Four of the eight boys rescued from a flooded cave in Thailand have reunited with their families but will be kept in isolation behind glass, unable to touch their families, for another week.

The children, aged between 12 and 16, are being kept in a sterilised isolated unit in Chiang Rai hospital and will “be evaluated by doctors for five to seven days”, Thailand health secretary Dr Jessada Chokedamrongsook said.

Four of the eight boys who were retrieved from the cave in Northern Thailand have reportedly been visited by their families.

But they could only be seen through a glass window.

Thai health officials: rescued boys will now be in isolation for 1-2 days, inside a sterilized isolation unit, meaning no physical contact with their parents. A heartbreaking, necessary precaution at a time when all these kids and parents want to do is give one another a hug. pic.twitter.com/4efURwzBIF

— Matt Rivers (@MattRiversABC) July 8, 2018

There were concerns the boys, who are members of youth soccer team the Wild Boars, could have contracted a cave-dwelling virus or bacterial disease able to spread from animals to humans, the hospital’s spokesperson said in a statement on Monday.

“Living in a cave has a different environment, which might contain animals that could transmit any disease,” the spokesperson said.

But according to infectious diseases expert Professor Mark Walker, it’s “unlikely but possible” the children could have become infected with a disease transmittable by animals or water.

“Some potential infectious hazards are listeriosis, meliodosis and histoplasmosis.”

“Poor nutrition may lead to dampening of the immune system, and thus I think several days rest is precautionary, and allows medical staff to keep an eye out for any sign of infection,” Professor Walker told The New Daily.

The quarantining of the boys would be merely a “precaution”, according to Professor Walker, who is the national director of the Australian Infectious Diseases Research Centre at the University of Queensland.

The boys will have been quite malnourished after being trapped in the cave for two weeks, he said.

This can result in a weakened immune system and lead to a greater susceptibility to infections.

“I believe medical staff are trying to get them back on their two feet and ensure that they’ve had enough nutrients to be able to stand up to an infection,” Professor Walker said.

“So I don’t think that they’re particularly concerned that they’ve caught a ‘cave virus’, but it is best to be safe.”

The next round of rescue workers will be dispatched in roughly 20 hours to retrieve the other four boys and their coach who are still trapped in the cave.