Five people from two households in New Zealand became ill with ciguatera poisoning after eating fish imported from Fiji earlier this year.
The outbreak in Christchurch affected three males of 19 to 58 years old and two females – one aged in her 40s and the other in her 50s. One person was hospitalized and diagnosed with ciguatera poisoning but has since recovered.
In late May, Krazy Price Mart Ltd recalled a batch of frozen camouflage grouper (kawakawa) due to ciguatoxin. The item was sold as an individual whole gutted fish wrapped in clear plastic but was not labelled so had no date marking. It was available between March 10 and May 21, 2020 only at Krazy Price Mart Ltd in Christchurch.
Sample analysis and label issue
The first household purchased, cooked and consumed affected fish on April 18 and the second household bought the fish on May 3 but did not cook and eat it until one week later. In both houses, the cases had onset of symptoms within eight hours of having the product.
The link between the product and illness was identified by the local public health unit investigator who interviewed the notified cases. Both affected families had purchased the same product from the same retailer but on different days. A sample of the fish remaining in the freezer of one of the households has been sent for analysis but results are not yet available.
The Australia New Zealand Food Standards code sets out the legal labelling requirements for food sold in the two countries. Lot identification is required for food labels. The lack of this information on the labels is being followed up as part of an ongoing investigation. Enquiries with Fijian authorities and Krazy Price Mart Ltd, the importer and retailer of the affected fish, are continuing.
Ciguatera is an illness caused by eating fish containing certain toxins. The toxins come from a type of algae, and get into the fish either through it eating the algae, or eating fish that ate the algae. Fish that can cause poisoning include coral trout, barracuda, red snapper, donu, parrotfish, grouper, Spanish mackerel, red emperor, wrasse, reef cod, sturgeon fish, trevally, kingfish and moray eel.
Ciguatera in New Zealand
Ciguatera poisoning is relatively uncommon in New Zealand. The last outbreak in Canterbury was in December 2019 and there were two local outbreaks that year. The fish species implicated in this outbreak has been linked to previous cases and outbreaks.
During 2018, no cases or outbreaks of ciguatera fish poisoning were reported in EpiSurv, New Zealand’s database for notifiable disease surveillance. Using hospital data, four people were reported with ciguatera poisoning as the primary diagnosis. From 2009 to 2018, seven outbreaks were recorded, with no more than two in any year.
Ciguatera poisoning is not a notifiable disease in the country but acute gastroenteritis is under some circumstances such as where there is a suspected common source. It is generally associated with private imports of imported reef fish from the tropics and not usually from New Zealand caught fish.
Possible symptoms of poisoning include nausea, vomiting, diarrhea, muscle pain followed by neurological symptoms including headache, temperature reversal (hot things feel cold and cold things feel hot), dizziness, tingling, muscular weakness and irregular heartbeat. Onset of symptoms usually occur within six hours of eating the contaminated product and last a few days or weeks. Ciguatera toxin does not affect the appearance, odor or taste of fish. Freezing or cooking fish once it has been contaminated will not kill the toxin.
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