3.3 Verotoxigenic E. coli

Transcription

1 3.3 Verotoxigenic E. coli Verotoxigenic Summry E. coli Numer of VTEC cses, 214: 77 Crude incidence rte, 214: 15.4/1, Numer of VTEC-ssocited HUS, 214: 27 Numer of VTEC cses, 213: 71 Introduction The reported verotoxigenic Escherichi coli (VTEC) incidence rte in Irelnd is generlly high reltive to other Europen countries. In 212 (the ltest yer for which dt re pulished), the overll VTEC incidence rte in the Europen Union ws 1.59 per 1,, which ws 5.9% higher thn in The highest countryspecific rtes were oserved in Irelnd, the Netherlnds nd Sweden (12.3, 7.1 nd 5.8 per 1, popultion, respectively). For mny yers, Irelnd hs reported the highest VTEC incidence rte of ny Memer Stte in the EU, except in 211 when Germny reported the highest rte due to lrge VTEC O14 outrek linked with fenugreek seeds. 2-3 The dominnt trnsmission routes reported for VTEC infection in Irelnd hve een person-to-person spred, especilly in childcre fcilities nd mong fmilies with young children, nd wterorne trnsmission ssocited with exposure to wter from untreted or poorly treted privte wter sources. 4-7 Other importnt trnsmission routes identified interntionlly include food (often minced eef products or fresh produce such s lettuce nd spinch), nd contct with infected nimls or 3, 8-9 contminted environments. Mterils nd Methods Infection with verotoxigenic E. coli ecme notifile disese in 212; prior to tht VTEC were notifile since 24 under the ctegory Enterohemorrhgic E. coli (EHEC). Enhnced epidemiologicl informtion ws supplied s in previous yers y HSE personnel, nd the VTEC Ntionl Reference Lortory t the Pulic Helth Lortory, Cherry Orchrd Hospitl Dulin (VTEC-NRL t PHL) provided VTEC confirmtion nd typing dt. Dt from ll sources re mintined in the Computerised Infectious Disese Reporting (CIDR) system. Outreks of VTEC re notifile since 24 nd dt re provided to CIDR y the eight regionl pulic helth deprtments. The dt used in this report were extrcted from CIDR on 31 st August 215. Dt from the Centrl Sttistics Office (CSO) 211 census were used to provide denomintors for the clcultion of ntionl, regionl nd ge-specific incidence rtes in 214. Results Incidence In 214, there were 77 notifictions of VTEC, equting to crude incidence rte (CIR) of 15.4 per 1, (95% CI ). This compres to n overll incidence rte of 13.1 per 1, in 213, n increse of.9% nd n overll incidence rte of 12.1 per 1, in 212, n increse of 28%. Of the 77 VTEC notifictions in 214, 569 (8%) were clssified s confirmed cses (CIR % CI ), 136 s prole nd 2 s possile cses. The criteri under which notified cses were reported in 214 under the VTEC cse definition Tle 1. Numer of VTEC notifictions y criteri for notifiction, Irelnd, 214 Notifiction criteri Confirmed Prole Possile Totl Culture confirmtion Lortory confirmtion y PCR Serodignosis (vlid for HUS only) Reported solely on the sis of epidemiologicl link Clinicl HUS not meeting l or epi criteri Totl Symptomtic culture confirmed cses re clssified s confirmed cses, while symptomtic culture confirmed cses re clssified s prole cses Symptomtic PCR-confirmed cses re clssified s confirmed cses, while symptomtic PCR-confirmed cses re clssified s prole cses HPSC Annul Epidemiologicl Report

