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During 2020-2023, we sequenced Bayou virus from 2 patients in Louisiana, USA, with hantavirus cardiopulmonary syndrome. Direct virus sequencing demonstrated an inferred evolutionary relationship to previous cases. Our findings demonstrate that separate virus spillovers cause isolated cases and probable wide distribution of Bayou hantavirus in rodents across Louisiana.

To explore hantavirus infection patterns in Latin America, we conducted molecular and serologic hantavirus investigations among 3,400 febrile patients from Peru during 2020-2021. Reverse transcription PCR indicated that a patient from Loreto, in the Peruvian Amazon, was positive for Rio Mamore hantavirus (serum, 3.8 × 10 3 copies/mL). High genomic sequence identity of 87.0%-94.8% and phylogenetic common ancestry with a rodent-associated Rio Mamore hantavirus from Loreto in 1996 indicated endemicity. In 832 samples from Loreto, hantavirus incidence based on IgM ELISA of pooled Sin Nombre (SNV) and Andes virus (ANDV) nucleoproteins and immunofluorescence assay-based end-point titration using SNV/ANDV/Hantaan/Puumala/Saarema/Dobrava/Seoul hantaviruses was 0.5%. Across 3 ecologically distinct departments in Peru, SNV/ANDV IgG ELISA/IFA-based reactivity was 1.7%, suggesting circulation of antigenically distinct New World hantaviruses. Testing for arboviruses, nonendemic pathogens, and antigen-free ELISA corroborated nonspecific reactivity in 2 IgG and several IgM ELISA-positive serum samples. Hantavirus diagnostics and surveillance should be strengthened in Peru ad across Latin America.

Few cases of hantavirus pulmonary syndrome have been reported in northeastern Argentina. However, neighboring areas show a higher incidence, suggesting underreporting. We evaluated the presence of antibodies against orthohantavirus in small rodents throughout Misiones province. Infected Akodon affinis montensis and Oligoryzomys nigripes native rodents were found in protected areas of Misiones.

We report 5 human cases of hantavirus pulmonary syndrome found during surveillance in French Guiana in 2008-2016; of the 5 patients, 4 died. This pathogen should continue to be monitored in humans and rodents in effort to reduce the occurrence of these lethal infections in humans stemming from ecosystem disturbances.

We report a PCR survey of hantavirus infection in an extensive field vole (Microtus agrestis) population present in the Kielder Forest, northern England. A Tatenale virus-like lineage was frequently detected (≈17% prevalence) in liver tissue. Lineages genetically similar to Tatenale virus are likely to be endemic in northern England.

We report the recent epidemiology and estimated seroprevalence of human hantavirus infections in the Netherlands. Sixty-two cases were reported during December 2008-December 2013. The estimated seroprevalence in the screened municipalities in 2006-2007 was 1.7% (95% CI 1.3%-2.3%). Findings suggest that hantavirus infections are underdiagnosed in the Netherlands.

Andes hantavirus (ANDV) causes hantavirus cardiopulmonary syndrome in Chile and is the only hantavirus for which person-to-person transmission has been proven. We describe an outbreak of 5 human cases of ANDV infection in which symptoms developed in 2 household contacts and 2 health care workers after exposure to the index case-patient. Results of an epidemiologic investigation and sequence analysis of the virus isolates support person-to-person transmission of ANDV for the 4 secondary case-patients, including nosocomial transmission for the 2 health care workers. Health care personnel who have direct contact with ANDV case-patients or their body fluids should take precautions to prevent transmission of the virus. In addition, because the incubation period of ANDV after environmental exposure is longer than that for person-to-person exposure, all persons exposed to a confirmed ANDV case-patient or with possible environmental exposure to the virus should be monitored for 42 days for clinical symptoms.

In summer 2012, an outbreak of hantavirus infections occurred among overnight visitors to Yosemite National Park in California, USA. An investigation encompassing clinical, epidemiologic, laboratory, and environmental factors identified 10 cases among residents of 3 states. Eight case-patients experienced hantavirus pulmonary syndrome, of whom 5 required intensive care with ventilatory support and 3 died. Staying overnight in a signature tent cabin (9 case-patients) was significantly associated with becoming infected with hantavirus (p<0.001). Rodent nests and tunnels were observed in the foam insulation of the cabin walls. Rodent trapping in the implicated area resulted in high trap success rate (51%), and antibodies reactive to Sin Nombre virus were detected in 10 (14%) of 73 captured deer mice. All signature tent cabins were closed and subsequently dismantled. Continuous public awareness and rodent control and exclusion are key measures in minimizing the risk for hantavirus infection in areas inhabited by deer mice.

