31/05/2011. Epidemiology and Control Programs for Echinococcus multilocularis. - geography? - frequency? - risk factors? - geography? - frequency?

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1 Epidemiology and Control Programs for Echinococcus multilocularis - geography - frequency - risk factors Thomas Romig Universität Hohenheim Stuttgart, Germany - geography - frequency - risk factors Global distribution E. multilocularis in Europe, 1990 E. multilocularis in Europe,

2 Documented cases of human alveolar echinococcosis Spread or not - Individual assessment for each region (baseline data, lack of previous human cases etc.) Definition of non-endemicity Kern et al., 2003 Role of genetic characterization (EmsB, mt genes) - mainland island hypothesis - autochthonous focus in northern Italy Knapp et al., 2009 Prevalence in foxes (Baden-Württemberg, Germany) - geography Echinococcusmultilocularis in foxes in Baden-Württemberg (influence of control measures not shown) Universität Hohenheim, Parasitologie prevalence 0-9% 10-29% not examined 30-49% > 50% - frequency risk factors Mannheim Mannheim Mannheim Karlsruhe Karlsruhe Karlsruhe Stuttgart Stuttgart Stuttgart Ulm Ulm Ulm Freiburg Freiburg Freiburg 50 km 2

3 Prevalence in foxes (southern Bavaria, Germany) Prevalence in foxes (Lower Saxony, Germany) Berke et al., % % (1 / 8) % % 4-35 % Average prevalence (8459 foxes) 12% 15% 20% / 2003 Prevalence in musk rats River A Tauber 0,0% 25,6% (123) (78) B Kocher, 0,5% 30,8% Jagst (778) (468) C Brenz 2,8% 20,3% (358) (143) D div. 4,1% 14,8% (713) (61) E div. 0,8% 22,0% (1316) (150) F Neckar 3,8% 23,4 (131) (47) In southern Germany, the biomass of E. multilocularis in natural hosts has increased by approximately the factor 10 between the early 1990s and the early 2000s. Annual incidence of human AE in Switzerland (Schweiger et al., 2007) : 0, : 0,26 Deficiencies in sampling design and / or comparability of diagnostic methods...but... Trends in most areas are towards prevalence increase (Netherlands, Belgium, France, Germany, Austria, Poland, Slovakia...) More recent trends Stable situations 3

4 31/05/2011 Annual hunting indices of foxes in Baden-Württemberg (Wildforschungsstelle BW) n E. multilocularis in foxes, central Swabian Jura (prevalence (%) and 95% C.I.) (25-41) (33-51) (42-57) (29-48) (29-48) (34-53) 100,000 80,000 60,000 40,000 20,000 Red fox: Population change between 1985 and geography from Chautan et al. (1999), mod. - frequency - risk factors 3-4x 2-3x 1-2x Microtus arvalis Arvicola terrestris Ondatra zibethicus Myodes glareolus (Muridae) 4

5 Human AE cases in and grassland proportion in the Doubs department, France Prevalence rates (x 10,000) Feb 1997 Grassland % Prev.* x 10,000 > 35 % % 0-20 % Xi 2 wcc, p = Monte Carlo, p = 0.05 * urban cantons (bold) removed E. multilocularis in foxes, central Swabian Jura (prevalence (%) and 95% C.I.; population indices) Micr. / Arv (25-41) 85 / (33-51) 72 / (42-57) 96 / (29-48) 28 / (29-48) 26 / km Source: Giraudoux et al., (34-53) 61 / 48 Linked to species (e.g. via predation rate, susceptibility) Are cyclic population dynamics favourable or not Diversity of factors in different ecosystems Alteration of host behaviour: urban foxes Risk factors for E. multilocularis in urban areas (from D. Hegglin, adapted) Forest Urban periphery City City centre R nord Human population, anthropogenic food Fox density U west U east R east Frequency of intermediate hosts Proportion of voles as fox prey R west Increased risk for alveolar echinococcosis Estimated gene flow Wandeler et al Mol Ecol. 5