2 is outlined in Tle 1. As the clssifiction of VTEC cses chnged significntly upon the mendment of the Irish VTEC cse definition in 212, it is not vlid to directly compre the numer of notifictions y cse clssifiction with the period efore 212. Of the 74 cses with lortory evidence of infection, 233 cses were reported s eing infected with E. coli O26 (5.1 per 1,; 95% CI ), 177 with E. coli O157 (3.9 per 1,; 95% CI ), 29 with other VTEC strins, nd 4 cses hd mixed VTEC infections, eing infected with more thn one VTEC strin. The one prole cse reported on the sis of n epidemiologicl link to confirmed cse, ws linked to n E. coli O157 outrek. Figure 1 illustrtes the distriution of VTEC cses in Irelnd y serogroup since Compred to 213, the serogroup distriution in 214 represents 2.4% decrese in O157 infections, 7.8% increse in O26 infections, nd 12.4% increse in other non-o157/o26 infections. Severity of illness Five hundred nd sixty-eight (8.3%) of the 77 notified cses were symptomtic, 22 (38.7%) of Numer of notifictions which developed loody dirrhoe (42.3% when only symptomtic cses where the loody dirrhoe vrile completed re included). Twenty-seven individuls (3.8%) developed HUS, decrese of 12.9% on 213 (n=31). There ws one deth in confirmed VTEC cse; three other persons dignosed with VTEC infection in 214 lso died, ut their deths were not reported s due to VTEC. Where reported (n=688), 237 (34.4%) of notified cses were hospitlised (4.% of symptomtic cses). Of the 27 HUS cses, 13 were infected with E. coli O157, eight with E. coli O26 nd one ech with E. coli O13, O111, O145 nd ungrouple (Tle 2). The remining two HUS cses were reported s possile VTEC notifictions. HUS cses rnged in ge from 9 months to 68 yers nd 77.8% (n=21) of the cses were in children under 1 yers of ge. Seventeen of the HUS cses were spordic cses, eight were prt of fmily outreks (including two cses in one household), nd two were prt of generl outrek (i.e. two cses in childcre setting). Numer of notifictions Yer Jn Fe Mr Apr My Jun Jul Aug Sep Oct Nov Dec Month of notifiction Totl O157 non-o men Figure 1. Annul numer of confirmed nd prole VTEC cses y serogroup, Irelnd Note: For simplicity in this figure, cses with mixed VTEC O157/other serogroup infections re included in the dt for O157, s re prole cses linked to known E. coli O157 outreks. Non-O157 dt includes cses with mixed non-o157 infections nd prole cses linked to known O26 outreks Figure 2. Sesonl distriution of the numer of VTEC notifictions in Irelnd, 214 nd the men of Tle 2. Numer of VTEC notifictions y serogroup nd verotoxin nd HUS sttus, Irelnd, 214 Serogroup HUS non-hus Totl O157 VT O157 VT1+VT O26 VT1 1 1 O26 VT O26 VT1+VT Other VT1 Other VT2 Other VT1+VT No orgnism 2 5 Totl For simplicity mixed infections were recorded s O157 if t lest one strin ws O157, s O26 if t lest one strin ws O26 ut not O157, nd s Other if only non-o157 non-o26 strins were detected. Includes one prole cse epi-linked to n O157 VT2 outrek HPSC Annul Epidemiologicl Report

3 Sesonl distriution Figure 2 shows the sesonl distriution of notifictions in 214 reltive to the men monthly numer of cses in the yers Despite the increse in the numer of notifictions, the typicl summer sesonl pek ws mintined, the pek month ws July followed y Septemer/Octoer nd April/My. An increse in Decemer ws lso noted in 214. Similr to previous yers, during 214 there ws vrition in the sesonl distriution y serogroup, with VTEC O157 showing the typicl pek in numers in lte summer / erly utumn; in contrst, VTEC O26 notifictions peked in July with smller pek in My (Figure 3). Other non-o157 serogroups were lso more common in erly summer in 214. Unlike previous yers, in 214 n upsurge in VTEC O157 nd O26 notifictions ws lso oserved in Decemer. Numer of notificitons Jn Fe Mr Apr My Jun Jul Aug Sep Oct Nov Dec Month of notifiction O26 O157 Other VTEC Figure 3: Sesonl distriution of VTEC notifictions y serogroup, Irelnd 214 NW were significntly lower