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Volume 32, Number 7—July 2026
Synopsis
Outbreak of Legionnaires’ Disease Linked to Newly Installed Residential Water Heaters, the Netherlands, 2022–2023
Daphne F.M. Reukers
, Sjoerd M. Euser, Alvin A. Bartels, Martijn G. Keet, Marijke Boot, Wilhelmina L.M. Ruijs, and Petra S. Brandsema
, Sjoerd M. Euser, Alvin A. Bartels, Martijn G. Keet, Marijke Boot, Wilhelmina L.M. Ruijs, and Petra S. Brandsema
Table
Case characteristics in outbreak of Legionnaires’ disease linked to newly installed residential water heaters, the Netherlands, 2022–2023*
| Case no. |
Cluster no. |
Illness onset date |
Age, y/sex |
Died |
Diagnostic method |
Legionella pneumophila serogroup 1 detected, sequence type |
New brand A water heater |
Installation date |
||
|---|---|---|---|---|---|---|---|---|---|---|
| Clinical |
Environmental |
Match† |
||||||||
| 1 |
1 |
2022 Nov |
76/F |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2022 Oct |
| 2 |
1 |
2022 Dec |
70/F |
N |
Culture, UAT |
Y, ST37 |
Y, ST37 |
Y |
Y |
2022 Oct |
| 3 |
1 |
2023 Jan |
73/F |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2023 Jan |
| 4 |
1 |
2023 Jan |
84/F |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2022 Oct |
| 5 |
2 |
2022 Dec |
70/M |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2022 Oct |
| 6 |
2 |
2022 Dec |
63/M |
Y |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2022 Oct |
| 7 |
NA |
2022 May |
59/M |
N |
Culture, UAT |
Y, ST37 |
No sampling |
NA |
N; probable travel-associated case |
NA |
| 8 |
NA |
2022 Jul |
88/M |
N |
Culture, UAT |
Y, ST37 |
No sampling |
NA |
Y |
2022 Jul |
| 9 |
NA |
2022 Aug |
62/M |
N |
Culture, PCR, UAT |
Y, ST37 |
No sampling |
NA |
Y |
2022 Jul |
| 10 |
NA |
2022 Sep |
90/M |
Y |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2022 Jun |
| 11 |
NA |
2022 Oct |
57/M |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2022 Oct |
| 12 |
NA |
2023 Jan |
85/M |
Y |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2022 Nov |
| 13 |
NA |
2023 Feb |
76/F |
N |
Culture, UAT |
Y, ST37 |
Y, ST37 |
Y |
Y |
2022 Aug |
| 14 |
NA |
2023 Feb |
82/F |
Y |
Culture, UAT |
Y, ST37 |
Y, ST37 |
Y |
Y |
2022 Oct |
| 15 |
NA |
2023 Mar |
93/M |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2023 Jan |
| 16 |
NA |
2023 Mar |
71/F |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2023 Jan |
| 17 |
NA |
2023 May |
55/F |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2023 Mar |
| 18 |
NA |
2023 May |
69/M |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2023 Apr |
| 19 |
NA |
2023 Jun |
77/F |
N |
Culture, PCR, UAT |
Y, ST37 |
Y, ST37 |
Y |
Y |
<6 mo before illness onset |
| 20 |
NA |
2023 Jul |
58/F |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2023 Mar |
| 21 |
NA |
2023 Jul |
81/F |
N |
Culture, UAT |
Y, ST37 |
Negative |
N |
N |
>2 y before illness onset |
| 22 |
NA |
2023 Aug |
80/F |
N |
UAT |
Y, ND |
Y, ST37 |
N |
Y |
2023 Jul |
| 23 | NA | 2023 Aug | 77/F | N | UAT | Y, ND | Y, ST37 | N | Y | 2023 Jul |
*NA, not applicable; ND, not determined; ST, sequence type; UAT, urinary antigen test. †Genotypical match between the clinical and environmental isolate, both containing Legionella pneumophila serogroup 1 sequence type 37.
Page created: May 13, 2026
Page updated: June 02, 2026
Page reviewed: June 02, 2026
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