Human Infections by Non-Rodent-Associated Hantaviruses in Africa

Divergent Hantavirus in Somali Shrews (Crocidura somalica) in the Semi-Arid North Rift, Kenya

Hantaviruses are zoonotic rodent-borne viruses that are known to infect humans and cause various symptoms of disease, including hemorrhagic fever with renal and cardiopulmonary syndromes. They have a segmented single-stranded, enveloped, negative-sense RNA genome and are widely distributed. This study aimed to investigate the circulation of rodent-borne hantaviruses in peridomestic rodents and shrews in two semi-arid ecologies within the Kenyan Rift Valley. The small mammals were trapped using baited folding Sherman traps set within and around houses, then they were sedated and euthanatized through cervical dislocation before collecting blood and tissue samples (liver, kidney, spleen, and lungs). Tissue samples were screened with pan-hantavirus PCR primers, targeting the large genome segment (L) encoding the RNA-dependent RNA polymerase (RdRp). Eleven of the small mammals captured were shrews (11/489, 2.5%) and 478 (97.5%) were rodents. A cytochrome b gene-based genetic assay for shrew identification confirmed the eleven shrews sampled to be Crocidura somalica. Hantavirus RNA was detected in three (3/11, 27%) shrews from Baringo County. The sequences showed 93-97% nucleotide and 96-99% amino acid identities among each other, as well as 74-76% nucleotide and 79-83% amino acid identities to other shrew-borne hantaviruses, such as Tanganya virus (TNGV). The detected viruses formed a monophyletic clade with shrew-borne hantaviruses from other parts of Africa. To our knowledge, this constitutes the first report published on the circulation of hantaviruses in shrews in Kenya.

[Shrew-borne hantaviruses (Hantaviridae: Orthohantavirus) in the Far East of Russia]

INTRODUCTION

Insectivores are newly recognized hantaviral reservoir worldwide. Four distinct shrew-borne hantaviruses (family Hantaviridae) have been identified in two regions located in southern and northern part of the Russian Far East, two genetic variants of Seewis virus (SWSV), Lena River virus (LENV), Kenkeme virus (KKMV) and Yakeshi virus (YKSV). Here, we describe geographic distribution of shrew-borne hantaviruses in southern part of the Russian Far East: Jewish Autonomous region, Khabarovsk Krai, Primorsky Krai and Sakhalin region.

MATERIALS AND METHODS

Lung samples from shrews of genus Sorex, captured in the four regions of Far Eastern Russia, were examined for hantavirus RNA using reverse transcription polymerase chain reaction (RT-PCR). Phylogenetic analysis of the partial nucleotide sequences of viral genome was conducted using MEGA X software.

RESULTS

New genetic variant of YKSV was identified in new reservoir host, long-clawed shrew (S. ungiuculatus) from Sakhalin Island. Genetic variant of SWSV, ARTV-Sc, has been found to circulate among S. caecutiens on the seacoast of Khabarovsk and Primorsky Krai. KKMV virus and second genetic variant of SWSV, ARTV-St, were found in S. roboratus and S. tundrensis, respectively from Jewish Autonomous region.

CONCLUSION

Sorex-borne hantaviruses were found in all studied regions of Far Eastern Russia. Our results demonstrated co-evolution of SWSV, KKMV, and YKSV viruses throughout the geographic distribution of its hosts.

Occurrence of Rickettsia spp., Hantaviridae, Bartonella spp. and Leptospira spp. in European Moles (Talpa europaea) from the Netherlands

The European mole (Talpa europaea) has a widespread distribution throughout Europe. However, little is known about the presence of zoonotic pathogens in European moles. We therefore tested 180 moles from the middle and the south of the Netherlands by (q)PCR for the presence of multiple (tick-borne) zoonotic pathogens. Spotted fever Rickettsia was found in one (0.6%), Leptospira spp. in three (1.7%), Bartonella spp. in 69 (38.3%) and Hantaviridae in 89 (49.4%) of the 180 moles. Infections with Anaplasma phagocytophilum, Babesia spp., Neoehrlichia mikurensis, Borrelia spp., Spiroplasma spp. and Francisella tularensis were not found. In addition, in a subset of 35 moles no antibodies against Tick-borne encephalitis virus were found. The obtained sequences of Bartonella spp. were closely related to Bartonella spp. sequences from moles in Spain and Hungary. The Hantaviridae were identified as the mole-borne Nova virus, with high sequence similarity to sequences from other European countries, and Bruges virus. Though the zoonotic risk from moles appears limited, our results indicate that these animals do play a role in multiple host-pathogen cycles.

