Orthobunyavirus antibodies among humans in selected parts of the Rift Valley and northeastern Kenya.

Ngari, Bunyamwera, Ilesha, and Germiston viruses are among the mosquito-borne human pathogens in the Orthobunyavirus genus, family Bunyaviridae, associated with febrile illness. Although the four orthobunyaviruses have been isolated from mosquito and/or tick vectors sampled from different geographic regions in Kenya, little is known of human exposure in such areas. We conducted a serologic investigation to determine whether orthobunyaviruses commonly infect humans in Kenya. Orthobunyavirus-specific antibodies were detected by plaque reduction neutralization tests in 89 (25.8%) of 345 persons tested. Multivariable analysis revealed age and residence in northeastern Kenya as risk factors. Implementation of acute febrile illness surveillance in northeastern Kenya will help to detect such infections.

Hantavirus: emergency department response to a disaster from an emerging pathogen.

In May 1993, the appearance of critically ill patients with unexplained respiratory distress was noted in the Four Corners area formed by New Mexico, Arizona, and Colorado. This epidemic was ultimately linked to a hantavirus, an emerging pathogen. The impact on the emergency department of a new infectious disease with respiratory distress is described. A model is proposed to manage infectious disease disasters. Emerging infections that are important to emergency physicians are discussed. Recommendations that focus on disaster management and prevention of the spread of an unknown pathogen are developed.

Isolation of the causative agent of hantavirus pulmonary syndrome.

Investigation of a recent outbreak of acute respiratory illness in the southwestern United States resulted in the recognition of a new disease, hantavirus pulmonary syndrome (HPS) with high mortality. Different animals and cell lines were used in attempts to isolate the causative agent. A previously unknown hantavirus was passaged in laboratory-bred deer mice, recovered from lung tissues of a deer mouse, Peromyscus maniculatus, and propagated in the E6 clone of Vero cells. Virus antigen was readily detected in the infected cells by an indirect immunofluorescence assay, using convalescent-phase sera from HPS patients. By electron microscopy, the virus was shown to have the typical morphologic features of members of the genus Hantavirus, family Bunyaviridae. Virus sequences corresponded to those previously detected by a nested reverse transcriptase-polymerase chain reaction assay of hantavirus-infected specimens from rodents and humans. This newly recognized virus, the etiologic agent of HPS, has been tentatively named Muerto Canyon virus.

Genome structure and variability of a virus causing hantavirus pulmonary syndrome.

A previously unrecognized hantavirus (family Bunyaviridae) has recently been detected and shown to be associated with a severe respiratory illness with high mortality, termed hantavirus pulmonary syndrome (HPS). This disease has now been identified throughout the western United States. We present nucleotide sequence characterization of the three RNA segments composing the HPS virus genome and address the question of the apparent emergence of this highly lethal virus. No evidence of genetic reassortment with previously recognized hantaviruses was found, each RNA segment being unique and approximately 30% different at the nucleotide level to the segments of the closest relative, Prospect Hill virus. These findings, together with the observed extensive genetic diversity of HPS viruses and examples of geographic clustering of distinct virus genotypes, suggest that HPS and associated virus have likely existed undetected for many years. The virus genome M segment was determined to be 3696 nucleotides in length and encode G1 and G2 proteins, 652 and 488 amino acids in length. The S segment was found to be 2059 nucleotides in length and to encode a nucleocapsid protein, 428 amino acids in length. S segment analysis also revealed an unusually long noncoding region with numerous repeats and evidence for a potential NSS protein encoded in an overlapping frame.

Outbreak of Hantavirus pulmonary syndrome in the southwestern United States. Response of pathologists and other laboratorians.

During late spring and early summer of 1993, national and international media called worldwide attention to a cluster of deaths in the southwestern United States. These patients succumbed to a rapidly progressive severe respiratory distress syndrome. After notification of state and national health agencies in mid-May, a major effort was launched to determine the cause of this often fatal respiratory distress syndrome, to advise the public on safety measures, and to determine the method of spread of this "mystery illness." Within weeks of recognition of the early cases, the Centers for Disease Control and Prevention announced the probable agent, a Hantavirus. This report details the response of pathologists, medical technologists, and other laboratory scientists to this new viral epidemic, with emphasis on activities that occurred within New Mexico.

[Pulmonary syndrome caused by Hantavirus--a new syndrome with high mortality]. / Hantavirus-orsakat pulmonellt syndrom--ny infektionssjukdom med hög dödlighet.

An outbreak of a previously unknown, severe infectious disease with rapidly fatal respiratory distress was reported from Southwestern USA in May 1993. The case fatality rate was about 60 per cent. Using PCR hantavirus RNA could be demonstrated in lungs and other tissues from patients. Mice and others rodents, e g Peromyscus maniculatus, were shown to be a reservoir of the virus. This new virus, designated Four Corner virus, has been further characterised and seems to be closely related to Puumala virus that causes nephropathia epidemica (hemorrhagic fever with renal syndrome) in Scandinavia and Central Europe.

Utilization of autopsy RNA for the synthesis of the nucleocapsid antigen of a newly recognized virus associated with hantavirus pulmonary syndrome.

A newly recognized hantavirus was recently found to be associated with an outbreak of acute respiratory illness in the southwestern United States. The disease, which has become known as hantavirus pulmonary syndrome, has an unusually high mortality (64%). Virus isolation attempts have been unsuccessful thus far, resulting in a lack of homologous antigen for use in diagnostic assays. For this reason, a molecular approach was initiated to produce recombinant homologous antigen. The virus nucleocapsid (N) protein was selected, since N has been shown to be a sensitive antigenic target in other hantavirus systems. The N protein open reading frame of the virus S genome segment was synthesized from frozen autopsy tissue by polymerase chain reaction amplification, followed by cloning and expression in Hela cells (vaccinia-T7 RNA polymerase system) and Escherichia coli. N protein-expressing Hela cells served as excellent antigens for an improved indirect immunofluorescence assay. Use of the E. coli-expressed N protein in an enzyme-linked immunosorbent assay improved the sensitivity and specificity when compared with heterologous antigens used previously. Preliminary analysis also indicates that the higher sensitivity could result in earlier detection of infected persons. These data demonstrate that even in the absence of a virus isolate, the necessary homologous antigen can be produced and can serve to improve the detection and diagnostic capabilities needed to combat this newly recognized fatal respiratory illness in the United States.

Genetic identification of a hantavirus associated with an outbreak of acute respiratory illness.

A mysterious respiratory illness with high mortality was recently reported in the southwestern United States. Serologic studies implicated the hantaviruses, rodent-borne RNA viruses usually associated elsewhere in the world with hemorrhagic fever with renal syndrome. A genetic detection assay amplified hantavirus-specific DNA fragments from RNA extracted from the tissues of patients and deer mice (Peromyscus maniculatus) caught at or near patient residences. Nucleotide sequence analysis revealed the associated virus to be a new hantavirus and provided a direct genetic link between infection in patients and rodents.

Update: hantavirus pulmonary syndrome--United States, 1993.

A unique hantavirus has been identified as the cause of the outbreak of respiratory illness (hantavirus pulmonary syndrome [HPS]) first recognized in the southwestern United States in May 1993. The habitat of the principal rodent reservoir for this virus, Peromyscus maniculatus (deer mouse), extends throughout most of the United States except the Southeast. Through October 21, 1993, HPS has been confirmed in 42 persons reported to CDC from 12 states (Figure 1). This report summarizes major clinical, pathologic, and diagnostic findings in patients with this newly recognized syndrome; addresses the use of the investigational antiviral drug ribavirin; and presents revised screening criteria for national surveillance.