European Bat Lyssaviruses in the United Kingdom: Focus on Changing Epidemiology and Detection Methods Aminu Shittu. Department of Public Health and Animal Production, Faculty of Veterinary Medicine, Usmanu Danfodiyo University, Sokoto.

Overview Introduction Distribution The Rhabdoviridae family Importance of EBLVs Diagnostic tests Diagnosis Past and current situations in the UK Surveillance and control in the UK Future strategies Control scenarios Conclusions/recommendations

Introduction BATS –Kingdom: Animalia –Phylum: Chordata –Class: Mammalia (20%) –Infraclass: Eutheria –Superorder: Laurasiatheria –Order: Chiroptera –Distribution: worldwide –Habitat: caves, old buildings, trees

Distribution

The geographical distribution of Eptesicus serotinus in Europe

First description in the Hebrew Talmud Various Arabic writings

Rabies Lagos – bat Makola Duvenhage European Bat Lyssavirus type 1 (EBLV – 1) European Bat Lyssavirus type 2 (EBLV – 2) Australian Bat Lyssavirus (ABL) The Rhabdovirus fami ly

European Bat Lyssaviruses EBLVs in Europe – 1954 Genetics – N &/or G genes EBLV – 1 2 lineages 1a & 1b Majority in E. serotinus EBLV – 2 First isolated in 1984 from human biologist Isolated in 1986 in M. daubentonii and M. dasycneme

VirusGenotypeGeographical originOriginal HostSecondary Host Classical Rabies virus (RABV) 1Worldwide*Dog, Fox, Cat, Wolf, Skunk, Racoon, Mongoose, American bat Mammals, Man Lagos Bat Virus (LBV)2NigeriaFrugivorous batCat, Dog Mokola Virus (MOKV)3NigeriaShrews, RodentsCat, Dog, Man Duvenhage Virus(DUVV)4South Africa, Zimbabwe Insectivorous batMan (1971) European Bat Lyssavirus 1a/1b (EBLV-1a/ EBLV-1b) 5Denmark, Germany, Netherlands, Poland, Russia, Slovakia, France, Spain Insectivorous bat (esp. E. serotinus) Man (1985) European Bat Lyssavirus 2a/2b (EBLV- 2a/ EBLV-2b) 6Netherlands, UK, Finland, Switzerland Insectivorous bat (Myotis daubentonii, Myotis dasycneme) Man (1986, 2002) Australian Bat Lyssavirus (ABLV) 7Australia, PhilippinesInsectivorous bat (S. flaviventris), Frugivorous bats (genus Pteropus) Man (1996) Aravan (ARAV)UnclassifiedSouthern KyrgyzstanInsectivorous bat (M. blythii) Unknown Khujand (KHUV)UnclassifiedNorthern TajistanInsectivorous bat (M. mystacinus) Unknown West Caucasian Bat Virus (WCBV) UnclassifiedCaucasusInsectivorous bat (Miniopterus schriebersii) Unknown Irkut Virus (IRKV)UnclassifiedEastern SiberiaInsectivorous bat (Murina leucogaster) Unknown Lyssavirus classification, with geographical origin, original and secondary host species

The importance of EBLV rabies Bat rabies is an emerging zoonosis Public health threat High risk groups: – Bat handlers – Cavers – Researchers – Wildlife officers – Veterinarians

The importance of EBLV rabies (2) Rabies is a zoonotic disease which is invariably fatal in all humans that are not vaccinated and do not get post- exposure treatment 5 cases of human exposure in Europe so far including a fatal case in Scotland (2002) Spillover of EBLV-1/EBLV-2 into humans, sheep, stone marten and domestic cats has been reported (see Harris et al. 2006). EBLV is endemic in some European countries’ bat population and the possibility of infected bats coming to the UK cannot be ruled out. Likelihood of impact

Diagnostic tests Direct fluorescent antibody test (dFA) (Standard test for rabies) RT-PCR Other tests Electron Microscopy (EM) Histopathology Immunoperoxidase staining Virus Isolation TestSpecimen requiredTest detectsTime taken to obtain result Fluorescent antibody test fresh brainVirus antigen4 hours RT-PCRvirus or tissuevirus genome1-2 days Histopathologyformalin-fixed braincharacteristic lesions 2 days Immunoperoxidase staining formalin-fixed brainVirus antigen2 days Virus isolation using mouse neuroblastoma cells fresh brainLive virus3 days

Rabies Diagnosis (1) Direct Fluorescent Antibody Test (DFAT) Detection of virus nucleocapsid protein infected tissues Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) Can be used to detect presence of pan-lyssavirus in saliva or oropharyngeal samples (specific primers can be used detect specific EBLV) Rabies Tissue Culture Inoculation Test (RTCIT) Homogenised suspension of suspect tissue (brain or saliva) is inoculated into tissue culture for isolation of virus

