On Monday, a New Jersey man died after been diagnosed with Lassa fever after returning from Liberia this month.

The fever is a viral disease common in West Africa. It exhibits similar symptoms as found in Ebola such as diarrhea, vomiting and bleeding. However, it is less infectious and far less likely to be fatal. Compared to about 70% of Ebola patients, about 1% of Lassa patients die.

The patient who died returned from Liberia to Morocco and arrived at New York City's JFK International Airport on May 17. According to CDC, the patient did not have a fever on departure from Liberia.

However, Dr. Tom Frieden, director of the CDC in Atlanta, said he fell critically ill and after his return suffered from multiple organ failure.

He went to hospital with a sore throat, fever and fatigue the next day. The hospital asked about his travel and then released him.

On May 21, he returned with worsening symptoms and was transferred to a treatment center prepared to treat viral hemorrhagic fevers. The blood samples submitted to the CDC tested positive for Lassa fever.

The CDC said he was in isolation when he died Monday evening. The department is working with public health officials in order to gauge people who had contact with the patient. They will be monitored for 21 days to see if symptoms occur.

CDC mentioned that it is the sixth known occurrence of Lassa fever in New Jersey since 1969. The last case was reported in Minnesota in 2014.

The department said the transmission of Lassa fever documented in the US has never been person-to-person. The virus is not transmitted through casual contact. It might get transmitted through direct contact with a sick person’s blood or bodily fluids, through mucus membrane, or through sexual contact.