Hantavirus

Hantaviruses are causative agents of some severe human illnesses, including hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). The viruses are maintained by rodent hosts, and humans acquire infection by inhaling virus-contaminated excreta from infected animals. To examine the epidemiology of hantavirus infections in Japan and Far East Russia, we conducted epidemiological surveys in these regions. In Japan, anti-hantavirus antibodies were found in four rodent species, Clethrionomys rufocanus, Rattus norvegicus, R. rattus, and Apodemus speciosus. Although no new HFRS cases have been officially reported over the past 20 years in Japan, one member of the Japan Ground Self-Defense Force did test positive for hantavirus antibody. Repeated surveys in Far East Russia have revealed that two distinct hantavirus types cause severe HFRS in this region. Hantavirus sequences identified from A. peninsulae, fetal HFRS cases in Vladivostok, and Amur virus are highl...

Hantavirus Cardiopulmonary Syndrome (HCPS) is a disease caused by Hantavirus, which is highly virulent for humans. High temperatures and conversion of native vegetation to agriculture , particularly sugarcane cultivation can alter abundance of rodent generalist species that serve as the principal reservoir host for HCPS, but our understanding of the compound effects of land use and climate on HCPS incidence remains limited, particularly in tropical regions. Here we rely on a Bayesian model to fill this research gap and to predict the effects of sugarcane expansion and expected changes in temperature on Hantavirus infection risk in the state of São Paulo, Brazil. The sugarcane expansion scenario was based on historical data between 2000 and 2010 combined with an agro-environment zoning guideline for the sugar and ethanol industry. Future evolution of temperature anomalies was derived using 32 general circulation models from scenarios RCP4.5 and RCP8.5 (Representative greenhouse gases Concentration Pathways adopted by IPCC). Currently, the state of São Paulo has an average Hantavirus risk of 1.3%, with 6% of the 645 municipalities of the state being classified as high risk (HCPS risk ! 5%). Our results indicate that sugarcane expansion alone will increase average HCPS risk to 1.5%, placing 20% more people at HCPS risk. Temperature anomalies alone increase HCPS risk even more (1.6% for RCP4.5 and 1.7%, for RCP8.5), and place 31% and 34% more people at risk. Combined sugarcane and temperature increases led to the same predictions as scenarios that only included temperature. Our results demonstrate that climate change effects are likely to be more severe than those from sugarcane expansion. Forecasting disease is critical for the timely and efficient planning of operational control programs that can address the expected effects of sugarcane expansion and climate change on HCPS infection risk. The predicted spatial location of HCPS infection risks obtained here can be used to prioritize management actions and develop educational campaigns.

Objectives: To determine the clinical and laboratory predictors of fatality among patients with Hantavirus infection. Materials and methods: A retrospective study was conducted on the patients with Hantavirus infection between April 2009 and October 2011 at the Black Sea and the Mediterranean regions in Turkey. Demographic, clinical and laboratory findings of fatal cases and non-fatal cases at the admission were compared. Results: Twenty-two patients with confirmed Hantavirus infection were evaluated. Five patients died (22.7%). The cause of death was massive bleeding. The rate of hemorrhage was significantly higher in the fatal cases than non-fatal cases (p<0.001). Massive gastrointestinal hemorrhage was seen in four of these patients, cerebral hemorrhage in two and both gastrointestinal and pulmonary hemorrhage in one. Disseminated intravascular coagulation (DIC) was present in four of the fatal cases and a remarkable cause of the bleeding (p=0.02). White blood cell count (WBC) (p=0.002), creatine phosphokinase (CPK) (p=0.011), blood-urea-nitrogen (BUN) (p=0.014), C reactive protein (CRP) (p=0.005) and D-dimer levels (p=0.001), prothrombin time (PT) (p=0.023), activated partial thromboplastin time (aPTT) (p=0.001) and international normalized ratio (INR) (p=0.021) were significantly higher, and platelet counts (p=0.038) significantly lower in the fatal cases. Optimum diagnostic cutoff points for specific laboratory parameters which may be predictive of fatality were; WBC=16,000 µL-1, PLT=30000 µL-1, PT=19.7 s, aPTT=36 s, INR=1.2, D-dimer=9.3 µg/mL, CPK=600 U/L, BUN=47 mg/dL and CRP=13.4 mg/dL. Conclusions: Physicians should be aware of the high fatality risk for patients with Hantavirus infection with hemorrhage, elevated WBC, CPK, BUN, CRP, PT, aPTT, INR and D-dimer and reduced platelet counts. J Microbiol Infect Dis 2012; 2(4): 155-159