We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

In 2009, human Dobrava-Belgrade virus (DOBV) infections were reported on the Black Sea coast of Turkey. Serologic and molecular studies of potential rodent reservoirs demonstrated DOBV infections in Apodemus flavicollis and A. uralensis mice. Phylogenetic analysis of DOBV strains showed their similarity to A. flavicollis mice-borne DOBV in Greece, Slovenia, and Slovakia.

In the past 20 years of surveillance for hantavirus in humans in the United States, 624 cases of hantavirus pulmonary syndrome (HPS) have been reported, 96% of which occurred in states west of the Mississippi River. Most hantavirus infections are caused by Sin Nombre virus, but cases of HPS caused by Bayou, Black Creek Canal, Monongahela, and New York viruses have been reported, and cases of domestically acquired hemorrhagic fever and renal syndrome caused by Seoul virus have also occurred. Rarely, hantavirus infections result in mild illness that does not progress to HPS. Continued testing and surveillance of clinical cases in humans will improve our understanding of the etiologic agents involved and the spectrum of diseases.

We report molecular evidence of Tula hantavirus as an etiologic agent of pulmonary-renal syndrome in an immunocompromised patient. Acute hantavirus infection was confirmed by using serologic and molecular methods. Sequencing revealed Tula virus genome RNA in the patient's blood. This case shows that Tula virus can cause serious disease in humans.

We investigated synanthropic small mammals in the Ethiopian Highlands as potential reservoirs for human pathogens and found that 2 rodent species, the Ethiopian white-footed mouse and Awash multimammate mouse, are carriers of novel Mobala virus strains. The white-footed mouse also carries a novel hantavirus, the second Murinae-associated hantavirus found in Africa.

We identified Dobrava-Belgrade virus infection in Turkey (from a strain related to hantavirus strains from nearby countries) in a patient who had severe symptoms leading to panhypopituitarism, but no known risk for hantavirus. Our findings emphasize the need for increased awareness of hantaviruses in the region and assessment of symptomatic persons without known risk factors for infection.

We associated Laguna Negra virus with hantavirus pulmonary syndrome in Mato Grosso State, Brazil, and a previously unidentified potential host, the Calomys callidus rodent. Genetic testing revealed homologous sequencing in specimens from 20 humans and 8 mice. Further epidemiologic studies may lead to control of HPS in Mato Grosso State.

To better describe the genetic diversity of hantaviruses associated with human illness in South America, we screened blood samples from febrile patients in Chapare Province in central Bolivia during 2008-2009 for recent hantavirus infection. Hantavirus RNA was detected in 3 patients, including 1 who died. Partial RNA sequences of small and medium segments from the 3 patients were most closely related to Andes virus lineages but distinct (<90% nt identity) from reported strains. A survey for IgG against hantaviruses among residents of Chapare Province indicated that 12.2% of the population had past exposure to >1 hantaviruses; the highest prevalence was among agricultural workers. Because of the high level of human exposure to hantavirus strains and the severity of resulting disease, additional studies are warranted to determine the reservoirs, ecologic range, and public health effect of this novel strain of hantavirus.

To confirm circulation of Anajatuba virus in Maranhao, Brazil, we conducted a serologic survey (immunoglobulin G ELISA) and phylogenetic studies (nucleocapsid gene sequences) of hantaviruses from wild rodents and persons with hantavirus pulmonary syndrome. This virus is transmitted by Oligoryzomys fornesi rodents and is responsible for hantavirus pulmonary syndrome in this region.

To explore geographic and host-taxonomic patterns of hantaviruses in Paraguay, we established sampling sites in the Mbaracayu Biosphere Reserve. We detected Jabora virus and Itapua37/Juquitiba-related virus in locations approximately 20 m apart in different years, which suggested sympatry of 2 distinct hantaviruses.

We present the molecular identification of Apodemus agrarius (striped field mouse) as reservoir host of the Dobrava-Belgrade virus (DOBV) lineage DOBV-Aa in 3 federal states of Germany. Phylogenetic analyses provided evidence for multiple spillover of DOBV-Aa to A. flavicollis, a crucial prerequisite for host switch and genetic reassortment.

