Climate change and biodiversity loss as drivers. Presented by Annapaola Rizzoli at the "Perth II: Global Change and the World's Mountains" conference in Perth, Scotland in September 2010.

1. Fondazione Edmund Mach
San Michele all’Adige (I)
Global Change and
the World's Mountains
Perth, Scotland, 26-30 September 2010
Climate change and biodiversity loss as
drivers for zoonotic diseases emergence in
the Alps: the case of tick- borne encephalitis
Annapaola Rizzoli, DVM, PhD
Roberto Rosà, Heidi Hauffe, Markus Neteler,
Valentina Tagliapietra, Daniele Arnoldi, Francesca Cagnacci

2. Tick-borne encephalitis in Europe
•Tick-borne encephalitis virus (TBEV) is a single-stranded RNA virus that
belongs to the genus Flavivirus
•Three subtypes: W European (WE), Siberian (SIB), and Far Eastern (FE)
• Transmitted to humans mostly through the bite of an infected tick of the
Ixodes species, primarily I. ricinus (European subtype) or I. persulcatus
(Siberian and Far Eastern subtypes).
• The prevalence of TBE increased
by almost 400% in the last 30 years (14,000 cases/year)
• TBE is endemic in temperate regions
of Europe and Asia but new foci are discovered
• Evidences of altitudinal shift in many regions

3. Network of independent but synergistic biological and non-biological factors
Examples of data from Estonia, Latvia, Lithuania, Slovenia and Czech Republic.
Industria l employee s,
% of pre -1990 le ve l
employees
Ind ustr ial outp ut,
100 LT
80
Reduced Environmental
Socio-economic 60
industrial awareness?
transition 40 pollution
output LV
20
Global brightening ??
1 97 0
1 98 0
1 99 0
2 00 0
Decline of
agriculture Higher Higher TBE incidence Sudden increase
unemployment in Spring temperature
% unemployment
15 60 LV
SI
% of mean for 1986-88
TBE cases/100,000 population
Nationl catt le herd,
100
10
40 ES 24 21-30.Apr
Mean daily max temp
SI 8 1.Mar-20.Apr
80
5 CZ 20
6
60
20 16
0 4
40 CZ
1 97 0
1 98 0
1 99 0
2 00 0 2 12
20 LV 0
197 0
198 0
199 0
200 0
0 8
1970
1980
1990
2000
20
CZ -2 4
1970
1980
1990
2000
1970
1980
1990
2000
0
More wealth
1970
1975
1980
1985
1990
1995
2000
2005
nat ional land area
50 & leisure SI
40 20
% of tot al
wooded LV
30
Increased co-feeding
0
transmission of TBEV More hosts
1970
1980
1990
2000
20
10
field crops LV Greater human for adult ticks
0
exposure to ticks More infected ticks
1970
1980
1990
2000
20 LV CZ
in forests?
wild boar/1000 ha
20
15
Roe deer &
15
10 10
100
Adult ticks , May
LV 5
Regeneration of 80
5
Increase in rodent 60
0 0
shrubs
1970
1980
1990
2000
populations
1970
1980
1990
2000
40
(transmission hosts) 20
0
1970
1980
1990
2000
More ticks
Courtesy: Sarah Randolph
Šumilo D, Randolph SE et al (2008) Revs Med Virol Sumilo D, Randolph SE, et al PLoS ONE (2007) e500

4. Ecological factors affecting
Ecological factors
TBEv circulation within natural foci
R0

5. Key hosts threshold density and TBE persistence
Parameter estimates obtained from Trentino data
Threshold density of and from literature
competent
rodent hosts 10
Roe deer density (ha-1) – Log scale
1
“Diverting”
effect’
Range of observed of deer
0.1 host density
R0 < 1 R0 = 1 R0 > 1
Threshold
0.01 density and a
positive effect
of deer
density on tick
0.001
abundance
0.1 1 10 100
Rodent density (ha-1) – Log scale
TBE model

6. Complex dynamics in time and space
m L NL 1L c1N LH1 N L (1   NL / k N k L )
R0,TBE 
dT  g N

7. Upsurge of TBE in northern Italy
Graph showing numbers of mean annual incidence (n. of cases/100.000 inhabitants)
and annual TBE confirmed human cases in the positive provinces

8. Changes in climate
MAP of TBE positive and TBE negative provinces
• Increase of Avg.yr.Tmin on a 50yr
period was 0.75 °C
• Increase of Avg.yr.Tmax on a 50yr
period was 1.7 °C
• Decrease of Avg.yr.prec on a 50yr
period was -180mm Trends in annual total precipitation (top), annual minimum (middle)
and maximum (bottom) daily air temperature in the TBE-negative provinces (left panels)
and TBE-positive provinces (right panels) in northern Italy from 1950 to 2006
(Rizzoli et al., Plos one, 2009)

9. Changes in deer abundance
Changes in roe deer density in provinces TBE positive (Trento
and Belluno) and TBE negative (Sondrio)
7
6
5
4 Trento
Belluno
3 Sondrio
2
1
0
53
65
69
71
73
75
77
79
81
83
85
87
89
91
93
95
97
99
01
03
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
19
20
20
Boxplot of mean values of coppice to high forest ratio (cop.hfor)(left panel)
and mean values of roe deer abundance (right panel) in TBE positive and TBE
negative provinces of northern Italy (Rizzoli et al., Plos one, 2009)

10. Changes in forest cover and structure
- 14% of the total wooded areas increased
from 1950 to 2002
- Major increase in
- high stand mixed forest (184%)
- broad leaf coppices (359%)
- total mixed coppices (154%)
Mean coppice and high forest cover recorded in TBE-negative provinces (left panel)
and TBE-positive provinces (right panel) (Rizzoli et al., Plos one, 2009)

11. Conclusion
Protection from natural hazards, including infectious diseases, and health
protection are considered among the most relevant services provided by mountain
ecosystems;
 Global changes, including the invasion by alien species, are favouring the
emergence of several animal and zoonotic diseases in world’s mountains;
Habitat changes and biodiversity loss favor TBD’s emergence: TBD’s pathogens
circulation is in fact supported mostly by generalist species (rodents, large game
species, I. ricinus)
Urgent need to better understand the effects of multi-trophic interactions under a
global change scenario across altitudinal gradients
Emerging diseases in mountains should be addedd to the “emerging
themes” to be covered by integrated research strategies because of their
dramatic impact on well being and economy

12. Acknowledgements
The Reseach Fund of
the Autonomous
Province of Trento
Contacts
annapaola.rizzoli@iasma.it