When symptoms set in three weeks ago, he initially brushed them off as a bad hangover.
The sensation of feeling "crap and tired" stuck around, he said, so he headed to the doctor for a blood test.
"My liver levels - normally they should be around 40 enzymes, apparently. Mine were like, 2400. So they were very high, and they asked me, 'could you please get into hospital now'," he said.
The symptoms of Hepatitis A can include fever, diarrhoea and nausea.
Two weeks on from his hospital stay, the man said he was still dealing with fatigue and jaundice, or yellowing of the skin and eyes.
"Everyone's sort of taking the joke that I look like part of The Simpsons," he said.
"It's definitely hit me pretty hard, I feel. I haven't really done much. This week I've been to work, done about half to three-quarter days then come home and had a quick power nap."
There was no knowing for certain that frozen berries had caused his woes.
When an open packet in his freezer was tested, it returned negative results.
Yet Hepatitis A has the potential to incubate for up to 50 days, he said, so berries he ate weeks ago could be to blame.
New Zealand Food Safety said it had linked 11 of the country's cases by genomic sequencing, "meaning they were all likely exposed to the same source".
The other two results are pending.
Auckland-based paediatrician and hepatitis expert Helen Evans said Hepatitis A could spread from person to person.
Fortunately, she said that could be thwarted with soap and clean surfaces.
"It's contagious through what we call the faecal-oral route, which basically means that the most important mechanism to prevent it is good hand hygiene," she said.
"Within a household people will be touching the same surfaces, eating the same food. So you can sometimes see Hepatitis A within family members. But it's not as infectious in the same way as something like Covid would be, through respiratory drops," she said.
Evans said small Hepatitis A outbreaks occurred in Aotearoa every so often: frozen berries were also the culprit when four people were diagnosed with the disease in 2015.
For each case, Evans said symptoms could range from very mild to severe.
Abdominal pain could put people off eating or drinking, she said, meaning they became dehydrated.
For that reason, she said parents should be mindful of their children's health.
"Often children are more likely to go to the hospital because they don't understand the need to keep up with hydration when they're unwell. Little children in particular can often become quite dehydrated quite quickly. So that's often a reason why younger children might appear to be more severely affected," she said.
The man in Christchurch said he was surprised Pam's berries had remained on shelves until 11 days after his diagnosis.
It was in the hospital that he first learnt about warnings in the news to boil frozen berries, over a "suspected" link to Hepatitis A.
Having missed those news stories, he questioned why there couldn't have been a warning label placed near frozen berries in supermarkets.
"Just until the link is confirmed ... just so you realise you're taking a risk, that there is an outbreak. That could be a good incentive."
Beyond that, he was taking his brush with the disease in his stride, calling it an "eye-opener" to keep watch for any health warnings.
It had not been enough to deter him from berries altogether, he said.
"Apparently I'm immune now. So once I'm back healthy I'll be eating them again ... I don't see a point in hiding away from it, 'cause I like them," he said.
New Zealand Food Safety is continuing to ask people to take extra precautions with frozen berries.
It said heat treating them would kill the virus.
- RNZ
