Hantavirus pulmonary syndrome treated with inhaled nitric oxide

Neutralizing antibodies and Sin Nombre virus RNA after recovery from hantavirus cardiopulmonary syndrome

Patients who later have a mild course of hantavirus cardiopulmonary syndrome (HCPS) are more likely to exhibit a high titer of neutralizing antibodies against Sin Nombre virus (SNV), the etiologic agent of HCPS, at the time of hospital admission. Because administering plasma from patients who have recovered from HCPS to those in the early stages of disease may be an advantageous form of passive immunotherapy, we examined the neutralizing antibody titers of 21 patients who had recovered from SNV infection. Even 1,000 days after admission to the hospital, 6 of 10 patients had titers of 800 or higher, with one sample retaining a titer of 3,200 after more than 1,400 days. None of the convalescent-phase serum samples contained detectable viral RNA. These results confirm that patients retain high titers of neutralizing antibodies long after recovery from SNV infection.

Viral hemorrhagic fevers including hantavirus pulmonary syndrome in the Americas

The term viral hemorrhagic fever refers to an acute systemic illness with a propensity for bleeding and shock. The viral hemorrhagic fevers endemic in the Americas include yellow fever, dengue hemorrhagic fever, the South American hemorrhagic fevers, hantavirus pulmonary syndrome, and hemorrhagic fever with renal syndrome. Because these diseases are primarily zoonotic, the distribution of any given virus is generally restricted by the distribution of its natural reservoir or arthropod vector. A high index of suspicion, detailed investigation of the travel and exposure history of the patient, and a basic understanding of the incubation periods and distributions of the various reservoirs of hemorrhagic fever viruses are imperative, as are prompt notification and laboratory confirmation. Clinical management is largely supportive, with a special emphasis on safe nursing practices to prevent nosocomial transmission.

Infection with Sin Nombre hantavirus: clinical presentation and outcome in children and adolescents

OBJECTIVE

Sin Nombre hantavirus (SNV) is the leading causative agent of hantavirus cardiopulmonary syndrome (HCPS) in the United States and Canada. Relatively few cases of HCPS have involved children. This report describes the clinical characteristics of a series of pediatric cases of SNV infection in the United States and Canada from 1993 through March 2000.

METHODS

We analyzed clinical and laboratory data on 13 patients who were </=16 years old with SNV infection from 1993 through March 2000 identified from a database at the University of New Mexico.

RESULTS

The patients ranged from 10 to 16 years of age, with a median of 14. Fifty-four percent were female. Fifty-four percent were Native American. The most common prodromal symptoms were fever, headache, and cough or dyspnea (100%); nausea or vomiting (90%); and myalgia (80%). The most common physical findings at admission were tachypnea (67%) and fever (56%); hypotension was seen in 33% of patients. On admission, all patients manifested thrombocytopenia (median platelet count: 67 000/mm(3)) and elevated lactate dehydrogenase (median level: 1243 IU/L), and >85% of patients had elevated levels of serum aspartate aminotransferase, alanine aminotransferase, and hypoalbuminemia. Leukocytosis and hemoconcentration were seen in less than one third of patients at admission. HCPS developed in 12 of the 13 patients (92%), and 4 of those 12 died (33% case-fatality ratio). The majority of HCPS patients (8 of 12 [67%]) were critically ill and required mechanical ventilation. Extracorporeal membrane oxygenation was used in 2 patients, 1 of whom survived. An elevated prothrombin time (>/=14 seconds) at admission was predictive of mortality.

CONCLUSIONS

Infection with SNV in children and adolescents causes HCPS with a clinical course and mortality rate similar to that described in adults. We believe that early recognition of HCPS in children and adolescents and appropriate referral to tertiary care centers that are experienced with HCPS are important in reducing mortality.

Hantavirus Pulmonary Syndrome in the United States

Since the first outbreak of hantavirus pulmonary syndrome (HPS) in 1993, understanding of the vast distribution and potential impact of hantaviruses has grown. At least 277 cases of HPS have been documented in the United States. The full clinical spectrum has yet to be elucidated, and one outbreak suggested the possibility of person-to-person transmission. New research has identified the b-3 integrins as cellular receptors for hantaviruses and has determined the pivotal role of the immune system in pathogenesis. Rapid diagnosis has been facilitated by a new immunoblot assay to detect Sin Nombre virus infection. Treatment remains primarily supportive; however, a placebo- controlled trial of ribavirin is ongoing. Extracorporeal membrane oxygenation may be a potential therapy in severe cases; inhaled nitric oxide needs further study. Vaccines developed against hantaviruses associated with hemorrhagic fever and renal syndrome might be effective against HPS-associated strains.

Hantavirus pulmonary syndrome in Brazil: clinical aspects of three new cases

Hantavirus pulmonary syndrome (HPS) has been recognized recently in Brazil, where 28 cases have been reported as of September 1999. We report here the clinical and laboratory findings of three cases whose diagnoses were confirmed serologically. All the patients were adults who presented a febrile illness with respiratory symptoms that progressed to respiratory failure that required artificial ventilation in two of them. Laboratory findings were most of the time consistent with those reported in the United States in patients infected with the Sin Nombre virus, and included elevated hematocrit and thrombocytopenia; presence of atypical lymphocytes was observed in one patient. The chest radiological findings observed in all the patients were bilateral, diffuse, reticulonodular infiltrates. Two patients died. Histopathological examination of the lungs of these patients revealed interstitial and alveolar edema, alveolar hemorrhage, and mild interstitial pneumonia characterized by infiltrate of immunoblasts and mononuclear cells. In the epidemiologic investigation of one of the cases, serologic (ELISA) tests were positive in 3 (25%) out of 12 individuals who shared the same environmental exposure. HPS should be included in the differential diagnosis of interstitial pneumonia progressing to acute respiratory failure.