What is the origin of the hantavirus outbreak?: Argentina reconstructs the journey of the deceased Dutch couple

BarcelonaWhile the hantavirus-affected cruise ship is already heading towards the Canary Islands, the unknowns about the origin of the outbreak remain open. The World Health Organization (WHO) has downplayed the possibility that the infection was caused by the presence of rodents on board the vessel, so the most probable hypothesis at this point is that the first two fatalities, a Dutch couple, had contracted the virus before boarding the ship and that, once there, they had infected other passengers. Argentina, from where the cruise ship departed, has reconstructed the journey of the man and woman before embarking on the sea voyage. In the last four months, they had been in a large part of this country, but also in Chile and Uruguay, on a bird-watching trip. The strain responsible for the outbreak is native to the Andes and circulates in some of the areas where the couple had been.

According to the Argentine Ministry of Health, outbreaks had already been detected in previous years in the provinces of Chubut, Río Negro, and Neuquén, as well as in southern Chile. Regarding the current source of contagion, however, no case has been detected that is not related to the infections identified on the cruise ship. With the aim of determining the possible origin of the outbreak, Argentine technical teams will travel to Ushuaia to capture and analyze rodents that may be infected. Argentina will also send the RNA of the Andes strain and technical material to laboratories in Spain, Senegal, South Africa, the Netherlands, and the United Kingdom to conduct approximately 2,500 diagnostic tests.

Itinerary

Field epidemiologists, who in English are known as disease detectives, try to find out the origin of the outbreak by tracing the last weeks of infected people and the places they have been during that time, explains ISGlobal researcher and Antoni Trilla Clinical Hospital epidemiologist. The key is to find associations and patterns that allow us to conclude how the first contagion that triggered the outbreak occurred. The first thing to do is to determine what disease it is, in this case it is already known to be hantavirus, and how it is transmitted, which is mainly through rodents, although the Andes strain is also transmitted from person to person.

This is why professionals are now reconstructing the Dutch couple's journey to see if they find infected rodents. According to the Argentine Ministry of Health, the two tourists arrived in Argentina on November 27 last year and traveled around the country by car for 40 days, then went to Chile on January 7. Once there, they continued their journey by car for another 24 days. They returned to Argentina at the end of January to visit the province of Neuquén, where hantavirus cases have been detected on other occasions, and twelve days later they returned to Chile. From there they crossed to the Argentine province of Mendoza, in the west, to make a twenty-day journey to the province of Misiones, which borders Brazil and Paraguay.

Finally, on March 13, they crossed by land to Uruguay and on March 27, they returned to Argentina to go to the city of Ushuaia, in the province of Tierra del Fuego, from where the cruise ship set sail on April 1. The first passenger to show symptoms was the man of this couple, seventy years old, who died on the British island of Saint Helena, while his wife, 69 years old, died in South Africa, from where she was supposed to fly to the Netherlands.

Trilla explains that the deaths of the supposed first two infected individuals in the outbreak make the epidemiologists' investigation tasks difficult, as they will not be able to know all the details of their journey with exactitude. Normally, when professionals have a clear understanding of the origin of an outbreak, a conclusive sample is needed to confirm it. The expert explains that sometimes the origin of an outbreak is never definitively determined and that, beyond knowing what triggered it, the priority is to cut off the chains of contagion to prevent the disease from spreading.