The distribution pattern of Halicephalobus gingivalis in a horse is suggestive of a haematogenous spread of the nematode

Abstract

The majority of Halicephalobus gingivalis-infections in horses have been fatal and are usually not diagnosed before necropsy. Therefore, knowledge about the nematode and the pathogenesis of infection in horses is limited. This has resulted in an on-going discussion about the port of entry and subsequent dissemination of H. gingivalis within the host. The present case of H. gingivalis-infection in a horse was diagnosed ante mortem. Post mortem findings, the distribution pattern of H. gingivalis nematodes in the brain, a high prevalence of inflammation in close relation to blood vessels, and the presence of the nematode in multiple organs with a disseminated pattern of distribution strongly suggested a haematogenous spread of the nematode in the horse.

Fatal Human Meningoencephalitis due to Halicephalobus Nematodes, Germany

“…In the present case, contact with contaminated wood or waste paper that was recycled in the paper mill might have been the source of infection. In horses, hematogenous spread and tissue migration of the nematodes has been demonstrated [ 2 ]. For human and equine CNS and disseminated halicephalobiasis, no established treatment exists, and the nematodes have shown a certain degree of tolerance to ivermectin and benzimidazoles [ 6 , 13 , 14 ].…”

Diseases of the Equine Urinary System

“…50 Nematodes can be identified by histologic examination of the kidneys within regions of granulomatous inflammation or free within the urine. 48,50 Renal Pelvis Nonsteroidal anti-inflammatory drugs (NSAIDs) are a common therapy to ameliorate pain and inflammation associated with acute and chronic diseases in veterinary medicine. Most NSAIDs are capable of reversibly inhibiting the conversion of arachidonic acid to prostaglandins by cyclooxygenase.…”

“…1,45,46 Granulomas in multiple organs, including the kidneys, are associated with the rhabditiform nematode Halicephalobus gingivalis infection in equids. 29,[47][48][49][50][51] The presence of parasites in close proximity to blood vessels and associated inflammation supports the pathogenesis of a hematogenous dissemination to multiple organs, including the kidney, by this parasite in equids. 50 Nematodes can be identified by histologic examination of the kidneys within regions of granulomatous inflammation or free within the urine.…”

“…29,[47][48][49][50][51] The presence of parasites in close proximity to blood vessels and associated inflammation supports the pathogenesis of a hematogenous dissemination to multiple organs, including the kidney, by this parasite in equids. 50 Nematodes can be identified by histologic examination of the kidneys within regions of granulomatous inflammation or free within the urine. 48,50 Renal Pelvis Nonsteroidal anti-inflammatory drugs (NSAIDs) are a common therapy to ameliorate pain and inflammation associated with acute and chronic diseases in veterinary medicine.…”

Parasitic and zoonotic meningoencephalitis in humans and equids: Current knowledge and the role of Halicephalobus gingivalis

“…The method of infection is unclear but it is presumed to be contamination of oral mucosa or skin wounds ( Anderson et al, 1998 ). It is presumed that the nematodes enter the tissues through wound lesions and are carried to other parts of the body through haematogenous route in blood and lymph ( Henneke et al, 2014 ) or through the optic nerve – optic tract and that the contamination of ocular wounds would be the entrance ( Rames et al, 1995 ). Transmammary infection from mare to foal has been reported once ( Wilkins et al, 2001 ).…”