Neurological disease suspected to be caused by tick‐borne encephalitis virus infection in 6 horses in Switzerland

Magouras, Ioannis; Schoster, Angelika; Fouché, Nathalie Elisa; Gerber, Vinzenz; Groschup, Martin H.; Ziegler, Ute; Fricker, Raffael; Griot, Christian; Vögtlin, Andrea

doi:10.1111/jvim.16533

Cited by 6 publications

(7 citation statements)

References 54 publications

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“…Most domestic animals are considered to be useful sentinels for TBE risk in humans [ 40 ]. Although there are only a few reports of clinical TBE infections in horses, seroprevalence studies suggest that infections in horses are common in TBE-endemic areas [ 41 , 42 ]. Infected animals with no apparent disease play a role in the maintenance and spread of TBEV either as the tick harbor or diseased dead-end hosts [ 43 ].…”

Section: Discussionmentioning

confidence: 99%

An Overview of Tick-Borne Encephalitis Epidemiology in Endemic Regions of Continental Croatia, 2017–2023

Vilibic-Cavlek,

Krcmar,

Bogdanic

et al. 2024

Microorganisms

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Background: Tick-borne encephalitis (TBE) represents an important public health problem in Europe. We analyzed the epidemiology of TBE based on data from humans, animals, and Ixodes ricinus ticks in endemic regions of continental Croatia. Methods: In the period from 2017 to 2023, cerebrospinal fluid (CSF) and serum samples of 684 patients with neuroinvasive diseases, 2240 horse serum samples, and 300 sheep serum samples were tested for TBEV. In addition, 8751 I. ricinus ticks were collected. CSF samples were tested using RT-PCR. Serological tests (serum, CSF) were performed using commercial ELISA, with confirmation of cross-reactive samples by a virus neutralization test. Results: Eighty-four autochthonous human TBEV cases were confirmed. The majority of patients were in the age group of 40–69 years (58.3%) with a male predominance (70.2%). TBE showed a bimodal seasonality with a large peak in April–August and a small one in October–November. In addition to humans, TBEV IgG antibodies were found in 12.2% of horses and 9.7% of sheep. Seasonal tick abundance corresponds to the reported number of human infections. Conclusions: Continental Croatia is still an active natural focus of TBE. Continuous monitoring of infections in humans, sentinel animals, and ticks is needed for the implementation of preventive measures.

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Section: Discussionmentioning

confidence: 99%

An Overview of Tick-Borne Encephalitis Epidemiology in Endemic Regions of Continental Croatia, 2017–2023

Vilibic-Cavlek,

Krcmar,

Bogdanic

et al. 2024

Microorganisms

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“…Unequivocal etiologic diagnosis was often not achieved [17,18]. Recent reports described clinical signs in more detail and based the diagnosis on the presence of TBEV-specific IgM antibodies and/or the increase of TBEV-specific (neutralizing) antibodies in paired serum samples [20,21]. Complete blood count and biochemistry is non-specific but, nonetheless, important to rule other differential diagnoses.…”

Section: Discussionmentioning

confidence: 99%

“…Sporadic reports of equine neurological cases associated with TBEV were published in 1981 from Switzerland [17] and in 1999 from Austria [18]. After almost two decades of silence, several cases from Austria (n = 1) [19], Germany (n = 1) [19], and Switzerland (n = 7) [20,21] were described. Seroprevalences in equines in Europe range from 0.8% in Northern Germany [22] to 37.5% in Lithuania [23].…”

