The hantavirus outbreak aboard the cruise ship MV Hondius has been upstaged in world health news by the Ebola outbreak in the Congo, but the hantavirus investigation is far from over.
Health officials in Argentina were seen dutifully trapping hundreds of forest rats for examination this week, with an eye toward conclusively establishing where the disease aboard the Hondius came from.
The most widely-discussed theory of the hantavirus outbreak’s origin is that a pair of elderly Dutch birdwatchers named Leo and Mirjam Schilperoord contracted the hantavirus while hunting for birds at a massive landfill near the town of Ushuaia in Tierra del Fuego, Argentina, in late March.
Leo Schilperoord became ill five days after putting out to sea aboard the Hondius and died five days after that. Mirjam got off the boat with her husband’s body at the island of St. Helena on April 24, flew to Johannesburg, South Africa while visibly ill, and died in Johannesburg the day after she arrived. Leo is generally thought to have been “Patient Zero” for the outbreak.
Officials in Tierra del Fuego have disputed this theory, arguing there is no hard evidence that the Schilperoords contracted the hantavirus in Ushuaia, or even that Leo Schilperoord died from it.
Hantavirus has a long incubation period that can make the timing of infections difficult to determine and, although Leo indisputably died after manifesting symptoms consistent with the dangerous disease, he was not positively confirmed to have been infected. If he was infected, he could have contracted the hantavirus during the weeks he spent traveling by land through Argentina and Chile before coming to Ushuaia and boarding the Hondius. The ship also stopped at South Georgia Island, where Schilperoord did some more birding before he became visibly sick and entered intensive care in the Hondius sick bay.
The World Health Organization (W.H.O.) still lists Leo as a “probable case,” not a confirmed case, and notes that “no microbiological tests were performed” on him. His wife is considered a confirmed hantavirus fatality because she was given PCR (polymerase chain reaction) tests after arriving in Johannesburg.
Argentine investigators planted about 150 box traps in the forests around Ushuaia on Monday night, as part of an extensive fieldwork program to determine if hantavirus-infected rats are present anywhere near the city.
The Andes strain of the hantavirus that plagued the Hondius is the only strain known to be transmitted between humans, but humans more commonly contract it by coming into contact with droppings from pygmy rice rats. The specific species of rat associated with the Andes hantavirus is not commonly found in Tierra del Fuego, but a related subspecies does live in the area.
Argentina’s state-backed Malbran Institute said it planned to catch rats for three days and then bring the samples to Buenos Aires for extensive hantavirus testing, which could take about a month to complete.
Local officials maintain there has never been a confirmed hantavirus infection near Ushuaia, or in Tierra del Fuego for that matter. The issue is of great importance to the province, which depends on tourism and does not wish to become infamous as Hantavirus Ground Zero if the disease actually came from somewhere else.
“The province has never done this kind of testing before. It’s important that we rule out the possibility of transmission occurring here,” Tierra del Fuego health ministry spokesman Martin Alfaro said on Tuesday.
Tierra del Fuego’s director of epidemiology, Juan Petrina, has suggested the Schilperoords might have contracted hantavirus while they were traveling through Patagonia, which has more of a history with hantavirus outbreaks.
“The epidemiological situation in the area hasn’t changed much. We haven’t had any cases, and it has already been 45 days since the vessel set sail,” Petrina said last week.
Patagonian officials say the Dutch couple did not pass through their province during the window of time when they could have been infected. The couple also spent time in Chile and Uruguay.