An Overview of Anthropogenic Actions as Drivers for Emerging and Re-Emerging Zoonotic Diseases

Population growth and industrialization have led to a race for greater food and supply productivity. As a result, the occupation and population of forest areas, contact with wildlife and their respective parasites and vectors, the trafficking and consumption of wildlife, the pollution of water sources, and the accumulation of waste occur more frequently. Concurrently, the agricultural and livestock production for human consumption has accelerated, often in a disorderly way, leading to the deforestation of areas that are essential for the planet's climatic and ecological balance. The effects of human actions on other ecosystems such as the marine ecosystem cause equally serious damage, such as the pollution of this habitat, and the reduction of the supply of fish and other animals, causing the coastal population to move to the continent. The sum of these factors leads to an increase in the demands such as housing, basic sanitation, and medical assistance, making these populations underserved and vulnerable to the effects of global warming and to the emergence of emerging and re-emerging diseases. In this article, we discuss the anthropic actions such as climate changes, urbanization, deforestation, the trafficking and eating of wild animals, as well as unsustainable agricultural intensification which are drivers for emerging and re-emerging of zoonotic pathogens such as viral (Ebola virus, hantaviruses, Hendravirus, Nipah virus, rabies, and severe acute respiratory syndrome coronavirus disease-2), bacterial (leptospirosis, Lyme borreliosis, and tuberculosis), parasitic (leishmaniasis) and fungal pathogens, which pose a substantial threat to the global community. Finally, we shed light on the urgent demand for the implementation of the One Health concept as a collaborative global approach to raise awareness and educate people about the science behind and the battle against zoonotic pathogens to mitigate the threat for both humans and animals.

Kiwira Virus, a Newfound Hantavirus Discovered in Free-tailed Bats (Molossidae) in East and Central Africa

A novel hantavirus, named Kiwira virus, was molecularly detected in six Angolan free-tailed bats (Mops condylurus, family Molossidae) captured in Tanzania and in one free-tailed bat in the Democratic Republic of Congo. Hantavirus RNA was found in different organs, with the highest loads in the spleen. Nucleotide sequences of large parts of the genomic S and L segments were determined by in-solution hybridisation capture and high throughput sequencing. Phylogenetic analyses placed Kiwira virus into the genus Mobatvirus of the family Hantaviridae, with the bat-infecting Quezon virus and Robina virus as closest relatives. The detection of several infected individuals in two African countries, including animals with systemic hantavirus infection, provides evidence of active replication and a stable circulation of Kiwira virus in M. condylurus bats and points to this species as a natural host. Since the M. condylurus home range covers large regions of Sub-Saharan Africa and the species is known to roost inside and around human dwellings, a potential spillover of the Kiwira virus to humans must be considered.

Identification of novel orthonairoviruses from rodents and shrews in Gabon, Central Africa

In Africa, several emerging zoonotic viruses have been transmitted from small mammals such as rodents and shrews to humans. Although no clinical cases of small mammal-borne viral diseases have been reported in Central Africa, potential zoonotic viruses have been identified in rodents in the region. Therefore, we hypothesized that there may be unrecognized zoonotic viruses circulating in small mammals in Central Africa. Here, we investigated viruses that have been maintained among wild small mammals in Gabon to understand their potential risks to humans. We identified novel orthonairoviruses in 24.6 % of captured rodents and shrews from their kidney total RNA samples. Phylogenetic analysis revealed that the novel viruses, Lamusara virus (LMSV) and Lamgora virus, were closely related to Erve virus, which was previously identified in shrews of the genus Crocidura and has been suspected to cause neuropathogenic diseases in humans. Moreover, we show that the LMSV ovarian tumour domain protease, one of the virulence determination factors of orthonairoviruses, suppressed interferon signalling in human cells, suggesting the possible human pathogenicity of this virus. Taken together, our study demonstrates the presence of novel orthonairoviruses that may pose unrecognized risks of viral disease transmission in Gabon.

