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presence of viral particles in the salivary gland of calomys musculinus infected with junin virus by a natural route.calomys musculinus, a wild cricetid rodent, is one of the main reservoirs of junin virus. six of these animals were infected by being placed in close contact with animals that had been experimentally infected with the virus. they were sacrificed at 10, 15 and 20 months after contact, and their salivary glands were studied by ultrastructural, immunohistochemical and virological methods. two animals developed chronic viremia and low titers of complement-fixing antibodies. these animals were the on ...1979218895
experimental neuroinvasiveness of wild and laboratory junin virus strains.the neuroinvasiveness of candid 1 and xjcl3 laboratory strains and cbalv4454 and cbafha5069 wild strains of junin virus was studied in albino mice, guinea pigs, and a south american wild rodent, calomys musculinus (cm), of different ages inoculated by a non-neural route. infectivity in brain, blood and organs, as well as lethality, were determined. the results with the 3 hosts indicate that junin virus neuroinvasiveness is virus-strain-dependent, host species- and age-dependent, with the candid ...19921329167
junin virus activity in rodents from endemic and nonendemic loci in central argentina.small mammals were trapped during a 21-month period at 27 farm sites in 15 localities within and beyond the known endemic area for argentine hemorrhagic fever (ahf). prevalence of junin virus (jv) was assessed by antigen-capture enzyme immunoassay (elisa) on samples of body fluids and/or organs from 3, 282 captured rodents. infection in rodent populations was variable (0-3.7%) among localities but, in all cases, was lower than previously reported rates. overall prevalence was 1.4% in the ahf epi ...19911650148
rapid vascular clearance of two strains of junin virus in calomys musculinus: selective macrophage clearance.clearance of junin (jun) virus strains with different virulence for calomys musculinus (cm) was followed using the candid #1 virulent and cbafha 5069 attenuated strains. in addition, virulent virus albino mice (am) were included as control host and venezuelan equine encephalitis (vee-vi) virus as control virus. the virus inoculum (vo) and the blood samples (vt) obtained at different times post-inoculation (p.i.) were titrated on vero cells and the cleared plaque forming-units (pfu) were calculat ...19911681712
[blood parameters variation in calomys musculinus infected with junin virus, strain xjcl3].the aim of this study was to analyze the alterations in homeostasis induced by junin virus during acute and persistent infection of c. musculinus. virus presence in brain, hematological response and glycemia levels were evaluated. newborn c. musculinus inoculated with 4000 dl50 of junin virus, strain xjcl3 by intraperitoneal route developed a typical acute disease, with 50-70% mortality. virus was isolated from brain starting day 6 post-infection (fig. 1) and the peak titer (10(8) dl50/ml) was r ...19901966622
hantavirus infection in laboratory and wild rodents in argentina.serum samples from urban and laboratory rats, laboratory mice and wild and laboratory cricetids in argentina were tested by immunofluorescence and plaque reduction neutralization tests to investigate prevalence of anti-hantavirus antibodies. a total of 102 sera were obtained from laboratory rodents in 4 different animal-rooms, 31 from harbor rats and 30 from wild cricetids in 1985-1987. anti-hantavirus antibodies were detected in 22.5% of rattus norvegicus in 3 of the animal-rooms but harbor rat ...19901981381
vertical transmission of junin virus in experimentally infected adult calomys musculinus.the response to infection with junin virus, wild strain cba an 9446, and the antenatal and postnatal transmission of the pathogen in its natural host, calomys musculinus, were studied. intranasal infection in adult animals (90-120 days) did not produce mortality or illness during the 150-day period of observation. from day 21 to 150 after infection, 50% of the animals showed viral persistence with shedding of virus in both urine and saliva. the remaining half became seropositive, and no infectio ...19902177742
neurovirulence of wild and laboratory junin virus strains in animal hosts.the neurovirulence of candid #1 and xjcl3 laboratory strains and cbalv4454 and cbafha5069 wild strains of junin virus was studied in albino mice, guinea pigs, and a south american wild rodent, calomys musculinus, of different ages inoculated by the intracerebral route. infectivity in brain and organs, lethality, and neuropathological lesions were determined. the laboratory and wild strains showed similar neurovirulence only in 2-day-old mice. the neurovirulence of laboratory strains decreased wi ...19902177781