During 5,230 trapping nights, 672 small mammals were trapped in the areas where most hantavirus pulmonary syndrome (HPS) cases occur in Uruguay. Yellow pygmy rice rats (Oligoryzomys flavescens) were the only rodents that showed evidence of antibodies to hantavirus, with a seroprevalence of 2.6%. The rodents were trapped in all the explored environments, and most of the seropositive rodents were found in habitats frequented by humans. Nucleotide sequences were obtained from four HPS case-patients and four yellow pygmy rice rats of the M genome segment. Sequence comparison and phylogenetic analysis showed that rodent-borne viruses and viruses from three HPS case-patients form a well-supported clade and share a 96.4% identity with the previously characterized Central Plata hantavirus. These results suggest that yellow pygmy rice rat (O. flavescens) may be the host for Central Plata, a hantavirus associated with HPS in the southern area of Uruguay.

Hantaviruses infect humans via inhalation of viral particles in infected rodents&#39; secretions such as saliva, urine and faeces or via direct contact with infected rodents. The rodent species that are known as the carriers of Dobrava (DOBV), Puumala (PUUV), Saaremaa (SAAV), Tula (TULV) and Seoul (SEOV) viruses are found in our country. The presence of specific antibodies against hantaviruses have been demonstrated in rodents collected from Black Sea and Aegean Regions of Turkey in 2004 for the first time. The first hantavirus-related hemorrhagic fever with renal syndrome (HFRS) cases were reported in Black Sea region in 2009. The determination of the hantavirus prevalence in wild life and rodent populations in the field is crucial for the information about hantavirus-related cases and to clarify the state of risk. There is no commercial product optimized for the screening of rodent serum samples in terms of HFRS agents like DOBV and PUUV that are widely seen in Eurasia as well as ...

Wild rodents (n5330) were trapped around the villages of Altındere and
Cos¸andere (Maçka, Trabzon Province), Ayder, Ortan, and Yolkiyi (Çamlıhemşin, Rize Province), and Bozdağ (Ödemiş)¸, İzmir Province) in
northeastern and western Turkey during April 2004. Samples were tested for arenavirus, hantavirus, and cowpox virus (family Poxviridae, genus Orthopoxvirus, CPXV) antibodies by using immunofluorescence assays (IFAs). Antibodies against arenaviruses were found in eight of 330 (2.4%) rodents. Arenavirus-sero-positive animals were found from all study sites. Antibodies to Puumala virus (family Bunyaviridae, genus Hantavirus, PUUV) were detected in four of 65 Microtusvoles tested. Of the PUUV-IFA-positive voles, one Microtus guentheri lydius was caught from Izmir, and one Microtus roberti and two Microtus rossiaemeridionalis were captured near Trabzon. All 264
Apodemus spp. mice tested negative for anti-bodies to Saaremaa virus (family Bunyaviridae, genus Hantavirus, SAAV); the single Dryomys
nitedula tested negative for both PUUV and SAAV antibodies. Only one (0.3%) of the rodents, an Apodemus sylvaticus from Trabzon
area, tested seropositive to CPXV. This is the iirst serologic survey for rodent-borne viruses in their natural hosts in Turkey. Although these
preliminary results support presence of several virus groups with zoonotic potential, additional studies are needed to identify the specific
viruses that are present in these populations.
Key words: Arenaviruses, hantaviruses, poxviruses, rodent-borne viruses, rodents, seroprevalence.

Hantaviruses which are the members of Bunyaviridae, differ from other members of this family since they are transmitted to humans by rodents. More than 200.000 cases of hantavirus infections are reported annually worldwide. Hantaviruses can lead to two different types of infection in humans, namely, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). HFRS is the most common type of hantavirus infection in Europe and Asia and the most common virus types are Dobrava, Puumala, Hantaan and Seoul. A total of 25 hantavirus suspected cases have been reported from the Western Black Sea region of Turkey and 12 of these were confirmed serologically as &quot;Puumala&quot; subtype. Serological tests such as indirect immunofluorescence assay (IFA), are used for diagnosis and typing of the hantaviruses, however, since cross-reactions are common between the subtypes, the results of these tests should be confirmed by other methods. In this report two cases with han...

Hantaviruses, well-known human pathogens, have only recently been identified on the African continent. Tigray virus (TIGV) was found in Ethiopia in 2012 in a Murinae species, Stenocephalemys albipes, but the genetic data obtained at that time were too limited to correctly assess its phylogenetic position within the hantavirus tree. We used high throughput sequencing to determine the complete genome of TIGV, which showed a typical han-tavirus organisation. The large (L), medium (M), and small (S) genome segments were found to be 6532, 3594 and 1908 nucleotides long, respectively, and the 5′ and 3′ termini for all three segments were predicted to form the panhandle-like structure typical for bunyaviruses. Nucleotide-based phylogenetic analyses revealed that all three coding segments cluster in the phylogroup III sensu Guo et al. (2013). However, while TIGV S segment is basal to the Murinae-associated hantaviruses, the M and L segments are basal to the Soricomorpha-associated hantaviruses. TIGV is the first Murinae-borne hantavirus showing this inconsistent segmental clustering in the hantavirus phylogenetic tree. We finally propose non-exclusive scenarios that could explain the original phylogenetic position of TIGV.

