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Emerging Infectious Diseases Update: Hantavirus Disease -- United States, 1993

Since the recognition of acute hantavirus-associated respiratory disease in the United States in May 1993, laboratory evidence of acute hantavirus infection has been confirmed in 30 persons in the southwestern United States; 20 (67%) of these persons have died. Of those 30 persons, 23 resided in the four-corners region (14 in New Mexico, six in Arizona, and three in Colorado). Previously reported cases outside the four-corners states occurred in a Nevada resident (1) and a Texas resident (2), neither of whom had traveled to the four-corners area, and a resident of another state who had traveled to and presumably was infected in the four-corners area (3). This report summarizes the other four confirmed cases and describes two cases under investigation; all of these cases occurred outside the four-corners area during July 1992-August 1993. Confirmed Cases

Louisiana. During June 1993, a 58-year-old Louisiana bridge inspector who had not traveled to the four-corners area died following an illness characterized by bilateral interstitial infiltrates and hypoxemia. Polymerase chain reaction (PCR) evidence of hantavirus infection was found in lung tissue, and nucleotide sequence analysis of viral genetic material PCR-amplified from the lung suggests the presence of a previously unrecognized hantavirus most closely related to but distinct from both the Prospect Hill virus and the virus circulating in the four-corners area.

Nevada. In August 1993, a 51-year-old central Nevada resident rapidly developed bilateral interstitial infiltrates and hypoxemia over 12 hours following a 6-day illness characterized initially by fever, myalgia, nausea, and vomiting, which progressed to coughing and shortness of breath. The patient, who developed high-titered immunoglobulin M (IgM) antibodies to hantavirus, had not traveled to the four-corners area. As of August 11, the patient remained hospitalized.

California. Two cases have been confirmed in California. In the first, in July 1993, a 27-year-old field biologist, who was working on the eastern slope of the California Sierra Nevada mountain range, had acute onset of an illness characterized by 2 days of fever, myalgia, and headache. The patient developed rapidly progressive bilateral interstitial infiltrates and hypoxemia and died the following day. Hantavirus infection was confirmed by IgM serology, PCR, and a positive immunohistochemical stain for hantavirus antigen on lung tissue. The second case was in a 29-year-old ranch worker on the California coast who died of rapidly progressive respiratory failure during September 1992, following 3 days of fever, myalgia, and cough. Recent immuno- histochemical staining of preserved autopsy tissues revealed hantavirus antigen. Neither person had recently traveled to the four-corners area. Other Investigations

CDC is assisting state health departments in other investigations, including 1) a California man who had serologic evidence of past hantavirus infection following recovery from a hantavirus-compatible illness during April 1993 and 2) a 16-year-old Oregon youth in whom hantavirus antigen was identified by immunohistochemical staining of lung tissue saved from autopsy in July 1992. The California man, but not the Oregon teenager, had traveled to a four-corners state during the month before onset of illness.

Reported by: J Bertman, MD, Mono County Health Dept, Bridgeport; H Meyers, MD, Orange County Health Dept, Santa Ana; A Chovil, Santa Barbara County Dept of Health, Santa Barbara; R Jackson, MD, GW Rutherford, III, MD, State Epidemiologist, California Dept of Health Svcs. C Ward, MD, TB Callister, MD, H Hayes, Nye Regional Medical Center, Tonopah; LM Oksenholt, DO, D Jones, MD, S Parker, MD, Reno; D Nelson, AF DiSalvo, MD, State Health Laboratory, D Kwalick, MD, State Health Officer, Div of Health, Nevada State Dept of Human Resources. K Hedberg, MD, D Fleming, MD, State Health Div, Oregon Dept of Human Resources. KJ Steier, DO, Dept of Medicine, EA Conway Medical Center, Louisiana State Univ, Monroe; L McFarland, DrPH, State Epidemiologist, Office of Public Health, Louisiana Dept of Health and Hospitals. Div of Field Epidemiology, Epidemiology Program Office; National Institute for Occupational Safety and Health; Div of Bacterial and Mycotic Diseases, Div of Vector-Borne Infectious Diseases, Scientific Resources Program, and Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases, CDC.

Editorial Note

Editorial Note: Newly recognized cases of acute illness with evidence of hantavirus infection in Louisiana, Nevada, and California, along with previously recognized cases in Nevada and Texas, further demonstrate that hantavirus-associated respiratory illness is not confined to the four-corners area of the southwestern United States. Distinctive hantavirus nucleotide sequences have been identified from a person with acute illness in Louisiana; this information, together with confirmation of human disease in areas of Texas (2) and Louisiana outside the known range of Peromyscus maniculatus (4) -- the implicated reservoir in the four-corners area -- suggests the existence of an additional hantavirus with a different rodent reservoir in the south central United States (3,5,6). The continued occurrence of hantavirus disease underscores the importance of minimizing risk for exposure to rodents and their excreta. Interim recommendations for hantavirus infection risk reduction have been developed (7). This document contains specific recommendations for reducing rodent shelter and food sources in and around the home, recommendations for eliminating rodents inside the home and preventing them from entering the home, precautions for preventing hantavirus infection while rodent-contaminated areas are being cleaned up, prevention measures for persons who have occupational exposure to wild rodents, and precautions for campers and hikers. Investigations of cases of recognized and suspected human hantavirus disease and potential rodent reservoirs are ongoing.


  1. CDC. Update: hantavirus disease -- southwestern United States, 1993. MMWR 1993;42:570-2.

  2. CDC. Update: hantavirus infection -- United States, 1993. MMWR 1993;42:517-9.

  3. CDC. Update: outbreak of hantavirus infection -- southwestern United States, 1993. MMWR 1993;42:495-6.

  4. Kirkland GL Jr, Layne JN, eds. Advances in the study of Peromyscus (Rodentia). Lubbock, Texas: Texas Tech University Press, 1989.

  5. CDC. Update: outbreak of hantavirus infection -- southwestern United States, 1993. MMWR 1993;42:441-3.

  6. CDC. Update: outbreak of hantavirus infection -- southwestern United States, 1993. MMWR 1993;42:477-9.

  7. CDC. Hantavirus infection -- southwestern United States: interim recommendations for risk reduction. MMWR 1993;42(no. RR-11).

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