calomys callidus as a potential junin virus reservoir.the present study investigated whether c. callidus, a species belonging to the calomys genus, is capable of developing experimentally a persistent junin virus (jv) infection. newborn and adult cricetids were inoculated with the attenuated xj-clone 3 strain of jv by intracerebral or mucosal route. the present results indicate that the species is susceptible to jv infection, capable of shedding virus chronically through saliva and developing a persistent infection as shown by the detection of viru ...19892542433
effect of persistent infection with junin virus on growth and reproduction of its natural reservoir, calomys musculinus.the effect of infection with junin virus on growth and reproduction of its natural reservoir, calomys musculinus, was studied. eighty-five c. musculinus were inoculated intranasally at birth with 100 tcid50 of cba an 9446 strain of junin virus and observed for 480 days. no clinical signs of neurologic illness were registered. infected animals showed an increased mortality rate of up to 70% between days 24-40 post-infection. this period of high mortality was preceded by low weight gain during lac ...19872825553
[isolation of junin virus from blood and peripheral lymphocytes of infected calomys musculinus].neonatal calomys musculinus experimental infection with junín virus (jv) xjcl3 strain causes either death or a persistent infection in the major part of surviving animals. jv can be isolated from peritoneal macrophages early during infection, and from brain and salivary glands during the chronic state of disease. it was of interest to investigate the appearance of virus in blood of infected animals. for this purpose, we decided to study the development of viremia in inoculated cricetids. a high ...19852829277
is vertical transmission sufficient to maintain junin virus in nature?the quantitative contribution of vertical transmission to the prevalence rate of junin virus infection in subsequent generations of its natural reservoir, calomys musculinus, was analysed. data on mortality and reproduction of c. musculinus infected at birth with a wild strain of junin virus were used to estimate the infection-dependent relative survival rate (beta = 0.4849) and relative fertility of the infected host (alpha = 0.2088). prevalence rates of infection, obtained by mathematical simu ...19882838581
epidemiology of argentine hemorrhagic fever.present knowledge points to horizontal transmission as the most significant mechanism for junín virus maintenance in the main natural reservoirs, namely calomys musculinus and calomys laucha. the existence of naturally infected akodon azarae, both within and outside the endemic area, as well as the finding that other species, ecologically and phylogenetically related to the main reservoirs, such as akodon molinae and calomys callidus, can experimentally develop persistent infections with virus s ...19882841151
differentiation of junin virus and antigenic variants isolated in vivo by kinetic neutralization assays.the major natural reservoir of junin virus, the aetiological agent of argentine haemorrhagic fever, is the cricetid calomys musculinus. neonatal animals experimentally infected with junin virus (xjcl3 strain) developed typical disease and approximately 80% of them died. most survivors become persistently infected. antigenically variant viruses were isolated from the blood and brain of infected cricetids during the acute and chronic stages of the disease. these variants could be distinguished fro ...19882841418
administration of antithymocyte serum modifies the response of calomys musculinus to junin virus infection.approximately 80% of calomys musculinus inoculated with an attenuated strain of junin virus (jv) developed a lethal encephalitis. antithymocyte serum, a potent suppressor of t-cell-mediated immunity, was studied for its effect on jv pathogenicity. early administration of an anti-c. musculinus thymocyte serum (acts) to neonatal animals significantly diminished clinical disease and death and abrogated brain damage, which is usually associated with viral presence in the brain. late acts administrat ...19863009353
role of calomys musculinus peritoneal macrophages in age-related resistance to junin virus infection.in nature, the cricetid calomys musculinus is the principal host of junin virus, the etiological agent of argentine hemorrhagic fever. in the experimental infection, adult c. musculinus survived whereas newborns died after intraperitoneal inoculation with the xj.cl3 strain of junin virus. the role of peritoneal macrophages in this age-related resistance was studied. junin virus multiplied in cultivated macrophages from either neonatal or adult animals and, therefore, it was not possible to corre ...19863009700
