WHO Downgrades Hantavirus Outbreak on Cruise Ship After US Case Found False Positive

Context On May 13 the WHO reported eleven hantavirus cases linked to the cruise ship MV Hondius in the South Atlantic. One case involved Dr. Stephen Kornfeld, an American physician who assisted with the outbreak after the ship’s doctor fell ill. His nasal swab taken in early May had produced a faint positive result in one Dutch laboratory and a negative result in another, leading the WHO to label the finding inconclusive but still count it as a case.

Key Facts - Kornfeld’s repeat PCR test and serology (antibody) test both returned negative, indicating no current infection and no prior exposure to hantavirus. - Two Dutch labs processed his swabs; one reported a negative result, the other a faint positive, which can arise from low viral load or contamination. - After the negative follow‑up tests, the WHO subtracted one case, reducing the outbreak total from eleven to ten. - Kornfeld has been moved from a biocontainment unit to a quarantine unit at Nebraska Medical Center, where other U.S. passengers are monitored.

What It Means The revised count reflects the standard practice of confirming initial PCR findings with repeat molecular and serological testing before classifying a case. A faint positive alone does not confirm infection, especially when subsequent tests are negative and no antibodies are detected. For passengers, the risk of ongoing hantavirus transmission remains low, but health officials continue to monitor for symptoms.

Watch for any further updates from the WHO or national health agencies regarding additional testing of passengers or crew, and for guidance on preventive measures for travelers on similar vessels.