Download Emerging Vibrio risk in the Baltic Sea in response to ocean warming

Emerging Vibrio risk in the Baltic Sea in response to
ocean warming
Dr Craig Baker-Austin
Centre for Environment, Fisheries and Aquaculture Science (Cefas)
Weymouth,
Dorset,
United Kingdom
[email protected]
EURL for monitoring bacteriological and viral contamination of bivalve
molluscs.
Climate Change: The last 150 years
Of the warmest 20 years on record (1851-2011) all have been in
the last 25 years.
Source: University of East Anglia, Climate Research Unit (2011).
Recent surface seawater temperature changes
(IPCC fourth assessment report 2007).
Source: IPCC Fourth Assessment Report (2007).
Vibrio wound infections - differing levels of severity
V. vulnificus. Most dangerous Vibrio pathogen. Causes
necrotising (tissue death) wound infections. Very high
mortality rate (20-25%), can lead to 60% mortality rate if
infection progresses to septicaemia (blood poisoning). At risk
groups – the elderly, diabetics, individuals with liver
dysfunction and/or compromised immune systems.
Picture courtesy: Ruppert et al. (2004).
Picture courtesy: Ottavianii et al. (2010).
V. cholerae (non O1/O139). Second most dangerous
Vibrio pathogen. As with V. vulnificus can cause necrotic
wound infections, although many cases involve reoccurring
ear infections. Mortality rate much lower, but can increase
significantly in at risk groups – particularly where the elderly,
those with liver complaints, and persons with compromised
immune systems are involved.
V. parahaemolyticus and V alginolyticus. Amongst the least
pathogenic Vibrio infections. Few fatalities, and very
rarely progress to more serious infections. Can usually be
treated with antibiotics and/or topical treatments. Normally
cut/wound infections and ear infections associated with
swimming.
Picture courtesy: Reilly et al. (2011).
Poleward expansion of Vibrio disease?
Alaska, USA
V. parahaemolyticus (2004)
NW Spain
V. parahaemolyticus (1999,
2004)
Baltic Sea
Vibrio spp. (1994, 2004, 2006)
Vladivostok, Russia
Vibrio parahaemolyticus (1997)
Pacific NW, USA
V. parahaemolyticus (1997)
Chile
V. parahaemolyticus (2003 ongoing)
New Caledonia
V. vulnificus (2008/9, 2012)
y = 0.0682x + 16.359
R² = 0.679, p> 0.001
19
18.5
18
Vibrio risk
threshold
17.5
17
16.5
16
15.5
2007
2002
1997
1992
1987
15
1982
Sea surface temperatures (Celcius)
Average summer (June-September) sea surface
temperatures, Europe 1982-2009
Year
Regionally, Europe’s seas are warming faster than anywhere else on Earth
Source: Baker-Austin, C., et al. (2012) unpublished data
Current rates of warming
White Sea – Maximum
SST change: 1.49 ± 0.03
(°C/decade ± s.e.m.)
Gulf of Finland – Maximum
SST change: 1.00 ± 0.02
(°C/decade ± s.e.m.)
Danish/German border –
Maximum SST change: 0.91 ±
0.02 (°C/decade ± s.e.m.)
Source: http:www.CoastalWarming.com
Only one of environment on Earth warming as fast
Hudson Bay, Canada –
Maximum SST change: 1.44
± 0.02 (°C/decade ± s.e.m.)
Baltic Sea area – the ‘crucible of climate
change’
Picture courtesy: Joaquin Trinanes, USC, Spain
Sea surface salinity in Europe
Optimal Vibrio growth
Possible Vibrio risk?
Source: Baker-Austin et al Nature Climate Change (2012).
Notable recent Vibrio outbreaks in Europe
Spain (1999) – 64
cases of V.
parahaemolyticus
traced to shellfish
consumption
(Lozano-León et al.
2003).
Spain (2004) – 80 cases of
V. parahaemolyticus.
Pandemic strain (O3:K6)
identified at outbreak
Spain (1989) – 8 cases of V.
(Martinez-Urtaza et al.
parahaemolyticus associated with
2005).
fish and shellfish consumption.
Baltic (1989-2010) – Numerous
reported cases of wound
infections (Vibrio spp.) in the
Baltic Sea area. Almost all
recreational exposure to
seawater during summer
months. Numerous fatalities
linked to V. vulnificus and
non-O1 V. cholerae
infections.
Italy (2004) and France
(2005) - several V.
parahaemolyticus O3:K6
strains identified based on
retrospective analysis of
clinical cases. Sporadic V.
cholerae (non O1) cases.
