Hantavirus pulmonary syndrome in Manitoba

The first confirmed case of hantavirus pulmonary syndrome in Manitoba was diagnosed in 1999. To define better the risk of exposure to hantaviruses in this area, the clinical features and epidemiological factors pertaining to this case were described, and a serological survey of rodents collected near the patient''s residence was undertaken. Small mammals were collected using live traps, were anesthetized via inhalation of isoflurane and were bled. Human and mouse serologies were undertaken using an ELISA to detect hantavirus-specific immunoglobulin G and/or immunoglobulin M antibodies. In addition, a full medical and epidemiological assessment, as well as individual risk factor and exposure analysis, were conducted. A 27-year-old Manitoba woman presented with severe respiratory distress and diffuse bilateral air space disease radiologically. Despite extremely aggressive measures, including mechanical ventilation, antibiotics, fluid management and inotropic support, the patient''s condition rapidly deteriorated, and she died 8 h after admission. Hantavirus pulmonary syndrome was confirmed by the detection of immunoglobulin M and immunoglobulin G antibodies to the Sin Nombre virus (SNV) in her sera and by the demonstration of SNV genomic sequences in her lung tissue. Exposure to hantavirus likely occurred in and around the home or in the rural area in which she resided. A total of 252 small mammals, primarily deer mice (Peromyscus maniculatus), were collected from 17 different sites at or near where the patient lived. Antibodies to SNV were detected in 28 of 244 (11.5%) deer mice, which were collected within 9 km of the residence of the fatal case, indicating that these rodents are a significant reservoir for SNV in this area.Key Words: Deer mice, Hantavirus pulmonary syndrome, HPS, Peromyscus maniculatus, Rodents, Serosurvey, Sin Nombre virusHantavirus pulmonary syndrome (HPS) was initially recognized in the southwestern United States in 1993 (1). An outbreak of HPS was caused by a hantavirus originally called the ''Muerto Canyon'' or ''Four Corners'' virus (2), but which is now named the ''Sin Nombre'' virus (SNV) (3). Since the original identification of the SNV, at least 12 other species of hantavirus have been identified in the Americas, including six that are known to be the etiological agent of HPS (3). Cases of HPS have been recognized in Canada but, to date, SNV is the only species of hantavirus that has been documented to cause HPS in this country.Although the SNV has been shown to infect many rodent species, the deer mouse, Peromyscus maniculatus, is the primary reservoir of SNV in the southwestern United States (4). The deer mouse is widely distributed in Canada (5) and is believed to excrete SNV in urine, saliva and feces (6). Human infection usually occurs when aerosolized virus is inhaled (3,6).As of January 1, 2000, 32 Canadian cases of HPS had been confirmed in the laboratory. All cases were reported in British Columbia, Alberta, Saskatchewan or Manitoba, with a case fatality rate of 37.5%, including the case described below (7). Patients ranged in age from 15 to 62 years (mean 39 years), and the majority (19 of 32 [60%]) were male (7). Before 1999, human cases of HPS had not been recognized in Manitoba. However, in July 1999, a female died from HPS; she had recently relocated from McAuley, Manitoba to Brandon, Manitoba. To gain further information regarding this case, local public health authorities conducted a full medical and epidemiological assessment, as well as individual risk factor and exposure analysis. Personnel from the Zoonotic Diseases and Special Pathogens (ZDSP) program trapped and bled small mammals in and around the patient''s principal residence and at 17 other sites within 9 km of this residence in southwest Manitoba.The present paper describes the clinical presentation and laboratory findings for the first confirmed HPS case in Manitoba, as well as the distribution and prevalence of hantavirus infections in the small mammals collected at 17 sites in southwestern Manitoba.     

Hantavirus pulmonary syndrome: at the crossroads

The initial identification in 1993 of hantavirus pulmonary syndrome as a novel, highly fatal respiratory illness among American Indians in the southwestern USA in 1993 opened the window to the recognition of a well-established pan-American zoonosis with a myriad of causative viruses and rodent vectors, although all are New World hantaviruses among New World sigmodontine rodents. The clinical spectrum of symptoms has also been expanded to include asymptomatic infection through to fulminant hemorrhagic fever. Although the use of ribavirin, an antiviral drug, was disappointing in an early, open-labeled trial, early detection and supportive care is much better refined. However, much work remains in probing the pathogenesis of this syndrome to help define and explore therapeutic options and the mechanism of person-to-person transmission with Andes virus, one of the viruses that cause hantavirus pulmonary syndrome. Current remote sensing efforts and longitudinal ecologic investigations need to be expanded in order to focus prevention efforts better.     

Hantavirus pulmonary syndrome in Manitoba.

