Four days after Thomas E. Duncan was admitted to a Dallas hospital to be treated for Ebola, officials acknowledged that they had still not cleaned up towels and sheets he used in the apartment he shared with four others, according to the New York Times. Officials say health workers are hesitant to clean out the apartment out of fear that they might be vulnerable to the disease.

"The house conditions need to be improved," Dr. David Lakey, the Texas Health commissioner, told the Times.

The delay in properly taking care of Duncan's residence has occurred amid growing concern in Dallas and elsewhere that the Ebola virus may spread. Dallas Superintendent of Schools Mike Miles said attendance throughout the city dropped 10 percent on Thursday, after reports surfaced that five schoolchildren had come into contact with Duncan. None of the children, who are being held in isolation until the 21-day incubation period of the disease elapses, has shown symptoms of the disease.

Health officials in Dallas have reached out to at least 80 people in the area who may have had contact with Duncan, who contracted Ebola after assisting an infected woman in Liberia on Sept. 15. After traveling to the United States, Duncan began showing symptoms of the disease in the Dallas apartment he shares with family members. He went to Texas Health Presbyterian Hospital and was sent home with antibiotics under the mistaken belief that his illness was minor. After his symptoms worsened Sunday, Duncan was readmitted to the hospital, where he has been in treatment since.

In another case, NBC News reported Thursday evening that American cameraman freelancing for the network in Liberia has tested positive for Ebola and will be flown back to the United States for treatment. The news team will be quarantined for 21 days.

The freelancer was hired Tuesday to work with chief medical editor and correspondent Dr. Nancy Snyderman on assignment in Monrovia, reporting on the outbreak. He came down with symptoms Wednesday, immediately quarantined himself and sought medical advice. He tested positive Thursday. NBC News is withholding his name at his family's request.

"We are doing everything we can to get him the best care possible," said NBC News President Deborah Turness. "He will be flown back to the United States for treatment at a medical center that is equipped to handle Ebola patients. We are consulting with the CDC, Medicins Sans Frontieres and others."

Meanwhile, officials in Utah and Hawaii have effectively ruled out that patients there had Ebola after conducting examinations of patients who had shown signs of fever and had traveled in Africa recently.