experimental infection of akodon molinae (rodentia, cricetidae) with junín virus.experimental infection with the xj-clone 3 strain of junín virus in laboratory bred akodon molinae, a cricetid rodent inhabiting the borders of endemic argentine hemorrhagic fever areas, was studied. suckling animals inoculated intracerebrally proved sensitive and became chronically infected. sixty percent of the rodents showed neurologic involvement, with mortality reaching 60%. virus was recovered from the brain at 7, 15, 21, 37, and 57 days postinfection (pi). by immunofluorescence (if), vira ...19863009705
antigenic variants of junín virus isolated from infected calomys musculinus. brief report.junín virus establishes a long-term persistent infection in its natural host, calomys musculinus. virus recovered from blood of infected animals from 14 to 61 days p.i. behaved antigenically distinct to parental virus, as shown by cross neutralization assays. the emergence of antigenic viral variants occurs during both the acute and persistent state of infection.19863015087
[effect of cyclophosphamide on the development of infection in calomys musculinus with junin virus]. 19853022105
geographic patterns of allele frequencies in calomys musculinus reservoir-host of junin virus. 19863543610
[response of calomys musculinus to experimental infection with junin virus]. 19826290832
[present status of zoonotic hemorrhagic fevers of south america].since 1958, the geographical distribution of argentine hemorrhagic fever (ahf) has especially extended non only into the province of buenos aires but also towards the provinces of santa fe and cordoba, leading to an estimated population at risk of about 1.2 m inhabitants. recent epidemiological field studies has confirmed the major role of calomys musculinus and c. laucha rodents in both transmission to man and conservation of junin virus in nature. however, the human infection may result essent ...19937819800
calomys musculinus, the natural reservoir of argentine haemorrhagic fever, is a semipermissive host for a mouse-attenuated mutant of junin virus.c167, a mouse-attenuated strain of junin virus derived from the xjc13 strain, also displayed reduced virulence for the south american cricetid calomys musculinus, a natural reservoir of this virus in nature. intracerebral inoculation of c. musculinus with 500 pfu of c167 produced only 25% mortality, whereas the parental xjc13 killed 85% of the animals. the attenuation of c167 for this cricetid was lower than for albino mice. the multiplication of c167 in c. musculinus-derived embryo or kidney fi ...19947839011
prevalence of infection with junin virus in rodent populations in the epidemic area of argentine hemorrhagic fever.we report the results of indirect fluorescent antibody screening for antibody to junin virus in 1,101 sera from small mammals captured on two mark-recapture grids in the epidemic area of argentine hemorrhagic fever. twenty-six of 29 seropositive animals were the cricetid rodent calomys musculinus, for a 30-month prevalence of 7.9% in that species. combining these data with previously published data on antigen detection provided an estimated total prevalence of infection of 10.9% for this, the pr ...19947985747
heterogeneity and stability characteristics of candid 1 attenuated strain of junin virus.fourteen clones of candid 1 strain of junin virus were studied in terms of their attenuation and stability for 9 days-old mice. the cluster analysis of the efficiency of lethal infection, namely the virulence (lethality) indicates (pfu/ld50) of the clones showed that the strain population is heterogeneous. it is constituted by subpopulations with lower and higher virulence as compared to the parent strain. moreover, one or two passages through mice and calomys musculinus, the main junin virus re ...19938105651
in vitro selection of junin virus antigenic variants.the establishment of an experimental persistent infection with junin virus, the aetiological agent of argentine hemorrhagic fever, involves the emergence of antigenic variants in brain and blood of the cricetid calomys musculinus. we demonstrate that antigenic variants can also be isolated in vitro under the selective pressure of polyclonal antibodies and from a long-term infected c. musculinus primary embryo fibroblast culture. the participation of neutralizing antibodies and host cells in the ...19938382041
the role of mononuclear blood cells in experimental junin virus spread to the central nervous system.the neuroinvasiveness of junin virus depends on the viral strain, animal species, and age. the role of infected blood cells in hematogenous junin virus spread to the central nervous system (cns) was studied by determining the growth in pheripheral mononuclear cells and brain tissue of candid 1 and xjcl3 laboratory strains, in calomys musculinus and guinea pigs. the present study demonstrated that junin virus replicates in circulating peripheral lymphocytes and macrophages of 11-day-old guinea pi ...19958825295
