Hantavirus Surveillance

On November 14th, District staff, in conjunction with the California Department of Public Health, trapped and tested rodents for Sin Nombre hantavirus at San Pedro Valley County Park.  Staff set 100 traps and caught twenty six rodents in them.  Each rodent was anesthetized, then measured and checked for parasites.  Laboratory staff then drew blood for the hantavirus antibody test.  After recovering from anesthesia, each rodent was carefully released at the exact location where it was trapped.  Staff tested a total of twenty four mice.  Test results showed that none of the animals tested had antibodies to Sin Nombre Virus.

Sin Nombre Virus is the strain of hantavirus that causes Hantavirus Pulmonary Syndrome (HPS) in California.  It is typically contracted through exposure to the dried urine of Peromyscus maniculatus (deer mice) in enclosed spaces.  One to five weeks after exposure, an individual may experience flu-like symptoms, followed by nausea and vomiting, then difficulty breathing.  Surveillance from 1975 to present day has shown a 7.5% infection rate of Peromyscus mice at trapping sites along the coast and at San Bruno Mountain in San Mateo County, but no human cases of HPS have been determined to be contracted within the county.  Counties in California where exposure to Sin Nombre Virus is highest are Mono, Inyo, Mariposa, Tuolumne, Nevada and Kern Counties.