Importation of canid rabies in a horse relocated from Zimbabwe to South Africa.

The article discusses a case where a 2-year-old Thoroughbred colt, moved from Zimbabwe to South Africa, developed signs of rabies five months after relocation. The diagnosis was confirmed through laboratory tests and the virus was identified as a type of canid rabies, common in domestic dogs and jackals in Zimbabwe.

Case Background

• In July 2003, a 2-year-old Thoroughbred colt was moved from Harare, Zimbabwe to the Ashburton Training Centre in Pietermaritzburg, South Africa.
• Five months after this transition, the colt started presenting with clinical signs that suggested an infection with rabies. These symptoms included uncoordination, muscle tremors, and the horse biting at itself.

Diagnostic Procedure

• To confirm the clinical diagnosis, brain tissue from the horse was submitted for laboratory analysis.
• The fluorescent antibody test, a commonly used method for diagnosing rabies, was utilized. In this test, antibodies mixed with fluorescent dyes attach to the rabies virus, allowing for visualization under a special microscope.
• The diagnosis was further solidified by the use of reverse-transcription polymerase chain reaction (RT-PCR), a method used to detect the presence of specific genetic material in any pathogen, including a virus.

Confirmation and Identification of Virus

• Phylogenetic analysis, a study of evolutionary relationships between organisms, was performed on the nucleotide sequence of the cytoplasmic domain of the glycoprotein and the G-L intergenic region of the rabies virus found in the horse’s brain tissue.
• The results confirmed the presence of canid rabies virus, a type of rabies virus predominantly associated with canids, the family to which dogs and jackals belong.
• The particular strain of the rabies virus originated from an area in Zimbabwe that is endemic for rabies in domestic dogs (Canis familiaris) and side-striped jackals (Canis adustus).