She said according to investigations done the same day (Jan. 1) all the patients ate cockles (kerang) which they collected from Sepanggar waters at noon that day.
"Between 3pm and 6pm on Jan. 1, they started to show symptoms of food poisoning with tingling in the neck, vomiting, drowsiness and short of breath. All the patients were sent to hospital for treatment where two were admitted while four received outpatient treatment," she said.
She said the two patients suffered critical symptoms of unconsciousness with severe anaphylactic shock and were diagnosed with Paralytic Shellfish Poisoning (PSP).
"The first victim, aged 14, was discharged from the ward upon his family's request and passed away in his home on Jan. 2, while the second victim a nine-year-old boy, passed away while being warded on Jan. 4," she said.
The Fisheries Department, meanwhile, advised people to refrain from consuming any type of shellfish or bivalves.
Its Director Rayner Stuel Galid said there was a positive toxic sample from Papar northwards to Tuaran as high as 6,000 Mouse Units (Mus).
"The level is evidently very high because a reading of 400 MU is already toxic and dangerous," he said. Rayner said the red tide phenomenon had also been detected in waters off Papar, Putatan, Kota Kinabalu and Tuaran as well as Sitompok Lake in Kuala Penyu.
He said the sample collected from Sepanggar early Saturday detected type Beliung with 3,300 MUs.
"This included oysters, mussels, cockles and any type of clam-like seafood, however, fish, prawns and crabs are safe for consumption," he added.
The department had in early December last year issued a Red Tide warning advising the people from consuming any type of shellfish or bivalves obtained from the sea.
Eating toxic shellfish can cause paralytic shellfish poisoning (PSP) in humans. PSP is caused by saxitoxin, which is produced by the dinoflagellate, Pyrodinium bahamanse (var. compressum) and is one of the most potent toxins known to scientists.
"Deep sea fishes, squids, and crabs can be consumed but they must be cleaned thoroughly and the gills must be discarded," he said.
The first recorded PSP case in Sabah was in 1976 where 202 victims suffered and saw seven deaths.
Since then, PSP occurrences have been detected every few years off the West Coast.
Early symptoms of PSP include tingling of the lips and tongue, which may begin within minutes of eating poisonous shellfish or may take an hour or two to develop.
Depending on the amount of toxin a person has ingested, symptoms may progress to a sensation of "pricking of pins and needles" of the skin and then loss of control of arms and legs, followed by difficulty in breathing.
Some people have experienced a sense of floating or nausea, he said, adding if a person consumes enough poison, muscles of the chest and abdomen become paralysed.
He said death could result in as little as two hours, once the muscles used for breathing become paralysed.