Anaplasmosis: Is the bacterial disease a problem in the Northern Plains?
July 8, 2016
Buzz about anaplasmosis, a bacterial disease that affects the red blood cells of cattle has South Dakota cattle producers wondering if the disease, which can be common in cattle herds raised in warmer climates, has become established in the Northern Plains.
"The simple answer is no, not as of yet," explains Russ Daly, Professor, SDSU Extension Veterinarian, State Public Health Veterinarian.
Although cattle in South Dakota have been diagnosed with the disease, Daly said cattle producers should not be overly concerned because the conditions that favor the long-term establishment of the disease are not currently issues in South Dakota.
"Cattle which are anaplasmosis-positive found in South Dakota are usually cattle that have been transported here from endemic areas of the country," he said. "The conditions here, in contrast to those in the Southern U.S., are not hospitable for the infection to become well-established in our herds."
“The simple answer is no, not as of yet.” Russ Daly, SDSU Extension veterinarian
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Daly explained that anaplasmosis persists in cattle herds in certain parts of the country because of two things: a vector (tick) population that is active throughout most of the year and a population of persistently infected cattle.
"Tick activity serves to move the bacteria from infected cows and bulls to non-infected animals – oftentimes calves," he said. "In the Northern Plains, neither one of those factors are yet present. Tick populations are active for a relatively short time period, and more importantly, there is not a large resident population of infected cattle for which to serve as a source of the bacteria."
More about Anaplasmosis?
Once a red blood cell is infected with the Anaplasmosis germ, the animal's body recognizes it as abnormal and destroys it.
If an excessive number of red blood cells are infected and removed, anemia results and the blood is no longer able to adequately supply oxygen to the body's cells.
Anemia appears as weakness, rapid breathing, pale mucous membranes, and – if severe – collapse and death, especially when the animals are exerted.
"These signs almost exclusively happen in adult cows or bulls; calves can be infected but rarely show outward signs," Daly said.
Antibiotics, typically tetracyclines, are approved to control the disease in infected beef cattle (medication options are more limited for lactating dairy cattle).
"The medication keeps the infection down to the point where clinical disease is less likely, but it doesn't cure a persistently infected animal from the infection, nor does it prevent a susceptible animal from becoming infected," Daly said.
As a disease of blood cells, anaplasmosis is spread through transfer of blood. In areas where the infection is maintained, this occurs through tick bites.
"The bacteria can also be spread mechanically by biting flies and instruments such as needles carrying blood between animals," Daly said.
Even though anaplasmosis is not yet endemic here, Daly encourages cattle producers bringing animals in from endemic areas to be aware of its potential and ask their veterinarian for advice prior to purchase.
"A vet-to-vet inquiry about the anaplasmosis status of prospective purchases is a good idea, as is blood testing of animals imported from those areas," he said.
He added that although blood tests for anaplasmosis are good for screening, false positive results can occur. A polymerase chain reaction (PCR) test can be used to confirm infection status.
If a beef producer finds himself with positive cattle, Daly said a good practice would be to isolate them from the rest of the herd to minimize the possibility that biting flies or needles could spread the infection to the herd's susceptible animals.
In dairies, changing needles and palpation sleeves after working with infected animals is recommended.
The Bottom Line
Although anaplasmosis is not a common problem in the Northern Plains, Daly reminds cattle producers that other vector-borne diseases – vesicular stomatitis, for example – have popped up in our neighborhood when the conditions become favorable.
"Keep tabs on anaplasmosis and other emerging disease issues through conversations with your veterinarian and SDSU Extension livestock specialist," he said.