Anaplasmosis in cattle
Also called Gall sickness
A tick-borne bacterial infection of red blood cells in cattle, sheep, goats and buffalo that causes fever and anaemia. Recovered animals often stay carriers and can relapse when stressed.
Cause and spread
- Cause
- Bacteria of the genus Anaplasma, mainly Anaplasma marginale in cattle and Anaplasma ovis in sheep.
- How it spreads
- By many kinds of ticks, mechanically by biting flies, and through contaminated needles and dehorning or other surgical instruments. Signs usually appear 2 to 5 weeks after infection.
Signs to watch for
- Fever and loss of appetite
- Pale or yellow gums from anaemia
- Weakness, weight loss and drop in milk yield
- Relapse of signs in carrier animals when stressed or immune-weakened
Many diseases look alike. Only a laboratory test can tell them apart, so please see a veterinarian for any sick animal.
How it is diagnosed
Parasites are seen in Giemsa-stained blood smears as small dots at the edge of red cells. Antibody tests and PCR are also used; PCR can miss very low levels in chronic carriers.
- Usually the first testBlood Smear ExaminationLooks for the organism at the edge of red blood cells.
- Confirms the diseaseAnaplasma PCRDetects the genes of the bacteria.
- Confirms the diseaseBovine Haemoparasite PCR ProfileDetects Anaplasma with Babesia, Theileria and Trypanosoma.
- Supports the diagnosisComplete Blood Count (CBC)Shows anaemia.
Prevention and control
- Control ticks and biting flies
- Use a separate, clean needle and instrument for each animal
- Chronically infected cattle can relapse when stressed or immune-weakened, so keep carriers in mind when buying animals
- In some countries, a milder species of Anaplasma is used as a live vaccine
Where this information comes from
- Anaplasmosis in Ruminants · Merck Veterinary Manual
- Ehrlichiosis and Anaplasmosis (factsheet) · Center for Food Security and Public Health, Iowa State University
General information for animal owners and veterinarians, last checked October 2026. It does not replace the advice of your veterinarian, who should decide which tests and treatment your animal needs.