thn the ntionl crude incidence rte (Tle 3). The incidence of E. coli O157 ws significntly higher in HSE-W nd significntly lower in HSE E when compred with the ntionl crude incidence rte. With the exception of the HSE NW, in seven of the eight HSE res, the incidence of non-o157 infections ws t lest twice tht of E. coli O157 infections (Tle 3). The highest incidence of HUS mongst VTEC cses ws in HSE-NE, despite eing rnked sixth in the overll VTEC incidence rtes (Tle 3). Age-sex distriution As in previous yers, the highest reported ge-specific incidence rte ws in the -4 yers ge group (92 per 1,). Incidence rtes were higher mong femles in the mjority of the ge groups; however, the incidence rte ws higher in mles compred with femles in the -4 yers ge group (Figure 5). Lortory typing In 214, the serogroup nd verotoxin profiles of VTEC isoltes/smples referred to the VTEC-NRL t PHL, Cherry Orchrd Hospitl re displyed in Tle 4. The most common serogroup reported ws VTEC O26 (n=233), followed y VTEC O157 (n=178). Among the other serogroups listed y the World Helth Orgnistion s hving the highest ssocition with HUS interntionlly, there were 18 VTEC O13 cses, 1 VTEC O111, nd 31 VTEC O145. Compred with 213, there ws n 82% increse in the numer of VTEC O145 notified in 214 (17 nd 31 cses, respectively). The numer of serogroup 146 qudrupled in 214, compred with 213 (2 nd 5 cses, respectively). As usul mong VTEC O157 in Irelnd, isoltes contining the genes for verotoxin 2 (vt2) were more common (82.6%) thn strins contining genes for oth vt1 nd vt2. Among the VTEC O26 strins those contining the genes for oth vt1 nd vt2 ccounted for the mjority of these strins (54%), followed y vt1 Tle 3. Numer nd crude incidence rtes of y serogroup nd HSE re, nd numer nd crude incidence rte of VTECssocited HUS y HSE re, Irelnd, 214 HSE-re Numer [CIR; 95% CI] VTEC O157 Numer [CIR; 95% CI] non- O157 VTEC c Numer [CIR; 95% CI] ll VTEC d Numer [CIR; 95% CI)] VTECssocited HUS E 27 [1.7; ] 69 [4.3; ] 96 [5.9; ] 6 [.4;.7-.7] M 15 [5.3; ] 51 [18.1; ] 66 [23.4; ] 3 [1.1 ;.-2.3] MW 21 [5.5; ] 85 [22.4; ] 17 [28.2; ] 5 [1.3;.2-2.5] NE 15 [3.4; ] 4 [9.1; ] 55 [12.5; ] 6 [1.4;.3-2.5] NW 13 [5.; ] 4 [1.6;.3-3.1] 17 [6.6; ] 1 [.4;.-1.2] S 28 [4.2; ] 92 [13.8; ] 12 [18.1; ] 2 [.3;.-.7] SE 16 [3.2; ] 1 [2.1; ] 116 [23.3; ] [.;.-.] W 44 [9.9; ] 85 [19.1; ] 13 [29.2; ] 4 [.9;.2-1.8] IE 179 [3.9; ] 526 [11.5; ] 77 [15.4; ] 27 [.6;.4-.8] Rtes per 1, clculted using CSO census 211 for denomintor dt For simplicity, cses with mixed VTEC O157/other serogroup infections re included in the dt for O157, s re prole cses linked to known E. coli O157 outreks. c Non-O157 dt includes cses with mixed non-o157 infections nd prole cses linked to known O26 outreks. d Possile cses (i.e. those with no ssocited orgnism re lso included in this column), nd therefore the totl in this column will not lwys e the sum of the previous two columns. HPSC Annul Epidemiologicl Report 214 Regionl distriution In 214, the highest VTEC incidence rtes overll were reported in the HSE-W followed y the HSE-MW, HSE-M nd HSE-SE, where the rtes were significntly higher thn the ntionl crude incidence rte (Tle 3). The incidence of VTEC overll in HSE-E nd HSE- -7-

