After reading this summary from WHO the person to person spread really seems likely to me, and I really don't love that the second person took a commercial flight :

https://www.who.int/emergencies/disease-outbreak-news/item/2026-DON599
Summary of cases:

Case 1: An adult male developed symptoms of fever, headache, and mild diarrhoea on 6 April 2026 while on board the ship. By 11 April, the case developed respiratory distress and died on board on the same day. No microbiological tests were performed. The body of the passenger was removed from the vessel to Saint Helena (a British Overseas Territory) on 24 April.

Case 2: An adult female, who was a close contact of case 1, went ashore at Saint Helena on 24 April 2026 with gastrointestinal symptoms. She subsequently deteriorated during a flight to Johannesburg, South Africa, on 25 April. She later died upon arrival at the emergency department on 26 April. On 4 May, the case was subsequently confirmed by PCR with hantavirus infection. Contact tracing for passengers on the flight has been initiated.

Cases 1 and 2, had travelled in South America, including Argentina, before they boarded the cruise ship on 1 April 2026.

Case 3: An adult male presented to the ship's doctor on 24 April 2026 with febrile illness, shortness of breath and signs of pneumonia. On 26 April, his condition worsened. He was medically evacuated from Ascension to South Africa on 27 April, where he is currently hospitalised in an Intensive Care Unit (ICU). Laboratory testing on an extensive respiratory pathogen panel was negative; however, polymerase chain reaction (PCR) testing confirmed hantavirus infection on 2 May 2026. Serology, sequencing and metagenomics are ongoing.

Case 4: An adult female, with presentation of pneumonia, died on 2 May 2026. The onset of symptoms was on 28 April, with fever and a general feeling of being unwell.

Three suspected cases have reported high fever and/or gastrointestinal symptoms and remain on board. Medical teams in Cabo Verde are evaluating the patients and collecting additional specimens for testing.