Imported fatal hantavirus pulmonary syndrome.

To the Editor: Hantavirus pulmonary syndrome (HPS) is characterized by fever, gastrointestinal symptoms, respiratory distress, elevated hematocrit, hypoalbuminemia, and thrombocytopenia. Most cases in North America are acquired from rodent vectors and are caused by the Sin Nombre virus. Person-to-person transmission has been reported for Andes virus (1,2) but not for Sin Nombre virus (3). We describe a patient with fatal hantavirus pulmonary syndrome.

The patient was a previously healthy 15-year-old Canadian girl. In the spring of 2006, she had traveled to the Santa Cruz-San Jose de Chiquitas corridor of Bolivia with her parents and siblings for a 4-week visit (Figure), where they stayed with family and friends on their farms. The family noted rodent droppings outside but no rodents were seen. The patient had no known exposure to rodents or rodent droppings after her return to Canada.

[FIGURE OMITTED]

On day 26 after her return from Bolivia, the patient sought treatment at a community hospital at 6:30 AM for malaise and mild fever. During the night before seeking treatment, she had mild confusion. Her initial blood pressure was 99/50, heart rate 97, and oxygen saturation 96% on room air. Her hemoglobin was 192 g/L (reference range 117-149), platelets 82 x 109/L (reference range 165-400), and leukocyte count 7.5 x [10.sup.9]/L (reference range 3.9-10.2). She was initially treated with 3 liters of normal saline and repeat hemoglobin tests showed a value of 206 g/L. Due to ongoing hypotension and hypoxia, she was intubated and sedated. Rocuronium was used as a paralytic agent to facilititate high pressure mechanical ventilation and maintain patient-ventilator synchrony. Dopamine and epinephrine were given as intravenous drips. Arrangements were made for the patient to be transferred to a tertiary pediatric care center for possible extracorporeal membrane oxygenation. During air transport, she had an asystolic cardiac arrest. While administering cardiopulmonary resuscitation, members of the healthcare team were exposed to a considerable volume of pulmonary edema fluid expelled from the patient's endotracheal tube. Few, if any, were able to maintain adequate protection with face shields or protective eyewear. Resuscitation efforts were unsuccessful, and the patient was pronounced dead on arrival at the tertiary care center at 7:26 PM. Postmortem examination showed evidence of marked pulmonary edema, diffuse alveolar damage, and lymphoid inflammation in the pulmonary interstitium.

Serologic examination of an acute blood sample was immunoglobulin M (IgM) positive for Sin Nombre virus, but low optical densities indicated potential for an infection with a related hantavirus rather than Sin Nombre virus. Subsequently, reverse transcription-PCR (RT-PCR) on blood in EDTA and lung tissue followed by sequence analysis confirmed an Andes-like hantavirus infection. None of the 40 household and healthcare contacts of the patient had symptoms compatible with HPS during an 8-week monitoring period. Two contacts with nonspecific symptoms were tested and found to be negative for hantavirus-specific IgM and IgG and negative by RT-PCR.

Additonally, a seroprevalence survey of close contacts and assessment of level of contact was conducted. Close contacts were defined as persons who lived in the same household as the patient, were in the same enclosed space for >2 hours, or provided healthcare to her while she was symptomatic. Twenty-eight (62%) of 45 close contacts provided serum over the next 5 months. All serum samples were negative for Sin Nombre and Andes IgG and Sin Nombre IgM by ELISA. Fourteen (50%) of the 28 completed a self-administered questionnaire which assessed the type and intensity of contact. Of these, 12 were healthcare workers and 2 were friends. One friend had contact with the patient 3 days before she died, a friend and a healthcare worker had contact with her on the day before her death, and the rest of the healthcare workers had contact with the patient on the day she died.

To our knowledge, this is the first imported case and the tenth case of HPS reported in British Columbia, Canada, since 1994 (2006 BC Annual Summary of Reportable Diseases, available from www.bccdc.org/content.php?item=33) (4). Six of these 10 cases were fatal. All cases except the 1 described here have been locally acquired Sin Nombre infections. Sin Nombre virus is endemic in the Peromyscus maniculatus (deer mice) population in most of British Columbia (5).

