further experiments on the action of antithymocyte serum in experimental junín virus infection.rabbit anti-mouse thymocyte serum (ats) administrated as late as 7 days after infection suppressed host cell-mediated responsiveness to intracerebrally injected junín virus, thereby diminishing the morbility and mortality of this infection. it did not affect either the humoral antibody response or the virus titer in brain. this findings suggest that: a) in mouse brain cells, junín virus infection is basically non-cytopathic: b) cell-mediated immunity is responsible for morbility and mortality an ...19767942
[infection of alouatta carayá (mono aullador) by junín virus]. 197898811
[infection of new world primates with junin virus. i. alouatta carayá]. 1978105225
ultrastructural and immunohistochemical study of the human kidney in argentine haemorrhagic six lethal cases of argentine haemorrhagic fever (ahf) a disease caused by junin virus, kidney samples were studied by means of immunofluorescent and electron microscopic techniques.--the ultrastructural studies showed that the distal and collecting tubes presented a large number of virus like intracytoplasmic particles. those particles were present in the lumen of the endoplasmic reticulum cisternae and showed two distinct morphological aspects. some of them were of high electron density and ...1975171826
cross-protection between tacaribe complex viruses. presence of neutralizing antibodies against junin virus (argentine hemorrhagic fever) in guinea pigs infected with tacaribe virus.cross-protection between junin virus and five other tacaribe complex viruses and the serological response of guinea pigs inoculated with tacaribe virus are reported here. previous infection with tamiami or pichinde viruses significantly delayed guinea pig deaths. a 58% survival rate was found among animals immunized with three doses of amapari virus, while guinea pigs inoculated with one dose of machupo or tacaribe virus were fully protected against junin virus. neutralization tests performed in ...1975178627
rna composition of junin virus.junin virus grown in bhk-21 cells was labeled with [3h]uridine and highly purified by differential and isopycnic centrifugation. the rnas extracted with phenol and analyzed by polyacrylamide gel electrophoresis were shown to be composed of four large species (33, 28, and 18s) and three small ones (4, 5, and 5.5s). this pattern was similar to ones already reported for other arenaviruses. however, there was a striking difference when the virus labeling was performed in the presence of actinomycin ...1976178925
experimental biology and pathogenesis of junin virus infection in animals and man.a fatal disease resembling argentine haemorrhagic fever of man has been produced in guinea-pigs and mice by inoculation with junin virus. infected guinea-pigs show macroscopic and microscopic haemorrhagic lesions, marked bone marrow changes, decreased leukocytes and platelets in the peripheral blood, and impairment of immunological response. this response permits differentiation between pathogenic (xj) and attenuated (xj cl(3)) strains. guinea-pigs inoculated with the xj cl(3) strain develop an ...1975182401
[drugs inhibitory junin virus replication: glucoseamine, 2-deoxy-d-glucose and bis-benzimidazole]. 1976187895
junín virus infection of guinea pigs: electron microscopic studies of peripheral blood and bone marrow.thin sections of peripheral white blood cells and samples of bone marrow from guinea pigs infected with junín virus were examined by electron microscopy. in peripheral blood cells, 40% of the granulocytes showed cytoplasmic lysis seven days after viral infection. after day 11 up to 80% of these cells showed morphological alterations. however, no intra- or extracellular viral particles were detected in these samples. microscopy of bone marrow preparations revealed that 10% of the cells were alter ...1977191539
a rapid method for detecting junin virus viremia in the guinea pig.a method for detecting junin virus viremia in guinea pigs is described. the method consists of infecting bhk-21 cells with blood samples from infected guinea pigs; 48 h later, junin virus antigens are detected in the cells by indirect immunofluorescence. application of this technique to patients with argentine hemorrhagic fever may lead to the quickest method for the virologic diagnosis of this disease.1977197047
studies of blood coagulation and pathology in experimental infection of guinea pigs with junin virus. 1978207791
[cellular hypersensitivity in the infection of mice by junin virus. iii. experience with cr51 an antitheta serum].several aspects of the appearance and development of delayed hypersensitivity in mice infected with junin virus are described. the results obtained showed that the development of the immunological mechanisms occurs irrespective of age. spleen cells of donor mice inoculated with one i.p. dose of junin virus had a poor cytotoxic activity, as demonstrated by 51cr release and adoptive immunity procedures. spleen cells treated with anti-theta serum and complement did not strikingly affect the develop ...1977208110
