Mystery still surrounds the nausea, headaches and dizziness experienced by visitors to a Hoogeveen pet shop on Monday that led to 26 people being hospitalised and caused a major health scare in the northern town.

Scientists at the Groningen medical centre said on Tuesday that the problems may have been caused by a ‘poisonous substance’ and ruled out an infectious disease or a ‘biological cause’.
All 26 patients are set to be sent home today, a spokesman said.
Everyone who was hospitalised is said to have become ill after visiting the Annan Animal Centre pet shop. The entire area around the pet shop was sealed off on Monday evening as officials in protective clothing began their investigations.
A further 77 people who were in close proximity to the shop were quarantined in a nearby community centre. They were allowed home last night.
Meanwhile, some 200 people have so far called a special telephone helpline, news agency ANP reported. Of them, 40 people say they have symptoms and have been advised to visit their GP.
Scientists are also looking at whether there is a connection between the mysterious outbreak and the death of a caiman crocodile in the shop last weekend.