4 only (42.1%) nd those contining vt2 mking up the remining 9.1% of VTEC O26. In contrst, the mjority (8.6%) of O145 strins were vt2-postive. Furthermore, vt1-contining strins mde up the mjority of O13 strins (88.8%), while VTEC O111 comprised minly of nd vt1+vt2-contining (9%) strins (Tle 4). Risk fctors Under the enhnced surveillnce system for VTEC, risk fctor informtion is routinely collected on VTEC notifictions (Tle 5). Exposure to frm nimls or their feces nd exposure to privte well wter were reltively common mong cses; 34.2% nd 32.% reported these exposures respectively. However, oth were less commonly reported thn in 213 nd in 212. According to CSO dt, in the generl popultion, round 1.1% of households re served y privte wells, indicting tht, on ntionl sis, exposure to privte wells ppers to e more common mong VTEC cses thn mong the generl popultion. Unlike slmonellosis, foreign trvel plys only minor role in VTEC infection in Irelnd, with the overwhelming mjority of infections cquired indigenously. Where the informtion ws ville, just under qurter of VTEC cses in 214 reported ttendnce t childcre fcility (CCF). When these nlyses were restricted to notified VTEC under five yers of ge, 47.8% reported ttendnce t childcre fcility. This is higher thn the proportion of children in the generl popultion who use non-prentl childcre (42%) s reported y the Centrl Sttistics Office. 1 Outrek nd environmentl investigtions The outrek surveillnce system plys key role in our understnding of VTEC trnsmission in Irelnd. Eightythree VTEC outreks were notified in 214, which included 275 of the 77 VTEC notifictions. Twenty-two outreks were due to VTEC O157, 38 to VTEC O26, 12 were mixed VTEC strin outreks, nd 11 were cused y other VTEC strins. The mjority of outreks (88%) were fmily outreks, with ten generl outreks notified. The 73 fmily outreks resulted in 134 persons ecoming ill, n verge of 1.9 (rnge 1-4) persons ill per outrek, Crude incidence rte E M MW NE NW S SE W IE HSE-re O157 O26 Other rtio Figure 4: Crude incidence rte VTEC O157, O26 nd other serogroups y HSE re, Irelnd, rtio of non-o157 to O157 incidence while the ten generl outreks resulted in 68 persons ecoming ill, n verge of 6.8 (rnge 2-23) persons ill per outrek. Sixty-nine outreks occurred in privte homes, eight involved childcre fcilities, one ws community outrek, three involved extended fmilies nd the loctions for two outreks ws not specified. The suspected modes of trnsmission re listed in Tle 6. Person-to-person spred is consistently the most common mode of VTEC trnsmission reported in Irelnd, prticulrly etween young children, nd ws suspected to hve plyed role in 45 (54%) VTEC outreks in Tle 4. Serotype nd verotoxin (vt) profiles for strins ssocited with lortory confirmed VTEC cses, s determined t the VTEC-NRL t PHL, Cherry Orchrd Hospitl, 214 Serogroup vt1 vt1+vt2 vt2 Totl O O O O O O O O O O O O O O O O O O O O O O8 2 2 O15c 1 1 O O O O128c 1 1 O128d 1 1 O O O OE Ungrouple Mixed Totl HPSC Annul Epidemiologicl Report

5 214 in which 14 persons were reported ill (Tle 6 nd Figure 5). Forty of these outreks were reported s eing solely due to person-to-person trnsmission, including six of the outreks which occurred in CCFs. Animl/environmentl contct nd wterorne trnsmission were joint second s the most common reported routes of trnsmission. Animl/environmentl contct ws reported to hve contriuted to nine outreks (1.8%) with 16 persons ill. All were fmily outreks in privte houses. This is similr to the numer of VTEC outreks due to this trnsmission route, notified in 213 (Figure 6). Wterorne trnsmission ws reported to hve contriuted to nine outreks (1.8%) with 19 persons ill. This is similr to the numer of wterorne VTEC outreks reported in 213 ut less thn hlf the numer reported in 212 (Figure 6). Two were generl outreks nd seven were fmily outreks; with privte wells suspected in eight of the nine outreks. One outrek (fmily outrek, 3 persons ill) ws reported s eing suspected to e