Rabies diagnosis (2) Mouse Inoculation Test Inoculation of homogenised suspect tissue into cerebellum of 48h old mice for later virus isolation Modified Fluorescent Antibody Virus NeutralisationTest (mFAVN) Can be used on pooled saliva or blood samples for detection of antibodies to EBLV Histopathology Detection of negri bodies in brain tissue

Vaccination HumanAnimals Two rabies vaccines licensed for use in the UK (Aventis Pasteur, Rabipur) Oral route (Live vaccine) Animals Rabies vaccines (Only inactivated rabies vaccines are licensed for use in the UK)

Past and current situation of EBLV-1 in the UK EBLV-1 seroprevalence in bats: 1 serotine bat in the South of England (2005) 1 serotine bat in Scotland (2007)

Past and current situation of EBLV-2 in the UK EBLV-2 seroprevalence in bats: The seroprevalence in Daubenton’s bats in England and Scotland is estimated at 2% (95% confidence interval 1 to 5%) 8 infections with EBLV-2 confirmed in Daubenton’s bats

Surveillance of bat Lyssaviruses Sample submission: members of public and bat conservation groups Sick, injured or suspect cases, captive bats Testing animals and humans bitten by suspect bat

Strengths and weaknesses of surveillance Bias due to location and bat conservationist activity Not a representative sample Sensitivity – only method by which EBLVs detected in the UK

The control of EBLVs in the UK Current strategies: The public Bat handlers

Current control strategies Health education Raising awareness Public: No bat handling If pet is bitten: advice on potential risk and report any suspicious signs to the local vet. Bat handlers: If bitten seek medical advice Prevent direct contact - gloves Pre-exposure vaccination and Post-exposure treatment

Stokesay Castle exa mple Follow up possible human contacts Advise to receive post exposure treatment Public access to second floor was not allowed Signs informing visitors about the bats Staff checking for bats before opening

But does the classical rabies vaccine protect humans against EBLV? Genotype 1: classical rabies Genotype 5: EBLV1 Genotype 6: EBLV2

Future Strategies Legislation changes Compulsory vaccination of bat handlers Wild bats: cannot control their movement, vaccinate using RAORAL V-RG Quarantine bats coming in ships from other countries Prevent colony establishment in certain buildings (e.g. schools, hospitals) Preventive immunization of populations living in highly endemic areas

Control Scenarios

Translocation of Wild bat colony Geographic translocation of bats could potentially spread EBLV Natural, accidental or deliberate means Protracted incubation period allows survival of the virus Bats undergo hibernation to extend survival

What could be done; -Consult bat conservationists -If suspect EBLV should be tested -If positive should be killed -If negative would have to be housed

Identified in Novel Bat Species Currently in only two species found in the UK Testing finds antibodies/antigen in naive species; -Surveillance will expand -Communicate to bat conservationists and public

Infected bats in public places Infected bat found which roosts in public area; -Random sampling of roost -Slaughter not an option -Possibly move population?? -Warn public and protect staff

4.EBLV found in bats away from public As negligible risk to humans – continued surveillance: –Collection of excreta for virus detection and serology –Marking of sampled bats –Collection and testing of dead/sick bats

4.EBLV found in bats away from public If clinical disease detected: –Epidemiological data: destruction of bat colony ineffective disturbs metacolony may cause dispersion of infected animals. –Enhanced surveillance.

5.EBLV found in carnivores Transmission of lyssaviruses from bats to terrestrial mammals and humans rare, none so far in UK BUT –EBLV1 demonstrated in sheep in Denmark –Lyssaviruses isolated in cattle/foxes in Canada.

5.EBLV found in carnivores If infected bat preyed upon by foxes or cats FOXES CATS POSITIVE -> PTS BUT difficult to detect until showing CS or seen attack PREVENTION : cats indoors during high risk periods i.e. summer & evenings where bats resident. EDUCATION Very difficult! Oral baits: BUT classical rabies oral vaccine not protective against EBLV1 Culling near urban areas?

6. EBLV clinical disease in humans In highly unlikely event of outbreak in humans: –Pre & post exposure vaccination –EDUCATION –Signs/barriers near colonies: prevent access & direct bat movements –Bat-proofing buildings –Vaccinating/culling bats?

Conclusions/recommendations EBLVs can cause fatal infections in humans Bats can excrete EBLV in saliva but amounts are unknown Public health risk of EBLV in bats cannot be ignored but is hard to assess Active and passive surveillance Improved detection methods Translocation factors