The first cases, a Dutch man and his wife, who died nearly three weeks after him, had spent more than three months traveling through Argentina, Chile and Uruguay on a birding trip before they boarded the Hondius in Ushuaia, Argentina’s southernmost city, on April 1, according to the WHO. That trip “included visits to sites where the species of rat that is known to carry Andes virus was present,” WHO Director-General Tedros Adhanom Ghebreyesus said at a Thursday briefing. Landfill theory Last week, The Associated Press, citing two Argentine officials investigating the origins of the outbreak, said the government’s leading hypothesis was that the couple contracted the virus while bird-watching in Ushuaia and may have been exposed to rodents at the city’s landfill. The landfill theory made some birding enthusiasts uneasy and prompted some authorities, locals and others to defend Ushuaia, a city of nearly 85,000 that draws tourists to its Antarctic cruise ships and abundant, watchworthy bird population. Esteban Daniels, a birding guide in Ushuaia, said the landfill attracts eye-catching birds — the white-throated …