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Hantavirus pulmonary syndrome in Washington, 2006
(updated 7/14/06)
Between January 1, 2006
and July 14, 2006, there have been three reported cases of hantavirus
pulmonary syndrome (HPS) in Washington State. They have occurred in
Whatcom, Yakima, and Okanogan counties: two were fatal. National data
indicates that there has been an increase in HPS cases this year
throughout the Western United States. This increase is reported in a
June 9, 2006 issue of
Morbidity and Mortality Weekly Report.
Since its recognition in
1993, there have been 32 reported cases of hantavirus pulmonary syndrome
in Washington State (1-5 cases/year) with 11 associated deaths (map).
The risk for HPS occurs throughout the state, particularly in rural
areas. HPS usually affects previously healthy adults. The median age of
HPS cases in Washington State is 36 years old (range 19-75 years). This
coincides with HPS statistics nationally that show 451 cases
with a case fatality rate of 35% and a median age of 38 years (range
10-83 years).
Hantavirus pulmonary
syndrome is caused by Sin Nombre virus which is carried by deer
mice (Peromyscus maniculatus). Deer mice occur throughout
Washington State, especially in rural areas. The virus is aerosolized
and then inhaled when people disturb rodent droppings or nests. Most
exposures occur when people are cleaning, living, visiting or working in
rodent infested buildings, homes, barns, and garages. Mice are
asymptomatic and there are no available tests to determine if rodent
droppings are infectious, or if a person has been exposed.
Hantavirus pulmonary
syndrome develops 1 to 6 weeks after exposure to Sin Nombre virus
infected mouse droppings and urine. HPS typically begins with a few days
of flu-like illness (fever, muscles aches, headache, non-productive
cough, fatigue, inappetance) that is followed by rapidly progressive
pulmonary edema (bilateral pulmonary infiltrates) and severe
cardio-respiratory compromise. Thrombocytopenia, presence of
immunoblasts, leukocytosis with a left shift, and hemoconcentration are
characteristic laboratory findings and serial monitoring of complete
blood counts is recommended in suspected cases. Although there is no
specific treatment, patients require hospitalization for pulmonary and
hemodynamic support. Emergency room physicians and primary health care
providers are encouraged to consider HPS in patients with the hallmark
signs and symptoms (flu-like illness followed by acute respiratory
distress requiring oxygen supplementation, pulmonary infiltrates,
thromobocytopenia, leukocytosis with left shift, circulating
immunoblasts, hemoconcentration) and to immediately report suspected
cases to their local health departments.
Diagnosis of HPS
involves detection of virus-specific IgM and IgG antibodies in serum
with an ELISA test. Laboratory testing should be performed or confirmed
at a reference laboratory, such as the Washington State Public Health
Laboratory. Contact your local health jurisdiction to arrange testing.
Reporting requirements
for HPS in Washington can be found at
http://www.doh.wa.gov/notify/nc/hantavirus.htm. More
information about HPS can be found at:
http://www.cdc.gov/ncidod/diseases/hanta/hps/index.htm |