[Hantavirus Disease: An Update]

In addition to the well-known clinical early symptoms of hantavirus disease (fever, flank and abdominal pain as well as arthralgia), unusual neurological changes in the context of infection come into focus. The spectrum of neurological symptoms ranges from transient myopia to severe pareses in the context of Guillain-Barré syndrome. In endemic areas, rapid IgM tests for initial assessment are of certain value for differential diagnosis. For therapeutic approaches, only supportive measures up to transient dialysis are available.Molecular genetic analysis and comparison of hantavirus strains of patients and mice from the same geographical area allowed molecular characterization of different outbreak regions. In the meantime, the Puumala viruses of the main outbreak regions in Germany are molecularly well characterized; therefore, the nucleotide sequence of the virus strain detected in a patient makes it possible to draw conclusions about the geographic region where the patient's infection took place.The human pathogenic hantaviruses being prevalent in Germany are the Puumala virus (reservoir: bank vole) and the Dobrava-Belgrade virus, genotype Kurkino (reservoir: striped field mouse). Recently, the molecular detection of further hantaviruses in patients with hantavirus disease was achieved. It can be concluded that also the Seoul virus (reservoir: rats) and the Tulavirus (reservoir: field mouse and related species) occasionally cause hantavirus disease in Germany.New results revealed that human infections can occur not only by the generally accepted route of inhalation of virus-containing aerosols, but also by ingestion of virus-containing materials.For patients with hantavirus infection or disease, it can be assumed that they are not infectious for their environment. A new systematic review could not confirm a human-to-human transmission previously postulated for South American hantaviruses.While all known human pathogenic hantaviruses are transmitted by rodents, other hantaviruses have been recently detected in shrews, moles, and bats. The clinical significance of these new viruses is quite unclear as yet.

Design of a Multi-Epitopes Vaccine against Hantaviruses: An Immunoinformatics and Molecular Modelling Approach

Hantaviruses are negative-sense, enveloped, single-stranded RNA viruses of the family Hantaviridae. In recent years, rodent-borne hantaviruses have emerged as novel zoonotic viruses posing a substantial health issue and socioeconomic burden. In the current research, a reverse vaccinology approach was applied to design a multi-epitope-based vaccine against hantavirus. A set of 340 experimentally reported epitopes were retrieved from Virus Pathogen Database and Analysis Resource (ViPR) and subjected to different analyses such as antigenicity, allergenicity, solubility, IFN gamma, toxicity, and virulent checks. Finally, 10 epitopes which cleared all the filters used were linked with each other through specific GPGPG linkers to construct a multi-antigenic epitope vaccine. The designed vaccine was then joined to three different adjuvants-TLR4-agonist adjuvant, β-defensin, and 50S ribosomal protein L7/L12-using an EAAAK linker to boost up immune-stimulating responses and check the potency of vaccine with each adjuvant. The designed vaccine structures were modelled and subjected to error refinement and disulphide engineering to enhance their stability. To understand the vaccine binding affinity with immune cell receptors, molecular docking was performed between the designed vaccines and TLR4; the docked complex with a low level of global energy was then subjected to molecular dynamics simulations to validate the docking results and dynamic behaviour. The docking binding energy of vaccines with TLR4 is -29.63 kcal/mol (TLR4-agonist), -3.41 kcal/mol (β-defensin), and -11.03 kcal/mol (50S ribosomal protein L7/L12). The systems dynamics revealed all three systems to be highly stable with a root-mean-square deviation (RMSD) value within 3 Å. To test docking predictions and determine dominant interaction energies, binding free energies of vaccine(s)-TLR4 complexes were calculated. The net binding energy of the systems was as follows: TLR4-agonist vaccine with TLR4 (MM-GBSA, -1628.47 kcal/mol and MM-PBSA, -37.75 kcal/mol); 50S ribosomal protein L7/L12 vaccine with TLR4 complex (MM-GBSA, -194.62 kcal/mol and MM-PBSA, -150.67 kcal/mol); β-defensin vaccine with TLR4 complex (MM-GBSA, -9.80 kcal/mol and MM-PBSA, -42.34 kcal/mol). Finally, these findings may aid experimental vaccinologists in developing a very potent hantavirus vaccine.

