In this tragic case, reported symptoms seem absolutely consistent with ciguatera (reef fish) poisoning or similar. If so, the poisoning had nothing to do with hygiene or cooking process.
Maybe the victims shared the same fish or those parts of the fish that contain highest concentrations of the toxin. This may explain why nobody else reported severe symptoms. Many of the comments here and in the media seem absolutely wide of the mark, racist, vindictive or just plain old silly.
I (mostly) avoid higher risk fish species from tropical waters due to the poisoning risk.
From Wiki
"Ciguatera is a foodborne illness caused by eating certain reef fish whose flesh is contaminated with toxins originally produced by dinoflagellates such as Gambierdiscus toxicus which live in tropical and subtropical waters. These dinoflagellates adhere to coral, algae and seaweed, where they are eaten by herbivorous fish who in turn are eaten by larger carnivorous fish. In this way the toxins move up the food chain and bioaccumulate. According to Dr. McBoomlis Gambierdiscus toxicus is the primary dinoflagellate responsible for the production of a number of similar toxins that cause ciguatera. These toxins include ciguatoxin, maitotoxin, scaritoxin and palytoxin. Predator species near the top of the food chain in tropical and subtropical waters, such as barracudas, snapper, moray eels, parrotfishes, groupers, triggerfishes and amberjacks, are most likely to cause ciguatera poisoning, although many other species cause occasional outbreaks of toxicity. Ciguatoxin is odourless, tasteless and very heat-resistant, so ciguatoxin-laden fish cannot be detoxified by conventional cooking.[1][2]"