replication of dengue and junin viruses in cultured rabbit and human endothelial cells.the flavivirus dengue and the arenavirus junin are both associated with a hemorrhagic shock syndrome in man. we have demonstrated the replication of these viruses in vitro in both rabbit and human endothelial cells by viral titers and immunofluorescent antibody studies. rabbit endothelium established in continuous culture was derived from vena cava, while human cells in primary culture were derived from umbilical veins. in rabbit endothelium, dengue-2 virus passaged through monkey kidney monolay ...1978208980
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
effect of glucosamine on the replication of the arenavirus junín in vero cells.when vero cells infected with junín virus are cultured in the presence of 16 mm glucosamine, no infectious virus is produced and no surface antigens or virions are detected. cytoplasmic viral antigen, however, is synthesized normally.1979218900
temperature sensitivity of the arenavirus junin isolated from persistently infected vero cells.a persistently infected cell culture was established from vero cells surviving primary infection with wild-type junin virus (jvwt). the cells were refractory to superinfection by both junin virus and the related tacaribe virus. replication of virus released from the persistently infected cells (jvpi) was inhibited at 39 degrees. jvpi did not interfere with jvwt at 37 degrees, and it was inactivated at 37, 40, 43, 46 and 50 degrees much more rapidly than was jvwt.1979222707
immunofluorescent anti-junin virus antibodies in argentine hemorrhagic fever.immunofluorescent anti-junin virus antibodies were detected in 15 nonfatal cases of argentine hemorrhagic fever between the 2nd and 3rd week after onset of symptoms. in most cases, antibodies appeared by the day of clinical improvement, or between 2 and 4 days later. it was interesting to note that in 5 of 11 cases studied, the first positive serum sample presented anti-junin virus immunofluorescent antibodies in iga. in 2 of these 5 cases, iga was the only immunoglobulin with antibody activity ...1979227813
[infection of guinea pigs with an attenuated strain of junin virus xjcl3]. 1979232740
[a new biological marker for differentiating tacaribe and junin viruses: rk13 cells]. 1979502831
directions for future research on the pathogenesis of arenaviral infections.the pathogenesis of arenavirus infection is considered separately for the haemorrhagic fever (hf) syndrome and for lymphocytic choriomeningitis (lcm) virus infection of rodents. experimental models of hf have received only limited study, mainly because of the virulence of the causal agents. two useful models (junin virus in guinea-pigs and machupo virus in rhesus monkeys) are now available and an attempt is made to delineate crucial questions for future studies, including the physiology of shock ...19751085229
[callithrix jacchus infection with junin virus. new experimental model in argentinian hemorrhagic fever]. 1978216877
immunoperoxidase tracing of junin virus neural route after footpad determine the pathway adopted by peripherally inoculated junin virus (jv) to reach the cns, rat tissues were serially harvested to trace the sequence of viral progression from right hind footpad to brain. immunoperoxidase (pap) labeling of viral antigen, concomitantly with infectivity assays and histological examination of each selected sample, were carried out. as from the 2nd week post-infection (pi), neurological disease inducing 100% mortality at 1 month was evident. at day 5 pi, viral an ...19921309637
[congenital infection by junin virus in mice]. 1978216874
correlation between cyclophosphamide-induced viral susceptibility and depletion of junin virus-induced suppressor contrast to lymphocytic choriomeningitis virus, another arenavirus, junin virus (jv), the etiologic agent of argentine hemorrhagic fever, when inoculated into suckling mice, induces lethal meningoencephalitis characterized by a delayed-type hypersensitivity (dth)-like immune response. however, the adult balb/c mouse is resistant to infection and no dth reaction can be seen. this different viral sensitivity may be related to the development of an antigen non-specific dth-suppressor cell pathwa ...19921315368
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
[cellular hypersensitivity in the infection of mice by junin virus. i. passive transfer].the data presented confirm previous evidence of delayed hypersensitivity in mice following infection with junin virus. adaptive transfer of sensitized cells from adult mice which had received 5 junin virus injections into preinfected newborn mice shortened their survival by 72 hours. it was clear, however, that the development of the immunological mechanism in adult mice occurred under certain conditions. this evidence was confirmed by the observations that the induction of cell-mediated immunit ...1977208109
