Prevalence of pathogens in ticks feeding on humans Tinne Lernout
Contexte Available data for Belgium: localized geographically questing ticks or feeding ticks on animals collection at one moment in time or short period
Methods
Methods Collection of ticks attached to humans by citizens Period 1 st April 31 st October 2017 Through website Tekennet.be/TiquesNet.be: Short questionnaire (data on geographical location of bite and circumstances) generation of personal code Tick attached on piece of paper with transparent tape + code Sent by postal mail to Coda-Cerva. No stamp Ticks stored at -20 C
Press release 30/03/2017
Identification of species and stage Stage: size / number of legs / genital aperture Gender: size of scutum / genital aperture Species: length of mouthparts, scutum (shape/color/pattern), colour, RIVM Photo M. Madder
DNA extraction At Coda-Cerva (current Sciensano) Homogenisation of individual nymph and adult ticks in MEM using a tissue lyser (3min, 25Hz) and a 5mm metal bead; larvae pooled by month of tick bite DNA extraction from the homogenate using the MagMAX total nucleic acid Isolation kit and the MagMAX Express-24 purification system (Life Technologies) Contact: nick.deregge@sciensano.be
Analysis of pathogens At RIVM in the Netherlands (Hein Sprong) Multiplex PCR for Borrelia burgdorferi sensu lato (s.l.), Anaplasma spp., Borrelia miyamotoi, Candidatus Neoehrlichia mikurensis, Rickettsia spp. and Babesia spp. Methods (PCR, qpcr and sequencing) are described in Jahfari S. et al. PLoS Negl Trop Dis. 2016 Oct 5;10(10)
Results
Collection of ticks
Species : 99% Ixodes ricinus Ixodes ricinus Ixodes hexagonus Larva Nymphe Adult Adult Dermacentor reticulatis
% I. ricinus I. hexagonus D. reticulatis Larva 5.2% 83 1 0 Nymph 76.6% 1 221 4 0 Adult female 15.6% 239 6 3 Adult male 2.6% 40 0 2 Total 1 583 13 5 Number of ticks 500 450 400 350 300 250 200 150 100 50 0 Nymph Aprl May June July Aug Sep Oct Number of ticks analysed by species and by month Daniel M et al. Parasit Vectors. 2015 Sep 18;8:478
Prevalence Borrelia burgdorferi s.l. Nb of ticks % positives 95%CI Brussels 20 0 - Flanders 881 14.2 12.0 16.7 Wallonia 614 13.8 11.3 16.8 Total 1515 13.9 12.2 15.7 Species: B. afzelii (52%), B. garinii (21%), B. spielmani (7%), B. burgdorferi s.s. (5%), B. bavariensis (1%), B. Valaisiana (14% - pathogenicity?) Overall mean prevalence of Borrelia infection in ticks in Europe: 13.7% (range: 0 49) Rizzoli A. et al. Euro Surveill. 2011;16(27):pii=19906
By province 35 30 % positive ticks for Bb sl 25 20 15 10 5 0 Antwerp Limburg Vlaams Br Oost Vl West Vl Br Wallon Liège Lux Namur Hainaut N=348 N=238 N=200 N=60 N=35 N=169 N=143 N=122 N=107 N=73
Other tick-borne diseases Human cases in Belgium (per year) Brussels (n=20) Flanders (n=881) Wallonia (n=614) Total (n=1515) % pos questing ticks % pos feeding ticks animals Anaplasma phagocytophilum 1 conf 20 probable 0 2.2 % (1.4-3.3) 1.5% (0.8-2.8) 1.8% (1.3-2.7) 1.2-3.0% 9.5-22% Borrelia miyamotoi None 5% (0.7-29.3) 2.5% (1.6-3.8) 2.1% (1.2-3.6) 2.4% (1.7-3.3) 1.1-1.6% - Candidatus Neoehrlichia mikurensis None 0 3% (2.0-4.3) 2.8% (1.7-4.4) 2.8% (2.1-3.8) 0.4% - Babesia spp. None 0 1.4% (0.8-2.4) 1.6% (0.9-3.0) 1.5% (1.0-2.2) 1.1-1.6% 1.3% Rickettsia spp. 20-25 imported cases 5% (0.7-29.3) 7.6% (6.0-9.6) 5.7% (4.1-7.8) 6.8% (5.6-8.2) - 14-17%
Human cases in Belgium (per year) Brussels (n=20) Flanders (n=881) Wallonia (n=614) Total (n=1515) % pos questing ticks % pos feeding ticks animals Anaplasma phagocytophilum 1 conf 20 probable 0 2.2 % (1.4-3.3) 1.5% (0.8-2.8) 1.8% (1.3-2.7) 1.2-3.0% 9.5-22% Borrelia miyamotoi None 5% (0.7-29.3) 2.5% (1.6-3.8) 2.1% (1.2-3.6) 2.4% (1.7-3.3) 1.1-1.6% - Candidatus Neoehrlichia mikurensis None 0 3% (2.0-4.3) 2.8% (1.7-4.4) 2.8% (2.1-3.8) 0.4% - Babesia spp. None 0 1.4% (0.8-2.4) 1.6% (0.9-3.0) 1.5% (1.0-2.2) 1.1-1.6% 1.3% Rickettsia spp. 20-25 imported cases 5% (0.7-29.3) 7.6% (6.0-9.6) 5.7% (4.1-7.8) 6.8% (5.6-8.2) - 14-17%
Subspecies Babesia B. venatorum (77.3%) B. divergens (13.6%) B. microti (9.1%) Rickettsia Ixodes ricinus: all R. helvetica R. raoultii : in 2/5 dermacentor ticks
Larvae 0/7 pools larvae positive for B. burgdorferi s.l. 1/7 pools larvae positive for B. miyamotoi 4/7 pools larvae positive for R. helvetica
Co-infections 4% of nymphs and adult ticks carried 2 pathogens and 4 ticks were infected with 3 pathogens Overview of pathogen combinations
Future Data can be used in addition to other factors for risk maps for Lyme borreliosis Screening for other pathogens (TBEV, francisella tularensis?) A new study in 3-4 years will allow to follow-up evolution
Conclusions Lyme borreliosis can be contracted all over the country. But no panic, 86% ticks borrelia-free Prevalence in all regions below 20% antibiotic prophylaxis not recommended (BAPCOC) Presence of other tick-borne pathogens (although low prevalence), with aspecific clinical symptoms important to raise awareness Prevention of tick bites: http://www.tekenbeten.be/ or https://www.wiv-isp.be/matra/cf/cf_tiques.aspx BAPCOC: http://overlegorganen.gezondheid.belgie.be/nl/node/4639
References OTBD Claerebout et al. Parasit Vectors. 2013;6:183 Cochez et al. Zoonoses Public Health. 2015 Aug;62(5):331-3a De Keukeleire et al. Vector Borne Zoonotic Dis. 2017 Feb;17(2):108-115 Heylen et al. Environ Microbiol. 2016 Mar;18(3):988-96 Lempereur et al. Parasitol Res. 2012 Apr;110(4):1525-30 Lempereur et al. Clin Microbiol Infect. 2015 Jan;21(1):96.e1-7
Acknowledgements All the citizens who collected the ticks My colleagues from Sciensano: Katrien Tersago, Laurence Geebelen and David Jaminé for their help in identification of ticks & Nick de Regge and Célia Thoraval for DNA extraction Hein Sprong and Manoj Fonville from RIVM in the Netherlands for the PCR analyses The study was financed by the Flemish Agentschap Zorg en Gezondheid and by the Walloon Agence pour une Vie de Qualité