THE HAGUE, Netherlands (AP) — Countries around the world are preparing to deal with the more than 140 passengers and crew members on board a hantavirus-stricken cruise ship headed for the Canary Islands.The vessel is expected to reach the Spanish island of Tenerife, off the coast of West Africa, early Sunday.At least three passengers have died, and several other people have been infected.Hantavirus is usually spread by the inhalation of contaminated rodent droppings and isn’t easily transmitted between people. Some scientists believe the Andes virus implicated in the cruise ship outbreak may be able to spread between people in rare cases. But the World Health Organization says the risk to the wider public from the outbreak is low. Symptoms usually show between one and eight weeks after exposure.AdvertisementAdvertisementAuthorities and the cruise operator have been providing updates, but some key information is still lacking.Here’s what we don’t know:Where the outbreak originatedArgentine investigators suspect a Dutch couple may have first contracted the virus while on a bird-watching trip before they boarded the cruise ship in Argentina on April 1. But no organization has confirmed where or how they acquired the disease.Argentina’s Health Ministry has zeroed in on the nation’s southernmost town, Ushuaia. Officials plan to travel there in the coming days, according to a written statement to The Associated Press.What happens next to the remaining passengersSpanish authorities are preparing to receive the remaining passengers and crew members on Tenerife. Officials said Friday that passengers will be evacuated in small boats to buses only once their repatriation flights are ready to take them.AdvertisementAdvertisementThe United States has agreed to send a plane to the Canary Islands to pick up its citizens, as will the British government. Other countries have not yet made their plans public, and it is not clear how long boat passengers will have to wait for their flights.Spain has requested medically equipped planes for passengers experiencing symptoms, Virginia Barcones, the country’s head of emergency services, said Friday.How many people may have been exposedCruise operator Oceanwide Expeditions and Dutch officials said Thursday that more than two dozen people from at least 12 different countries left the ship at the remote island of St. Helena in the South Atlantic on April 24.They included a Dutch woman who disembarked with her husband’s body. He was the first passenger to die, but it wasn’t until May 2 that health authorities first confirmed hantavirus in a ship passenger.AdvertisementAdvertisementThe delay left countries scrambling to track the passengers who got off the ship some two weeks earlier.The passengers included a resident of the remote island of Tri …