A visitor to the Cook Islands was later admitted to hospital after picking up a rare waterborne bacterial infection seen in New Zealand only twice before.
The 68-year-old, who had been visiting family, was taken to a hospital emergency department in Auckland after four days of fevers and swelling, blistering and pain in both his legs.
The man had other existing conditions, including poorly controlled type 2 diabetes mellitus, obesity, gout and stage 4 chronic kidney disease. He also had cellulitis and lymphangitis in both legs.
Blood tests eventually showed the presence of Shewanella algae, a rare but potentially severe waterborne bacterium that causes soft-tissue and skin infections. It is often found in salty or warm water.
The case has been highlighted in a New Zealand Medical Journal article published today by authors Joachim Tan, Richard Babor and Tim Cutfield.
Mystery surrounds source of infection
Dr Cutfield is an infectious diseases and general physician who works in the Department of Infectious Diseases at Middlemore Hospital in South Auckland.
“It’s a pretty rare but severe infection caused by an uncommon bacteria,” he said. “The reason we thought it was worth publishing was that it enforces well-known but important lessons for people who treat this sort of infection all the time.
“We really don’t know where this bacteria came from in this poor person’s case.”
Shewanella infections have been reported only twice in New Zealand: a person who got it after a cut to his leg from the lid of a fish bin while fishing, and another who was exposed to fresh water in Rotorua.
Exactly how this latest case picked up the bacterium is unknown.
The article says the man denied “seawater immersion” or coral injury while on holiday, though he had stayed in a coastal area of an outer Cook Island.
“He had, however, consumed raw fish,” the report says.
“It was thought that the likely route of infection for our patient was gut translocation of Shewanella algae with subsequent haematogenous dissemination to the lower limbs, secondary to ingestion of raw fish.”
The authors say another hypothesis is the near-simultaneous inoculation of both the man’s legs by sea or shower water.
Cutfield was adamant that members of the public should not be afraid of eating raw fish in the Cook Islands – a delicacy for locals and tourists alike.
“No one should be feeling like it’s dangerous to keep doing that. This is pretty rare stuff.”
Cutfield is among a group of Kiwi health specialists who often travel to the Cook Islands to help with work for Te Marae Ora, the Cook Islands’ Ministry of Health.
“I certainly will be eating ika mata [raw fish] when I go back to work in a few weeks’ time.”
He acknowledged that soft-tissue and skin infections disproportionately affected people of Pacific Island descent. At Middlemore Hospital, just under half of adult admissions for cellulitis were Pasifika, he said.
“I guess it’s a sign that, even though this is a very rare case, there’s a lot more work to be done to improve prevention of these infections and improve the treatments we have available – and hopefully work towards getting people better quicker and back to their normal lives.”
The authors concluded that, although true bilateral cellulitis is uncommon, it should not be discounted as a cellulitis mimic in the presence of sepsis.
“Recent travel, aquatic exposure and seafood ingestion should be routinely considered risk factors for uncommon causes of cellulitis that may be resistant to standard empiric antibiotic treatment, such as Shewanella.”
Vaimoana Mase is the Pasifika editor for the Herald’s Talanoa section, sharing stories from the Pacific community. She won junior reporter of the year at the then Qantas Media Awards in 2010 and won the best opinion writing award at the 2023 Voyager Media Awards.