Prevalence of Orthohantavirus-Reactive Antibodies in Humans and Peri-Domestic Rodents in Northern Ethiopia

In 2012, Tigray orthohantavirus was discovered in Ethiopia, but its seasonal infection in small mammals, and whether it poses a risk to humans was unknown. The occurrence of small mammals, rodents and shrews, in human inhabitations in northern Ethiopia is affected by season and presence of stone bunds. We sampled small mammals in two seasons from low- and high-density stone bund fields adjacent to houses and community-protected semi-natural habitats in Atsbi and Hagere Selam, where Tigray orthohantavirus was first discovered. We collected blood samples from both small mammals and residents using filter paper. The presence of orthohantavirus-reactive antibodies in blood was then analyzed using immunofluorescence assay (human samples) and enzyme linked immunosorbent assays (small mammal samples) with Puumala orthohantavirus as antigen. Viral RNA was detected by RT-PCR using small mammal blood samples. Total orthohantavirus prevalence (antibodies or virus RNA) in the small mammals was 3.37%. The positive animals were three Stenocephalemys albipes rats (prevalence in this species = 13.04%). The low prevalence made it impossible to determine whether season and stone bunds were associated with orthohantavirus prevalence in the small mammals. In humans, we report the first detection of orthohantavirus-reactive IgG antibodies in Ethiopia (seroprevalence = 5.26%). S. albipes lives in close proximity to humans, likely increasing the risk of zoonotic transmission.

A comprehensive screening of the whole proteome of hantavirus and designing a multi-epitope subunit vaccine for cross-protection against hantavirus: Structural vaccinology and immunoinformatics study

Hantaviruses are an emerging zoonotic group of rodent-borne viruses that are having serious implications on global public health due to the increase in outbreaks. Since there is no permanent cure, there is increasing interest in developing a vaccine against the hantavirus. This research aimed to design a robust cross-protective subunit vaccine using a novel immunoinformatics approach. After careful evaluation, the best predicted cytotoxic & helper T-cell and B-cell epitopes from nucleocapsid proteins, glycoproteins, RdRp proteins, and non-structural proteins were considered as potential vaccine candidates. Among the four generated vaccine models with different adjuvant, the model with toll-like receptor-4 (TLR-4) agonist adjuvant was selected because of its high antigenicity, non-allergenicity, and structural quality. The selected model was 654 amino acids long and had a molecular weight of 70.5 kDa, which characterizes the construct as a good antigenic vaccine candidate. The prediction of the conformational B-lymphocyte (CBL) epitope secured its ability to induce the humoral response. Thereafter, disulfide engineering improved vaccine stability. Afterwards, the molecular docking confirmed a good binding affinity of -1292 kj/mol with considered immune receptor TLR-4 and the dynamics simulation showed high stability of the vaccine-receptor complex. Later, the in silico cloning confirmed the better expression of the constructed vaccine protein in E. coli K12. Finally, in in silico immune simulation, significantly high levels of immunoglobulin M (IgM), immunoglobulin G1 (IgG1), cytotoxic & helper T lymphocyte (CTL & HTL) populations, and numerous cytokines such as interferon-γ (IFN-γ), interleukin-2 (IL-2) etc. were found as coherence with actual immune response and also showed faster antigen clearance for repeated exposures. Nonetheless, experimental validation can demonstrate the safety and cross-protective ability of the proposed vaccine to fight against hantavirus infection.

