Food-borne parasites: the point of view of human public health

Transcription

1 Food borne parasites Food-borne parasites: the point of view of human public health Opistorchis Qat Fasciola Trichinella Titia Kortbeek & Joke van de Giessen 1 2 Public Health Definition WHO Focus on entire populations and not individual patients or diseases Vaccination and control of infectious diseases Safer and healthier foods Safe drinking water non infectious campaigns like motor-vehicle safety etc 3 PH refers to all organised measures (whether public or private) to prevent disease, promote health, and prolong life among the population as a whole. 0 Public Health Potentional spreading of the infection Common source: food, water transmission human to human Contineous transmission animal to humans 4 High burden of disease : Disability adjusted life years (DALYs) High costs of disease Havelaar AH, Haagsma JA, Mangen MJ, Kemmeren JM, Verhoef LPB, Vijgen SMC, Wilson M, Friesema IHM, Kortbeek LM, Duynhoven YTHP van, Pelt W van. Disease burden of foodborne pathogens in the Netherlands, 2009 International Journal of Food Microbiology Int J Food Microbiol Jun 1;156(3): Epub 2012 Apr Mangen MJ, Bouwknegt M, Friesema IH, Haagsma JA, Kortbeek LM, Tariq L, Wilson M, van Pelt W, Havelaar AH. Cost-of-illness and disease burden Ranking of food-related pathogens in the Netherlands in Int J Food Microbiol Mar 2;196:

2 Situation in Europe Notification yes/no: different per country Transmission route: food, water of human to human different per country Incidence different per country Food-borne parasites important for public health? Based on ranking using multicriteria: Criteria FAO/WHO expert workshop 2012 ECDC ranking for Europe Outbreaks? different per country and parasite: most common: cryptosporidium 5 6 Multicriteria used (FAO/WHO global ranking, 2012): Public health criteria Economic costs

3 ECDC ranking blue: surveillance ECDC 9 10 What happens with the less important parasites? Food-borne Parasites? Endemic in Europe Giardia : human to human and water born; very few food born outbreaks; proportion foodborn? Cryptosporidium: many waterborne outbreaks; few food-borne outbreaks; proportion foodborn? Toxoplasma: vegetables and fruits: riskfactor in Cook study. Attribution different food products: QMRA meat route, but no information about environment. Congenital Toxo not foodborn

4 Food-borne Parasites? Endemic in Europa Echinococcus granulosus Echinococcus multilocularis Clinical symptoms Echinococcus granulosus Proportion Foodborn? Echinococcus multilocularis Parasitic infections imported Turkye: E. granulosus ;E. multilocularis Eastern Europa Trichinella, E. granulosus ;E. multilocularis Latin America: Trypanosoma cruzi (chagas), T. gondi atypical but more virulent strains FBP human diagnostics and reference labs How many infections in humans are detected and how many missed? Diagnostic methods differ: intestinal parasites : stool samples; direct detection ) tissue parasites :serology and /or direct detection) Serology: tendency to go from in house test to commercial test: Quality control and CE mark (The CE mark, or formerly EC mark, is a mandatory conformity marking for certain products sold within the European Economic Area (EEA) since 1985.)

5 FBP human diagnostics and reference labs FBP human diagnostics and reference labs No gold standard No reference materials Limited QC schemes available Human diagnostics: No consensus about the best methods No official EU reference laboratory Exception: Toxoplasma: Gold standard Sabin Feldman ( risk for technicians) Reference : IgG standard and IgM standard (new standard produced by NIBSC Several QC schemes: e.g. UKNeqas, national schemes in different countries Standard Toxoplasma DNA 17 Some countries: official national reference laboratory Some countries several (self appointed) reference labs Some : no official reference lab Expertise in serology : decreasing in medical microbiology Most labs rely on commercial kits: can we rely on them? 18 Human Diagnostics Available, reliable : Toxoplasma serology : IgG yes, IgM debatable Trichinella:?? Commercial kits: two examples Cysticercosis Ldbio blot Sensitivity: limited number positive samples very positive samples; Specificity: control group? leave out possible crossreactive samples ; take very negative samples;. increases specificity Price : most kits very expensive (>500 for 24 strips) 2010 sometimes a smear: is there a band beneath it? aspecific bands: significance? bands not always visible (positive control different in batches: 12 KD) 19 5

