Can Hantavirus Infection Spread Among Humans?

In Sweden, a form of hemorrhagic fever with renal syndrome called nephropathia epidemica occurs primarily in the northern parts of the country. It is a zoonosis, that is, an infectious disease that is normally transmitted between animals and humans when a bank vole, for instance, releases Puumala hantavirus via its saliva, urine, and feces. Normally humans become infected by breathing in dust polluted by virus from bank vole secretions or by direct contact with the animal.

It has recently been shown in South America that the Andes hantavirus, which is closely related to the Puumala hantavirus, can in some cases be transmitted among humans. The Umeå team's findings indicate that a possible path of contagion for hantavirus disease might be human saliva. During last year's outbreak of nephropathia epidemica in northern Sweden, saliva samples were collected from 14 patients in Västerbotten County, and virus RNA was found in the saliva in ten cases. It is not clear whether the virus found in human saliva is capable of infecting another human, but this question is now being studied intensively.

Nephropathia epidemica, is a serious disease, and patients coming to hospitals often have high fevers, headaches, muscle pain, and abdominal pain, and are in generally poor condition. In Sweden some 2,200 cases of nephropathia epidemica were reported in 2007, and more than 800 of them were from Västerbotten County. Up to 30% of those who were diagnosed with nephropathia epidemica wind up in the hospital, and in Västerbotten County two deaths occurred in 2007. In South and North America infections by close relatives of the Puumala hantavirus lead to death in 40% of cases.

The Umeå team consists of Associate Professor Magnus Evander and resident specialist physician and doctoral candidate Lisa Pettersson at the Division for Virology and Assistant Professor Clas Ahlm and Post-Doctoral Fellow Jonas Klingström at the Division for Infectious Diseases, all at the Department of Clinical Microbiology, Umeå University. Other co-authors are Jonas Hardestam and Åke Lundkvist, Swedish Institute for Infectious Disease Control, Stockholm. The findings will soon be published in the journal Emerging Infectious Diseases.