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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. Envelope G-protein Matrix protein.
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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 familylyssavirus genusgenotypes Envelope G-protein Matrix protein 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
Incidents of confirmed fatal EBLV1 infections in humans 1977 old girl bitten in finger Ukraine 15-year (Rabies Bulletin Europe 1987; 4:12) 1985 11-year old girl bitten in lower lip Belgorod, Russia (Rupprecht et al., 1994)
Incidents of confirmed fatal EBLV2 infections in humans 1985 30-year old male, bat-researcher Helsinki, Finland (Lumio et al., 1986) 2002 56-year old male bat worker Angus, Schotland (Fooks et al., 2002)
Numbers of lyssavirus tested serotine bats in the Netherlands (1984 - 2003)
Geographical Distribution of the Serotine bat, Netherlands (1986 – 1993) Bat detector (green),, Actual sighting (black)
Geographical Distribution of the Serotine bat, Netherlands (1986 – 1993) Bat detector (green),, Actual sighting (black)
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 biteHigh estimate • 2000-2005: 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 biteLow 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-Verschoor RIVM Joke van der Giessen RIVM Reina van der Heide RIVM Katsuhisa Takumi RIVM Betty RAM Verstraten CIDC Hans Kramps CIDC Toon Pover CIDC Peter HC Lina Naturalis Wim HM van der Poel Animal Sciences Group, Wageningen University Research