Screening of Forestry Workers in Guadalajara Province (Spain) for Antibodies to Lymphocytic Choriomeningitis Virus, Hantavirus, Rickettsia spp. and Borrelia burgdorferi

Exposure to Lymphocytic choriomeningitis virus (LCMV), hantaviruses, Rickettsia spp. and Borrelia burgdorferi among forestry workers from a province in central Spain (Guadalajara) was examined by serological screening. This is the first such study in this rural area, where people often live and work in proximity to domestic and wild animals. Immunofluorescent analyses of the serum of 100 forestry workers detected IgG antibodies to LCMV in 2% (CL 95% 0.55%-7.0%) of this population, to hantaviruses in 4% (CL 95% 1.6%-8.3%) for the serum amyloid A (SAA) serotype, and 2% (CL 95% 0.55%-7.0%) for the Seoul virus (SEO) serotype (samples also positive for SAA), to Rickettsia in 8% (CL 95% 4.1%-15%) (3% (CL 95% 1.0%-8.5%) for R. typhi and 5% (CL 95% 2.2%-11.2%) for R. slovaca, and to B. burgdorferi in 7% (CL 95% 3.4%-13.8%). The number of people who have been exposed to these organisms is commonly underestimated since most infections are asymptomatic. Greater epidemiological surveillance may therefore be recommended.

Detection of possible spillover of a novel hantavirus in a Natal mastomys from Guinea

To date, only two rodent-borne hantaviruses have been detected in sub-Saharan Africa. Here, we report the detection of a yet unknown hantavirus in a Natal mastomys (Mastomys natalensis) in Méliandou, Guinea, in 2014. The phylogenetic placement of this virus suggests that it might represent a cross-order spillover event from an unknown bat or eulipotyphlan host.

Co-circulation of distinct shrew-borne hantaviruses in the far east of Russia

Insectivores are the new emerging reservoir of hantaviruses. Here, we describe Lena virus (LENV), a novel hantavirus harbored by the Laxmann`s shrew (Sorex caecutiens), which is also the host of Artybash virus (ARTV). Genetic analysis of the complete genomic sequence shows that LENV is in distant relation to ARTV and other Sorex-borne hantaviruses, suggesting that LENV has emerged from cross-species transmission. Additionally, new genetic variant of ARTV, designated as ARTV-St, was identified in tundra shrews (Sorex tundrensis). Finally, distinct insectivore-borne hantaviruses are co-circulating in the same localities of far eastern Russia: LENV, ARTV and Yakeshi in the forest site, while ARTV, ARTV-St, and Kenkeme virus in the meadow field site.

Hantavirus entry: Perspectives and recent advances

Hantaviruses are important zoonotic pathogens of public health importance that are found on all continents except Antarctica and are associated with hemorrhagic fever with renal syndrome (HFRS) in the Old World and hantavirus pulmonary syndrome (HPS) in the New World. Despite the significant disease burden they cause, no FDA-approved specific therapeutics or vaccines exist against these lethal viruses. The lack of available interventions is largely due to an incomplete understanding of hantavirus pathogenesis and molecular mechanisms of virus replication, including cellular entry. Hantavirus Gn/Gc glycoproteins are the only viral proteins exposed on the surface of virions and are necessary and sufficient to orchestrate virus attachment and entry. In vitro studies have implicated integrins (β_1-3), DAF/CD55, and gC1qR as candidate receptors that mediate viral attachment for both Old World and New World hantaviruses. Recently, protocadherin-1 (PCDH1) was demonstrated as a requirement for cellular attachment and entry of New World hantaviruses in vitro and lethal HPS in vivo, making it the first clade-specific host factor to be identified. Attachment of hantavirus particles to cellular receptors induces their internalization by clathrin-mediated, dynamin-independent, or macropinocytosis-like mechanisms, followed by particle trafficking to an endosomal compartment where the fusion of viral and endosomal membranes can occur. Following membrane fusion, which requires cholesterol and acid pH, viral nucleocapsids escape into the cytoplasm and launch genome replication. In this review, we discuss the current mechanistic understanding of hantavirus entry, highlight gaps in our existing knowledge, and suggest areas for future inquiry.

