The Centers for Disease Control and Prevention on Thursday reported that no secondary Andes virus infections were identified among 88 U.S. residents monitored after an outbreak aboard an international cruise ship. On May 4, CDC was notified of seven cases of severe acute respiratory illness, including three deaths, later confirmed to be caused by Andes virus, among 147 persons aboard a ship in the Atlantic Ocean.
Andes virus is the only hantavirus known to spread from person to person, according to CDC. It is endemic to areas of South America and can cause hantavirus pulmonary syndrome, which has a case-fatality rate of approximately 40%. No specific treatment or vaccine is available. The United States has reported one documented case of Andes virus, an imported case in 2018.
The ship originally departed from Argentina and carried 88 passengers and 59 crew members representing 23 nationalities, CDC said. The index patient developed symptoms on April 3. Initial patients had fever and gastrointestinal symptoms, and four rapidly progressed to respiratory failure and shock. One critically ill passenger was medically evacuated to South Africa on April 27, where testing confirmed Andes virus infection on May 5. No cases occurred among passengers who were U.S. residents.
Twenty-eight U.S. residents traveled on the cruise. Ten disembarked before infection was confirmed aboard the ship. The remaining 18 departed Tenerife on May 10 and arrived in the United States on May 11 aboard a Department of State-chartered flight with biocontainment capability. Sixteen passengers were transported to the University of Nebraska Medical Center in Omaha; 15 went to the National Quarantine Unit, and one asymptomatic passenger was admitted to a special pathogen treatment center there for evaluation. One symptomatic passenger and a travel companion were transferred to a special pathogen treatment center in Georgia. Whole-blood tests for Andes virus were negative for the repatriated passengers.
CDC and state and local health departments also monitored 60 additional U.S. residents potentially exposed on two April 25 commercial flights boarded by a passenger with symptomatic Andes virus infection. In all, 88 contacts across 27 jurisdictions completed 42 days of monitoring, the upper end of the known incubation period. Monitoring ended on June 5 for one person, June 6 for 69, and June 21 for 18. All Andes virus PCR test results were negative. Serologic testing was negative for both antibody types in 26 of 27 contacts tested. For one contact who might have been exposed to hantavirus previously, only the immunoglobulin G result was positive.
By June 2, six additional outbreak cases had been identified worldwide, for a total of 13 cases, including three deaths, CDC said. All cases occurred among persons aboard the cruise ship. Local health authorities assessed and monitored approximately 653 potentially exposed persons from 33 countries.
CDC said the absence of secondary infections among monitored U.S. contacts should not be interpreted as evidence that no transmission risk existed. Close quarters and shared spaces aboard the ship created numerous opportunities for exposure. Health care providers should consider Andes virus in patients with compatible illness after travel to areas where the virus is endemic, or after exposure to a person with suspected or confirmed infection, and should promptly notify public health authorities.