Identification of Anaplasma spp. rickettsia isolated from horses from clinical disease cases in Poland.

The study investigates the cause of disease symptoms, such as fever, joint swelling, poor coordination and low platelet count, in five horses. It was discovered that the diseases were associated with the genetic material of a particular tick-borne bacteria. Treatment with a specific antibiotic led to gradual recovery.

Objective of the Study

• The aim of the study was to identify the root cause of clinical symptoms experienced by five horses. Their symptoms included fever, joint swelling (oedema), lack of coordination (ataxia), and low thrombocyte (platelet) count (thrombocytopenia).

Methods and Findings

• The researchers used the Polymerase Chain Reaction (PCR) technique – a method used to amplify select sections of DNA – for their study.
• The PCR analysis revealed presence of the Anaplasma/Ehrlichia spp. bacteria in the blood of the five horses.
• The primers EHR 521 and EHR 747 used in the PCR process, which help start the DNA synthesis, resulted in a DNA product of 247 base pairs (bp).
• The sequence of the PCR product showed 97.6 – 99.6% similarity to the sequence of 16S RNA of the Anaplasma phagocytophilum, a species of bacteria known to be pathogenic to horses.
• The specific sequence similarity was found with the 16S RNA Anaplasma phagocytophilum gene number EU 090186 listed in the GenBank – a database of all publicly available genetic sequences.

Treatment and Recovery

• Following the diagnosis, the horses were treated with intravenous administration of an antibiotic, oxytetracycline. They received a dose of 8 mg per kg of body mass for a period of 7 days.
• The treatment resulted in a gradual recovery from the symptoms.