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Volume 32, Number 8—August 2026
Dispatch
Emergent Vibrio parahaemolyticus Gastroenteritis Outbreaks, New Zealand, 2019–2022
, Shevaun Paine, Jing Wang, Xiaoyun Ren, David Winter, Graham C. Fletcher, Anne-Marie Perchec-Merien, and Jackie Wright
Table
Epidemiologic and molecular characteristics of Vibrio parahaemolyticus acute gastroenteritis cases linked to outbreaks in New Zealand, May 13, 2019–April 20, 2022*
| Characteristic | All outbreaks | Outbreak 1 | Outbreak 2 | Outbreak 3 | Outbreak 4 |
|---|---|---|---|---|---|
| Notification date range; season(s) |
2019 May 13–Jun 18; late autumn–winter |
2020 Jun 08–Jul 27; winter |
2021 Feb 09–Apr 28; late summer–autumn |
2021 Nov 15–2022 Apr 20; late spring–autumn |
|
| No. cases (confirmed, probable) |
117 (116 confirmed, 1 probable) |
23 (23 confirmed) |
16 (16 confirmed) |
21 (21 confirmed) |
57 (56 confirmed, 1 probable) |
| Sex, no. (%) | |||||
| M | 60 (51) | 14 (61) | 10 (63) | 10 (48) | 26 (46) |
| F |
57 (49) |
9 (39) |
6 (37) |
11 (52) |
31 (54) |
| Age, y, range (median) | 17–90 (57) | 23–80 (59) | 38–77 (61) | 17–83 (53) | 17–90 (53) |
| Patient ethnicity, no. (%) | |||||
| Māori | 53 (45) | 15 (65) | 8 (50) | 10 (48) | 20 (35) |
| Pacific peoples | 11 (9.4) | NA | 2 (13) | 2 (9.5) | 7 (12) |
| Asian | 2 (1.7) | NA | NA | NA | 2 (3.5) |
| European or Other |
51 (44) |
8 (35) |
6 (38) |
9 (43) |
28 (49) |
| Cases by NZDep Index quintile,† no. (%) | |||||
| 1 (least deprived) | 17 (15) | 2 (8.7) | 1 (6.3) | 4 (19) | 10 (18) |
| 2 | 12 (10) | 0 (0) | 1 (6.3) | 3 (14) | 8 (14) |
| 3 | 24 (21) | 4 (17) | 1 (6.3) | 4 (19) | 15 (26) |
| 4 | 25 (21) | 7 (30) | 4 (25) | 4 (19) | 10 (18) |
| 5 (most deprived) |
39 (33) |
10 (43) |
9 (56) |
6 (29) |
14 (25) |
| No. districts with cases; top 3 districts by case count (no.) |
15; Canterbury (25), Bay of Plenty (15), Counties Manukau (13) |
8; Bay of Plenty (7), Waitemata (6), Counties Manukau (5) |
9; Counties Manukau (5), Waikato (3), Bay of Plenty (2) |
7; Southern (7), Nelson Marlborough (5), Canterbury (4) |
13; Canterbury (20), Northland (7), Bay of Plenty (6) |
| Hospitalized cases, no. (%) |
43 (37) |
8 (35) |
7 (44) |
5 (24) |
23 (40) |
| ST, no./total (%)‡ | |||||
| ST36 | 5/5 (100) | 5/5 (100) | NA | NA | NA |
| ST50 | NA | NA | 7/7 (100) | 4/4 (100) | 16/23 (70) |
| Other ST |
NA |
NA |
NA |
NA |
7/23 (30) |
| Cases with pathogen subtyping, no. (%)§ |
90 (77) |
8 (35) |
16 (100) |
15 (71) |
51 (89) |
| Cases with ST tdh/trh profile (no.) |
ST50 tdh+/trh+ (70); ST50 tdh+/trh– (1); ST36 tdh+/trh+ (8); ST199 tdh+/trh+ (1); ST3 tdh+/trh– (1); ST8 tdh–/trh+ (1); ST55 tdh–/trh– (1); ST1140 tdh+/trh– (1); ST2549 tdh–/trh– (4); ST2903 tdh–/trh– (1) ¶; ST2904 tdh–/trh– (1) ¶ |
ST36 tdh+/trh+ (8) |
ST50 tdh+/trh+ (16) |
ST50 tdh+/trh+ (15) |
ST50 tdh+/trh+ (39); ST50 tdh+/trh– (1); ST3 tdh+/trh– (1); ST8 tdh–/trh+ (1); ST55 tdh–/trh– (1); ST199 tdh+/trh+ (1); ST1140 tdh+/trh– (1); ST2549 tdh–/trh– (4); ST2903 tdh–/trh– (1)§; ST2904 tdh–/trh– (1) ¶ |
| Implicated source(s) by case (no.)# |
NA |
Raw or part-cooked mussels (23) |
Raw or part-cooked mussels (12), fish (4), shellfish unspecified (3), lobster (1) |
Raw or part-cooked mussels (20), sea urchin (1) |
Raw or part-cooked: oysters (17; 7 ST50), mussels (14; 10 ST50), sea urchin (8; 6 ST50), lobster (7; 7 ST50), pāua (5; 4 ST50), pipis (4; 4 ST50), clams (1; 1 ST50), shellfish unspecified (2; 0 ST50), fish (3; 3 ST50) |
| Supplier(s) |
NA |
Commercial to superstores (23) |
Commercial to superstores (15), food premise (2), unknown (3) |
Commercial to superstores (20), self-collected sea urchin (1) |
Self-collected (38), store bought (17), unknown (6) |
| Costal location(s) | NA | Coromandel region upper North Island mussel-growing area | Coromandel region upper North Island mussel-growing area | Marlborough region upper South Island mussel-growing area; North Island | New Zealand-wide North and South Island coastal regions |
*NA, not applicable; NZDep, New Zealand Deprivation Index; ST, sequence type. †NZDep 2018 quintile whereby 1 is least and 5 is most socioeconomically deprived. ‡No. hospitalized cases with specified core-genome multilocus sequence type infection out of the total no. hospitalized cases with available ST results. §V. parahaemolyticus subtyping results (tdh/trh toxin gene profile and ST) for all cases with an isolate referred for subtyping. ¶Novel strains that were assigned sequence types during the investigation. #No. cases reporting consuming specified types of seafood within the incubation period for illness; some cases reported consuming more than 1 type of seafood so counts may exceed number of cases. For multi-ST outbreak 4, no. cases reporting specific seafood exposures is also presented for ST50 cases in parentheses.