Westfriese Flora in Bovenkarspel. Netherlands (Holland)

Year course 10 number 4 1999( legionella pneumonia)

The epidemic from legionella pneumonia among visits from the Westfriese Flora in Bovenkarspel.

JW de boer, arts-infectieziekten, GGD Zuid-Kennemerland, now gedetacheerd in RIVM/ CIE
FAN Slijkerman, arts-infectieziekten, GGD West-Friesland
EPF Yzerman, arts-microbioloog, Streeklaboratorium Haarlem

The author details at as reports; they realize it that they report about activity where many in the country have contribute: collaborator from GGD's, laboratory, LCI, service from inspection, hospital and RIVM. Their stakes be and remain from large interest in the rounding off from the work that assertive still sole month z though require.

Position from business after four week

The first patients

In the second week from March 1999 become twelve patients with a atypical pneumonia incorporate in the Westfries Gasthuis( WFG) in hoorn.
The concern man and woman those to beforehand healthy real, scattered live in the regio West-Friesland, with a age between the 35 and eighty year; to thus growth no community factor known.
Attention from them wrong in such bad condition that breathing at the Intensive Care Unit( ICU) necessary growth. On account of the restricted number ICU beds became vacant to naburige hospital.
The generate from the pneumonia growth unknown, thought became on a virus.

On Wednesday 10 march, against midnight, alarm honor the director from the WFG the GGD West-Friesland. At the same time became the regional inspection at the height bring. The GGD early those same night in the ministry from VWS after whether from out the regular notification clusters from pneumonia known real. The follow morning, Thursday eleven march, find a further inventory atie place by treat specialist, the WFG and the GGD-arts. Hereby come to beforehand that the half from the patients growth vaccinate against influenza, that definite in the enviroment from the patients no secondary illness cases find become, that the half from the patients geographical ge clusterd growth round Bovenkarspel and that one from the patients in the WFG meanwhile deceased growth.
On account of the seriousness from the situation find deliberation place between the GGD and the office from the rural Cošrdinatie structure infection disease fight( LCI). The growth from the big interest about if fast possible the correct( laboratory) diagnosis to pose about the treatment here at off to voice. So far shout both the WFG as the regional inspection specialist from the AMC in consult.

About 15. 00 hour find rapidity consideration place in the WFG, where in doctors and a doctor-microbioligist from the AMC, the secertary from the LCI and the GGD-arts exsiting real. At base from clinical datum became a urine fast test at legionella pneumophila type one execute in attention patients with atypical pneumonia. These test appear in seven from them positive. The patient with a negative result have in further realize a other clinical image. Tile gauge time constateerden doctor microbiology from region laboratory Haarlem in two about ge place patients out the WFG also a positive result with same test. On the conclusion from the noon appear first residents virus diagnostic in five from the patients negative to its. At Thursday evening eleven march become the service do the house doctor in West-Friesland telephone warn from out the WFG and become the hospital in Noord-Holland telephone inform by the regional inspection. At that moment became still out go from the assumption that the a regional problem concern.

The hypothesis

Participant on the rapidity consideration suggest a possible connection with the if even terminate Westfriese Flora in Bovenkarspel( NH), a annual back make the flower graft and tone position, where in the run from the time a agrarian and a household exhibition be to held. This year became the Flora, those in total approximately eighty. 000 visits pull, hold from 19 to 28 February. Visit on the Flora fit inside the in cub atietijd from the geconstat honor cases from legionella pneumonia. On Thursday evening eleven and Friday morning 12 march take the GGD West-Friesland a orient the case-control study out among 10 patients and 21 from their neighborhood enjoyment and( controls), about after to go whether definite a community risk factor growth. The ge handle question list growth conform the LCI-protocol like used in the regular notification, supplement with the question whether definite a exhibition growth visit. Obvious became that the patients with legionella pneumonia significant subject then their neighborhood enjoyment a visit on the Westfriese Flora have bring. On Friday morning advice the regional inspection that scattered in hospital from Noord-Holland lake patients real incorporate with a atypical pneumonia. This give, together with the if even since connection with the Flora, lead in the administration corpse rejection soverleg( BAO) on friday morning to the do go out from country corpse alarm. The media become from the situation on the height established and the office from the LCI request the GGD's the in the weekend service do the house doctor to warn about extra alert to its on legionellose. Tile gauge ert ijd have the ministry from VWS a information line For doctor and a public line open established about question from apprehensive citizen to reply word.