The first confirmed case of hantavirus pulmonary syndrome in Manitoba was diagnosed in 1999. To define better the risk of exposure to hantaviruses in this area, the clinical features and epidemiological factors pertaining to this case were described, and a serological survey of rodents collected near the patient's residence was undertaken. Small mammals were collected using live traps, were anesthetized via inhalation of isoflurane and were bled. Human and mouse serologies were undertaken using an ELISA to detect hantavirus-specific immunoglobulin G and/or immunoglobulin M antibodies. In addition, a full medical and epidemiological assessment, as well as individual risk factor and exposure analysis, were conducted. A 27-year-old Manitoba woman presented with severe respiratory distress and diffuse bilateral air space disease radiologically. Despite extremely aggressive measures, including mechanical ventilation, antibiotics, fluid management and inotropic support, the patient's condition rapidly deteriorated, and she died 8 h after admission. Hantavirus pulmonary syndrome was confirmed by the detection of immunoglobulin M and immunoglobulin G antibodies to the Sin Nombre virus (SNV) in her sera and by the demonstration of SNV genomic sequences in her lung tissue. Exposure to hantavirus likely occurred in and around the home or in the rural area in which she resided. A total of 252 small mammals, primarily deer mice (Peromyscus maniculatus), were collected from 17 different sites at or near where the patient lived. Antibodies to SNV were detected in 28 of 244 (11.5%) deer mice, which were collected within 9 km of the residence of the fatal case, indicating that these rodents are a significant reservoir for SNV in this area.     

Hantavirus pulmonary syndrome in pregnancy.

This comprehensive case review of hantavirus pulmonary syndrome (HPS) during pregnancy in 5 women characterizes the effect of Sin Nombre virus infection on maternal and fetal outcomes. Histopathologic, serological, and clinical information were evaluated for evidence of vertical transmission. Maternal ages ranged from 20 to 34 years and gestational ages from 13 to 29 weeks. Symptoms, physical findings, and laboratory values other than those related to pregnancy were not noticeably different from those of nonpregnant patients with HPS, although fevers were somewhat lower. One maternal death and 2 fetal losses occurred. Gross, microscopic, and immunohistochemical examination for hantavirus antigen were done on 2 fetal autopsies and 3 placentas showing no evidence of transplacental hantavirus transmission. There was no serological evidence of conversion in the 3 surviving children. Maternal and fetal outcomes of HPS appear similar to those of nonpregnant HPS patients and of pregnant patients with other causes of acute respiratory distress syndrome. No evidence of vertical transmission of Sin Nombre virus was found.     

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 β-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 placebocontrolled 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: Report of four Alberta cases

Four Alberta cases of hantavirus pulmonary syndrome are reported. Three cases required intensive care, with one experiencing a fulminant course resulting in death. A fourth case with milder illness was identified after epidemiological investigations. Ribavirin was used in one patient who experienced a successful outcome. A recent open label trial has not supported the efficacy of this drug. The epidemiology of Peromyscus maniculatus, the primary rodent host, and the clinical features of this syndrome are summarized.     

Evolutionary relationships between papovaviruses and their hosts

The papovaviridae family consists of two genera, the papillomaviruses (PV) and the polyomaviruses (Py-V). Both genera are distinguished by morphological (larger sizes of the PV) and several biological characteristics. The genomes of either of the two genera share highly conserved DNA regions and a common antigenic determinant, located in their major capsid polypeptides. On the basis of these data an evolutionary relationship among the members of PV and Py-V, respectively, has been suggested. No homology has been found for either DNA- or protein sequences between PV and Py-V and the question of a common ancestor for both viral genera remains open. We have started to characterize the genome of a papilloma producing papovavirus of the Syrian hamster (HaPV). Most of the known biological characteristics of the HaPV suggest it should be classified as a papilloma-like virus. However, the molecular weight of about 3.5 X 10(6) daltons found for the circular duplex DNA lies within the range given for SV 40 and polyoma virus (Py). Analysis of the HaPV genome by cleavage with 21 different restriction endonucleases, location of specific binding sites of phage T 4 gene 32 protein and E. coli RNA polymerase on the viral DNA demonstrated that the HaPV differed distinctly from all other currently known papovaviruses. The HaPV genome was also analyzed by filter hybridization and electron microscopy under conditions of varied stringency for nucleotide sequence homology with the genomes of different papovaviruses of both genera. Whereas no homologous DNA regions could be found between the genomes of HaPV and the human PV types 1 and 4, only under nonstringent conditions (Tm-43 degrees C) stable hybrids were formed between HaPV-, SV 40- and the DNA of a PV isolated from Mastomys natalensis (MnPV). On the other hand extensive homology was detected between the genomes of HaPV and Py even under stringent hybridization conditions (Tm-28 degrees C). The homologous DNA segments mapped on the Py and partially on the SV 40 genome were found to be the most strongly conserved DNA regions among the Py-V genus. These results are discussed with respect to a classification of the HaPV within the papovaviridae family.     

