Mr Duncan, shown here at a 2011 wedding in Ghana

 Ebola patient Thomas Eric Duncan, the first known person with the disease to enter the United States, has died, Texas Health Resources officials said on Wednesday.
Duncan has been in a Dallas hospital receiving treatment since being diagnosed with Ebola after arriving in the United States from Liberia last month. He had been in critical condition, and people who have had contact with him have been isolated and are being monitored for symptoms.
In another development, travelers arriving in the United Stated from Liberia, Sierra Leone and Guinea will face mandatory screening measures for the deadly virus as soon as this weekend, federal officials said The additional screening may be extended to passengers from other nations where the outbreak has occurred, officials said.
Countries in West Africa, where the deadly outbreak is centered, are supposed to screen passengers before they are allowed to depart. Under the new measures, such travelers must also answer questions and have their temperature taken once they arrive in the United States, officials said.