Hantavirus pulmonary syndrome (HPS) is an increasing health problem in Brazil because of encroachment of sprawling urban, agricultural, and cattle-raising areas into habitats of subfamily Sigmodontinae rodents, which serve as hantavirus reservoirs. From 1993 through June 2007, a total of 884 cases of HPS were reported in Brazil (case-fatality rate 39%). To better understand this emerging disease, we collected 89 human serum samples and 68 rodent lung samples containing antibodies to hantavirus from a 2,500-km-wide area in Brazil. RNA was isolated from human samples and rodent tissues and subjected to reverse transcription-PCR. Partial sequences of nucleocapsid protein and glycoprotein genes from 22 human and 16 rodent sources indicated only Araraquara virus and Juquitiba virus lineages. The case-fatality rate of HPS was higher in the area with Araraquara virus. This virus, which may be the most virulent hantavirus in Brazil, was associated with areas that have had greater anthropogenic changes.

Serologic and genetic analyses indicate that a Juquitiba-like hantavirus circulates in Maldonado, Uruguay. This virus is carried by 2 rodent species, Oligoryzomys nigripes and Oxymycterus nasutus. The same hantavirus in 2 nonrelated species can be explained by a spillover infection or a host-switching event.

Dobrava-Belgrade virus (DOBV) is a European hantavirus that causes hemorrhagic fever with renal syndrome (HFRS); case-fatality rates in Balkan countries are as high as 12%. To determine causative agents, we examined 126 cases of DOBV-associated HFRS in central and southern European Russia. In central Russia (Lipetsk, Voronezh, Orel regions), outbreaks were caused by a DOBV variant (DOBV-Aa) carried by Apodemus agrarius. In southern Russia (Sochi district), where HFRS is endemic, HFRS cases were caused by a new DOBV variant (DOBV-Ap), found in A. ponticus, a novel hantavirus natural host. Both viruses, DOBV-Aa/Lipetsk and DOBV-Ap/Sochi, were isolated through Vero E6 cells, genetically characterized, and used for serotyping of the HFRS patients' serum. The clinical severity of HFRS caused by DOBV-Aa resembles that of HFRS caused by Puumala virus (mild to moderate); clinical severity of disease caused by DOBV-Ap infections is more often moderate to severe.

Phylogenetic analyses, based on partial medium- and large-segment sequences, support an ancient evolutionary origin of a genetically distinct hantavirus detected by reverse transcription-PCR in tissues of northern short-tailed shrews (Blarina brevicauda) captured in Minnesota in August 1998. To our knowledge, this is the first evidence of hantaviruses harbored by shrews in the Americas.

Thottapalayam virus (TPMV) has been placed in the genus Hantavirus of the family Bunyaviridae by virtue of its morphologic features and overall genetic similarities to well-characterized rodentborne hantaviruses. This virus has been isolated from the Asian house shrew (Suncus murinus); however, whether TPMV is naturally harbored by an insectivore host or represents spillover from a rodent reservoir host is unknown. Our analysis of published and unpublished data on the experimental host range, genetics, and molecular phylogeny of TPMV supports coevolution of TPMV with its nonrodent reservoir host. Future studies on the epizootiology of TPMV and investigations of new shrewborne hantaviruses will provide additional insights into the evolutionary origin of hantaviruses in their rodent and insectivore reservoir hosts. Such investigations may also provide clues about determinants of hantavirus pathogenicity and virulence.

Hantaviruses are rodent-borne, emerging viruses that cause life-threatening human diseases in Eurasia and the Americas. We detected hantavirus genome sequences in an African wood mouse (Hylomyscus simus) captured in Sangassou, Guinea. Sequence and phylogenetic analyses of the genetic material demonstrate a novel hantavirus species, which we propose to name "Sangassou virus."

In an epizootiologic survey of 122 rodents captured in Vladivostok, Russia, antibodies positive for hantavirus were found in Apodemus peninsulae (4/70), A. agrarius (1/39), and Clethrionomys rufocanus (1/8). The hantavirus sequences identified in two seropositive A. peninsulae and two patients with hemorrhagic fever with renal syndrome (HFRS) from the Primorye region of Far East Russia were designated as Solovey and Primorye, respectively. The nucleotide sequences of the Solovey, Primorye, and Amur (obtained through GenBank) sequences were closely related (>92% identity). Solovey and Primorye sequences shared 84% nucleotide identity with the prototype Hantaan 76-118. Phylogenetic analysis also indicated a close relationship between Solovey, Primorye, Amur, and other viruses identified in Russia, China, and Korea. Our findings suggest that the Korean field mouse (A. peninsulae) is the reservoir for a hantavirus that causes HFRS over a vast area of east Asia, including Far East Russia.