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.     

Hantavirus pulmonary syndrome clinical findings: evaluating a surveillance case definition

Clinical cases of hantavirus pulmonary syndrome (HPS) can be challenging to differentiate from other acute respiratory diseases, which can lead to delays in diagnosis, treatment, and disease reporting. Rapid onset of severe disease occurs, at times before diagnostic test results are available. This study's objective was to examine the clinical characteristics of patients that would indicate HPS to aid in detection and reporting. Test results of blood samples from U.S. patients suspected of having HPS submitted to the Centers for Disease Control and Prevention from 1998-2010 were reviewed. Patient information collected by case report forms was compared between HPS-confirmed and test-negative patients. Diagnostic sensitivity, specificity, predictive values, and likelihood ratios were calculated for individual clinical findings and combinations of variables. Of 567 patients included, 36% were HPS-confirmed. Thrombocytopenia, chest x-rays with suggestive signs, and receiving supplemental oxygenation were highly sensitive (>95%), while elevated hematocrit was highly specific (83%) in detecting HPS. Combinations that maximized sensitivity required the presence of thrombocytopenia. Using a national sample of suspect patients, we found that thrombocytopenia was a highly sensitive indicator of HPS and should be included in surveillance definitions for suspected HPS. Using a sensitive suspect case definition to identify potential HPS patients that are confirmed by highly specific diagnostic testing will ensure accurate reporting of this disease.     

Hantavirus pulmonary syndrome: Report of the first Canadian paediatric case

Hantavirus pulmonary syndrome (HPS) was first recognized as a severe respiratory illness transmitted through rodent excreta in the southwestern United States in 1993. As of November 1997, 175 cases have been reported in the United States. The mortality rate of this disease has been reported to be as high as 52% in the United States, and the majority of the cases (94%) involved adults. Twenty-one cases have been recognized in Canada. This paper describes the first Canadian paediatric case and discusses some of the clinical features of this disease.     

Hantavirus pulmonary syndrome in northern Alberta, Canada: clinical and laboratory findings for 19 cases.

We reviewed the clinical and laboratory findings for 19 cases of hantavirus pulmonary syndrome (HPS) identified either serologically or by immunohistochemical testing of archival tissue at our tertiary care center. Fever (95%), cough (89%), and dyspnea (89%) were the most common presenting symptoms. The most prevalent presenting signs were respiratory abnormalities (95%) and tachycardia (84%). Common laboratory findings included thrombocytopenia (95%) and leukocytosis (79%). Elevated aspartate aminotransferase and lactate dehydrogenase levels were found in all patients tested. Intubation was required in 58% of the patients, and inotropic support was required in 53%. Our study confirms that serological responses appear early during clinical illness, making the enzyme immunoassay a useful tool for the diagnosis of acute HPS. The mortality (26%) and severity of disease that we observed among patients with HPS appear to be less than those reported elsewhere.     

Hantavirus pulmonary syndrome due to Andes virus in Temuco, Chile: clinical experience with 16 adults

STUDY OBJECTIVES: To describe the clinical features and laboratory abnormalities of 16 adults with confirmed Hantavirus pulmonary syndrome (HPS) due to Andes virus in Temuco, Chile. DESIGN: A retrospective chart review abstracting clinical, radiologic, laboratory, and epidemiologic data. SETTING: ICU of the university teaching hospital in Temuco, Chile. PATIENTS: Sixteen patients with HPS treated between 1997 and 1999. RESULTS: Patients were aged from 19 to 45 years, 82% were men, and 88% were farm or timber workers with occupational acquisition of HPS. After an incubation period ranging from 5 to 25 days, a prodromal influenza-like phase frequently was accompanied by abdominal symptoms. From 1 to 7 days later, respiratory insufficiency and hemodynamic instability suddenly appeared. In 81%, hemorrhage was evident; in 63%, moderate-to-severe bleeding occurred. The most prominent laboratory abnormalities were hemoconcentration, leukocytosis, thrombocytopenia, altered partial thromboplastin time (PTT), creatine kinase, transaminases, and hyponatremia. Creatinine elevation was common, with clinical importance in two patients. All patients had severe hypoxemia and pulmonary edema. Fifteen patients received supportive treatment, and 5 patients were treated with corticosteroids. The mortality rate was 43.8%. CONCLUSIONS: Bad prognostic factors appeared to be severe hypotension, lower PaO(2)/fraction of inspired oxygen values, prolonged PTT, hemorrhage, greater volume load, and profuse bronchorrhea. The effects of treatment with corticosteroids could not be determined. Hemorrhage and renal involvement were common in our patients, features not often described in the North American literature of Sin Nombre virus HPS.     

