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, Sweden2Dept. Biomedical Sciences & Veterinary Public Health, Swedish University ofAgricultural 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

Foto: Carl-Johan UtsiAlso granted by;The Hjärre fondationFuture Animals/SLU

• Photos: Carl-Johan

Utsi

Ticks are central when studying climate sensitive infections (CSIs)

Arthropod vectorborne CSIs - subgroupsTransmission routes

• 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

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

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/profylaxMedical treatmentVaccine available for TBEUnder development for some of the diseases

Ticks are vectors for several zoonotic diseases

Photo: Anders Lindström

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

Number of ticks/county

Ixodes ricinus or common tick

Results

• 4500 ticks were received.

• Expanded geographical distribution. Ticks

from all northern communities except one

(Arjeplog).

• Tick species identification, mainly Ixodes

ricinus as far as this

(in addition I. trianguliceps ).

No I.persulcatus (yet…).

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, roedeermay also get infected/act as reservoirs

Photo A. Albihn

Babesiosis 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 infected

• Collection of Swedish official animal disease data

• Anaplasmosis no cases of the notifiable A. marginale

• A. phagocytophilum is not compulsory to report but310 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 Lindström

Retrospective data collection on Anaplasmosis and Babesiosis

Anaplasmosis noted by

the Swedish Farm and

Animal Health

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.

Anaplasmosis in sheep2004 – 2017

Location in

• Traditional county

multiple cases 2004-2011

• New county

mainly cases 2012-2017

Albihn, 2019, unpublished

Babesiosis noted by the

Swedish Farm and Animal

Health organisation.

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.

Babesiosis in cattle2004 – 2017

Location in

• Traditional county

multiple cases 2004-2011

• New county

mainly cases 2012-2017

Albihn, 2019, unpublished

Anaplasmosis 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)

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 Lindström

Conclusion