argentine hemorrhagic fever. alterations of the complement system and anti-junin-virus humoral response.we investigated immunologic mechanisms and the role of complement in the pathogenesis of argentine hemorrhagic fever, a disease caused by the junin virus, a member of the arenavirus group. total serum complement activity was reduced to 68 per cent of control values in patients with severe or moderate disease (p less than 0.001). c2, c3 and c5 values were also low (12 to 60 per cent) during the early acute period of the disease. however, serum c4 content was increased to 160 per cent of the contr ...1978207985
enhanced resistance against junin virus infection induced by corynebacterium parvum.the effects of intraperitoneal administration of corynebacterium parvum on the course of junin virus infection in mice were investigated. this treatment produced enhanced resistance to the virus infection, evidenced by an increase in both survival times and the proportion of survivors. the protective effect was dependent upon the dose of c. parvum, and 280 mug/g of body weight was found to be the optimal dose. in various experiments, about 80% of the infected animals receiving this dose survived ...1978205508
a longitudinal study of junin virus activity in the rodent reservoir of argentine hemorrhagic fever.we monitored junin virus (jv) activity in rodent populations for 30 months at seven mark-recapture grids located in agricultural fields and adjacent roadsides and fence lines in endemic and nonendemic areas of argentine hemorrhagic fever. blood and oral swabs taken from rodents captured at five-week intervals were analyzed by enzyme-linked immunosorbent assay for jv antigen (ag). calomys laucha and c. musculinus were the most frequently captured rodents, making up 47% and 22% of captures, respec ...19921335214
[experimental infection of the guinea pig with junin virus. clinical picture, dissemination, and elimination of the virus]. 1977197371
aerosol infection of rhesus macaques with junin virus.the purpose of our work was to determine if aerosols of junin virus can infect rhesus macaques and if the disease is the same as that produced by virus inoculated parenterally. the 6 macaques exposed to the virus by aerosol became acutely ill during the 3rd week after exposure, and all died. three died by day 21, while the remainder died after 1 month. junin virus was found primarily in visceral organs of those animals dying before 21 days after infection and in the central nervous system tissue ...19921371270
cytotoxicity and cytoadherence of human and murine polymorphonuclear leukocytes against junin virus infected targets in the absence of anti-viral antibody and complement.human and murine polymorphonuclear leukocytes (pmn) lysed l cells infected with junin virus (jv) in an in vitro system free of antiviral antibody and complement. infected vero cells proved to be resistant to the cytolytic effect. murine pmn showed an increased adherence on jv-infected l cells but did not attach to vero cells. the opposite was observed with human pmn, which did adhere to infected vero cells but not to infected l cells. these results indicate that pmn activity may be an early mech ...19911649909
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
[vero cells persistently infected with junin virus. ii. isolation of the virus]. 1977197369
junin virus structural proteins.polyacrylamide gel electrophoresis of purified junin virus revealed six distinct structural polypeptides, two major and four minor ones. four of these polypeptides appeared to be covalently linked with carbohydrate. the molecular weights of the six proteins, estimated by coelectrophoresis with marker proteins, ranged from 25,000 to 91,000. one of the two major components (number 3) was identified as a nucleoprotein and had a molecular weight of 64,000. it was the most prominent protein and was n ...1977189088
[interference associated with cell cultures chronical by infected with the junin virus].supernatants from vero cells persistently infected with junin virus interfered with cytolitic and lethal activities of standard virus. two vero cell sublines, chronically infected with junin virus named vrj1 and vrj3, were obtained after prolonged cultivation of cells which survived primary infection. vfj1 was maintained over a period of 48 days, by biweekly serial transfers while vrj3, similarly treated, was cultivated for 385 days. one of the characteristics of these cell lines was resistance ...1976188079
[subclinical infection, clinical infection and vaccination with junin virus]. 1976180380
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
[vertical transmission of junin virus in a closed colony of mice]. 1975175236
