New Zealand is reporting an increase in most major foodborne infections in 2022, according to recently released data.
The data come from the notifiable disease surveillance system EpiSurv and the Department of Health’s hospitalization database, which are independent. The report was published by New Zealand Food Safety (NZFS), an agency of the Ministry for Primary Industries (MPI).
Most of the 27 outbreaks (253 cases in 2022) were linked to commercial food operators, with only 5 linked to food prepared by consumers at home. There is also a nationwide outbreak of Vibrio parahaemolyticus with 60 cases and no familiar location or supplier.
In 2022, the number of Campylobacter, Salmonella, Shiga toxin-producing Escherichia coli (STEC) and Listeria infections increased compared to 2021. Suggested reasons include more overseas travel and the easing of restrictions imposed during the COVID-19 pandemic.
Campylobacter and Salmonella
There have been 5,878 cases of Campylobacter, of which 4,148 are estimated to be foodborne and 999 have been hospitalized.
Children aged 1 to 4 reported the highest notification rates, while seniors aged 70 and older had the highest hospitalization rates. EpiSurv has 128 notices citing overseas travel as a risk factor, compared with 394 in 2019, 66 in 2020 and seven in 2021.
EpiSurv has 94 cases in 11 outbreaks, with three foods listed as possible modes of transmission. The New Zealand Food Safety Authority investigated two other outbreaks. Two were related to chicken, one to shrimp, and one to liver or unpasteurized cheese. For the second year in a row, there have been no raw milk-related outbreaks.
There have been 750 cases of salmonella, 371 of which are estimated to be foodborne, and 212 have been hospitalized.
In 2022, 120 notifications in EpiSurv listed overseas travel as a risk factor, compared with 349 in 2019, 49 in 2020 and none in 2021. Notification and hospitalization rates were highest in the under 1 year age group.
Isolates from 654 notified cases were typed. Salmonella Typhimurium is the most common, followed by Salmonella Enteritidis and Salmonella Bovis.
Of the five outbreaks, three reported food as a possible mode of transmission. An outbreak of Salmonella Typhimurium affecting 25 people was linked to travel to Fiji, airports or aircraft food. The other two cases totaled 13, including eight hospitalizations, four in each outbreak. The New Zealand Food Safety Authority is investigating two further clusters of salmonella cases.
An epidemic is related to imported sesame products. Sequencing of clinical isolates revealed that the cases had the same sequence type and were closely related to the Syrian sesame product outbreak in Europe. The outbreak resulted in the recall of tahini and halva. Product testing found the presence of Salmonella Kintambo, Salmonella Amsterdam and Salmonella Orion.
E. coli and listeria
There were 1,022 E. coli infections, 390 of which were estimated to be foodborne E. coli infections. There has been one death and 67 hospitalizations.
The highest reported rates of STEC infection were in the 1 to 4 year old age group, followed by the under 1 year old age group. Isolates from 694 notified cases were typed. Of the 707 typed isolates, 259 were E. coli O157 and 448 were non-O157. As in previous years, the most common non-O157 serotypes are E. coli O26:H11 and E. coli O128:H2.
Hemolytic uremic syndrome (HUS) has been reported in 19 STEC cases. The relevant serotypes are mainly O157:H7 and O26:H11.
In five outbreaks, one of which had three patients, food was a possible mode of transmission. It is related to ham or meat pizza in mobile food units.
EpiSurv reported 39 listeria infections and six deaths, but hospital data showed 40 patients were admitted to hospital. Listeriosis reporting and hospitalization rates are highest in the 70+ age group.
One of the outbreaks started in December 2021 but was reported in 2022. There are 2 confirmed cases and 1 death. Cheese was identified as a possible source. Listeria was detected in this batch of products and a recall has been initiated.
Other pathogens and outbreak highlights
One person was reported to be infected with Bacillus licheniformis and Bacillus megaterium. The suspected source was samosas from a food service store due to the unpleasant odor. Laboratory testing of samosas came back positive for Bacillus spp.
A nationwide outbreak of hepatitis A has been linked to imported frozen berries, with a total of 35 cases of hepatitis A reported. The event runs until 2023. Among the 2022 cases, 7 did not consume imported frozen berries and were likely secondary transmission. Hepatitis A virus was detected in a bag of frozen berries opened by a patient.
Five norovirus outbreaks documented food or food handlers as possible modes of transmission. Health officials investigated two other outbreaks. Questionable sources include salads and oysters.
Between 2021 and 2022, there were 60 patients in the Vibrio parahaemolyticus outbreak. Forty patients were reported to have consumed raw or undercooked seafood. A histamine burst affected two people. The New Zealand Food Safety Authority is also investigating two other suspected histamine (mackerel) fish poisoning incidents, one in February and another in April 2022, and six cases.
There were two recorded hospitalizations for ciguatera poisoning. Two cases of suspected poisonous shellfish poisoning were received. One box contains raw, recreationally collected kina, while the other contains edible shrimp, clams and crayfish.
Clostridium perfringens caused an outbreak with five patients. The incident is related to potentially undercooked chicken nuggets being served to the school. A Shigella outbreak resulted in two cases, and dried cacti from the Pacific Islands were the likely source of infection. A giardia outbreak sickened four people and was linked to raw milk, but no milk samples were taken. Cases also live on a farm, so animal exposure may be a factor.
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