Insect & Vector-borne Threats - Climate Change in Alaska

Insect & Vector-borne
Disease
Increasing Concerns for Alaska
Jeffrey G Demain, MD, FAAAAI, FAAP
Director, Allergy Asthma & Immunology Center of Alaska
Associate Clinical Professor, University of Washington

Disclosures
I am not an expert on the topic of global warming.
• Research
• Genentech
• Novartis
• CSL Behring
• Speaker
• Genentech
• Novartis
• Teva
• Sanofi-Aventis
• Astra-Zeneca
I have no potential conflicts of interest relevant to this topic.

Impact on Health
in Alaska
Increased Stinging and
Biting Insects
Potential Risk of
Vector Borne Disease

Vector borne diseases
Arthropod borne viruses
• Tick-borne Encephalitis
• West Nile Virus
• Northway Virus
• Snowshoe hare Virus
Emerging public health threats
Emerging public health threats
in the arctic regions of Canada,
Alaska & the Russian
Federation

Vector borne diseases
Mosquitos that transmit
WNV are present in the
US and Canadian Arctic:
- Aedes canadiensis
- Aedes Vexans
- Culex pipiens
- Culex resuan
Dead bird surveillance
conducted 2000-2006 in
Alaska did not identify
WNV
57.5 o N
Furthest north
57.5 o Latitude N
(2004)
Adapted from Alan Parkinson PhD, CDC, Arctic Investigations Program

Tick-borne Encephalitis (TBE)
• Over the past 20 years there has been a
substantial increase in TBE in Sweden
and shifts in northern latitude distribution.
• This increase has been linked to global
warming and a change toward milder
winters and earlier arrival of spring.
• Increases in tick prevalence and infection 59.26 N
• Ixodes ricinus is the main vector for
• Lyme borreliosis
• Tick-borne encephalitis
Lindgren E, Gustafson R. The Lancet, 2001;358:16-18

Tick-borne Encephalitis, Sweden
Early
1980s
Mid‐
1990s
59.26 N 59.26 N
Juneau is 58.18 N.
Lindgren et al. 2000

Changing gPatterns
of Insects

Increasing Hymenoptera
in Alaska
• The number of hymenoptera in Fairbanks
estimated to have increased 10 fold in 2006*
• Jack Whitman, a biologist with the
Department t of Fish & Game**
• Trapped 3,461 YJ on his property in a week
• Used 3 homemade traps
• Destroyed 9 aerial nests in three weeks
• Estimated over 12,000 YJ
• This pattern was similar throughout the state
• Insects adapt well to warmer temperature***
*C ti ithD kSik PhD UAFE t l
*Conversation with Derek Sikes, PhD, UAF Entomology
**Mowry T, Fairbanks Daily Miner, Aug 13, 2006
***Frazier M, et al, Am Nat 2006. 512-520

Hymenoptera Related
Deaths in Alaska
• 2 deaths from hymenoptera stings in
Fairbanks during the summer of 2006
Demain, J. G. & Gessner, B. D. Increasing incidence of medical visits due to
insect stings in Alaska. Alaska Epidemiology Bulletin 13 (2008)

Increase in ED visits for Stings at
Fairbanks Memorial
Stings in Fairbanks
200
180
160
140
120
# patients
presenting to
Fairbanks ED for
sting reaction
100
80
60
40
20
0
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Demain, J, Gessner, B, McLaughlin J, Sikes,D, Foote,T . Allergy & Asthma Proceedings,2009. in press
Trend

Venom Reactions
Patients Referred to
25
Patients
AAIC for Evaluation
20
of Sting Reactions
15
10
5
0
1999 2000 2001 2002 2003 2004 2005 2006 2007
ses
Number of Ca
25
20
15
10
5
y = 2.35x - 4693.5
R 2 = 0.8491; p

Increase in Medical Visits for Stings Among
Alaska Medicaid id Recipients i (0ver 132,000)
ears
Rate
p er 1000 0 p erson-y
9.0
8.0
70 7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1999 2000 2001 2002 2003 2004 2005 2006
Any diagnosis
Primary diagnosis
Any diagnosis, unique events
Linear (Any diagnosis)
Chi-Square S p

Does temperature change
correlate with changing
patterns of hymenoptera ?
200
180
160
140
120
100
80
Stings in Fairbanks
# patients
presenting to
Fairbanks ED for
sting reaction
Trend
60
40
20
0
1990
90
1991 91
1992 92
199393
199494
199595
199696
199797
1998 98
1999
2000
2001 01
200202
200303
200404
200505
200606
9.0
[5]
Tanana Valley Clinic, Department of Pediatrics, Fairbanks
e ars
e p er 1000 p erson-ye
Rate
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1999 2000 2001 2002 2003 2004 2005 2006
Any diagnosis
Primary diagnosis
Any diagnosis, unique events
25
20
15
10
Patients
5
0
1999 2000 2001 2002 2003 2004 2005 2006 2007
Demain, J, Gessner, B, McLaughlin J, Sikes,D, Foote,T . Allergy & Asthma Proceedings,2009. in press

Epidemiologic Regions of Alaska
Northern
http://climate.gi.alaska.edu/ClimTrends/Change/TempChange.html
alaska edu/ClimTrends/Change/TempChange html
Interior
Anchorage/Mat-Su
Southwest
Gulf Coast
Southeast

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Annual
Winter
1999-2001
2004-2006
Percent change in insect
Largest
temperature
temperature
insect sting
insect sting
sting incidence (Х 2 for
Region Community Increase* Increase* incidence † incidence † trend, p-value) ‡
Northern Barrow 3.8 6.1 16 119 626% (13, p

Results
• Each of the three databases revealed an increasing trend for
patients t seeking medical care for bites & stings (p

Distribution or Survival
of Insects
• Arthropods are extremely temperature sensitive
• Climate changes have impacted life cycles and
expanded inhabitable territory
• Mosquitoes and plant communities are migrating to
higher ground as permafrost thaws and glaciers retreat
• Beetle plagued forests in Alaska have impacted over
4,000,000 acres
• Lepidoptera are expanding their northern boundaries in
the northern hemisphere
• Ticks (Ixodes ricinus) that transmit Lyme borreliosis and
viral encephalitis have extended northwards in Sweden
associated with fewer winter days below 10 degrees
and more summer days above 50 degrees

Climate Change and Insects in the Arctic
• The average Arctic temperature
have increased at almost twice
the rate of the rest of the world in
the past two decades the Arctic
may serve as a sentinel site for
early detection of changes in the
epidemiology of infectious
diseases due to climate change

The Arctic:
Our Window to the Future?