The first two recognized cases of rapidly fatal hantavirus pulmonary syndrome in Pennsylvania occurred within an 8-month period in 1997. Illness in the two patients was confirmed by immunohistochemical techniques on autopsy material. Reverse transcription-polymerase chain reaction analysis of tissue from one patient and environmentally associated Peromyscus leucopus (white-footed mouse) identified the Monongahela virus variant. Physicians should be vigilant for such Monongahela virus-associated cases in the eastern United States and Canada, particularly in the Appalachian region.

Five species of sigmodontine rodents have been identified in Argentina as the putative reservoirs of six circulating hantavirus genotypes. Two species of Oligoryzomys are associated with the genotypes causing hantavirus pulmonary syndrome, Oligoryzomys flavescens for Lechiguanas and O. longicaudatus for Andes and Oran genotypes. Reports of human cases of hantavirus pulmonary syndrome prompted rodent trapping (2,299 rodents of 32 species during 27,780 trap nights) at potential exposure sites in three disease-endemic areas. Antibody reactive to Sin Nombre virus was found in six species, including the known hantavirus reservoir species. Risk for peridomestic exposure to host species that carry recognized human pathogens was high in all three major disease-endemic areas.

We determined the prevalence of Sin Nombre virus antibodies in small mammals in southeastern Arizona. Of 1,234 rodents (from 13 species) captured each month from May through December 1995, only mice in the genus Peromyscus were seropositive. Antibody prevalence was 14.3% in 21 white-footed mice (P. leucopus), 13.3% in 98 brush mice (P. boylii), 0.8% in 118 cactus mice (P. eremicus), and 0% in 2 deer mice (P. maniculatus). Most antibody-positive mice were adult male Peromyscus captured close to one another early in the study. Population dynamics of brush mice suggest a correlation between population size and hantavirus-antibody prevalence.

A mark-recapture longitudinal study of immunoglobulin G (IgG) antibody to Sin Nombre virus (SNV) in rodent populations in western Colorado (1994-results summarized to October 1997) indicates the presence of SNV or a closely related hantavirus at two sites. Most rodents (principally deer mice, Peromyscus maniculatus, and pinyon mice, P. truei) did not persist on the trapping webs much beyond 1 month after first capture. Some persisted more than 1 year, which suggests that even a few infected deer mice could serve as transseasonal reservoirs and mechanisms for over-winter virus maintenance. A positive association between wounds and SNV antibody in adult animals at both sites suggests that when infected rodents in certain populations fight with uninfected rodents, virus amplification occurs. At both sites, male rodents comprised a larger percentage of seropositive mice than recaptured mice, which suggests that male mice contribute more to the SNV epizootic cycle than female mice. In deer mice, IgG antibody prevalence fluctuations were positively associated with population fluctuations. The rates of seroconversion, which in deer mice at both sites occurred mostly during late summer and midwinter, were higher than the seroprevalence, which suggests that the longer deer mice live, the greater the probability they will become infected with SNV.

In Europe, hantavirus disease can hardly be called an emerging zoonosis; it is rather a rediscovered disease. Since 1934 an epidemic condition with primarily renal involvement has been described in Sweden. Nowadays, hundreds to thousands of cases per year are registered in Fennoscandia, fluctuating with the numbers of the specific Arvicoline-rodent reservoir, the red bank vole, which carries the main European serotype, Puumala (PUU). In the early 1980s, the rat-transmitted serotype, Seoul (SEO), caused laboratory outbreaks throughout Europe, and recent reports also suggest sporadic, wild rat-spread hantavirus disease. In the Balkans, at least four serotypes are present simultaneously: PUU, SEO, the "Korean" prototype Hantaan (HTN) or HTN-like types, and Dobrava, the latter causing a mortality rate of up to 20%. Moreover, recent genotyping studies have disclosed several PUU-like genotypes spread in Europe and/or Russia by other genera of the Arvicoline-rodent subfamily: Tula, Tobetsu, Khabarovsk, and Topografov. Their importance for human pathogenicity is still unclear, but serologic cross-reactions with PUU antigen might have caused their misdiagnosis as PUU-infections in the past.

Hantaviruses are carried by numerous rodent species throughout the world. In 1993, a previously unknown group of hantaviruses emerged in the United States as the cause of an acute respiratory disease now termed hantavirus pulmonary syndrome (HPS). Before than, hantaviruses were known as the etiologic agents of hemorrhagic fever with renal syndrome, a disease that occurs almost entirely in the Eastern Hemisphere. Since the discovery of the HPS-causing hantaviruses, intense investigation of the ecology and epidemiology of hantaviruses has led to the discovery of many other novel hantaviruses. Their ubiquity and potential for causing severe human illness make these viruses an important public health concern; we reviewed the distribution, ecology, disease potential, and genetic spectrum.