The time delay in treatment does nothing to improve the chances of recovery from Ebola. It also can increase the spread of the disease.
Mr Duncan's family hope an investigation into his care will follow.
Unlike a nurse in Spain diagnosed with the disease this week Duncan is believed to have contracted Ebola while in Liberia.
The as yet unnamed female nurse in Spain is the first known person to have contracted Ebola outside of Africa. The World Health Organisation has demanded answers after it appeared that clothing and equipment used by Spanish health care workers treating Ebola patients fell short of the mark.
Opinion: Countries and organisations will need to work together closely to prevent the further spread of Ebola.
People are scared of this deadly disease; in Africa this has meant people with symptoms have been hidden by loved ones or themselves, adding to the spread of the disease.
Filthy living conditions and similar in health facilities in African countries adds to the problems.
Specially trained western military personnel are being sent to the regions of Africa affected to try to help control the disease.
Images from the region create more fear but hopefully will make people sit up and take notice. At this time Ebola is not an air-borne disease but rather spread by contact with bodily fluids.
Good hygiene has never been more important.
Now that Ebola is not simply an African problem the race is on to find a cure and produce enough supplies of vaccines.
Thomas Eric Duncan's death is one of more than 4,000 but as an American death it will be headline news and make a difference.