First Swedish case of fatal equine parasitic encephalitis by Halicephalobus gingivalis

Abstract

Abstract Background: Halicephalobus gingivalis is a nematode with zoonotic potential which can cause fatal opportunistic infections in a wide variety of mammals. The parasite has never been diagnosed in Sweden, in any species, prior to the presented case.Case presentation: An imported 21-year-old Icelandic mare developed severe neurological symptoms. The horse was eventually euthanized and submitted for post-mortem examination where severe lesions in the kidneys was noted. Samples for histological examination were submitted, which revealed the presence of H. gingivalis in both renal and brain tissue. Phylogenetic analysis of the parasite determined it to belong to Linage 1.Conclusions: With the occurrence of H. gingivalis in Sweden, the disease should be added to the list of differential diagnoses in cases with acute onset of neurological disease in both horses and mammals including humans.