6 31/05/2011 E. multilocularis in European cities n prevalence 95% CI Village foxes in the Swabian Jura Zurich % 39-49% Deplazes et al, 2004 Geneva % 35-51% Deplazes et al, 2004 Stuttgart % 14-21% Deplazes et al, 2004 Prague 25 44% 24-65% Martinek et al, 2004 Pilsen 24 4% 0-21% Martinek et al, 2004 Vienna 71 1% 0-8% Duscher et al, 2005 Presence of urban foxes not in all cities and towns, and E. multilocularis prevalences vary widely Wildlife cycle in Wildtierzyklus the in city der Stadt Is that really so, and why Transmission by Übertragung auf pet animals Haustiere A brief look at other world regions... Role of dogs and cats risk dogs with high prevalence, but general dog population rarely infected (D and CH) dogs as risk factor in human case-control study susceptibility of cats 6

7 Arctic North America and western China (Tibet) Very diverse life cycles with several species of wild canids Domestic dogs are heavily involved and seems to be chiefly responsible for transmission to humans Japan Accidental anthropogenic introduction early in the 20th century from the Kurile Islands to Hokkaido E. multilocularis in foxes: prevalence change in Hokkaido Definitive hosts: Red fox (Vulpes vulpes) Intermediate hosts: Myodes rufocanus Myodes rutilus Myodes rex (Ito et al., 2004) Dense forest undergrowth of Sasa spp. supports high population densities of Myodes rufocanus Due to this, and in the absence of grassland rodents, the transmission of E. multilocularis in Japan occurs in non-anthropogenic environments. Options for E. multilocularis control - Education: information, avoidance of risk behaviour - Preventive treatment of owned dogs - Destruction of transmitting animals (stray dogs, foxes) - Anthelmintic treatment of foxes / stray dogs with baits 7

8 Deworming of foxes with baits 50 mg praziquantel per bait baits / km 2 (aircraft) Intervals 4 weeks - 6 months indirect direct Droncit bait (Bayer) containing 50 mg praziquantel Larger trials: E. multilocularis prevalence in foxes during and after baiting campaigns with praziquantel (Droncit ) 3400 km 2, 20 baits / km 2 km 2 months baits/km2 Prevalence change SW-Germany 3, % - 15% NE-Germany 5, % - 1-3% Hokkaido % - 6% SE-Germany % - 1% Tackmann et al. 2001; Tsukada et al. 2002; Romig et al. 2007; König et al. 2008) Conclusion: - drastic prevalence reduction can be achieved by largescale approaches - no eradication () - long-term political commitment necessary - focussed approaches necessary König et al

9 31/05/2011 Zurich: Positive fox faeces from treated and non-treated areas (N=1205) Small-scale approaches in urban / periurban areas and rural villages 100% winter 99/00 (N=221) spring 00 (N=201) summer/aut. 00 (N=322) winter 00/01 (N=346) Summer/autumn 01 (N=605) 90% 80% % positive faeces (+/- CI) 70% 60% 50% 40% 30% 20% 10% 0% Non treated 1 km2km2-areas 6 km2km2-area Hegglin et al., Emerging Infectious Diseases 9, 2003, (modified) Home ranges of synanthropic foxes in a rural village in southern Germany Peri-urban area in Annemasse, E France: 2,5 year campaign (5 distributions per year) 13.3% to 2.1% (spring prevalence, copro-elisa) Comte et al., 2010 Distribution of baits and prevalence in foxes (PCR) Information, no active control 20 Silvatic Incidence low 18 Endemicity of human alveolar echinococcosis Incidence high Synanthropic Wildlife (fox) transmitted Anthelmintics in baits Fox destruction 12 Destruction not acceptable Auslagen 10 ohne Auslagen 8 Anthelmintics in baits Dog transmitted Stray dogs 6 Anthelmintics in baits Destruction acceptable Dog destruction 4 Owned dogs 2 Risk behaviour / No risk behaviour by aircraft Preventive treatment by owners / vets 2004 Information, no active control by hand 9

10 Thank you! 10