WNV, Italian approach. Simonetta Pupella

Transcription

1 WNV, Italian approach Simonetta Pupella

2 I, the undersigned speaker, declare that in carrying out the function stated above at this event, I do not have any personal or third-party commercial interests, and that any relationships that I have had in the last two years with subjects with commercial interests are not such as to influence my function in order to draw any advantage. Simonetta Pupella National Blood Centre

3 Table of Contents Epidemiological data of WNV outbreaks in Italy National surveillance plan Adopted strategy for the blood safety Vector Index (VI) experience

4 WNV - Europe

5 WNV Italy Affected areas

6 WNV - Italy

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8 Italian Region Circulation of WNV Italy 2013 No. of WNND Cases 2013 No. of blood donations tested No. of positive Donations (WNV fevers) (NAT yield) Apulia Basilicata Emilia Romagna 20 (16) Friuli Lombardy 10 (1) Sardinia Veneto 13 (13) TOTAL 44 (30) 284, (0,9 / 10 4 )

9 Casi confermati di WNND, Italia Autochthonous human cases of WNND Giu Lug Ago Set Ott Nov Giu Lug Ago Set Ott Nov Giu Lug Ago Set Ott Nov Giu Lug Ago Set Ott Nov Giu Lug Ago Set Ott Nov Giu Lug Ago Set Ott Nov Mese insorgenza sintomi ISS - CNESPS Epidemiology of Infectious Disease Unit 43 during the period from 5 regions 28 in 2012 from 4 regions 44 in 2013 from 4 regions

10 WNV in Italy Haemovigilance so far NO cases of WNV transfusion transmission have been detected

11 Classification of risk areas

12 Classification of risk areas in Italy Many geographical areas in Italy are «predisposed» Regions where WNV has been detected in vectors and/or animals at least once in the period: Emila Romagna Friuli Venezia Giulia Lombardy Sardinia Basilicata Regions where seasonal recurrences of human transmission occurred: Veneto Regions where transmission to humans occurred even if discontinously: Emila Romagna Friuli Venezia Giulia Lombardy Sardinia Basilicata

13 MoH: Italian WNV surveillance plan (published in 2010 and updated in the following years) Surveillance period: June 15 - November 15 (updated to November 30) for autochthonous cases, year round for imported cases Combined veterinary (mosquitos, birds, horses) and human surveillance Human surveillance of WN neuroinvasive diseases (Veneto region introduced surveillance of WN fevers in 2012) Risk areas classification: affected area province areas (secondary administrative unit) where autochthonous laboratory confirmed infections in horses and humans are detected surveillance area regions where the presence of competent vector is known and human WNND and horses confirmed cases are notified ISS - CNESPS Epidemiology of Infectious Disease Unit

14 Notification chain - data transmission Real-time transmission using a web based system Local Health Unit Regional Health Autority The access is limited (username and password). Regional and local authorities notify possible cases within 12 hours to MoH and National Institute of Health. Each possible, probable and confirmed case filled in the web-based form is immediately available for: MoH, National Centre for Epidemiology of the National Institute of Health National Transplant Centre National Blood Centre Ministry of Health Istituto Superiore di Sanità

15 Blood safety preventive measures Algorithm criteria for introducing screening and deferral measures in blood donors First line Trigger notification of confirmed human case of WNV neuroinvasive disease (to implement NAT testing in the provincial area and nationwide the 28 days deferral of donors coming from that area) Second line Evidence of intensive WNV circulation (wild birds, mosquitos, unvaccinated horses) The mathematical model of Biggerstaff & Petersen* has been used to assess the risk of transfusion transmission of WNV from viremic asimptomatic blood donors using epidemiological data of the previous season) * Biggerstaff BJ, Petersen RL. Estimated risk of transmission of West Nile Virus through blood transfusion in the US, Transfusion Aug;43(8):

16 Risk-based strategy applied in Cases of WNND L Population (2009) Incidence / 10 5 CI 95% Ferrara , Cases of WNND Incidence / 10 5 CI 95% Rovigo 6 2,43 0,89 5,28 Mantova 2 0,49 0,006 1,76 NAT yield / 10 4 Viremic donation estimated average risk / ,22-1, Average risk = / 10,000 donations - NAT Yield 0,51 0,55 / 10, Average risk = 0.19 / 10,000 donations - NAT Yield 0,33 / 10, Average risk = 0.26 / 10,000 donations - NAT Yield 1,2 / 10, Average risk = 0.8 / 10,000 donations - NAT Yield 0,9 / 10,000 Biggerstaff BJ, Petersen RL. Estimated risk of transmission of West Nile Virus through blood transfusion in the US, Transfusion Aug;43(8):

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18 Combines the rate of infection in mosquitoes with their density in a defined area in a week period. V.I. = Σ Ni Pi N = average density of vectors in active traps in a defined environment P = rate of infection estimated in each trap i = species of infected mosquitoes in case more than one WNV vector are present in the interested area There is no established threshold for any epidemiological situations. It seems that a V.I can predict a high risk of transmission to humans (depending on the overall epidemiological situation).

19 Correlation between VI and WND in the Veneto Region 2013 In Italy (Veneto region) it has been estimated that a V.I. 0.5 can strongly predict human transmission.

