Ticks on the move to the north - increased risk for new zoonotic infections?
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Ticks on the move to the north – increased risk
for new zoonotic infections?
Ann Albihn1,2, Giulio Grandi1,2 and Anna Omazic1
1National Veterinary Institute (SVA), Uppsala, Sweden
2Dept. Biomedical Sciences & Veterinary Public Health, Swedish University of
Agricultural Sciences, Uppsala, Sweden
One Arctic – One Health Conference 2019, Feb 7 – 9, Oulu, Finland
Climate change effects
on the epidemiology of
infectious diseases and
the impacts on Northern
societies
Also granted by; Foto: Carl-Johan Utsi
The Hjärre fondation
Future Animals/SLU
Ticks are central when studying climate sensitive infections (CSIs)
• Literature search about 37 potential CSIs together with climate change expressions.
• Revealed 11 179 publications - evaluation of 660 abstracts
• The abstract review process were slightly modified from Moher et al., 2009
Transmission routes Arthropod vectorborne CSIs - subgroups
• Photos: Carl-Johan
Utsi
Omazic et al., in manuscript
Climate change expands the geographical distribution of ticks to
higher latitudes and altitudes.
• Ticks are expanding northwards in Sweden (Jaenson et al., 2012)
• Their role as disease vectors in the north is unclear
One Arctic – One Health Conference 2019, Feb 7 – 9, Oulu, Finland
Ticks are vectors for several zoonotic diseases
Which diseases?
Tick-borne encephalitis (TBE) and
Borreliosis (Lyme disease) are well known.
But granulocytic anaplasmosis and
babesiosis are of growing concern in Swe.
How to handle tick-borne diseases?
Reduce tick-bites
Habitat modification, “dipping” and
pour on profylax
Disease specific treatment/profylax
Medical treatment
Vaccine available for TBE
Photo: Anders Lindström
Under development for some of the
diseases
Collection of ticks from the northern half of Sweden
• To investigate the northern expansion of ticks and
tick-borne pathogens
• Through a citizen science study year 2018
• Ticks found on animals or humans
• Morphological species identification
• Microbiological analysis with FLUIDIGM, a
microfluidic PCR-based technique for an
array of pathogens
SVA tick collection 2018
Results
• 4500 ticks were received.
• Expanded geographical distribution. Ticks
from all northern communities except one
(Arjeplog).
• Tick species identification, mainly Ixodes
Ixodes ricinus or ricinus as far as this
common tick (in addition I. trianguliceps ).
No I.persulcatus (yet…).
Number of ticks/county
SVA tick collection 2018 – New species detection as a side effect
• Hyalomma marginatum and H.
rufipes
• About 35 ticks
• Normal area is south of the Alps
• Vector for several diseases
• Large, quick, aggressive, beautiful
• Mainly found on horses
• Larva hitch-hike on migrating birds
• Development to an adult possible
due to long and hot summer
• Their possibility to over-winter is
doubtful
Hyalomma marginatum
Photo Artportalen
Attention in media
Anaplasmosis in sheep
• The most widespread TBD among animals
in northern Europe.
• Tick-borne fever, pasture fever, Ehrliciosis,
granulocytic anaplasmosis, (sjodagg Norway)
• High fever, abortion, reduced weight gain
and milk production, also subclinical
infection.
• Most serious is immunosuppression,
secondary infections with high mortality.
• Caused by Anaplasma phagocytophilum
• 300 000 lambs infected yearly in Norway
(Stuen, 2016.)
• E.g. cattle, horse, cat, dog, goat, roedeer
may also get infected/act as reservoirs
Photo A. AlbihnBabesiosis in cattle
• Significant problem in certain areas
• Piroplasmosis, summer disease
• Symptoms in adults not in calves -
hematouria, abortion, death
• Mainly B. divergens
• 4% of ticks in southern Sweden carry Babesia
spp (Karlsson & Andersson, 2016)
• Seroprevalence
• in southern Sweden 53% (38/71)
(Andersson et al., 2017)
• in southern Norway 27% (Hasle et al., 2010)
• E.g. dear, dog, may also get infectedRetrospective data collection on Anaplasmosis and Babesiosis
• Collection of Swedish official animal disease data
• Anaplasmosis no cases of the notifiable A. marginale
• A. phagocytophilum is not compulsory to report but
310 cases were diagnosed at SVA on ruminants year
2008-2018.
• Babesiosis 24 cases year 2005-2016,
• Notifiable B. major or B. bovis,
• B. divergens is not compulsory to report
Foto: Anders LindströmAnaplasmosis in sheep
2004 – 2017
Location in
• Traditional county Anaplasmosis noted by
multiple cases 2004-2011 the Swedish Farm and
• New county Animal Health
mainly cases 2012-2017 organisation.
104 cases at post-mortem
examination, from
diseased animals and/or
diagnosed at the lab.
A. phagocytophilum
Trend to increasing
numbers and a northern
expansion over the years.
Albihn, 2019, unpublishedBabesiosis in cattle
2004 – 2017
Location in
• Traditional county Babesiosis noted by the
multiple cases 2004-2011 Swedish Farm and Animal
• New county Health organisation.
mainly cases 2012-2017 143 cases diagnosed post-
mortem
B. divergens (in generall not
confirmed at the lab)
Trend to increasing numbers
and a northern expansion
over the years.
Albihn, 2019, unpublishedAnaplasmosis and Babesiosis in humans • Anaplasmosis (A. phagocytophilum) first European cases diagnosed in 1997, a few cases has also been diagnosed in Sweden • Babesiosis - increasing numbers of seropositive humans • Babesia (B. divergens and B. microti) in the southernmost Sweden (Skåne), (Svensson et al., 2018) • 16,3% 14/86 Borrelia infected group • 2,5% 5/197 control group • 11,5% of tick exposed humans in Germany (Hunfeld et al., 2012)
Conclusion
When diseases show up in new areas, the
unawareness may compromise protection of a
population and the recognition of clinical
symptoms.
In an immunologically unprotected population,
a new infection may cause more severe
clinical symptoms and/or higher mortality rate.
With new knowledge regarding the northern
distribution of ticks and TBD, we may be able
to identify new risk areas and to suggest
measures to minimize diseases.
Foto: Anders LindströmYou can also read
