NEW OPTION FOR TREATMENT OF
POTENTIALLY DEADLY ANAPLASMOSIS
Bovine anaplasmosis isn’t a new disease but it can come as a
surprise to producers who have not yet seen it in their herds.
“It is the most humbling experience. You think you’re doing your
best to prevent illness in your cattle, then anaplasmosis hits,” recalls
Jason Lewis of Division Ranch near Strong City, Kan.
“I thought I was doing everything I could for my herd, and it
was like a slap in the face. In one week, everything changed.”
September 2017 was when everything changed. Lewis received a
call from his youngest son, Jaron, who was checking on their herd
and reported eight cows were dead. “I was on the phone with my son
when one cow dropped dead right in front of him.” Lewis lost 14 head
in that outbreak, and he’s been vigilant ever since.
Dr. Kathryn Reif, assistant professor in the Department of Diagnostic
Medicine/Pathobiology in the College of Veterinary Medicine at
Kansas State University, has been studying anaplasmosis in cattle
for nearly 10 years. “Anaplasmosis is a disease caused by a bacterial
pathogen, Anaplasma marginale, the pathogen that lives inside red
blood cells of cattle. It is the destruction of those red blood cells
that ultimately causes the hallmark sign of anaplasmosis, which is
anemia,” Reif explained.
“Ticks are the natural vectors for disease transmission, and cattle
of all ages are susceptible to becoming infected. However, adult
animals about two years old or older are more susceptible to
showing greater clinical signs of disease because they are slower to
replace the destroyed infected red blood cells compared to calves,”
Reif added. “Once an animal is infected, those animals tend to
remain infected for the duration of their life and serve as reservoirs
for subsequent transmission events.”
Anaplasmosis, like bovine respiratory disease, can be difficult
to diagnose. Similar to Lewis, sometimes the first indication of
a problem is the discovery of dead cattle.1 Until now, tetracycline
antimicrobials, oxytetracycline or chlortetracycline (CTC) medicated
feed, were the only drugs used in the U.S. for treatment of
anaplasmosis. In some areas, vaccines are available to increase
resistance to animals developing clinical anaplasmosis.
In April, Bayer Animal Health received conditional approval from
the FDA for Baytril® 100-CA1 (enrofloxacin) Injectable Solution for
the treatment of clinical anaplasmosis associated with Anaplasma
marginale in replacement dairy heifers under 20 months of age and all
classes of beef cattle except beef calves less than 2 months of age and
beef bulls of any age intended for breeding.
“Baytril 100-CA1 contains the proven molecule, enrofloxacin,” said
Dr. Jim Little, veterinary scientific liaison with Bayer Animal Health.
“Because of the need for additional options for treatment of clinical
anaplasmosis in cattle, the FDA granted Baytril 100-CA1 a Conditional
Approval (CA) to make it available to cattle veterinarians and producers
sooner, pending a full demonstration of effectiveness.”
With positive cases of anaplasmosis in cattle found in almost every
U.S. state2,3, Lewis believes it isn’t a case of if, but when producers will
experience the disease in their herds.
Map indicates the greatest risk areas for anaplasmosis infections.
Source: Kansas State University
Little also reminded producers that tick control is an important part
of an overall parasite management program. “There are a variety of
effective parasiticides available in many convenient forms such as ear
tags, pour-ons and sprays.” However, when an anaplasmosis outbreak
hits, he reminds producers to “always consult your veterinarian for
See product label for complete product information, indications and
Federal law restricts Baytril 100-CA1 to use by or on the order of a
licensed veterinarian. Extra-label use of Baytril 100-CA1 in foodproducing
animals is prohibited.
1 Whittier, D. Anaplasmosis in beef cattle. Drover’s. https://www.drovers.com/article/anaplasmosis-beef-cattle Oct. 27, 2015. Accessed February 21, 2020.
2 Kocan K, de la Fuente J, Blouin E, et al. (2010). The natural history of Anaplasma marginale. Vet Parasitol. 167(2-4):95-107.
3 Iowa State University. VDL Anaplasmosis. Available at: https://vetmed.iastate.edu/story/vdl-anaplasmosis. Accessed: April 21, 2020.
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