The first action

The Outbreak management Team( OMT) come on Saturday 13th March for the first together. The OMT pose a case definet firm.

Prove case:
Visitor from the Westfriese Flora with a clinical image suitable in a pulmonary and a in filtraat on the thorax foto with a positive second on
L. pneumophila, whether with a four voudige titer increase from anti dust against L. pneumophila in serum, whether with a positive urine legionella antigeen test and in who no other generate be find;

Probable case:
Visitor from the Westfriese Flora with a clinical image suitable in a pulmonary and a infiltraat on the thoraxfoto with a a malige high titer
( high then whether even on one on 256) from anti dust against
L. pneumophila in serum, whether with a positive immunofluorescentie test, whether with a positive PCR for legionella and in who no other generate be find.

In the after this follow telephonic BAO became on base from the advice from the OMT private the RIVM dedication to yield about investigation to perform to the source. On the Flora real diverse fountain and a waterfall. The RIVM request the GGD Zuid-Kennemerland and the region laboratory for the people healthy health to quibble about support. This result honor those same evening in a samples from suspect hardware( fountain pump).
The follow day be the waterworks system from the Flora pump. On Sunday fourteen march became a among not to be found steam included in the centre for infection disease Epidemiologie( CIE) from the RIVM. In deliberation with the organization from the Flora became a provisional list from possible suspect, with name aerosol formative and waterfall velende, apparatus deploy and review with the inspection for the healthy health worry( IGZ). First priority growth to occurrence that these apparatus still further used if uden become. So far early the inspector infection disease the GGD-arts, in whose area a suspect apparatus suppose became, about the owner to prevail on the apparatus provisional not to employ. At the same time became request a sample name to organize. On these manner be suspect hardware safe established and became eventual exsiting remainder water pump in diverse company in the country. On Monday 15 march have the organization from the Flora on the CIE the complete list from stands available established. Telephone be by RIVM and IGZ, via the overcast GGD's in all position holder inquire whether potential risk full hardware on their position growth used. If became the list from suspect hardware supplement. Samples became on analogous mode organized. Super the beginning from the epidemic became a register bijge holding from patients those sick its become after a visit on the Flora; first became this done by the LCI, late be the about taken by the RIVM. Information about the patients reach the office from the LCI langs various weigh. Especially become via the information line from VWS many illness cases mentioned. Active tracing from cases find place via IGZ and GGD's.

The investigation the follow line and from investigation become in course definite about a number aspects from these epidemic further to good uderen.

1. Source among not to be found; out ge knit sample name from waterworks, tap point, water consumes and -vernevelende hardware. The specimens become on kweek definite by the region laboratory quibble. From every sample became a part for PCR investigation to the region laboratory Tilburg gestuurd. In total its in two week 118 specimens taken: from the water guidance network from the hallen where the Flora hold became and from various apparatus and installation in company those water in their position used.

2. Epidemiologisch investigation; this branch( execute by the CIE/ RIVM with assistance from the GGD's) fall apart in a case-control and a cohort investigation. The case-control investigation be directional on surrounding and host factor for the procure from legionella pneumonia. From the beginning from the epidemic became a case register named holding. On the GGD's be request about in the known patients with legionella pneumonia out their attending area a extensive questionnaire off to take and those to return to the CIE. Inside two day real in total 98 question registers inside. About in contact to come with visits on the Flora those as controls in the investigation if uden can become excepted, became on the municipality place Broec ask a resistant from living above the 40 year on to deliver. Hieruit its 5000 people geselecteerd and on write with the question whether they a visit have bring on the Flora and if yes, whether they prepare real on the investigation part to take. Inside two day react almost 500 people( the day after that still many more), from which definite 400 random become be selected as control for the study. They become again on write and extreme dead respond honor 98%. The cohort among not to be found find place among individual those prolonged( professional) on the Flora remain, about a relation to can lay between position place and expensive from residence with the chance on infection and clinical spectrum. In total its more then 1500 people on write those operative real on the Flora. On them became ask accurate on to give where they remain on the various day from the exhibition. Further become twice blood decrease about after to go whether they a eventual subklinische infection with L. pneumophila have by make

3. Microbiology investigation; this branch department( execute by the LIS/ RIVM, region laboratory quibble and Tilburg and deMedische microbiology from the Amsterdams medical centre) be directional on:

Evaluate from sensitiviteit and specifically from the urine antigeen test for legionella pneumophila serogroup 1( Binax now);
Infection of the lung lapse from diagnostic parameters: PCR, serologie IgG and IgM, ELISA urine-antigeen testen, urines nel test;
Value from the urinesnel test as screenings test in outbreaks;
Quality from diagnostic on legionella in the various microbiology laboratory on the hand from the datum in these specific outbreak;
Virulentie among not to be found from the isolated patients date;
Molecular typering from patient and date and about gevings isolation.

