The United States has diagnosed its first case of the deadly Ebola virus in a man who became infected in Liberia and traveled to Texas, US health officials said Tuesday.

The patient was hospitalized with symptoms that were confirmed to be caused by Ebola, which has killed more than 3,000 people in West Africa, a Centers for Disease Control and Prevention spokesman told AFP.

“He acquired the disease in Liberia,” the spokesman said, adding that the man, who has not been named, was not a healthcare worker.

Dr Brantly, left and Nancy Writebol: infected in West Africa, but now free

The man is the first person to be diagnosed with Ebola in the United States, although a handful of US medical workers who were infected in West Africa have been flown back to the United States for treatment. They have since recovered.

“The patient is an adult with a recent history of travel to West Africa,” the Texas Department of Health said in a statement.

“The patient developed symptoms days after returning to Texas from West Africa and was admitted into isolation on Sunday at Texas Health Presbyterian Hospital in Dallas.”

The world’s largest outbreak of Ebola has infected 6,574 people across five west African countries, and killed 3,091 since the start of the year, according to the World Health Organization.

The hemorrhagic fever causes a range of symptoms including fatigue, fever, muscle aches, vomiting, diarrhea and bleeding.

It can be spread by close contact with the bodily fluids of an infected person who is showing symptoms, or by touching the corpse of a person who died from Ebola.

The beginning of the West Africa outbreak has been identified as a two-year-old boy in Guinea who became sick with Ebola in December 2013.

Experts do not know how he came down with Ebola, but the New England Journal of Medicine has reported that he may have come in contact with an infected fruit bat, which are natural hosts for the virus.

Since then the disease has spread rapidly, primarily affecting Sierra Leone, Liberia, and Guinea and overwhelming the healthcare systems there.

The Ebola outbreak in Nigeria is almost over, US health officials said separately Tuesday, in a rare sign of authorities turning the tide on the highly contagious disease.

The CDC warned last week that a worst-case scenario could see Ebola cases explode to 1.4 million by January, but that such dire predictions could be avoided if resources are scaled up.

The United States has already treated patients who acquired Ebola during the West African outbreak, including Christian missionary doctors Kent Brantly and Rick Sacra, who have been declared free of the virus.

Another patient with suspected exposure to Ebola was hospitalized outside the US capital over the weekend, but it remains unclear whether that person has Ebola or not.