junin virus-induced non-specific suppressor cells interact with unrelated antigen-specific suppressor cells.junin virus (jv) infection of adult (resistant) balb/c mice induces antigen non-specific delayed-type hypersensitivity (dth) suppressor t cells, termed tsv, bearing the thy-1+, ly-1+2- phenotype. these cells may be related to survival to infection since dth reaction is associated with lethal meningoencephalitis. employing several xenogeneic red blood cell (rbc) sensitization schedules to induce different cell subpopulations, we have attempted to establish the target of jv-induced suppressor cell ...19911718851
a triple staining procedure to evaluate phagocytic role of differentiated determine whether phagocytic activity is affected by a viral infection known to induce astrocyte differentiation, a triple procedure (pap labeling for gfap, pas reaction for added baker's yeast cells and hematoxylin for nuclear staining of the whole monolayer) was applied to junin virus-inoculated cultures, as well as matched controls. the three-step staining simplified yeast cell count for subsequent statistical analysis, which discerned preferential uptake by differentiated rather than imma ...19911724055
ultrastructural and immunohistochemical studies in five cases of argentine hemorrhagic fever.ultrastructural and immunohistochemical studies on tissues from five patients with argentine hemorrhagic fever revealed previously undetected lesions caused by the viral infection. two types of particle were seen in the cells of all organs examined. the particles had some characteristics similar to those described for arenaviruses. however, the virus-like particles were intracellular, had a single membrane, and apparently originated by a process of budding into the endoplasmic reticulum cisterna ...197550390
studies of cell-mediated immunity to junín virus.junín virus is uniformly lethal in newborn mice, but fails to kill adult animals. but there is direct evidence that in older mice the immunological mechanism occurs when certain conditions are fulfilled. the present results showed that in junín virus infection of mice, the development of the immunological mechanism occurs irrespectively of age. the induction of a regular cell-mediated immunity appears to be intimately related to multiple injections of the virus. these results were confirmed by t ...197825006
inapparent infections with junin virus among laboratory workers. 1978632626
[in vitro interferon induction by junin virus; effect of pre-treatment with the inhibitor]. 1977561422
viral haemorrhagic fevers of man.this article reviews the current state of knowledge on the viral haemorrhagic fevers that infect man, namely smallpox, chikungunya fever, dengue fever, rift valley fever, yellow fever, crimean haemorrhagic fever, kyasanur forest disease, omsk haemorrhagic fever, argentinian haemorrhagic fever (junin virus), bolivian haemorrhagic fever (machupo virus), lassa fever, haemorrhagic fever with renal syndrome, and marburg and ebola virus diseases.1978310725
passive immunity against junín virus in mice.passive immunity, naturally acquired from immune mothers or artificially induced by the administration of homologous hyperimmune serum, conferred on suckling mice a high degree of resistance against infection with junín virus. maternal antibodies in the circulating blood of the young were not detectable in the first days after birth, but rised rapidly from the 8th to the 20th day of lactation. by cross-foster nursing experiments it was shown that the greater part of the transmission of passive i ...1975239579
[influence of the culture conditions on the regression of the cytopathogenic effect produced by junín virus in vero cells]. 1978231283
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
argentine hemorrhagic fever: a primate model.experimental junin virus infection of a new world primate, callithrix jacchus, was evaluated. the virus produced anorexia, loss of weight, thrombocytopenia, leukopenia, and hemorrhagic and neurological symptoms and terminated in death. virus was recovered from urine, blood samples and all tissues taken at autopsy. these preliminary observations show that several aspects of the experimental disease in c. jacchus are quite similar to severe natural argentine hemorrhagic fever of man.1979227811
current progress towards vaccines for arenavirus-caused diseases.the arenaviruses are primarily viruses of rodents, but some members of the group cause severe disease (argentine and bolivian haemorrhagic fevers and lassa fever) when transmitted to humans in the specific areas of the world where they are enzootic. current research of relevance to the provision of vaccines against these diseases, which highlights many of the problems encountered generally in the development of vaccines, is reviewed here. although one of the classical approaches to vaccine produ ...19921311492
a mouse attenuated mutant of junin virus with an altered envelope glycoprotein.the xjc13 strain of junin virus (jv) and the mouse-attenuated mutant c167 showed different gp38 peptide mapping after limited proteolysis with ficin and papain; viral infectivity of both viruses also exhibited a different susceptibility to protease treatment. a correlation between envelope glycoprotein alteration and jv virulence in neonatal mice is proposed.19902162164