foodorne, however the suspected food item ws not reported. For 29% (n=24) of VTEC outreks in 214, the trnsmission route ws reported s unknown or not specified (Tle 6 nd Figure 6). Summry The numer of VTEC notifictions remined stle in 214 reltive to 213, following sttisticlly significnt increse in 213 compred with 212. Since 211, there hs een continuous increse in non-o157 notifictions nd this trend continued in 214, reflecting the more widespred use of dignostic methods in the primry hospitl lortories tht detect oth O157 nd non-o157 VTEC. Interesting the incidence of VTEC O157 continued to decrese in 214. Guidnce for Lortory Dignosis of Humn Verotoxigenic E. coli Infection developed y The Lortory Su-Group of the VTEC Su-Committee of the HPSC Scientific Advisory Committee ws issued in Septemer 214. It is nticipted tht this will further contriute to co-ordinted pproch to VTEC dignosis in Irelnd. 11 Within the Europen Union, Irelnd continues to hve the highest incidence rte for VTEC, reporting over seven times the Europen verge in It is nticipted when the dt re ville cross Europe for 214, tht Irelnd will hve one of the highest reported incidence rtes in Europe gin Foodorne trnsmission ws the first recognised trnsmission route for VTEC infection historiclly, with minced eef, unpsteurised diry products, nd fresh produce consumed rw ll hving een implicted in outreks cross the world. Foodorne outreks typiclly comprise smll percentge of the totl numer of VTEC outreks in Irelnd nd 214 ws not n exception with foodorne outreks comprising 1.2% of the VTEC outreks notified. Tle 5. Numer of cses of VTEC (nd percentge where informtion ville) for selected risk fctors, Irelnd, 214 (n=77) Risk fctor Yes (% of known) No Unknown or not reported Food suspected 3 (6.1) Exposure to frm nimls or their feces 211 (34.2) 46 9 Exposure to privte well wter 22 (32.) Trvel-ssocited 21 (3.3) Attendnce t CCF c 137 (23.1) Attendnce t CCF c (mong <5 yrs) 128 (47.8) Composite vrile recoded from two different wter supply exposure enhnced vriles in CIDR Inferred from CIDR core vrile Country of Infection c CCF=childcre fcility Numer of notifictions Rte per 1, popultion Age group (yers) Femle - Cses Mle - Cses Femle - Rte Mle - Rtes Figure 5. Age-sex distriution VTEC notifictions, Irelnd, 214 HPSC Annul Epidemiologicl Report

6 Similr to 213, niml/environmentl contct ws reported s the second most common route of trnsmission for VTEC outreks in 214. This hs long een recognised s risk fctor for VTEC infection,8-9 nd cses due to this trnsmission route re not unexpected in Irelnd given the lrge cttle popultion, the high proportion of rurl dwellers, nd the lrge numer of frming fmilies. Fortuntely, none of these niml contct outreks were ssocited with pulic venues such s open frms, nd so the numers of people ffected were smll. Advice is ville on the HPSC wesite on how to minimise the risk of gstrointestinl infections following exposure to frm nimls nd environments, nd for the sfe recretionl use of frmlnd. 12 In 214, contminted drinking wter contriuted to similr numer of outreks s 213. As in previous yers, the mjority of the drinking wter ssocited outreks reported were linked with privte wter supplies. Exposure to wter from contminted untreted or poorly treted privte wter supplies hs historiclly een recognised s strong risk fctor for VTEC infection in Irelnd. 