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

Lyssavirus Main Animal Reservoirs Geograph. Distrib.

Rabies Dog, Cat, Fox Insectivorous bats/ Hematophagous bats

Worldwide

Lagosbat Fruit bats? Nigeria

Mokola Insectivore or Rodent species

N. Africa

Duvenhage Insectivorous bats? Africa

EBLV1 Eptesicus serotinus N. Europe

EBLV2 Myotis dasycneme Myotis daubentonii

NE Europe

ABL Fruit bat Pteropus species

Australia

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)

Eptesicus serotinus (Serotine bat)

Geographical distribution of Eptesicus serotinusin Europe

Numbers of lyssavirus tested serotine bats inthe 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)

EBLV in serotine bats per month

2000-2005

0

5

10

15

20

25

30

35

40

EBLV-neg

EBLV-pos

EBLV1a in bat’s body parts

(RT-PCR detection)

Brain Salivary

Gland

Neck

Skin

Medulla

oblongata

Fat

EBLV-positive

30 22 20 27 1

EBLV-negative

0 8 8 1 1

Incidents and contact types with serotine bats

2000-2005

Nature of contactRabid Not Total Prevalence

Bat bites in humans 5 12 17 29%

Human hand contact with bats 3 12 15 20%

Contact of unknown nature with humans

1 0 1 100%

Possible contact with cats 4 12 16 25%

Contact of unknown nature with cats 2 31 33 6%

Possible contact with dogs 0 1 1 0%

Contact of unknown nature with dogs 1 1 2 50%

No contact with human, cats, or dogs 16 13 29 55%

Unknown 7 45 52 13%

Human – bat contact incidents

Ο = EBLV-neg

Δ = EBLV-posPeople sometimes pick up rabid bats!

Cat- bat contact incidents

Ο = EBLV-neg

Δ = EBLV-posCats 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

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 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-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