More than two months after a mass poisoning at a Bali hostel left a young Chinese traveller dead and scores of guests violently ill, the incident remains mired in conflicting accounts and uncertainty.Many of the lingering questions are due to the possibility of overlapping causes behind the tragedy, with medical experts pointing to an unusual mix of symptoms that could reflect severe food poisoning, mismanaged fumigation or both.Amid the scrutiny, the hostel at the centre of the incident has...