90-Second Read: Argentina Authorities Trap Rats In Ushuaia, Hunt For Hantavirus Outbreak Source

The state-backed Malbrán Institute, Argentina's leading research center for infectious diseases, said the team would repeat the routine for the next three days before returning with the samples to the institute's main Buenos Aires laboratory to test for Hantavirus. But provincial officials further north in Patagonia where the Hantavirus is endemic insist that the first known victims of the outbreak, a Dutch couple passionate about birds, didn't visit during the window in which it is believed they got infected. Adamant that tourism-dependent Tierra del Fuego isn't the source of the cruise ship outbreak, health authorities here say they welcome a broader objective of the investigation: figuring out if their province has Hantavirus at all at a time of global warming. The Hantavirus has never been recorded in Ushuaia or the wider archipelago of Tierra del Fuego.

Health authorities here have fiercely rejected the national government's initial hypothesis that the chain of infections on the cruise began when the couple visited an Ushuaia landfill. Found throughout southern Chile and Argentina, the Andes virus may be able to spread between people in rare cases. But a subspecies can be found in the forests around Ushuaia, and scientists have never examined whether it can transmit the Hantavirus. Testing could take up to one month, but officials were tight-lipped about further details.

The scientists, wearing bright blue gloves and surgical masks, checked the 150 box traps they had set out the previous night, dropping dead rats into black plastic bags that they hoisted into pickup trucks bound for a makeshift lab where they said they'd draw blood samples. Tuesday's rat-trapping marks the start of fieldwork within Argentina's wider investigation into the origin of the contagion that struck the MV Hondius, killing three people, sickening several others and setting off a global scramble to trace passengers and their close contacts. Argentine investigators trudging through mud to retrieve the dead rats declined to speak to journalists about their work. The effort comes almost two weeks after the Argentine Health Ministry first announced it would send the team from the Malbrán Institute to Ushuaia.

They have both since died, complicating the efforts of Argentine investigators to retrace their path through the country with the aim of determining where they contracted the virus. Most clusters of the Andes virus, experts say, emerge from exposure to air contaminated with the feces and urine of the long-tailed pygmy rice rat known as the "colilargo" that runs rampant through the forests of northern Patagonia.