Lassa Fever Case Puzzles German Doctors

German doctors are puzzled by the first outbreak of Lassa fever outside Africa. They say three people are suspected of having been infected after having contact with an American who died of Lassa fever there last month.

"This is now the first documented outbreak of Lassa fever virus outside of Africa," the Robert Koch Institute, Germany's federal disease control agency, said in a statement.

The patient who died had been medical director of a missionary hospital in Togo.

"Three contacts of the Lassa fever patient who died at the end of February 2016 at the Cologne University Hospital have been diagnosed with the disease. All are under observation," the institute added. Later, on Saturday, Heinrich Heine University in Dusseldorf said it had withdrawn the positive diagnosos for two patients because the Lassa results could not be confirmed.

But it said they remained under observation and were still suspected of having Lassa.

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One of those infected was a mortician who handled the body.

Emory University Hospital in Atlanta is treating another American infected with Lassa. A hospital spokeswoman said there were no updates on the patient, who was flown from Togo last week. The patient was also working for a missionary organization, although Emory would not confirm whether it was the same one as the American who died in Germany.

Lassa experts say there's unusually widespread activity of the virus in West Africa now. It's being seen in countries where it had not been common, including Togo and Benin. An outbreak is also ongoing in Nigeria, according to the World Health Organization.

The Centers for Disease Control and Prevention says only a handful of Americans have ever been treated in the U.S. for Lassa. All were infected in West Africa.

Lassa is carried by rodents and people can catch it when rodent droppings or urine get onto food or into living areas. It's not related to Ebola, but in severe cases it can look like Ebola, with symptoms including fever and sometimes bleeding.

Severe cases can also be just as deadly as Ebola, says Robert Garry, a Tulane University virologist who studies Lassa in Sierra Leone, where it's common.

"When people come in very sick, we get mortality rates as high as 85 percent," Garry told NBC News.

The patient who died of Lassa in Germany has been identified as Todd DeKryger by the Forest Hills Baptist Church in Grand Rapids, Michigan.

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"Todd DeKryger — faithful servant of Jesus Christ in Togo, West Africa — passed away after an intense struggle with an infection," the church said in a statement on its website.

"He leaves behind a wife, 4 boys, and The Hospital of Hope where he was chief of staff and a surgical PA. He loved to share Jesus with everyone he interacted with and touched countless lives. He will be missed."

The hospital is run by the Association of Baptists for World Evangelism.

Garry says human to human transmission of Lassa is possible, although unusual. "We've seen it in families," he said.

He says patients in Kenema, Sierra Leone, are reluctant to come into a special Lassa clinic there that was overwhelmed by Ebola patients during the epidemic there. Many wait until they are too ill to be helped to come in, he said.

There's no specific treatment for Lassa, but supportive care, including giving patients saline to keep them hydrated, can help.

Medical missionaries have borne much of the burden of fighting outbreaks of disease in West Africa. Missionary doctors and volunteers were among the few Americans infected with Ebola in the epidemic there and several, including Nancy Writebol, Dr. Kent Brantly and Dr. Rick Sacra, were evacuated to the U.S. for treatment.