Oysters blamed for stomach bug

Raw oysters are thought to be linked to a sudden outbreak of a highly infectious gastrointestinal illness in Northland that has so far left at least 18 people sick.

Public health authorities in the region expect more cases to be notified to them this week as the illness spreads among family members and people in the wider community.

Northland medical officer of health Dr Jonathan Jarman said the condition, known as shigellosis, is a bacterial infection which causes watery diarrhoea and stomach cramps.

Symptoms can worsen to include severe stomach pains with blood and mucus in bowel motions.

Although not generally life-threatening, the illness can be severe and very serious in children under five and in the elderly.

Dr Jarman said Northland usually got only two or three shigellosis cases notified each year, so getting 18 cases notified since last Tuesday "very much points to an outbreak".

Initial inquiries by health protection staff suggested a link between the illness and oysters collected from the Opua marina in the Bay of Islands.

Signs have gone up at the marina warning people not to take and eat shellfish from the area.

Most shigellosis cases involve adults in Paihia, Moerewa, Kawakawa, Kaikohe and Dargaville.

Dr Jarman said people with diarrhoea and abdominal pain should see their doctor if symptoms were severe and the illness did not get better after one to two days, or if young children or elderly people were affected.