Borna Virus Encephalitis: an Example of Emerging Infection Revealed by a Neurological Presentation

Educational Workshop: Emerging viral diseases with neurological presentation - Amsterdam, April 9, 2016 Borna virus encephalitis: An example of emerging infection revealed by a neurological presentation

Dennis Tappe ESCMIDBernhard Nocht Institute eLibrary for Tropical Medicine, Hamburg, Germany by author Educational Workshop Emerging viral diseases with neurological presentation Overview

I. Zoonoses as emerging infections

II. A cluster of unusual human encephalitis cases: Identification of a novel zoonotic virus

III. Bornaviruses and disease ESCMIDIV. Open questionseLibrary by author Zoonoses as emerging infections ESCMID eLibrary by author The majority of emerging infections is caused

by zoonotic pathogens (1) Zoonoses from wildlife represent the most

significant fraction (1) Many of these emerging infections are of viral origin – some are fatal

ESCMID eLibrary(1) Jones et al., Nature 2008;451:990-3. by author x zoonotic

x

x x x x Numbers of EID events per decade ESCMID eLibraryJones et al., Nature 2008;451:990-3. by author Global distribution of relative risk of an EID event caused by zoonotic agents

ESCMID eLibraryJones et al., Nature 2008;451:990-3. by author ESCMID eLibrary by author Emerging viral infections Recently emerged or re-emerged, likely to cause significant disease in humans or animals Common causes: • genetic mutations of existing viruses • emergence of new viruses • expansion of viral host reservoirs • movement of known viruses from one species to another • suppression of host immune surveillance

Prominent examples of newly identified encephalitis viruses: Hendra and Nipah viruses during outbreaks in the 1990s ESCMID eLibraryMcGavern DB, Kang SS, Nat Rev Immunol. 2011;11:318-29. by author A cluster of unusual human encephalitis cases: Identification of a novel zoonotic virus ESCMID eLibrary by author Cluster of fatal encephalitis in Saxony-Anhalt No travel history in any patient June 2013: November 2013: Patient 2 Male, 62j; Male, 72j; Hypertension, Diabetes Hypertension, Obesity Encephalitis Death after 2 months Encephalitis Patient 3 Death after 4 months Patient 1 There is no mandatory public health notification November 2011: for encephalitides in Germany! Male, 63j; Notification because of unusual cluster: Three cases of fatal encephalitis with Hypertension • subacute onset • rapid progression Encephalitis ESCMID eLibraryDeath after 3 months by author Wat has happened? Initial symptoms: • Lethargy, constipation, shivers/fever • Nighttime agitation, confusion, ataxia, psychomotor slowing Later symptoms: • Myoclonus, tetraparesis, sopor, coma

MRI: Lesions temporal, parietal, insula, midbrain Patient 1 November 2011: Extensive serological Lumbar puncture: Male, 63j; and molecular examinations (serum, 11 cells/µl; lymphocytes Hypertension Protein 824 mg/L (<500) CSF, brain biopsy) normal Lactate 4.2 mmol/L (<2.1) Encephalitis ESCMIDGlucose ratio normal eLibraryDeath after 3 months by author Patient 1: CSF diagnostics

IgG Reibergram: IgM

BBB disruption plus local Ab synthesis (~20% of CSF Abs)

IgA

IgG CSF = Q (IgG) IgG Serum Albumin CSF = Q (Alb) AlbuminESCMID Serum eLibrary by author Serologies, PCRs in all 3 patients

ESCMID eLibraryHoffmann et al., N Engl J Med. 2015;373:154-62. by author

flowchart Diagnostic

- Intoxication? - Autoimmune Encephalitis? StudahlESCMIDet al., Drugs. 2013;73:131-58. eLibrary- Metabolic disorder? by author

flowchart Diagnostic

StudahlESCMIDet al., Drugs. 2013;73:131-58. eLibrary by author Brain tissue morphlogy Lymphocyte infiltration, edema – no bacteria, fungi, or parasites visible; molecular examinations negative

3 cases of subacute onset, rapidly progressive and fatal encephalitis with likely viral etiology (or autoimmune???)

ESCMIDCD8+ Lymphocytes eLibraryReactiveStudahl et alastrogliosis., Drugs. 2013;73:131-58. by author PCRs

In only 50% of the encephalitis cases an etiologic agent can be identified

Viral encephalitis has a low estimated incidence of 1.4-2.2 Studahl et al., Drugs. 2013;73:131-58. cases / 100,000 Studahl et al., Drugs. 2013;73:131-58.