a refined complement-enhanced neutralization test for detecting antibodies to junin virus.a refined, complement-enhanced, plaque-reduction neutralization test was developed for measuring neutralizing antibodies against junin (argentine hemorrhagic fever) virus. the assay measured neutralizing antibodies after natural as well as vaccine-induced junin virus infections. among vaccinated individuals, titers were 2-4-fold higher than those obtained with conventional assays, without loss of specificity. enhanced sensitivity was achieved by using a standardized complement source (vs human o ...19902170437
[neurological complications of argentinian hemorrhagic fever].the argentine hemorrhagic fever (ahf) is an infectious disease, endemo-epidemical, of viral etiology, produced by the junin virus and limited to the buenos aires province, south of córdoba, east of la pampa, and south of santa fe. it generally assails rural workers at harvest-time, especially during corn-harvest. the incubation period of the disease does not exceed 12 days. a feverish syndrome with asthenia, adynamia, myalgias, migraine, photophobia, epigastralgia etc., appear. the patient has a ...1977211453
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
heterozygosity and gene flow in populations of calomys laucha (rodentia, cricetidae).enzyme polymorphism was studied by means of starch gel electrophoresis on five population samples of calomys laucha collected in different sites and seasons. c. laucha, a cricetid rodent inhabiting preferentially cultivated fields in the central-eastern plains of argentina, is a reservoir-host of junin virus, agent of argentine hemorrhagic fever. results show high levels of genic variability in all the samples (p from 62.50 to 77.27; h from 0.118 to 0.163) and low genetic distance among populati ...19902194995
[heterologous immunization against junin virus. early protection]. 1978211366
early protection to junín virus of guinea pig with an attenuated junín virus strain.inoculation of guinea pigs with attenuated xjo junín virus (jv) strain confers protection against challenge with pathogenic xj-jv strain starting as early as 3 days post infection (p.i.). the protection increased continuously up to 100% by 30 days p.i. neither stimulation of non-specific cell mediated mechanisms by previous bcg sensitization nor circulating interferon (ifn) seemed essential for such protection. the early detection of the virus in guinea pig organs considered the site of primary ...19852413752
splenic dendritic cells and junin virus. 19862425232
candid no. 1 argentine hemorrhagic fever vaccine protects against lethal junin virus challenge in rhesus macaques.the protective efficacy of candid no. 1, a live-attenuated vaccine against argentine hemorrhagic fever (ahf), was evaluated in non-human primates. twenty rhesus macaques immunized 3 months previously with graded doses of candid no. 1 (16-127, 000 pfu), as well as 4 placebo-inoculated controls, were challenged with 4.41 log10 pfu of virulent p3790 strain junin virus. all controls developed severe clinical disease; 3 of 4 died. in contrast, all vaccinated animals were fully protected; none develop ...19921338783
[editorial: ultrastructure of bone marrow and peripheral blood of guinea pigs infected with junin virus]. 19751196119
clinical and epidemiological patterns of argentine haemorrhagic fever.the epidemiology of argentine haemorrhagic fever (ahf) is closely related to cricetine rodents acting as natural hosts of junin virus. the endemo-epidemic area, which has increased 5 times since the disease was first recognized 15-20 years ago, is located in a densely populated region of argentina. it has been shown that the virus of lcm is active in humans and rodents of the ahf endemic area; this demonstrates the simultaneous presence of two arenaviruses pathogenic for man in a given geographi ...19751085212
[experimental junin virus infection of guinea pigs. i. pathological anatomy]. 1976966989
junin virus replication in peripheral blood mononuclear cells of patients with argentine haemorrhagic study the relationship of junin virus (jv) to populations of peripheral blood mononuclear cells (pbmc) from patients with argentine haemorrhagic fever (ahf), blood samples were obtained during the acute period of disease and cultured as total, adherent, and non-adherent cell populations. jv was sequentially sought in these cell populations by using an infectious centre (ic) assay, whereas free jv in the supernatants was evaluated by plaque formation. ic were obtained in cultures of total pbmc ...19901975726
detection of junin virus by the polymerase chain reaction.argentine hemorrhagic fever is an often fatal human disease caused by junin virus, an rna-containing virus and member of the arenavirus family. this virus was detected in vitro by the polymerase chain reaction (pcr) procedure. a pair of junin virus-specific pcr dna oligonucleotide primers and an oligonucleotide probe were designed from a known portion of the viral rna sequence. rna was isolated from junin virus-infected monkey kidney cells and used to produce complementary dna (cdna) by reverse ...19921331150
