Public health hazard of European Bat lyssavirus, the Netherlands Wim H. M. aan der Poel, Katsuhisa Takumi, Elisabeth R. A. M. Verstraten, Peter H. C. Lina, Joke van der Giessen and Johannes A Kramps

Rhabdovirus family lyssavirus genus genotypes 1.Rabies 2.Lagos-bat 3.Mokola 4.Duvenhage 5.European Bat Lyssvirus type 1 (EBL1) 6.European Bat Lyssavirus type 2 (EBL2) 7.Australian Bat Lyssavirus (ABL) Core: N, NS, L proteins Envelope G-protein Matrix protein

Lyssavirus reservoirs and geographical distribution

Incidents of confirmed fatal EBLV1 infections in humans 1977 old girl bitten in finger Ukraine 15-year (Rabies Bulletin Europe 1987; 4:12) year old girl bitten in lower lip Belgorod, Russia (Rupprecht et al., 1994)

Incidents of confirmed fatal EBLV2 infections in humans year old male, bat-researcher Helsinki, Finland (Lumio et al., 1986) year old male bat worker Angus, Schotland (Fooks et al., 2002)

Eptesicus serotinus (Serotine bat)

Geographical distribution of Eptesicus serotinus in Europe

Numbers of lyssavirus tested serotine bats in the Netherlands ( )

Geographical Distribution of the Serotine bat, Netherlands (1986 – 1993) Bat detector (green),, Actual sighting (black)

EBLV in serotine bats per month

EBLV1a in bat’s body parts (RT-PCR detection) BrainSalivary Gland Neck Skin Medulla oblongata Fat EBLV- positive EBLV- negative 08811

Incidents and contact types with serotine bats Nature of contact RabidNotTotalPrevalence Bat bites in humans % Human hand contact with bats % Contact of unknown nature with humans % Possible contact with cats % Contact of unknown nature with cats231336% Possible contact with dogs0110% Contact of unknown nature with dogs11250% No contact with human, cats, or dogs % Unknown %

Human – bat contact incidents Ο = EBLV-neg Δ = EBLV-pos People sometimes pick up rabid bats!

Cat- bat contact incidents Ο = EBLV-neg Δ = EBLV-pos Cats seem avoid contact with rabid bats!

Risk of human rabies upon a bat bite f(i) = likelyhood of number of virus particles excreted (hardly any eperimental data) r = probability of infection after a bat bite High estimate p=1-f(0) (all contacts give infection) Low estimate p=r[1-f(0)] Based on mouse inoculation experiments and a single hit model (maximum likelyhood) r=1.6*10 -3

Risk of human rabies after bat bite High estimate : 17 bat bites reported 5/17 involved bats EBLV-positive (titers unknown) Exposure: 2.8 bites per year per 16.3 miljon people Infectious dose unknown Likelyhood of no virus excretion f(0) =12/17=0.7 -> likelyhood of virus excretion f(1) =1-f(0)=0.3 High estimate: all 5 bats infectious : => 2.8*0.3 = 0.8 cases per year Based on poisson distribution one could expect 1 case every 2 years (in case of no post-exposure treatment!)

Risk of human rabies after bat bite Low estimate Likelyhood of virus excretion f(1) =1-f(0)=0.3 Probability of infection based on mouse inoculation experiments and single hit model (maximum likelyhood) r=1.6*10 -3 Low estimate: 0.3*1.6*10 -3 = 5*10 -4 => one case per 700 years

Conclusions EBLVs can cause fatal infections in humans EBLV is endemic in the serotine bat in the Netherlands (~20%) Bats can excrete EBLV in saliva but amounts are unknown Public health risk of EBLVs in bats cannot be ignored but is hard to assess: one case every 2 to 700 years Active and passive surveillance of EBLVs in bats is indicated for public health protection

Acknowledgements Froukje Lodder-VerschoorRIVM Joke van der GiessenRIVM Reina van der HeideRIVM Katsuhisa TakumiRIVM Betty RAM VerstratenCIDC Hans KrampsCIDC Toon PoverCIDC Peter HC LinaNaturalis Wim HM van der PoelAnimal Sciences Group, Wageningen University Research