FAQs: Seoul virus, Hantaviruses, HPS, and HFRS

Is the Seoul virus a hantavirus?

Yes. Seoul virus is a member of the hantavirus family of rodent-borne viruses. This family also includes Sin Nombre virus, which is the most common hantavirus causing disease in the United States.  Most hantaviruses have only one or two rodent species as their natural host.  For Seoul virus, the natural host is the Norway rat (Rattus norvegicus) and the black rat (Rattus rattus), whereas for Sin Nombre it’s the deer mouse (Peromyscus maniculatus). In the rodents that carry them, these viruses don’t cause disease, but do cause life-long infection and shedding of the virus.  These viruses can occasionally spill over into other species of rodents, but they don’t cause chronic virus infections and shedding.

What is the difference between HPS and HFRS?

The severe disease associated with Sin Nombre virus infections is called hantavirus pulmonary syndrome (HPS). Most HPS infections lead to fever and body aches, progressing to severe breathing difficulties that frequently require hospitalization. Death occurs in approximately 38% of cases (or 38  of every 100 patients).  In contrast, the severe disease associated with Seoul virus is called hemorrhagic fever with renal syndrome (HFRS).  Most people who get infected with Seoul virus experience mild or even no symptoms.  However, in the severe form of the disease, patients can exhibit bleeding and kidney involvement, and death occurs in approximately 1-2% of cases (or 1-2 of every 100 sick individuals).