial use would include working with a partner who could help secure approval from USDA.