Section: Introductionmentioning

confidence: 99%

Severe Neurologic Disease in a Horse Caused by Tick-Borne Encephalitis Virus, Austria, 2021

de Heus,

Bagó,

Weidinger

et al. 2023

Viruses

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As evidenced by sero-epidemiological studies, infections of horses with the tick-borne encephalitis virus (TBEV) occur frequently in TBEV-endemic areas. However, there are only very few reports of clinical cases. A possible underreporting may be due to a variety of diagnostic challenges. In this study, ELISA and neutralization tests were applied to serum samples. Brain tissue samples were investigated for the presence of nucleic acids of TBEV, Equid alphaherpesvirus 1, Borna disease virus 1, West Nile and Usutu viruses, rustrela virus, as well as Eastern, Western, and Venezuelan equine encephalitis viruses with RT-qPCR, RT-PCR, and qPCR, respectively. TBEV-specific amplification products were subjected to Sanger sequencing. In addition, a direct fluorescent antibody test for rabies was performed. Clinical and patho-histological findings are reported. Using specific RT-qPCR and RT-PCR assays, TBEV nucleic acids were demonstrated in brain tissue samples. Sequencing revealed the Western (formerly Central) European subtype of TBEV as the etiological agent. A high titer of TBEV-specific neutralizing antibodies was found in the serum. RNAscope in situ hybridization revealed TBEV RNA confined to neuronal cell bodies and processes. No other pathogens or nucleic acids thereof could be detected. Diagnostic procedures need to be carried out early after the onset of neurological signs to allow for a final etiological diagnosis of acute TBEV infections in horses.

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“…West Nile virus (WNV), due to the different arthropods and geographical distribution of this virus (García‐Bocanegra et al ., 2018). However, WNV has been detected as an emergent virus in non‐endemic areas, challenging the diagnosis for different species because of the cross‐reactivity with related flaviviruses (García‐Bocanegra et al ., 2018; Magouras et al ., 2022). Neuropathological findings were similar to those previously reported in dogs with TBE (Kleeb et al ., 2021; Weissenböck et al ., 1998).…”

Section: Discussionmentioning

confidence: 99%

Suspected tick‐borne flavivirus meningoencephalomyelitis in dogs from the UK: six cases (2021)

Gonzalo‐Nadal,

Kohl,

Rocchi

et al. 2023

J of Small Animal Practice

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ObjectivesTick‐borne encephalitis virus and louping ill virus are neurotropic flaviviruses transmitted by ticks. Epidemiologically, tick‐borne encephalitis is endemic in Europe whereas louping ill's predominant geographical distribution is the UK. Rarely, these flaviviruses affect dogs causing neurological signs. This case series aimed to describe the clinical, clinicopathological, and imaging findings, as well as the outcomes in six dogs with meningoencephalitis and/or meningomyelitis caused by a flavivirus in the UK in 2021.Materials and MethodsObservational retrospective case‐series study. Clinical data were retrieved from medical records of dogs with positive serological or immunohistochemical results from three different institutions from spring to winter 2021.ResultsSix dogs were included in the study. All dogs presented an initial phase of pyrexia and/or lethargy followed by progressive signs of spinal cord and/or intracranial disease. Magnetic resonance imaging showed bilateral and symmetrical lesions affecting the grey matter of the thalamus, pons, medulla oblongata, and thoracic or lumbar intumescences with none or mild parenchymal and meningeal contrast enhancement. Serology for tick‐borne encephalitis virus was positive in five dogs with the presence of seroconversion in two dogs. The viral distinction between flaviviruses was not achieved. One dog with negative serology presented positive immunohistochemistry at post‐mortem examination. Three dogs survived but presented neurological sequelae. Three dogs were euthanased due to the rapid progression of the clinical signs or static neurological signs.Clinical SignificanceThese cases raise awareness of the presence of tick‐borne encephalitis as an emergent disease or the increased prevalence of louping ill virus affecting dogs in the UK.

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Neurological disease suspected to be caused by tick‐borne encephalitis virus infection in 6 horses in Switzerland

Cited by 6 publications

References 54 publications

An Overview of Tick-Borne Encephalitis Epidemiology in Endemic Regions of Continental Croatia, 2017–2023

An Overview of Tick-Borne Encephalitis Epidemiology in Endemic Regions of Continental Croatia, 2017–2023

Severe Neurologic Disease in a Horse Caused by Tick-Borne Encephalitis Virus, Austria, 2021

Suspected tick‐borne flavivirus meningoencephalomyelitis in dogs from the UK: six cases (2021)

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