According to Sowetan Jonas was rushed to Netcare Alberlito Hospital in KZN by ambulance immediately after he collapsed.
The star apparently could not speak for three days after the incident.
"People from my team saw me after I collapsed. As runners they could not help me but they were able to call an ambulance and notify my wife," he told the paper.
Doctors apparently suspect dehydration or something foreign found its way into his system.
"I am not well but they have put me on a drip. I am still far I miss my children so much," he added.
Jonas joined thousands of athletes for the gruelling marathon from Durban to Pietermaritzburg.
According to medical statistics released by the Comrades Marathon Association 17, 031 athletes started the race, but only 13, 852 successfully completed.
Apparently 400 runners were treated at the official medical tent mainly for deyhydration.
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