Source: Baker-Austin, C., L. Stockley, R. Rangdale, and J. Martinez-Urtaza. Environmental occurrence and clinical impact of Vibrio
vulnificus and Vibrio parahaemolyticus: a European perspective. Environmental Microbiology Reports, 2010.
Baltic Sea published
Vibrio cases
All from 4 years...2006, 2003, 1997 & 1994
Summer (May-Sept) SST warming trends in the
Baltic, 1982-2010
Key
6
12
25
50
75
Temperature (Celsius)
Number of days
23
22
21
**
20
19
18
Year
Source: Baker-Austin et al unpublished (2012).
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
17
Temperature analysis
• Infrared remote sensing makes use of sensors to detect infrared radiation emitted
from the Earth's surface. Satellites can be used to remotely detect and measure the
thermal infrared region. This radiation is emitted from warm objects such as the
Earth's surface. They are used in satellite remote sensing for measurements of the
Earth's land and sea surface temperature.
• For this work we have used the NOAA Polar orbiting environmental satellite
datasets. The dataset available is immense. We can effectively scrutinise any
region of the earth down to 1km resolution, daily from 1982-2011 for sea surface
temperature (SST). Sea surface salinity data from buoys/robotic instruments.
• We have also used long-term sea surface temperature records, such as the
Hadley Met Office and ICES data. Accurate information goes back to the mid 19th
Century (150+ years of information).
Epidemiological analysis
•
Across Europe (and often elsewhere) Vibrio infections are not generally
reported, as they are not notifiable pathogenic agents. This lack of
epidemiology is problematic in terms of assessing clinical impact.
•
To circumvent this, we obtained information from vibrio cases in the Baltic
from several different sources: 1) Published peer-reviewed papers (web of
science, scopus, NCBI, internet search engines). 2) Grey literature - such as
newspaper reports, bulletins from EU reference laboratories and European
surveillance websites (e.g. EpiNorth, EuroSurveillance), PhD & MSc theses.
3) Official statistics - from EU countries with some reporting capacity for
vibrios, such as Sweden, Finland, Germany. 4) Anecdotal reports – cases
reported by experts (academic and government scientists) in and around the
Baltic.
•
Where available, information regarding the timing, geographical location and
agent responsible was subsequently gathered.
Cases that were not
domestically acquired were removed and where suspected (e.g vibrio cases
reported during the winter) were subsequently removed from final analysis.
Epidemiological data
•
Large number of cases reported in and around the Baltic Sea & Eastern
North Sea area were identified from 1977-2010. 272 cases (96%) from
Baltic Sea area. Where reported, most cases reported are V. vulnificus and
V. cholerae (non O1/O139) wound infections. The vast majority reported
from 1997 onwards (234 cases, 85%).
•
The numbers of cases appears to follow national quality of monitoring –
Finland and Sweden have the best overall datasets - and highest numbers
of cases (125 and 68, respectively).
•
Significantly, there were numerous fatalities (e.g. Sweden, Germany &
Poland 2006, Germany 2003 & 2010, Denmark 1994). Most fatalities
caused by V. vulnificus (10) and V. cholerae (4).
•
Where specific timings of infections were reported, the vast majority
occurred during the summer May-October (~90 %). Several years are of
particular interest: 2006 (66 cases), 2003 (19 cases), 1997 (21 cases) 1994
(21 cases) and 2010 (35 cases). Crucially, these are extremely hot
summers.
2006 European heatwave
• The 2006 European heatwave was an
exceptional period of warm weather lasting over a
month – 26th June 2006 to 30th July 2006.
• Across most of western Europe, July 2006 was
the warmest month since official measurements
began. Temperatures peaked during the end of
July in the Baltic region (24th-29th July).*
• A huge number of Vibrio cases started
emerging in the Baltic - V. vulnificus, V. cholerae
(non-O1/O139), V. parahaemolyticus and V.
alginolyticus.
• Most cases were wound infections, attributed to
recreational exposure to seawater.
Baltic
Sea -and
Maximum
temperature
andSea
clinical
cases
Temperature
reported vibrio
cases in Baltic
area (1982-2010)
2006
60
22 ºC
40
21 ºC
*
20
20 ºC
Year
Source: Baker-Austin
Baker-AustinetetalalNature
unpublished
Climate (2012).
Change (2011).
