United States Department of Agriculture 

Animal and Plant Health Inspection Service

January 2024

Bovine Anaplasmosis

What is bovine anaplasmosis?

• Bovine anaplasmosis is caused by Anaplasma

marginale. A. marginale is a bacterial blood cell 

parasite that can infect wild and domestic 

animals including cattle, bison, water buffalo, 

African antelopes, and some species of deer.

• A. marginale is transmitted by many species of 

ticks, biting flies, and by re-use of blood 

contaminated equipment such as needles, 

dehorners, or castration instruments.

• Cattle of all ages can be infected and become ill,

but disease severity often increases with age. 

Once infected, many animals become lifetime 

carriers of the bacteria.

• Signs of infection include fever, weakness, 

weight loss, decreased milk production, 

constipation, increased aggression, difficulty 

breathing, and abortion. 

• Symptoms, such as anemia, may cause mucous 

membranes to turn yellowish or pale in color. 

However, the urine is not usually red as in 

babesiosis. 

• Signs/symptoms typically appear a month

after infection but can occur between 7 

and 60 days after infection.

• Diagnostic testing is required to confirm 

the presence of the pathogen. C-ELISA is 

a sensitive testing option, but PCR may 

also be used.

• There is no evidence A. marginale infects 

people.

• A. marginale can be treated using 

antibiotics such as tetracycline; however, 

even with treatment, cattle may remain 

carriers. 

Distribution of bovine anaplasmosis

• Throughout the world, bovine anaplasmosis 

is found in tropical and subtropical areas. In 

these areas, it can be a major burden to 

cattle production.

• In the United States, bovine anaplasmosis 

is endemic throughout the south, several

midwestern states, and western states and

has been reported in most states. 

Pasture Management and Tick Control

You can help control the spread of bovine

anaplasmosis by:

• Modifying tick habitat: keep grasses cut short 

and remove weeds and brush from grazing 

areas. 

• Restricting cattle from grazing in wooded 

areas or heavily tick-infested pastures to 

reduce tick exposure.

• Closely examining the health status of newly 

introduced animals. 

Information Sheet
United States Department of Agriculture 

Animal and Plant Health Inspection Service

• Regularly using Environmental Protection Agency 

(EPA) approved insecticide treatments (products 

that kill ticks and flies) on animals, vegetation, and 

equipment.

• Regularly inspecting cattle for flies and ticks. Ticks 

can be especially found in the ears, under the tail 

area, between the hind legs, and in udder skin folds.

• Treating animals for ticks with either EPA approved 

pesticides or Food and Drug Administration (FDA)

approved treatments. Make sure to follow label 

instructions.

• Reducing fly habitat by sanitation practices such as 

cleaning out hutches/stalls/pens/feeding lanes/bunks 

on a regular basis, properly managing manure, and 

securing storage of feed. 

Biosecurity Practices

• Protect yourself from ticks and flies by using 

insect repellents containing DEET, picaridin, 

IR3535, oil of lemon or eucalyptus, paramenthane diol, or 2-undecanone. 

• When handling livestock, do not use farm medical 

instruments like OB sleeves and needles on 

multiple animals. Thoroughly clean and sanitize

equipment and devices before and after use on 

each animal.

• If you suspect Anaplasma infection, experience 

livestock losses, or observe conditions such as 

signs of anemia, report these to a local

veterinarian immediately.

Report Suspicious Cases

Suspect cases should be reported to your State 

Animal Health Official. 

For more information, contact:

USDA, Strategy and Policy, Ruminant Health 

Center vs.sp.ruminant.health@usda.gov.

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