KOTA KINABALU, Malaysia - An ecologist from the state Forestry Department, Dr Reuben Nilus, said the caterpillar hairs could cause allergic reactions similar to pollen.
He said breeding season for these insects is usually in March, when they lay hundreds of eggs on leaves, from which after a week, tiny baby caterpillars hatch.
"That is the larvae stage, and when they grow to the caterpillar stage, they become active and eat leaves.
During this time, there will be many of them and these caterpillars have fine hairs that can travel through air and stick on to human skin," he said.
On Monday, 46 students of SM St Francis Convent were rushed to Queen Elizabeth Hospital, here after suffering from skin and eye irritations.
Doctors believed the students were exposed to pollen released from plants during strong winds while attending an afternoon assembly in the school's open hall.
"If you are exposed to pollen, you may get skin irritation, flu and fever. If it is only itchiness, there is a high possibility it could be because of exposure to caterpillar hairs," said Dr Rueben.
"Caterpillar fine hairs can travel through wind. When the hairs stick to a part of the body, symptoms will arise because of toxins in them.
A person who is exposed to caterpillar hairs may suffer from blisters, hives, itching, rashes, redness, swelling and eye irritation. Similar skin irritation could be caused from exposure to mites from rotten wood and pruned branches.
Dr Reuben said sap from a tree that was being trimmed would vaporise, expelling irritants that could cause inflamation.
Meanwhile, Deputy Health Minister Datuk Rosnah Abdul Rashid Shirlin said it had been confirmed that all 46 students suffered allergic reactions, but what caused the reactions had not been confirmed.
"All students were diagnosed with allergic reaction. However, the hospital has yet to identify the etiologic agent," she said.
"At the moment, the situation is under control and we advise those who suffer from similar irritation to consult a doctor immediately."