genetic diversity of the junin virus in argentina: geographic and temporal patterns.rna was purified from 39 strains of cell-cultured junin virus (jun) from central argentina, which included both human- and rodent-derived isolates (a total of 26 and 13, respectively), as well as from 2 laboratory jun strains, xj cl3 and xj #44. jun-specific primers were used to amplify a 511-nucleotide (nt) fragment of the nucleocapsid protein gene and a 495-nt fragment of the glycoprotein 1 (gp1) gene. genetic diversity among jun strains studied was up to 13% at the nt level and up to 9% at th ...200010873755
evaluation of an enzyme-linked immunosorbent assay for detection of antibodies to junin virus in rodents.junin virus is the etiological agent of argentine hemorrhagic fever, a serious rodent-borne disease. an enzyme-linked immunosorbent assay (elisa) to detect junin virus igg antibodies in rodents was evaluated using sera from 27 calomys musculinus and five calomys laucha, inoculated experimentally with a live attenuated strain of this arenavirus. the test performance was compared against an indirect immunofluorescence assay (ifa). the elisa had a sensitivity and specificity of 100% and a reproduci ...200211906733
gene flow among calomys musculinus (rodentia, muridae) populations in argentina.calomys musculinus is a sigmodontinae rodent inhabiting periodically disturbed habitats in the central eastern plains of argentina. it is the natural reservoir host of junin virus, the etiological agent of argentine hemorrhagic fever (ahf). in order to analyze the levels of gene flow among populations of this species, allozymic variability at 26 loci was studied in 291 individuals from the endemic zone of ahf and localities outside it. all populations showed high levels of polymorphism (he betwe ...200211990761
inheritance of random amplified polymorphic dna (rapd-pcr) markers and their use in population genetic studies of calomys musculinus (rodentia, muridae), the reservoir of argentine hemorrhagic fever.in order to assess the reliability of rapd markers in the estimation of the genetic structure of natural populations of the murid rodent calomys musculinus (reservoir of junin virus, ethiological agent of argentine hemorrhagic fever), we have analyzed the heritability of rapd bands in 10 parents and their offspring (33 individuals). fourteen out of a total of 119 bands obtained were absent in the parental patterns, but consistently amplified in offspring from some families. these bands can be el ...200112035619
restricted gene flow in calomys musculinus (rodentia, muridae), the natural reservoir of junin virus.random amplified polymorphic dna polymerase chain reaction (rapd-pcr) markers were used to evaluate the relative contribution of gene flow as a determinant of the population genetic structure of the wild rodent calomys musculinus (the reservoir of argentine hemorrhagic fever [ahf]) in central argentina. one hundred eighty-seven individuals from 13 populations (9 of them from the endemic zone of ahf and 5 from areas outside it) were analyzed using 78 polymorphic rapd loci. genetic variation withi ...200314691315
[pathology of persistent infection of calomys musculinus with an attenuated strain junin virus]. 198215170951
recent range expansion and low levels of contemporary gene flow in calomys musculinus: its relationship with the emergence and spread of argentine haemorrhagic fever.the geographic distribution of haplotype diversity in the rodent calomys musculinus, sampled from 16 wild populations of argentina, was analysed on two geographical scales. the species is the natural reservoir of the junin virus, the etiological agent of the argentine haemorrhagic fever (ahf). in all, 24 composite haplotypes were recognised in the mtdna d-loop region. haplotypes 1 and 2, internal in the network, were the most frequent and were present in almost all populations. the absence of la ...200415316554
argentine hemorrhagic fever vaccines.argentine hemorrhagic fever (ahf), an acute disease caused by junin virus (junv, arenaviridae), has been an important issue to public health in argentina since the early 1950s. the field rodent calomys musculinus is junv natural reservoir and human disease is a consequence of contact with infected rodents. a steady extention of ahf endemic area is being observed since the first reports of the disease. important achievements have been made in: (a) improvement of methods for the etiological diagno ...201121451263
junin virus infects mouse cells and induces innate immune responses.junín virus is the causative agent for argentine hemorrhagic fever, and its natural host is the new world rodent calomys musculinus. the virus is transmitted to humans by aerosolization, and it is believed that many of the clinical symptoms are caused by cytokines produced by sentinel cells of the immune system. here we used the junín virus vaccine strain candid 1 to determine whether mouse cells could be used to study virus entry and antiviral innate immune responses. we show that candid 1 can ...201121880772
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