6 Cysticercose Ldbio blot : changes over time Diagnostics Echinococcus PC PC 3,6,12, Changes in test conditions: incubation to 60 minutes: more background ( no warning in leaflet kit) PC very weak compared with previous batches kits Sensitivity?? Manufacturer: nothing wrong with the kit : its your problem Manufacturer: why do you use a Reagent controle? Don t do that! Nothing wrong with the kit : its your problem 22 Commercial kit : EM2+ ELISA Bordier Specificity in Dutch serum samples: Pienter 2 study Dutch population, all ages, Selection of the samples: Area where foxes are tested positive for Em Control area: foxes negative 1581 human serum samples of 6 municipalities in areas at risk and 5 control municipalities were tested. Em2plus ELISA (Bordier) Echinococcus multilocularis in house E. granulosus IgG ELISA. All positive samples were tested in an in house Immunoblot E. granulosus IgG1 to confirm the reactivity Commercial kit : EM2+ ELISA Bordier Regions Controle municipalities: 13,9% positive At risk municipalities: 8,7% positive Highest: Bergen (NH.) (18,8%) Korendijk (16,3%) Sittard-Geleen (14,3%). Lowest: Beek (0,7%) at risk municipality

7 Commercial kit : EM2+ ELISA Bordier results 169 out of 1581 sera tested positive in the ELISA 6 were positive in both Eg and Em ELISA (0.4 %) 120 sera (7,6%) Em2plus ELISA positive, Eg IgG ELISA negative, 43 sera (2,7%) Eg IgG ELISA positive and Em2plus ELISA negative 1412 sera (89,3%) all negative Immunoblot IgG 1 The reactivity of the ELISA positive samples ( Eg or Em or both) could not be confirmed by westernblot Age Age 1 Eg IgG ELISA pos (%) Em2plus ELISA pos (%) 1 or both ELISA s positief (%) Totaal 0 3 (4,5%) 9 (13,4%) 12 (17,9%) (3,3) 36 (23,5%) 41 (26,8%) (3,0%) 81 (6,0%) 116 (8,5%) 1361 total 49 (3,1%) 120 (8,0%) 169 (10,7%) 1581 Specificity? EM2+ ELISA in children: specificity <75 % WHO Paper claims specificity 100 % 36 of 48 children are autochtoneous Dutch 12 have other ethnic background: 2e gen. Western (3 children), 2e gen Mar/Turkish (1) and 2e gen. Surinaams/Arubaans/Neth.Ant (3) 2e gen.other non Western (5)

8 Diagnostics intestinal protozoa Big differences between countries in methods Microscopy, antigen detection or molecular detection Trained technicians Commercial kits (Ag detection) : some have poor quality many false positives Molecular detection: multiplex PCR QC schemes : Some countries : not available Some: available but expensive Are we able to pick up an outbreak? Not only detection but also typing 29 Eg,Em & Tsol Nelly Fournet Number of Cryptosporidium positive faecal samples by week of confirmation in 4 laboratories*, Netherlands, January 2010 to November % C. hominis type IbA10G2 (dominant strain) Weeks 36-38: 180 cases 20 in in 2011 England and Wales C. hominis type IbA10G2 (dominant strain) 40 Nb in 2010 Weeks 31-45: 472 cases 92 in Week *CBSL (Hilversum), Haarlem, Saltro (Utrecht) and Labmicta (Enschede) 8

9 Conclusions: Cryptosporidium increase Conclusion: Not an outbreak In UK and the Netherlands the same C.hominis type IbA10G2 No typing data available in Germany; no respons other countries Risk factors: maybe mineral water as proxy for?? No good method to discriminate within C. hominis type IbA10G2 Collaboration with Simone Caccio (ISS, Rome) and Rachel Chalmers (Swansea UK). We need To keep our experience in serology CE mark not for in house tests Reference materials: standards for other parasites One Health approach : collaboration human and animal parasitologists Collaboration regional or European level: use expertise of other laboratories QC schemes or alternatives (exchange samples; retesting regurlarly etc) for all parasites Work in progress: COST action (Cystinet; FBP) Recently started new ESCMID study group: ESCMID Study Group for Veterinary Microbiology ESGVM Chairperson:Professor Luca GUARDABASSI Secretary: Cindy Dirckx You can join ESGCP Chairperson: Titia Kortbeek Criteria: membership ESCMID (58 euro/year; incl CMI);

10 Thank you: Jeroen Roelfsema, Denise Hoek, Nahid Nozari, Sietze Brandes section parasitology IDS Joke van der Giessen Thank you! 37 10