Notes from the Field: Hantavirus Pulmonary Syndrome --- Maine, April 2011

On April 25, 2011, the Maine Center for Disease Control and Prevention was notified of a suspected case of hantavirus pulmonary syndrome (HPS) in a man aged 70 years with no recent out-of-state travel. The Maine resident went to a community hospital in early April with a 5-day history of fatigue, decreased appetite, weakness, chills, myalgias, and progressive shortness of breath. On examination, he was hypoxic and tachypneic. The patient was admitted with laboratory evidence of acute renal insufficiency, leukocytosis and thrombocytopenia, and appearance of diffuse bilateral infiltrates on chest radiograph. Two days later, he was transferred to a tertiary-care facility for management of respiratory failure with hypoxemia and worsening renal insufficiency. The next day, he was intubated and mechanically ventilated. Serum specimens demonstrated high titers of hantavirus reactive immunoglobulin M (1:6,400) and immunoglobulin G (1:1,600) antibodies. Hantavirus RNA was detected in the patient's blood. The patient was discharged to a skilled nursing facility 1 month after admission and is recovering with extensive rehabilitation.

HPS is caused by hantavirus infection. The virus is transmitted to humans by exposure to excreta or direct contact with infected rodents. An investigation revealed that the patient had potential exposure to rodent excreta on his farm. A grain storage shed was not rodent-proof and had grain on the floor. The patient reportedly had climbed a ladder to place rodenticide in the upper level of the shed, where insulation was contaminated with rodent droppings.

HPS is a life-threatening illness first identified in 1993 following an outbreak of unexplained, severe pulmonary illness in the southwestern United States (1). As of December 15, 2010, a total of 560 HPS cases from 32 states had been reported to CDC, including 529 since 1993; until this case, none of the cases had been diagnosed or contracted in Maine (2). However, potential reservoirs for pathogenic hantaviruses exist across the entire continental United States (3). This case highlights the importance of clinician and public awareness of HPS and avoidance of risk factors for hantavirus infection (i.e., exposure to rodent droppings in the home, vacation home, workplace, or campsite), even in regions of the United States that have not had documented cases previously. Early recognition of HPS can reduce mortality.

Reported by

Mohamad Mooty, MD, Imad Durra, MD, Div of Infectious Diseases, Eastern Maine Medical Center, Bangor; Vicki Rea, MPH, Patricia Snyder, MPH, Stephen D. Sears, MD, Lauren B. Ball, DO, Maine Center for Disease Control and Prevention. Adam MacNeil, PhD, Shelley Campbell, Gregory Kocher, Ute Ströher, PhD, Pierre E. Rollin, MD, Stuart T. Nichol, PhD, Div of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases; Susan E. Manning, MD, Career Epidemiology Field Officer Program, CDC. Corresponding contributor: Susan E. Manning, susan.manning@maine.gov, 207-287-3361.

References

1. CDC. Outbreak of acute illness---southwestern United States, 1993. MMWR 1993;42:421--4.
2. CDC. U.S. HPS cases, by state. Atlanta, GA: US Department of Health and Human Services, CDC. Available at http://www.cdc.gov/hantavirus/surveillance/state-of-exposure.html. Accessed June 10, 2011.
3. Mills JN, Amman BR, Glass GE. Ecology of hantaviruses and their hosts in North America. Vector Borne Zoonotic Dis 2010;10:563--74.