Equine Granulocytic Anaplasmosis.

This study investigates Anaplasma phagocytophilum, a tick-borne disease affecting horses. The research suggests that different strains of this disease have varying effects on different hosts, and it often co-occurs with other tick-borne illnesses. Common symptoms include fever, lethargy, loss of appetite, lameness and bleeding. The disease is typically diagnosed by blood testing and can be successfully treated with tetracycline.

Emerging Pathogens and Its Transmission

• Anaplasma phagocytophilum is an emerging pathogen that affects horses. The infection is transmitted through the Ixodid ticks.
• Recent studies suggest that multiple strains of A. phagocytophilum are circulating in both wild and domestic animals. These strains possibly have differential host tropisms and variations in their pathogenicity.
• A. phagocytophilum targets and survives within neutrophils, which are a type of white blood cell. When these cells get infected, the horse’s immune response is negatively impacted.

Co-Infections

• Co-infections, meaning simultaneous infection with multiple pathogens, are a common occurrence with this disease. In particular, Borrelia burgdorferi, another tick-borne pathogen, is often found alongside A. phagocytophilum.

Symptoms of the Disease

• A. phagocytophilum generally causes acute febrile illness in horses. The most common symptoms include fever, lethargy, loss of appetite, lameness and hemorrhages.

Disease Diagnosis and Treatment

• Diagnosis of A. phagocytophilum typically involves finding morulae (a certain developmental stage of the bacteria) within granulocytes in the peripheral blood. In addition, the DNA of A. phagocytophilum is detected using a specific approach known as polymerase chain reaction.
• The available treatment for this condition usually involves the use of a type of antibiotic called tetracycline. Reports suggest that anaplasmosis is a self-limiting disease, meaning it tends to resolve on its own over time, but the process can be expedited with the proper treatment regimen.