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
0
Temperature (Celsius)
Number of reported cases per year
80
Changing seasonality – more ‘vibrio’ days in the Baltic
2000-2010
1854-2010
By 2050
By 2020
(IPCC fourth assessment report 2007
Source: Baker-Austin et al Nature Climate Change (2012).
Adding relevant epidemiological risk factors
•
Seawater temperature and salinity are not the only factors that increase
potential risk of recreational (or shellfish)-associated vibrio infections.
•
Other physiochemical variables (e.g. Zooplankton abundance, recent mixing
events etc) that are likely to play a role in reducing or increasing vibrio
numbers.
•
We are currently in the process of using additional epidemiological risk
factors alongside the salinity-temp data to refine ‘risk’. Number of reported
cases as well as population density may play a significant role in determining
risk levels.
•
Several key data issues remain here – including overall poor epidemiology
data in Europe, hampering efforts to improve and refine risk models.
Ave. summer temp
Reported cases
Baltic, 2006
Ave. salinity
Population density
Vibrios and future epidemiological trends
•
Underlying conditions. The number of people with underlying risk factors
for vibrio infections are increasing steadily, across the EU and elsewhere –
these include individuals with liver dysfunction, diabetes and compromised
immune systems.
•
Ageing population. Another major risk factor for vibrio infections
(particularly V. vulnificus & V. cholerae non-O1). The UN predicts that by
2050 the number of people aged over 65 will be 33%, and will have
increased by 20% compared to 1950.
•
Contact with water. More people living by, and in contact with marine
water. 30+ million people live within 5 km of Baltic – enormous potential for
exposure during warm weather episodes.
•
Behavioural factors. Long-standing ‘old wives tale’ of washing open
wounds in seawater to sanitise cuts and grazes. A major risk factor –
should be discouraged, especially during summer months.
Visible cases
Vibrio epidemiology – the tip of the iceburg
Vibrio case correctly identified
and reported – data made
nationally and/or internationally
available to Vibrio community
Data not made publically
available to Vibrio community
Invisible cases
Vibrio not notifiable agent –
data not forwarded to national
or regional epidemiology centre
No formal identification of agent
responsible
Misdiagnosis of Vibrio illness
Case not serious or self limiting
and subsequently not reported
Source: Baker-Austin et al unpublished (2012).
Challenges and opportunities
•
The Baltic Sea and North Sea have both recently been
described as the ‘Crucible of Climate Change’. The Baltic and
North Sea are the fastest warming marine ecosystems on
Earth, where already huge ecosystem-level changes are
being detected. There are many challenges and opportunities
presented by this.
•
Datagaps: Huge data gaps in Europe - namely poor vibrio
epidemiology, a lack of joined-up surveillance systems and a
means of reporting cases to a centralised body in a timely
manner. The COVIS (Cholera and Other Vibrio Illness
Surveillance system) in the USA is an excellent template to
improve the situation in Europe.
Baltic Sea risk map, 27th July 2006
Developing a dedicated pan–European vibrio network
1. Centralised data sharing resource for vibrio experts in
Europe.
2. System of reporting vibrio infections to a central body.
3. Advice for the detection, treatment and prevention of vibrio
infections.
4. Centralised resource for dissemination of strains for research,
diagnostic purposes etc.
5. Online resource where remote sensing-based risk maps can
be accessed.
COVIS report form, courtesy CDC
Future work
•
Predicting and managing risk. Most Vibrio infections acquired in Europe
are preventable. Minimising risk using appropriate education programmes for
at risk groups may be an effective means of reducing the clinical impact of
these pathogens.
•
Improving epidemiology. There is a dire need to improve the basic
epidemiology of vibriosis in Europe, such as the timing, location, probable
route of exposure and agent responsible. Improving the epidemiology
requires coordination and effort across Europe, including clinical
microbiologists, public health practitioners and epidemiologists. We have a
template to achieve this though – such as reporting systems in the USA, Far
East, where vibriosis is more comprehensively and systematically reported.
•
Availability of tools to predict, track and elucidate outbreaks. The
availability of molecular tools, such as genome sequencing will allow us to
identify sources of outbreaks, identifying evolutionary relationships between
strains and potentially identify areas where cases may emerge.
Acknowledgements
• Joaquin Tristanes and Dr Jaime Martinez-Urtaza, University
of Santiago de Compestela, Spain
• Dr Rachel Hartnell, Dr Nick Taylor & Dr David Lees
• Professor Anja Siitonen, THL, Helsinki, Finland
• Professor James D. Oliver, UNC Charlotte & Dr Angelo
DePaola, FDA, Dauphin Island, Alabama, USA