4. Clinical investigation; this investigation( execute by the department visceral medical science from the Amsterdams medical centre) be directional on the clinical aspects from Legionellose and on( genetic determine) predetermind host factor those after infection with L. Pneumophila from influence its on the clinical amount.

The epidemic

Next the prove and probable cases be in the case-register a extra category from patients incorporate: possible cases. This its visitor from the Westfriese Flora with a clinical image suitable in a pulmonary, without available whether perform diagnostic. From the beginning from the epidemic to on 31 march 1999 its in total 233 cases mentioned( 109 prove, 51 probably and 99 possible). Give the visits number from 80. 000 be this a overall attack rate from zero, 2% for prove plus probable cases. Here from its meanwhile 22 individual deceased( case fatality rate from thirteen, eight% for prove and probable cases).

(There is replenishment)

Provisional analysis from the case-control study be execute with the datum from 110 certain plus probable cases.
The result here from cause a man/ woman ratio from 1, six: 1 see and a average age from 65 year( range: 25-91 year). From these cases real definite 104 as visitor on the Flora geweest, six patients have definite work as stand holder whether an derszins. The about big part from the visits( 94%) be only one day on the Flora geweest. The figure marks these 110 cases to first illness day.

The possible source from the epidemic

From the various apparatus and installation those on the Flora used its, be a number apriori suspect, by that they in the international literature already as source describe its. With name go the hereby about whirlpools, vernevelaars and fountain. In the draw up from the question registers and in the sequence from the sample name in the source tracing be herewith calculations hold. To now to have the investigation to the source from these illness still no final explanation on deliver. Well its definite indication for presence from legionella pneumophila in two whirlpools. From a water sample from a whirlpool appear a PCR assessment positive and from a filter from a other whirlpool appear the kweek positive for L. Pneumophila. By planning from stand holder those during the Flora legionella pneumonia have on run be a connection lay with visit on the consumer halls from the Flora.

The come the period

All effort remain directional on the behind fetch from the infection source from these epidemic. Both by the( her) sample, vary with laboratory technain as by the analyze from the first data from the case-control study and the cohort study become here on still hard work.

Replenishment on the article
"The epidemic from legionella pneumonia among visits from the Westfriese Flora in Bovenkarspel".

The number its based on datum in the register per 31 march 1999 and handle the follow case definition:

prove case:
Visitor from the Westfriese Flora with a clinical image suitable in a lung onsteking and a in filtraat on the thorax photograph with a positive result on L. Pneumophila, and/ whether with a positive serologie and/ whether with a positive urine antigeen test for L. Pneumophila.

Probably case:
Visitor from the Westfriese Flora with a clinical image suitable in a lung ignition and a infiltraat on the thorax photograph without laboratory confirmation like mention in a prove case.

Possible case:
Visitor from the Westfriese Flora and mentioned by treat doctor whether GGD in connection with a suspicion on a legionellose.

On sixteen April 1999 become more recent datum about the stand from business report in a between quick postage from the RIVM, after opschoning from the register( there is tabel 1). The discrepancy its as follow to explain.

In the between period its additional datum and modification enter come, and the definition its on sharpen. The number prove cases, that back run with 3, can explain become by that in the before count positive serologie' as prove became geclassificeerd, while in the between quick postage strictly criteria for serologisch evidence its handle( namely four fold titer increase whether seroconversie). Hereby its 3 prove cases probable cases become.

Besides it be the number probable cases with 6 back run. This concern cases from which in comparison with datum from the LCI appear, that not obvious growth whether definite language growth from rönt genologische confirmation( thorax photograph) from the pneumonia. Hereby be zo'n case
( dependent from laboratory diagnostic) to the class possible/ remaining displace. The total number cases in the between quick postage be low because in the group possible case in the infection disease bulletin all reports from patients those the Westfriese Flora visit have, its incorporate. In the between quick postage there and against its alone cases where in explicit clinical datum become mentioned in the category possible/ remaining incorporate and its cases without explicit mention from clinical datum as not to classificeren beyond consideration resigned.

Tabel 1. Datum in infection disease bulletin versus the between quick postage from the RIVM.