After unconfirmed theories started spreading that the hantavirus contagion that struck a cruise ship had originated in a landfill in Argentina’s southernmost city, where the boat departed, local authorities quickly pushed back.
“It’s a maneuver to smear the image of Ushuaia as a tourist destination,” said Martín Alfaro, the spokesman for the local health ministry in the province that includes Ushuaia — a windswept gateway to Antarctic cruises.
Malicious operators in neighboring Chile, he added, in what he described as a personal theory, might have spread rumors to position themselves “as the one entry door to Antarctica.”
As health authorities raced to trace the origin of a contagion that was unnerving a world still scarred by the global coronavirus pandemic, the scientific investigation became entangled with international finger pointing.
The two first known hantavirus victims — a Dutch couple — had embarked on a sprawling voyage across Argentina, Chile and Uruguay, making it hard for investigators to trace the origin of the infection.
And as deflections of the potential origin flourished, answers remained scant.
The Andes species of the hantavirus, which can be transmitted between humans and most likely caused the death of the two first patients who traveled on the ship, is endemic in three provinces across Argentina’s Patagonia, with several cases reported there every year, according to health authorities.
But the Argentine health ministry said on Tuesday that the Dutch couple had not visited any of those areas during the days in which it is believed they got infected.
The Andes species also exists in the Patagonian region in Chile, but the Chilean health ministry said in a statement that the Dutch couple had visited the country before the incubation period for the virus and ruled out that the contagion could have originated there.
Federico Lada, a spokesman for the Argentine health ministry, rejected the claim, saying that infection in Chile remained a possibility. “It’s not true,” he said, referring to the Chilean health ministry’s statement.
A difficult search
The Argentine government said scientists analyzed a viral sequence from one cruise passenger and found it most closely related to cases detected in 2018 in the Argentine province of Neuquén. But the authorities in the province said the Dutch couple had visited the region before the one- to six-week incubation window.
Argentine investigators were trying to reconstruct the expansive itinerary of the Dutch couple. They said the couple had spent recent months traveling through Argentina, Chile and Uruguay.
On the last leg of their trip before embarking on the MV Hondius in Ushuaia, the ministry said, they had spent 20 days traveling by car from the winemaking city of Mendoza to the northeastern province of Misiones, then spent two weeks in Uruguay. They returned to Argentina a few days before departing on the cruise on April 1, the ministry said.
Argentina regularly registers cases of hantavirus, but none of the areas that the couple had visited in recent weeks are considered at risk for the Andes species of the virus. The authorities said they were also capturing rats to investigate the virus.
The ongoing investigation, Mr. Lada said, was important to determine if the Andes species had spread to other provinces where it had not been reported before.
“It would be a risk for the country,” he said.
The Andes Species
The long-tailed colilargo, a tiny rat which eats berries and rose hips, has been causing cases of hantavirus in humans since at least 1996 in parts of Argentina’s Patagonia region. But unlike what happened on the MV Hondius, where at least 11 people got infected, health authorities in Argentina are generally able to quickly isolate cases and prevent uncontrolled spread.
In Bariloche, a city and prime tourist destination in the province of Río Negro, in Argentina’s Patagonia, a patient was currently hospitalized with hantavirus, said Dr. Rodrigo Bustamante, a doctor overseeing epidemiology at the Ramón Carrillo Hospital in San Carlos de Bariloche. The patient, Dr. Bustamante said, had no known connection to the boat.
Another patient was currently hospitalized with hantavirus in the neighboring province of Chubut, said Sergio Wisky, the health minister there. The patient, he pointed out, “worked in Chile’s woods.”
Dr. Wisky said he contracted hantavirus in 1996 while treating a patient during a deadly outbreak. In 2018, another outbreak in the province of Chubut, in the town of Epuyén, killed at least 11 people.
Since then, Dr. Wisky said, the province has implemented regular monitoring of rodents and specific protocols in case of an outbreak. In the three provinces where the Andes species of the virus is endemic, health officials said that they isolate people suspected of having the virus, trace their contacts and disseminate awareness about best behaviors to avoid getting sick.
Since 2018, each of the three provinces had only a handful of cases a year, officials said. On the boat, the virus was able to spread across close quarters.
“This likely happened because it hit a foreign cruise ship with doctors who probably weren’t familiar with the disease and weren’t aware of human-to-human transmission,” Dr. Bustamante said. “Over here we’ve known about that for a long time.”
The Ushuaia Landfill
In Ushuaia, the port city in the southern Tierra del Fuego province where the cruise started, residents had not been familiar with the hantavirus, since no cases had been registered there since record keeping began.
But the city suddenly found itself at the center of the news after media reports that the authorities were investigating a landfill there as the likeliest source of the contagion.
The Argentine health ministry said that was “not the most likely hypothesis.”
Several passengers aboard the MV Hondius were passionate bird watchers and the landfill in Ushuaia is a prime location for birders to spot the white-throated caracara, a local raptor bird. Still, several bird watchers in the area said such birds can be observed from outside the landfill, and tour guides said they were not aware of the Dutch couple visiting the area.
Juan Pavlov, the secretary of foreign policy at the Tierra del Fuego Tourism Institute, said it was unlikely the virus originated in the landfill, since the truckers and garbage collectors who work at the dump site never reported any symptoms.
“They would be sick, they would be infected and maybe dead,” he said.
The Argentine health ministry said that investigators would travel to Ushuaia to capture and analyze rodents in areas linked to the couple’s itinerary, with the objective of detecting the possible presence of the virus in an area which they thought was not affected by it.
The Andes species is normally not present in Tierra del Fuego, but Mr. Lada said they still need to be sure.
Mr. Pavlov said that he had to reassure tourism operators who called them worried about potential hantavirus. Ushuaia, he said, “was a scapegoat.”
Lucía Cholakian Herrera and Daniel Politi contributed reporting from Buenos Aires, and John Bartlett contributed reporting from Santiago, Chile.