Wild Rats, Laboratory Rats, Pet Rats: Global Seoul Hantavirus Disease Revisited

Recent reports from Europe and the USA described Seoul orthohantavirus infection in pet rats and their breeders/owners, suggesting the potential emergence of a “new” public health problem. Wild and laboratory rat-induced Seoul infections have, however, been described since the early eighties, due to the omnipresence of the rodent reservoir, the brown rat Rattus norvegicus. Recent studies showed no fundamental differences between the pathogenicity and phylogeny of pet rat-induced Seoul orthohantaviruses and their formerly described wild or laboratory rat counterparts. The paucity of diagnosed Seoul virus-induced disease in the West is in striking contrast to the thousands of cases recorded since the 1980s in the Far East, particularly in China. This review of four continents (Asia, Europe, America, and Africa) puts this “emerging infection” into a historical perspective, concluding there is an urgent need for greater medical awareness of Seoul virus-induced human pathology in many parts of the world. Given the mostly milder and atypical clinical presentation, sometimes even with preserved normal kidney function, the importance of simple but repeated urine examination is stressed, since initial but transient proteinuria and microhematuria are rarely lacking.

Đakrông virus, a novel mobatvirus (Hantaviridae) harbored by the Stoliczka's Asian trident bat (Aselliscus stoliczkanus) in Vietnam

The recent discovery of genetically distinct shrew- and mole-borne viruses belonging to the newly defined family Hantaviridae (order Bunyavirales) has spurred an extended search for hantaviruses in RNAlater®-preserved lung tissues from 215 bats (order Chiroptera) representing five families (Hipposideridae, Megadermatidae, Pteropodidae, Rhinolophidae and Vespertilionidae), collected in Vietnam during 2012 to 2014. A newly identified hantavirus, designated Đakrông virus (DKGV), was detected in one of two Stoliczka’s Asian trident bats (Aselliscus stoliczkanus), from Đakrông Nature Reserve in Quảng Trị Province. Using maximum-likelihood and Bayesian methods, phylogenetic trees based on the full-length S, M and L segments showed that DKGV occupied a basal position with other mobatviruses, suggesting that primordial hantaviruses may have been hosted by ancestral bats.

Hantavirus infection in Iranian patients suspected to viral hemorrhagic fever

BACKGROUND

Hantaviruses are a group of emerging pathogens causing hemorrhagic fever with renal syndrome and Hantavirus cardiopulmonary syndrome in human. This study was conducted to investigate Hantavirus infection among Iranian viral hemorrhagic fever suspected patients.

METHODS

From April 2014 to June 2016, 113 cases from 25 different provinces of Iran were analyzed for Hantavirus infection by IgM/IgG ELISA and pan-Hantavirus RT-PCR tests.

RESULTS

Although, viral genome was detected in none of the subjects, IgM and IgG antibodies were detected in 19 and 4 cases, respectively. Differentiation of the anti-Hantavirus antibodies according to virus species by EUROLINE Anti-Hantavirus Profile Kit revealed three Puumala virus IgM positive, one Hantaan virus IgM positive, one Hantaan virus IgM borderline, and two Puumala virus IgG borderline cases.

CONCLUSIONS

This study demonstrates the circulation of Hantaviruses in Iran and calls for further investigations of these life-threatening viruses in the country.