Puumala hantavirus (PUUV) is a zoonotic virus that causes nephropathia epidemica (NE) in humans, a mild form of haemorrhagic fever with renal syndrome. An average of 10 000 cases are reported annually in Europe, many of which occur in Fennoscandia. The incidence of NE is connected to the distribution and population density of the the bank vole (Myodes glareolus), the main host of the virus. In Fennoscandia, high incidences of NE occur at 3-4 year intervals due to the characteristic population cycles of this woodland rodent.
This study aimed to improve our understanding of PUUV microevolution by examining genetic features of the virus in several bank vole populations of Finland and Latvia.
Genetic variation in PUUV circulating in a bank vole population at Konnevesi in Central Finland was examined and monitored over five-years throughout a complete bank vole cycle, including two peak-phases in 2005 and 2008 and two population declines in 2006 and 2009 (i.e., viral bottlenecks). Altogether, 1369 bank voles were captured and 26.3% were detected PUUV-infected. Partial sequences of the three viral genome segments (Small, Medium and Large) were inspected from 365 PUUV genomes. Genetic diversity was 6.2% for the S segment, 4.8% for the M segment, and a surprisingly high 10.1% for the L segment. Each genome segment had accumulated mutations as a separate gene pool. The majority of nucleotide substitutions were synonymous and most of the deduced amino acid substitutions were conservative, suggesting a strong stabilizing selection operating at the protein level. Genetic markers found along the genome segments allowed for the recognition of two PUUV genogroups co-circulating in the host population. Even though one of the genogroups presented a higher genetic diversity, no signs of competition were observed between them. Nearly 80% the variants exhibited a transient existence, and frequently occurring variants were integrated by the most abundant segment genotypes suggesting a viral mutational robustness. A substantial portion (19.1%) of genomes appeared to be reassortants, with S and M typically being exchanged. Reassortant variants did not outcompete parental variants and were commonly transient. Reassortment was seasonal, occurring more frequently in autumn when infection risk increases. An imperceptible intra-genogroup reassortment could contribute to the steady state of the viral population, counteracting the effects of Muller’s ratchet.
Co-circulation and interaction of two distinct PUUV lineages (Finnish and North-Scandinavian) was monitored in a bank vole population at Pallasjärvi in Northern Finland. To date, seven genetic lineages have been detected, and they exhibit geographic structure within the host distribution. Here, we present new evidence of two lineages circulating in the same bank vole phylogroup (Ural clade). Genetic diversity within each PUUV lineage was modest (up to 1.7%) and most substitutions were synonymous. However, genetic differences between the two lineages were as high as 18.9%. Phylogenetic analysis revealed that these distinct lineages naturally reassort with a frequency to that genogroups circulating at Konnevesi, i.e., 32%. In contrast to Konnevesi, only M segment was exchanged between PUUV lineages at Pallasjärvi.
Two distinct PUUV lineages were also found to co-circulate in Latvia. One (Russian) has been previously described and the other awaits formal description. The novel Latvian lineage is considerably divergent from other PUUV lineages and several amino acid markers made it easily distinguishable. Phylogenetic analysis suggested an independent evolutionary history for the segments of the Latvian lineage. Similar to Pallasjärvi, both Russian and Latvian lineages were found in a single bank vole phylogroup (Carpathian clade), confirming earlier observations that PUUV lineages are not limited to a single host phylogroup.

In 1993 Sin Nombre virus was recognized as the cause of hantavirus pulmonary syndrome (HPS) and the deer mouse (Peromyscus maniculatus) was identified as the reservoir host. Surveillance by the Centers for Disease Control and Prevention and state health departments includes investigation to determine the likely site(s) and activities that led to infection, an environmental assessment of the home and workplace, and possibly rodent trappings at these sites. As of December 31, 1998, there were 200 confirmed cases from 30 states (43% case-fatality ratio). The national HPS case registry was examined to determine the incubation period of HPS. Review of 11 case-patients with well-defined and isolated exposure to rodents suggests that the incubation period of HPS is 9 to 33 days, with a median of 14-17 days. Case investigations allow a better understanding of the incubation time of HPS and may define high-risk behaviors that can be targeted for intervention.