Disseminated Halicephalobus deletrix infection in a horse.

The research article presents a case study of a 13 year-old horse that had a severe infection caused by the parasite Halicephalobus deletrix, affecting several organs which eventually led to the animal’s euthanasia.

Overview of the Case

• A 13-year-old Quarter Horse was brought for evaluation due to a draining tract and fracture in its right hemimandible (lower jaw bone) which had been present for 4 weeks.
• The horse started to show sign of pigmenturia (dark colored urine) two days before admission. This indicated possible problems with kidney function or damage to red blood cells.

Diagnostic Findings

• Radiography (X-Ray imaging) of the mandible showed a fracture in the vertical ramus (part of the lower jaw bone), loss of the right lower second premolar (a tooth), and a case of osteomyelitis (bone infection) affecting a large part of the affected lower jaw bone.
• Ultrasonography of the left kidney showed irregularities in its structure, hinting at potential problems in this organ as well.
• A histologic examination of tissue from the impacted mandible revealed granulomatous osteomyelitis and presence of multiple metazoan parasites identified as Halicephalobus deletrix. Granulomatous osteomyelitis is a chronic form of bone inflammation characterized by granulomas or nodules of immune cells that form as a result of prolonged inflammation.

Treatment and Outcome

• The horse was treated with antimicrobial drugs to address any bacterial infections and deworming agents to clear the parasites.
• A surgical debridement was also performed. Debridement is the process of removing dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue.
• However, the horse became atactic (had problems with motor coordination) 8 days after surgery, which led to its euthanasia on compassionate grounds.

Postmortem Findings

• A necropsy (post-mortem) examination found evidence of parasitic migration in the right mandible, kidneys, and the central nervous system (CNS). This meant that the parasites had moved from their original location in the mandible to other parts of the body, leading to widespread parasitic infection.