A Novel Hantavirus of the European Mole, Bruges Virus, Is Involved in Frequent Nova Virus Coinfections

Hantaviruses are zoonotic viruses with a complex evolutionary history of virus–host coevolution and cross-species transmission. Although hantaviruses have a broad reservoir host range, virus–host relationships were previously thought to be strict, with a single virus species infecting a single host species. Here, we describe Bruges virus, a novel hantavirus harbored by the European mole (Talpa europaea), which is the well-known host of Nova virus. Phylogenetic analyses of all three genomic segments showed tree topology inconsistencies, suggesting that Bruges virus has emerged from cross-species transmission and ancient reassortment events. A high number of coinfections with Bruges and Nova viruses was detected, but no evidence was found for reassortment between these two hantaviruses. These findings highlight the complexity of hantavirus evolution and the importance of further investigation of hantavirus–reservoir relationships.

Geographical distribution and relative risk of Anjozorobe virus (Thailand orthohantavirus) infection in black rats (Rattus rattus) in Madagascar

Background

Hantavirus infection is a zoonotic disease that is associated with hemorrhagic fever with renal syndrome and cardiopulmonary syndrome in human. Anjozorobe virus, a representative virus of Thailand orthohantavirus (THAIV), was recently discovered from rodents in Anjozorobe-Angavo forest in Madagascar. To assess the circulation of hantavirus at the national level, we carried out a survey of small terrestrial mammals from representative regions of the island and identified environmental factors associated with hantavirus infection. As we were ultimately interested in the potential for human exposure, we focused our research in the peridomestic area.

Methods

Sampling was achieved in twenty districts of Madagascar, with a rural and urban zone in each district. Animals were trapped from a range of habitats and examined for hantavirus RNA by nested RT-PCR. We also investigated the relationship between hantavirus infection probability in rats and possible risk factors by using Generalized Linear Mixed Models.

Results

Overall, 1242 specimens from seven species were collected (Rattus rattus, Rattus norvegicus, Mus musculus, Suncus murinus, Setifer setosus, Tenrec ecaudatus, Hemicentetes semispinosus). Overall, 12.4% (111/897) of Rattus rattus and 1.6% (2/125) of Mus musculus were tested positive for THAIV. Rats captured within houses were less likely to be infected than rats captured in other habitats, whilst rats from sites characterized by high precipitation and relatively low seasonality were more likely to be infected than those from other areas. Older animals were more likely to be infected, with infection probability showing a strong increase with weight.

Conclusions

We report widespread distribution of THAIV in the peridomestic rats of Madagascar, with highest prevalence for those living in humid areas. Although the potential risk of infection to human may also be widespread, our results provide a first indication of specific zone with high transmission. Gathered data will be helpful to implement policies for control and prevention of human risk infection.

The nucleocapsid protein of hantaviruses: much more than a genome-wrapping protein

The nucleocapsid (N) protein of hantaviruses represents an impressive example of a viral multifunctional protein. It encompasses properties as diverse as genome packaging, RNA chaperoning, intracellular protein transport, DNA degradation, intervention in host translation, and restricting host immune responses. These functions all rely on the capability of N to interact with RNA and other viral and cellular proteins. We have compiled data on the N protein of different hantavirus species together with information of the recently published three-dimensional structural data of the protein. The array of diverse functional activities accommodated in the hantaviral N protein goes far beyond to be a static structural protein and makes it an interesting target in the development of antiviral therapeutics.

Hantavirus surveillance and genetic diversity targeting small mammals at Camp Humphreys, a US military installation and new expansion site, Republic of Korea

