Report A Potentially Fatal Mix of Herpes in Zoos

摘要: Zoological Gardens Wuppertal, Hubertusallee 30,42117 Wuppertal-Sonnborn, GermanySummaryPathogens often have a limited host range, but some canopportunisticallyjumptonewspecies.Anthropogenicactiv-ities that mix reservoir species with novel, hence suscep-tible, [1] can provide opportunities for pathogensto spread beyond their normal range. Furthermore,rapidevolutioncanproducenewpathogensbymechanismssuch as genetic recombination [2]. Zoos unintentionallyprovide pathogens high diversity of fromdifferent continents and habitats assembled within aconfinedspace.Institutionsalerttotheproblemofpathogenspread to unexpected hosts monitor the emergence ofpathogens take preventative measures [3]. However,asymptomatic infections result in causative patho-gens remaining undetected host. Further-more, pathogen may remainundiagnosed if outcome infection is limited, inthe case compromised fertility, or more severeoutcomes are restricted less charismatic thatprompt only investigation. We illustrate this problemhere recombinant zebra herpesvirus infecting charis-matic including zoo polar bears over at least fouryears. The virus cause fatal encephalitis infects atleast five mammalian orders, apparently without requiringdirect contact infected animals [4–8].ResultsVirus IdentificationIn June 2010, two cohoused (Ursus maritimus),a threatened species, suffered epileptiform seizures theZoological Germany. 20-year-oldfemale, Jerka, presented symptoms first died 8 days afterthe onset clinical signs (see Movie S1 available online).Necropsy indicated moderate severe nonsuppurativeencephalitis gliosis unknown etiology ofdeath.Theperivascularlyaccentuatedinflammationconsistedof lymphocytes plasma cells. lesions were consistentwith infection, inclusion bodies associatedwith viral pathogens, herpesviruses, notidentified. 16-year-old male, Lars, survived after medicalintervention, which included intravenous administration ofa hypertonic electrolyte solution diazepam preventseizures (Movie S1). It took several weeks him fullyrecover.Faced many potential agents, we appliedPCR targeting eight plausible (Experi-mental Procedures) high-throughput DNA microarrays(ViroChip) extracted RNA from Jerka’s brain [9].The ViroChip test presence thousandknown sequences single assay isbiased toward human viruses sensitive than othermethods such PCR deep sequencing [10, 11]. isvery prone false negatives sequencetargeted by primers does not match perfectly. onlypathogen detected Jerka was related equidherpesvirus1(EHV1)[12])identifiedbyquantitativePCR.Addi-tional assays did detect othercandidate (Table 1). Western blot analysis usingantibodies against EHV1 IR6 protein [13] supported thefindingof nucleic acids anddemonstrated proteinexpression exclusively (Figure 1; Supple-mental Experimental Procedures).Virus PhylogeneticsEquid 9 (EHV9), thought originatedin plains (Equus burchelli) closely relatedto EHV1, has been known polarbears [14, 15]. domestic horse strains hasalso shown black bears(Ursus americanus)[8]. To determine identity viralstrainfromJerka,wesequencedportionsofsixgenes,namelyUL49.5,484bp;UL45,667bp;gC(UL44),1,523bp;Pol(UL30),810bp; gB (UL27), 1,140 bp; IR6, 342bp, phylogenet-ically compared obtained EHV1,EHV9,andmoredistantlyrelatedEHV4sequences(alignmentsavailable Supplemental Data Sets). All amplicons weredirectly sequenced cloned into standard plasmid vectors.Multiple individual clones per amplicon also sequencedto confirm direct sequencing.Thesequencinganalysesprovidednoevidenceforcoinfectionwith one EHV strain.Jerka’s clustered caballus)EHV1 divergent (1%–3%) nucleotidelevel formed sister lineage UL49.5, gC (UL44),Pol (UL30), genes 2A). UL45 gB(UL27) gene part Pol (UL30) nearlyidentical distinct strain zebras, designatedhere clearly different strainthat caused fatalities 2A, tree)[6]. havenot determined strain. Many thesubstitutions nonsynonymous changed amino acidsequenceswhencomparedtothereferencehorseEHV1strainAb4(TableS1).ZebraEHV1iswidespreadinzoozebrasandisknown infect four other orders ofmammals following experimental inoculation naturalinfection zoos 2)[4–7].Surprisingly, recombinantbetween EHV9, 5