Meningoencephalitis Caused by <i>Halicephalobus gingivalis</i> in a Thoroughbred Gelding

Abstract

A 6-year-old Thoroughbred gelding was euthanized after a 2-month period of abnormal neurological signs, such as circling left in his pen and hitting his head and body against the wall. After the horse was euthanized on the farm, a half of the brain and whole blood were submitted for diagnostic tests. Histopathological examination of the brain revealed granulomatous and eosinophilic meningoencephalitis with numerous intralesional nematodes, predominantly affecting the cerebrum. Multifocal malacic foci were scattered in the brain parenchyma. The intralesional parasites were identified as Halicephalobus gingivalis by morphological features and PCR testing. To the best of our knowledge, this is the first report of meningoencephalitis caused by H. gingivalis in the horse in Korea.

First description of a fatal equine infection with Halicephalobus gingivalis in Portugal. Relevance for public health

“…H. gingivalis infection in horses has been reported in five continents, usually involving a wide range of ages (from colts to aging adults) and breeds, leading almost invariably, to a fatal outcome (Anderson et al 1998;Lim et al 2015;Monoranu et al 2015). In Europe, the disease is reported in several countries, such as the United Kingdom, Belgium, Italy, Denmark, Spain, Iceland and Romania (Rames et al 1995;Anderson et al 1998;Br€ ojer et al 2000;Johnson et al 2001;Bryant et al 2006;Akagami et al 2007;Eydal et al 2012;Gracia-Calvo et al 2014;Jung et al 2014;Lim et al 2015;Taulescu et al 2015;Pintore et al 2017). Owners seek veterinary assistance mostly due to unexpected and unexplained onset of neurological symptoms, such as anorexia, ataxia, urinary incontinence, blindness, decreased menace and tonal reflexes, tremors and aggressiveness (Rames et al 1995;Anderson et al 1998;Br€ ojer et al 2000;Johnson et al 2001;Bryant et al 2006;Akagami et al 2007;Vasconcelos et al 2007).…”

Evaluation of the Variability of the ORF34, ORF68, and MLST Genes in EHV-1 from South Korea

“…EHV-1 was detected in 12 equine samples (3.55%, 12/338). The 134 horses with neurological symptoms did not have EHV-1 detected, and 51 of these samples had several parasites detected, such as strongyle and Halicephalobus gingivalis [ 21 ]. There were two aborted fetuses in 2015, three in 2016, one in 2018, and four lung samples and two nasal swabs from cases with respiratory symptoms in 2019.…”

Fatal human eosinophilic meningo-encephalitis caused by CNS co-infection with Halicephalobus gingivalis and West Nile virus

“…Equine infection by H. gingivalis has been described in diverse geographical locations including North America, Europe, Egypt, Brazil, and Japan and more recently in Korea and Australia [7,12,13]. The parasite displays neuro-tropism both in human and equine hosts leading to a debilitating form of meningo-encephalitis culminating either in death or euthanasia due to overwhelming disease [3][4][5][6][7]14].…”