20 VI approach in Emilia-Romagna Region five years experience gravid trap CO2 trap Fortnightly collection Collected mosquitoes were identified at species level and were pooled according to date, location, and species, with a maximum number of 200 individuals per pool Mosquito pools and bird samples were tested by a real-time PCR, according to the method of Tang et al. (2006). In press

21 Vector Index VI NiPi i species N number of Culex pipiens for traps for night P infected mosquitoes (MLE/1000) Vector Index 1,000 0,900 0,800 0,700 0,600 0,500 0,400 0,300 0,200 0,100 0,000 BO FE MO PC PR RE V.I. = weeks settimane 2013 Courtesy Dr. A.C. Finarelli & Dr. P. Angelini, Dept. of Public Health, Emilia Romagna Region

22 Province Cases/ * Mean Vector Index (28-35^ week) Max Vector Index Reggio Emilia 1, ,81 Modena 1, ,94 Ferrara 1, ,87 Parma 0, ,55 Bologna 0, ,63 Piacenza ,37 In each Province, a strong correlation between reported human cases and Vector Index (mean and maximum value) was found. Ravenna ,27 Forlì-Cesena Rimini * Population considered: Residents in Municipality under 100 mt a.s.l Vector Index Medio (28-35 sett) y = 0.85x R 2 = 0.87 Vector Index Max y = 1.40x R 2 = Log (1+casi per ab) Log (1+casi per ab) Courtesy Dr. A.C. Finarelli & Dr. P. Angelini, Dept. of Public Health, Emilia Romagna Region

23 Province Entomological surveillance results 2013 data First human case date WNND onset date WNF onset date First WNV positive mosquito pool Anticipation days of mosquito viral circulation vs. human case onset date MO 03 Aug 14 Aug 3 Jul 31 FE 06 Aug 13 Sep 17 Jul 20 BO 15 Aug 24 Aug 17 Jul 29 RE 16 Aug - 17 Jul 30 PR 11Sep 01 Sep 19 Jul 54 RA Jul PC Aug FC Aug Entomological surveillance showed viral circulation on average 32.5 days before the detection of the first human case in the corresponding area Courtesy Dr. A.C. Finarelli & Dr. P. Angelini, Dept. of Public Health, Emilia Romagna Region

24 17 LUG 17 LUG 31 LUG 08 AGO 19 AGO 01 SET 26 LUG 31 LUG 04 SET 03 LUG 17 LUG 31 LUG 03 AGO 07 AGO 14 AGO 18 AGO 25 AGO 07 SET 05 OTT 17 LUG 26 LUG 08 AGO 28 AGO 19 LUG 31 LUG 14 AGO 13 SET 19 SET 13 AGO 23 AGO 26 AGO 08 SET REAL SITUATION + «INTERCEPTED POSITIVE DONORS» STARTING BLOOD DONATION SCREENING AFTER FIRST ENTOMOLOGICAL EVIDENCE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER PIACENZA PARMA REGGIO EMILIA MODENA 20 AGO BOLOGNA FERRARA TOTAL NUMBER OF TESTS WNND CONFIRMED CASE ALERT START OF BLOOD DONATION SCREENING (REAL) POSITIVE MOSQUITOES POOL DATE POSITIVE MOSQUITOES POOL COMMUNICATION DATE WNV POSITIVE DONOR BEFORE FIRST WNND CASE («INTERCEPTED») WNV POSITIVE DONOR AFTER FIRST WNND CASE WNV POSITIVE DONOR BEFORE FIRST WNND CASE. NOT CLASSIFIED AS «INTERCEPTED».

25 Emilia Romagna Region Preliminary cost analysis (2013) 6 Provinces involved (PC, PR, RE, MO, BO, FE) Estimated number of tested donations from 1 st Jul to 30 th Nov: ~ Estimated cost of blood donation screening: ~ (VAT included) Estimated cost of Integrated Surveillance: ~ Every 27 days of postponement of blood donation screening (based on entomological surveillance results) would allow to save the total amount of the whole season s integrated surveillance cost. These estimates don t take into account the avoided burden of disease, according to prompt diagnosis of infected donors. Courtesy Dr. A.C. Finarelli & Dr. P. Angelini, Dept. of Public Health, Emilia Romagna Region

26 Summary ( ) Most of the affected areas are localized in North-Eastern Italy and WNND in humans seems to reoccur in the same provinces as in previous years 114 human cases of WNNID have been notified ( ), 43 in the last year 45 (forty-five) asymptomatic blood donors tested positive for WNV NAT (the relevant blood units were discarded) No WNV transfusion transmission was notified to either to the National Haemovigilance System or to the National Epidemiology Center (NEC) No significant impact on the blood supply (even if in Summer period) thanks to excellent inter-institutional and multi-disciplinary cooperation and to WNV NAT screening Optimal performance of the WNV dedicated NEC web site (24h available, real-time updated)

27 Future preventive efforts: Vector Index strategy Limits: the method has not been validated by all the regions during a sufficient number of seasons the procedures are not yet harmonized among the regions (definition of grids and cells for mosquito capture, identification of climatic setting, skills of entomologists) V.I. threshold definition? To be customized depending on different variables timing for mosquito testing results is not homogeneous depending on regional/interregional labs integration among different surveillance fields shall be still optimized at regional level.

28 Thanks for your attention! Simonetta Pupella National Blood Centre Istituto Superiore di Sanità Rome, Italy