6,7 This hs een prticulrly pronounced following periods of hevy rinfll. The HSE nd EPA hve oth developed resources for owners of privte wells, providing dvice on privte well mintennce Trnsmission y person-to-person spred, however, remined the most common trnsmission route reported in VTEC outreks nd ws involved in 54% of outreks. As usul, person-to-person spred ws most frequently ssocited with privte house nd childcre fcility outreks. Hndwshing nd exclusion of cses in risk groups from high risk settings remins key prevention mesures for VTEC Numer of outreks Yer of notifiction Person-to-person Wterorne +/- P-P Foodorne +/- P-P Animl contct/environmentl +/- P-P Other Unknown/not specified Figure 6. Numer of VTEC outreks y suspected trnsmission route nd yer, Irelnd Note: In this figure, reported trnsmission routes were grouped for simplicity. Any outrek where food contriuted ws reported s foodorne, ny outrek where wter contriuted ws reported s wterorne, ny other outrek where niml contct contriuted ws reported s niml contct. Person-to-person outreks include only those outreks reported s eing due only to person-to-person trnsmission. Tle 6. VTEC outreks y suspected mode of trnsmission, Irelnd, 214 Trnsmission Route Numer of outreks Numer ill Numer of ssocited CIDR Events Person-to-person Foodorne Person-to-person nd foodorne Wterorne Person-to-person nd niml contct Person-to-person nd wterorne Animl contct Environmentl / fomite Foodorne nd niml contct Unknown Not specified Totl HPSC Annul Epidemiologicl Report

7 References 1. EFSA nd ECDC The Europen Union Summry Report on Trends nd Sources of Zoonoses,Zoonotic Agents nd Foodorne Outreks in 213. Accessile online t 2. ECDC Epidemiologicl updtes on the VTEC O14 outrek. whts_new/pges/epidemiologicl_updtes.spx 3. EFSA Trcing seeds, in prticulr fenugreek (Trigonell foenumgrecum) seeds, in reltion to the Shig toxin-producing E. coli (STEC) O14:H4 211 Outreks in Germny nd Frnce DispForm.spx?List=32e43ee8%2De23%2D4424%2D783%2D &ID=455&RootFolder=%2Fen%2Fpress%2Fnews%2 FLists%2FNews 4. Grvey, P. et l. 21. Epidemiology of verotoxigenic E. coli in Irelnd, 27. Epi-Insight: 11(9) 5. Locking et l. 21. Escherichi coli O157 Infection nd Secondry Spred, Scotlnd, EID 17(3): O Sullivn et l. 28. Increse in VTEC cses in the south of Irelnd: link to privte wells? Eurosurveillnce 13(39) 7. HPSC. 28. Press relese. Householders must properly mintin privte wter supplies following increse in contmintion HPSC. PressReleses/28PressReleses/MinBody,3127,en.html 8. Locking et l. 21. Risk fctors for spordic cses of Escherichi coli O157 infection: the importnce of contct with niml excret. Epidemiol Infect. 127(2): cmridge.org/downlod.php?file=%2fhyg%2fhyg127_2%2f S pdf&code=6ed8f62e ec5f 14dcd 9. Griffin. 21. Review of the mjor outrek of E. coli O157 in Surrey, Centrl Sttistics Office. 29. Qurterly Ntionl Household Survey. Childcre. Qurter Accessed t cso.ie/en/medi/csoie/relesespulictions/documents/ lourmrket/27/childcreq427.pdf 11. HPSC Guidnce for Lortory Dignosis of Humn Verotoxigenic E. coli Infection produced y The Lortory Su-Group of the VTEC Su-Committee of the Helth Protection Surveillnce Centre Scientific Advisory Committee, Irelnd. Aville t Guidnce/ReportoftheHPSCSu-CommitteeonVerotoxigenicEcoli/ File,4544,en.pdf 12. HPSC. VTEC Guidnce. VTEC/Guidnce/ 13. Helth Service Executive Leflet on the Risk of illness from well wter Leflet_Precutions%2nd%2dvice%2for%2reducing%2 risk%2of%2illness%2from%2well%2wter.pdf 14. HPSC Preschool nd Childcre Fcility Sucommittee Mngement of Infectious Disese in Childcre Fcilities nd Other Childcre Settings. Accessile t HPSC VTEC (Verocytoxigenic E. coli) in Childcre Fcilities: Decision Support Tool for Pulic Helth. Accessed on Octoer 7 th t ReportoftheHPSCSu-CommitteeonVerotoxigenicEcoli/ File,4559,en.pdf HPSC Annul Epidemiologicl Report