Worldwide, imported cases of HPS are unusual, although HPS has been reported in countries that are in close geographic proximity or in travelers to disease-endemic areas (6-8). Fortunately, none of the persons exposed to the patient reported symptoms consistent with HPS during the incubation period, and none who were tested seroconverted. Seroprevalence surveys in Chile among healthcare worker contacts of patients with HPS caused by the Andes virus showed a prevalence of 0% (9). A report from Argentina showed that cases due to secondary transmission occurred mostly in non-healthcare workers after prolonged close contact in the prodromal period (10). In conclusion, we describe an imported case of fatal HPS due to an Andes-like hantavirus with no evidence of secondary transmission.

Acknowledgments

We thank Heinz Feldman and Harvey Artsob for coordinating the virologic workup and providing feedback on manuscript drafts; Deborrah McFadden for completing the autopsy; Bonnie Anderson for coordinating the local serosurveys; Sunny Mak for making the map used in the publication; and the public health staff at Northern Health Authority for conducting active surveillance and helping to coordinate the serosurvey.

References

(1.) Wells RM, Sosa Estani S, Yadon ZE, Enria D, Padula P, Pini N, et al. An unusual hantavirus outbreak in southern Argentina: person-to-person transmission? Hantavirus Pulmonary Syndrome Study Group for Patagonia. Emerg Infect Dis. 1997;3: 171-4.

(2.) Wells RM, Young J, Williams RJ, Armstrong LR, Busico K, Khan AS, et al. Hantavirus transmission in the United States. Emerg Infect Dis. 1997;3:361-5.

(3.) Vitek CR, Breiman RF, Ksiazek TG, Rollin PE, McLaughlin JC, Umland ET, et al. Evidence against person-to-person transmission of hantavirus to health care workers. Clin Infect Dis. 1996;22:824-6.

(4.) MacDougall L, Fyfe M, Bowie WR, Cooper K, McCauley GD, Morshed M. Hantavirus infection in British Columbia: an atypical case history and epidemiological review. BCMJ. 2005;47:234-40.

(5.) Drebot MA, Artsob H, Werker D. Hantavirus pulmonary syndrome in Canada, 1989-1999. Can Commun Dis Rep. 2000;26:65-9.

(6.) Espinoza R, Vial P, Noriega LM, Johnson A, Nichol ST, Rollin PE, et al. Hantavirus pulmonary syndrome in a Chilean patient with recent travel in Bolivia. Emerg Infect Dis. 1998;4:93-5.

(7.) Castillo C, Nicklas C, Mardones J, Ossa G. Andes hantavirus as possible cause of disease in travellers to South America. Travel Med Infect Dis. 2007;5:30-4.

(8.) Murgue B, Domart Y, Coudrier D, Rollin PE, Darchis JP, Merrien D, et al. First reported case of imported hantavirus pulmonary syndrome in Europe. Emerg Infect Dis. 2002;8:106-7.

(9.) Castillo C, Villagra E, Sanhueza L, Ferres M, Mardones J, Mertz GJ. Prevalence of antibodies to hantavirus among family and health care worker contacts of persons with hantavirus cardiopulmonary syndrome: Lack of evidence for nosocomial transmission of Andes virus to health care workers in Chile. Am J Trop Med Hyg. 2004;70:302-4.

(10.) Martinez VP, Bellomo C, San Juan J, Pinna D, Forlenza R, Elder M, et al. Person-to-person transmission of Andes virus. Emerg Infect Dis. 2005; 11:1848-53.

Steven Reynolds, * Eleni Galanis, * ([dagger]) Mel Krajden, * ([dagger]) Muhammad Morshed,* ([dagger]) David Bowering, * ([double dagger]) William Abelson, * and Tobias R. Kollmann *

* University of British Columbia, Vancouver, British Columbia, Canada; ([dagger]) British Columbia Center for Disease Control, Vancouver, British Columbia, Canada; and ([double dagger]) Office of Chief Medical Officer, Northern Health Region, British Columbia, Vancouver, British Columbia, Canada

Address for correspondence: Steven Reynolds, Critical Care Medicine, Vancouver Acute ICU2, JPPN 2nd Floor, Room 2438, 855 W 12th Ave, Vancouver, BC V5Z 1M9, Canada; email: [e-mail]