interferon response in the guinea pig infected with junín virus.the "in vivo" interferon (ifn) induction capacity of two junín virus strains--the attenuated xjcl3 and the intermediate virulent mc2--was studied in the guinea pig experimental model. three different doses of xjcl3 strain--2,000, 10,000, and 50,000 tcid50--and a single dose of 10,000 tcid50 of mc2 were assayed. animals were bled from day 0 to day 14 postinjection (pi) xjcl3 groups showed a constant serum ifn response. mc2 infection showed that 16% of the animals failed to develop interferonemia. ...19872445908
protective effect of a low-dose of cyclophosphamide in experimental infection of guinea pigs with junin virus.administration of cyclophosphamide (cy) to guinea pigs infected with a lethal strain of junin virus (jv) delayed the time of death, with survival of a small number of animals. virological studies showed a temporary decrease of virus concentration in blood and viscera shortly after the cy injection. in the pathological study no differences were found in the organic lesions present in cy-treated and nontreated animals, with the exception of the pulmonary alterations. in cy-treated guinea pigs the ...19892557385
formalin inactivated junin virus: immunogenicity and protection assays.the aim of this study was to determine if junin virus inactivated with formalin (fa) was immunogenic and able to elicit a protective response in the guinea pig. the xj-clone 3 strain of junin virus grown in vero cells was exposed to fa at 0 degrees c. the following inactivated antigens were prepared: a1, 0.1% fa for 50 hr; a2, 0.1% fa for 50 hr followed by concentration with polyethylene glycol (peg); b1, 0.05% fa for 70 hr; b2, 0.05% fa for 70 hr plus peg concentration; c, 0.1% fa for 50 hr fol ...19892559158
[rapid serologic diagnosis of argentinian hemorrhagic fever in whole blood].the usefulness of a method for detection of antibodies against junin virus in whole blood was tested. n: nih adult mice were inoculated with 10(3) pfu of attenuated xj-clon 3 junin virus strain by intraperitoneal route and blood was obtained by retro-orbital puncture at 21 days post-infection. one blood aliquot (50 microliters) was collected in tubes containing a stabilizer solution for whole blood and another was processed for serum obtention. immunofluorescent antibodies were tested on spot sl ...19892559426
actions of complement on junin virus.fresh sera from normal rhesus monkeys, guinea pigs, and rabbits inactivated 90%-99% of the infectivity of vero cell-passaged, attenuated strains of junin virus (jv) within 60 minutes. selective depletion studies showed that inactivation occurred by the classical complement pathway. complement had little effect on virulent jv strains. adsorption of the fresh sera with jv-infected vero cells showed that inactivation was not mediated by low levels of antibodies in normal sera. the cells used for pr ...19892546249
[protection against encephalitis in rats caused by a pathogenic strain of the junin virus, using peripheral inoculation of an attenuated strain].argentine hemorrhagic fever manifests itself in man either subclinically or in hemorrhagic or neurological forms, mortality reaching 20%. although candid 1 strain is undergoing pilot trials, current therapy still resorts to convalescent serum administration. a neurological model was used to evaluate protection conferred by the attenuated xjc13 junin virus strain. newborn rats inoculated intraperitoneally (ip) prove resistant, whereas 8-12 day-old animals infected by intracerebral route with the ...19892562073
[lysosomotropic compounds inhibiting the multiplication of junin virus].a number of lysosomotropic compounds of diverse chemical structure, ammonium chloride, procaine and chlorpheniramine, were found to inhibit the infection of vero cells by junín virus. viral replication was almost totally inhibited by 15 mm ammonium chloride, when added either before or within the first hour of infection and a significant inhibition (97.8%) was observed when it was added 8 hours after infection. these results agree with a model which postulates that arenavirus entry occurs by rec ...19911667699
astrocytic reaction predominance in chronic encephalitis of junin virus-infected rats.junin virus antigen distribution and astrocytic reaction to prolonged infection were characterized in rat brain by the pap technique. during the acute stage of neurologic disease following intracerebral inoculation, junin antigen was detected in 100% of animals, strongly in most neurons but also to a much lesser degree in scattered astrocytes, dropping to 20% of rats at 540 days postinfection. initially labeled in all brain areas, viral antigen gradually disappeared from hippocampus but persiste ...19892559956