Small mammal surveillance was conducted (2008-2010, 2012) at Camp (Cp) Humphreys, a US Army installation and new expansion site, Republic of Korea (ROK), to identify hemorrhagic fever with renal syndrome health threats to US military/civilian populations during its ongoing expansion phase. Small mammals were collected using Sherman live capture traps and transported to Korea University where they were euthanized, tissues removed, and assayed to determine hantavirus IgG antibody-positive and hantavirus-positive rates by RT-PCR. A total of 2,364 small mammals were captured over 11,300 trap nights (capture rate = 20.92%). Apodemus agrarius was the most commonly collected (76.65%), with capture rates of 9.62% and 21.70% for Cp Humphreys and the expansion site, respectively. Overall, Hantaan virus (HTNV) IgG antibody-positive (Ab+) rate for A. agrarius was 2.15% (39/1,812). A total of 5.43% (10/184) Crocidura lasiura, 0.79% (2/254) Microtus fortis and 2.44% (1/41) Micromys minutus were serologically IgG Ab+ for hantaviruses. HTNV-specific RT-PCR demonstrated that 28.2% (11/39) HTNV Ab+ A. agrarius harbored the 328-nt sequence of the GC glycoprotein-encoding M segment of HTNV. Among them, the whole genome sequences of 3 HTNV strains were obtained by conventional RT-PCR and Rapid Amplification cDNA Ends PCR. Phylogenetic analyses of the HTNV strains from Cp Humphreys and the expansion site, Pyeongtaek, show a greater diversity of rodent-borne hantaviruses compared to HTNV previously identified in Gyeonggi province of the ROK. Thus, this study provides significant insights for raising HFRS threat awareness, analysis, and risk reduction strategies in southern Gyeonggi province.

Dynamic Circulation and Genetic Exchange of a Shrew-borne Hantavirus, Imjin virus, in the Republic of Korea

Hantaviruses (family Bunyaviridae) are enveloped negative-sense tripartite RNA viruses. The natural hosts of hantaviruses include rodents, shrews, moles, and bats. Imjin virus (MJNV) is a shrew-borne hantavirus identified from the Ussuri white-toothed shrews (Crocidura lasiura) in the Republic of Korea (ROK) and China. We have isolated MJNV and determined its prevalence and molecular diversity in Gyeonggi province, ROK. However, the distribution and phylogeography of MJNV in other regions of ROK remain unknown. A total of 96 C. lasiura were captured from Gangwon and Gyeonggi provinces, ROK, during 2011–2014. Among them, four (4.2%) shrews were positive for anti-MJNV IgG and MJNV RNA was detected from nine (9.4%), respectively. Based on the prevalence of MJNV RNA, the preponderance of infected shrews was male and adult, consistent with the gender- and weight-specific prevalence of hantaviruses in other species. We monitored the viral load of MJNV RNA in various tissues of shrews, which would reflect the dynamic infectious status and circulation of MJNV in nature. Our phylogeographic and genomic characterization of MJNV suggested natural occurrences of recombination and reassortment in the virus population. Thus, these findings provide significant insights into the epidemiology, phylogeographic diversity, and dynamic circulation and evolution of shrew-borne hantaviruses.

Detection of Imjin Virus and Seoul Virus in Crocidurine Shrews in Shandong Province, China

INTRODUCTION

Recently, hantaviruses have been discovered in insectivores in Europe, Asia, Africa, and North America. Imjin virus (MJNV) was first isolated from the lung tissues of Ussuri white-toothed shrew (Crocidura lasiura) from South Korea in 2009. We aim to detect the species and prevalence of insectivore- and rodent-borne hantaviruses in shrews and rodents.

MATERIALS AND METHODS

Shrews and rodents were captured in Jiaonan County of Shandong Province, China, in 2014. RT-PCR was used to amplify viral RNA of Hantavirus species, including insectivore-borne Imjin virus (MJNV), rodent-borne Hantaan virus (HTNV), and Seoul virus (SEOV) from shrews and rodents.

RESULTS AND DISCUSSION

We found that MJNV infected 10.7% (19/178) of Crocidura shrews, but it infected none of rodents (0/475); we also found that 2 of 178 (1.1%) Crocidura shrews were PCR positive to SEOV. This study indicated that the major animal hosts of Imjin virus are shrews, and rodent-borne SEOV can infect shrews.

Hantavirus infection: a global zoonotic challenge

Hantaviruses are comprised of tri-segmented negative sense single-stranded RNA, and are members of the Bunyaviridae family. Hantaviruses are distributed worldwide and are important zoonotic pathogens that can have severe adverse effects in humans. They are naturally maintained in specific reservoir hosts without inducing symptomatic infection. In humans, however, hantaviruses often cause two acute febrile diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS). In this paper, we review the epidemiology and epizootiology of hantavirus infections worldwide.