郴州地区HCV基因型与病毒载量的相关性分析

目的了解本地区丙型肝炎的流行特征和基因型分布,并分析HCV基因1型与非基因1型病毒载量的关系。方法选择来自郴州地区的60例HCV RNA阳性的初治丙型肝炎患者,进行HCV RNA病毒载量及HCV基因分型检测,依据基因检测结果分为基因1型和非基因1型两组,并对两组进行病毒载量的比较。计量资料满足正态分布采用t检验,不满足正态采用秩和检验。结果本地区HCV基因型有1b、3b、6a、3a、2a、2a＋3a、5a型。其中,1b型25例,占41．6％,其次为3b、6a型各11例（18．3％）,3a型6例（10％）,2a型4例（6．6％）,2a＋3a型2例（3．3％）,5a型1例（1．7％）;HCV基因1型患者中,HCV RNA载量≤100IU／ml者1例、10^4～10^5IU／ml者4例、10^5～10^6IU／ml者10例、10^6～10^7IU／ml者10例;非基因1型患者中,HCV RNA载量≤10^4IU／ml者1例、10^4～10^5IU／ml者6例、10^5～10^6IU／ml者18例、10^6～10^7IU／ml者8例、HCVRNA载量≥100IU／ml者2例。两组病毒载量进行比较,差异无统计学意义（Z=-0．302,P=0．763．）。结论郴州地区HCV基因型以1b型为主,其次为3b和6a型,同时还存在3a型、2a型、5a型,以及2a／3a混合型。HCV基因1型与非基因1型病毒载量高低无区别。     

Noonan syndrome: relationships between genotype, growth, and growth factors

CONTEXT: Half of the patients with Noonan syndrome (NS) carry mutation of the PTPN11 gene, which plays a role in many hormonal signaling pathways. The mechanism of stunted growth in NS is not clear. OBJECTIVE: The objective of the study was to compare growth and hormonal growth factors before and during recombinant human GH therapy in patients with and without PTPN11 mutations (M+ and M-). SETTING, DESIGN, AND PATIENTS: This was a prospective multicenter study in 35 NS patients with growth retardation. Auxological data and growth before and during 2 yr of GH therapy are shown. GH, IGF-I, IGF binding protein (IGFBP)-3, and acid-labile subunit (ALS) levels were evaluated before and during therapy. RESULTS: Molecular investigation of the PTPN11 coding sequence revealed 12 different heterozygous missense mutations in 20 of 35 (57%). Birth length was reduced [mean -1.2 sd score (SDS); six m+ and two m- were < -2 SDS] but not birth weight. M+ vs. M- patients were shorter at 6 yr (P = 0.04). In the prepubertal group (n = 25), GH therapy resulted in a catch-up height SDS, which was lower after 2 yr in M+ vs. M- patients (P < 0.03). The mean peak GH level (n = 35) was 15.4 +/- 6.5 ng/ml. Mean blood IGF-I concentration in 19 patients (11 m+, eight m-) was low (especially in M+) for age, sex, and puberty (-1.6 +/- 1.0 SDS) and was normalized after 1 yr of GH therapy (P < 0.001), without difference in M+ vs. M- patients. ALS levels (n = 10) were also very low. By contrast, the mean basal IGFBP-3 value (n = 19) was normal. CONCLUSIONS: In NS patients with short stature, some neonates have birth length less than -2 SDS. Growth of M+ is reduced and responds less efficiently to GH than M- patients. The association of low IGF-I and ALS with normal IGFBP-3 levels could explain growth impairment of M+ children and could suggest a GH resistance by a late postreceptor signaling defect.     

Hantavirus pulmonary syndrome (HPS) in Guariba, SP, Brazil. Report of 2 cases.

Human infections caused by a hantavirus were reported in different regions of the State of S?o Paulo (SP), Brazil during the first six months of 1998. Two cases of fatal pulmonary syndrome occurred in May of 1998 in the City of Guariba, located in the Northeastern Region of SP. Both patients worked in a corn storage barn infested by rodents. These patients, after 2 or 3 days of non-specific febrile illness, developed a severe interstitial pneumonia spreading widely in both lungs, causing respiratory failure and death. At autopsy both patients showed lung interstitial edema with immunoblast-like mononuclear cell infiltrates, consistent with a viral etiology. Hantavirus infection was diagnosed by ELISA in both cases and by RT-PCR in one of the patients. Aspects of the clinical presentation, physiopathology and differential diagnosis of Hantavirus Pulmonary Syndrome are discussed.