ESCMID eLibraryHoffmann et al., N Engl J Med. 2015;373:154-62. by author All 3 patients were squirrel breeders

Body size 22-34 cm, Weight 0.5 – 1kg

Kept in large cages in gardens, originally from Costa Rica > Euthanazation of one animal, serological and molecular testing for pathogens: negative

VariegatedESCMIDsquirrel (Sciurus variegatoides eLibrary) by author Squirrel examination

ESCMID eLibraryHoffmann et al., N Engl J Med. 2015;373:154-62. by author Metagenomics

High throughput sequencing of squirrel metagenome from different organs Detection of short Borna virus-like sequences in various organs of the squirrel

ESCMID eLibraryHoffmann et al., N Engl J Med. 2015;373:154-62. by author Metagenomics Development of specific Bornavirus real time qPCRs based on sequence reads Positive results from the squirrel and all 3 patients (brain tissue, CSF)

ESCMID eLibraryHoffmann et al., N Engl J Med. 2015;373:154-62. by author Molecular Phylogeny

Complete coding sequences, NJ&ML

„Variegated Squirrel-1-Bornavirus (VSBV-1)“ ~ 70% sequence identity with BoDV

ESCMID eLibraryHoffmann et al., N Engl J Med. 2015;373:154-62. by author Antigen detection of VSBV-1 in brain tissue Detection of virus antigen in CNS

• of squirrels • and human patient (biopsy, autopsy)

All standard areas sampled from brain are positive in IHC and by PCR cortex, cerebellum, hippocampus, SN, thalamus, striatum, pons

ESCMID eLibraryHoffmann et al., N Engl J Med. 2015;373:154-62. by author Brain regions and target host cells for viruses causing meningitis and encephalitis

Grubaugh et al., Open Forum Infect Dis.. 2015;3:ofv182. ESCMID eLibrary by author Virus entry into the CNS

ESCMID eLibraryMcGavern DB, Kang SS, Nat Rev Immunol. 2011;11:318-29. by author Bornaviruses and disease

ESCMID eLibrary by author The Bornaviruses Bornaviridae: Order Mononegavirales (ssRNA-) • Nuclear replication • Cytoplasmic virion assembly • Non-lytic, persistent infection • Cell death by immune cells 8900 nt genome size • Neurotropic; all CNS cell types infected • Unknown receptor N protein = nucleoprotein X protein = regulatory function • Intraaxonal transport P protein = phosphoprotein M protein = matrix protein G protein = external glycoprotein L protein = RNA-dependant RNA polymerase Large amounts of transcripts and virus proteins, but very few virus particlesESCMIDproduced (90-130 nm) eLibrary by author The classic Borna disease Brain and spine infection in ungulates (horses and sheep) by Borna Disease Virus (BoDV)

Symptoms: • Loss of orientation, Apathy • Aggressiveness, Irritability, Startling • Anorexia, colic pain • Stand anomalies • Myoclonus

Transmission: • Via olfactory nerve and pharyngeal from the environment • IncubationESCMIDperiod of 2-6 months eLibrary by author Borna – What‘s in a name

The name refers to an epidemic in the city of Borna in 1894: stables of horses became sick

Virus (BoDV) characterized in 1994 (Lipkin et al., Proc Natl Acad Sci U S A. 1990;87:4184–4188.)

ESCMID eLibrary by author Natural reservoir of BoDV The bicolored shrew (Crocidura leocodon), an insectivore (Eulipotyphla)

Clinically asymptomatic No brain inflammation BoDV RNA and antigen in brain Seropositivity Bourg et al., Emerg Infect Dis. 2013;19:2064–2066.

> Similar to what is seen in variegatedESCMIDsquirrels for VSBV-1 eLibrary by author Open questions

ESCMID eLibrary by author Pathogenesis?

- Immune-mediated versus virus-mediated - Mode of transmission (bites, scratches) and entry into CNS?

> Virus culture, EM identification needed > Animal models needed

Where does the virus come from?

• Costa Rica? • Local origin in Germany? • NaturalESCMID host animal? > How many peopleeLibraryare then at risk? by author Only the tip of the iceberg?

• Are there more unknown human fatalities due to the novel virus? – encephalitic autopsy material is being examined

• Are there more symptomatically infected humans? – several thousand encephalitic CSF samples are tested

• Are there more asymptomatically infected or patients with mild symptoms? – a seroprevalence study in the breeder population is conducted (ELISA, IFAT, IB) with recombinant VSBV-1 proteins • PredispositionESCMID(medical preconditions ,eLibrary age)? by author Conclusions Identification of a novel disease/pathogen only by intensive interdisciplinary cooperation • Human medicine: Neurologists, Virologists, Neuropathologists • Veterinary medicine: Virologists, Pathologists

Clinical awareness! • Clinical notification of public health authorities due to clustering of unusual encephalitides in squirrel breeders

Maximum use of laboratory methods • Serology, PCR, Histology, Electronmicroscopy, Metagenomics, Immunohistochemistry Due to an increase of exotic pet keeping more infections withESCMIDunusual (and even novel )eLibrary pathogens are expected by author ESCMID eLibrary by author ESCMID eLibrary by author Acknowledgments

Friedrich-Loeffler-Institute: • Bernd Hoffmann, Dirk Höper, Maria Jenckel, Björn Abendroth, Jens Teifke, Rainer Ulrich, Martin Beer

Bernhard Nocht Institute: • Jonas Schmidt-Chanasit, Daniel Cadar, Dennis Tappe

Institute for Veterinary Pathology Gießen: • Christiane Herden

Local Public Health Authority: • Christian Lutter, Elisabeth van der Grinten

Neuropathology Magdeburg: • Christian Mawrin

Neurology Halle/Saale: • AnnemarieESCMID Boldt, Olaf Niederstrasser, Tobias Müller eLibraryThank you by author