CDC Alerts Clinicians About Potential for Imported Hantavirus Cases

The CDC has issued a Health Alert Network (HAN) health advisory on hantavirus, urging clinicians to be aware of the potential for imported cases of hantavirus disease in connection with an outbreak of Andes virus aboard a cruise ship.

While the risk of broad spread in the U.S. is “considered extremely unlikely at this time,” the agency noted that early symptoms can be easily confused with influenza or other viral illnesses. In addition, the virus may not be accurately detected in body secretions and excretions within the first 72 hours of symptom onset, so testing should be repeated after that window, the agency warned.

About 30 passengers disembarked the ship on April 24, returning to their home countries, including several Americans. Several state health departments confirmed to MedPage Today that they have individuals under monitoring.

The CDC said that symptoms typically appear 4 to 42 days after exposure — though some reports have suggested up to 8 weeks — and early symptoms can include fever, headache, muscle aches, nausea, and fatigue.

About half of patients experience headaches, dizziness, chills, and gastrointestinal symptoms including nausea, vomiting, diarrhea and abdominal pain, the agency said.

Late symptoms appear about 4 to 10 days after the initial phase of the illness and can include coughing, shortness of breath, and chest tightness.

However, patients can deteriorate rapidly, and delayed care reduces the chances of survival, CDC said. In severe cases, extra corporeal membrane oxygenation (ECMO) can significantly improve survival if started early.

Also, the critical phase of the illness is fairly short and survivors can recover quickly, CDC said.

Clinicians should include hantavirus pulmonary syndrome in the differential diagnosis for symptomatic patients who’ve had at least one epidemiologic risk factor, including direct physical contact or spending time in close or enclosed spaces with a symptomatic person with Andes virus; exposure to an infected person’s saliva, respiratory excretions, or other body fluids through sharing utensils or handling contaminated bedding; or breaches in infection prevention and control precautions.

These patients should also be tested for COVID, influenza, and other common causes of GI and febrile illness, CDC said.

The agency also recommended that healthcare providers follow its guidance for Andes virus infection control in healthcare settings when patients are suspected to have the disease. It recommends placing them in an airborne infection isolation room, as well as use of a gown, gloves, eye protection, and an N95 or higher-level respirator when entering the patient’s room.

People with hantavirus disease are generally only infectious while symptomatic, the agency said. Andes virus is the only type of hantavirus that has documented human-to-human transmission. It’s rare and typically requires prolonged contact with a symptomatic person.

From 1993 through 2023, there have been a total of 890 lab-confirmed cases of hantavirus in the U.S., with a case fatality rate of 35%.

On Friday, the CDC said it was planning to repatriate the American passengers from the cruise ship after it docks in the Canary Islands, which is expected to happen on Sunday.

They’ll be flown on a U.S. government medical repatriation flight to an Air Force base in Omaha and will be transported to a national quarantine center at the University of Nebraska Medical Center.

In a statement, the agency also said it had developed health guidance for those American passengers, which was delivered by the U.S. State Department. It also deployed a team of epidemiologists and medical professionals to the Canary Islands.

The HAN provided a disease timeline, beginning with the May 2 notification to the World Health Organization (WHO) of a cluster of severe acute respiratory illness among passengers and crew of the ship. At that time, there had been two deaths and one critically ill passenger.

As of May 8, WHO reported six confirmed cases, two suspected cases, and three deaths.

Investigations continue to assess the exposure risk of all American passengers on the ship or who may have been exposed to an infected cruise ship passenger on an aircraft, the agency said.

The ship left Argentina on April 1, traveling across the South Atlantic Ocean and stopping at several remote locations including Antarctica, South Georgia Island, Tristan da Cunha, St. Helena, and Ascension Island. It carried 147 people (n=86 passengers; 61 crew) from 23 countries.