peripheral blood leukocytes of patients with argentine hemorrhagic fever as effectors of antibody-dependent cell-cytotoxicity.peripheral blood mononuclear cells (pbmc) and polymorphonuclear leukocytes (pmnl) of patients with argentine hemorrhagic fever (ahf) were tested as effectors (e) of antibody-dependent cell cytotoxicity (adcc). 51cr labeled chicken red blood cells (crbc) coated with anti-crbc or normal rabbit serum were used as targets (t). three adcc assays were performed with both effectors from patients: on admission (i), 4 days after the transfusion of immune plasma (ii), and 30 days after the clinical onset ...19921331313
contrasuppressor cells induced by junin virus.intracerebral inoculation of junin virus (jv) in all susceptible mouse models available induces a lethal meningoencephalitis compatible with a delayed-type hypersensitivity (dth) immune response. in contrast, adult balb/c mice prove resistant to infection and no dth response is seen. jv inoculation in adult balb/c mice induces dth suppression to unrelated antigens such as sheep red blood cells. (srbc). this suppression is mediated by jv-induced t cells (tsv), which are operative from 1 to 24 day ...19901970806
macrophages are involved in age-dependent resistance of rats to junin virus infection.we attempted to correlate rat age with resistance to intraperitoneal infection with the xj strain of junin virus. accordingly, mortality, viral replication in macrophages and brain, as well as neutralizing antibody (na) levels were recorded in animals inoculated at 2, 5, 10 and 26 days of life. two-day-old animals demonstrated both the greatest mortality (86%) and viral replication in macrophages, allowing virus to reach the brain where high titers were detected. this age group also had the high ...19872822597
metal-based formulations with high microbicidal activity.substances were evaluated for their relative potencies in inactivating junin virus, escherichia coli, and spores of bacillus subtilis. under the conditions of our test, glutaraldehyde was the most efficient agent among all substances currently recommended for disinfecting and sterilizing medical devices. either copper or iron ions by themselves were able to inactivate virus with an efficiency similar to that of substances currently used for disinfection and sterilization. the microbicidal effect ...19921332611
[experimental junin virus infection in the mouse: rototype of the disease].as previously postulated, the pathological changes which develop in 1-4 day old mice after intracerebral inoculation of 1-1000 dl50 of junín virus prototype strain (xj), was designated as experimental hemorrhagic fever of the mouse ehfm. in this paper, virus distribution, hematological alterations, interferon and circulating antibody responses are described. a mortality of 93.45% occurred between 9 and 20 days post-infection (p.i.), with 81.6% of death occurring between 11 and 18 days p.i. this ...19751208899
tacaribe virus: a new alternative for argentine hemorrhagic fever vaccine.tacaribe virus is know to protect guinea pigs and primates against lethal challenge with junín virus. a long-term study on the effect of tacaribe virus infection in the guinea pig was carried out to determine the extent of cross-protection and whether antigen and/or viral persistence and tissue damage could be detected in immune animals. viral titers, antigen expression in organs, and histologic lesions were sequentially searched for up to 540 days postinfection (pi). neutralizing antibodies (ab ...19872828522
circulating interferon in the guinea pig infected with the xj, prototype junin virus strain.the interferon (ifn) induction capacity of the xj prototype strain of junín virus (jv) was investigated in the guinea pig model. circulating alpha ifn was detected in 50% of the animals from days 2 to 9 postinfection (pi) and in 100% at day 11 pi, when all animals were in the premortem stage. individual levels ranged from 20 to 1,280 guinea pig ifn units (gpifnu)/ml. a correlation between xj strain virulence and ifn titers was recorded. a possible role of ifn as a pathogenic factor in the outcom ...19882828536
a plasma inhibitor of platelet aggregation in patients with argentine hemorrhagic fever.hemorrhage in patients with lassa fever is associated with the presence of a circulating plasma inhibitor of platelet aggregation. this study was to determine whether patients with argentine hemorrhagic fever (ahf) develop a similar inhibitor. normal platelets showed significantly weaker aggregation responses to a sub-maximal dose of adenosine diphosphate (adp) when mixed with plasma from 10 patients with ahf (mean percent of control +/- 1 se = 57.2 +/- 6.7%) compared to those mixed with plasma ...19902160197
[immunopathology induced in the rat by junin virus].intra-cerebral infection of the 10-day-old rat with the xj prototype strain of junin virus induces an immunopathological encephalitis with 100% mortality. in contrast with previous observations, our present work with antithymocyte serum (ats) demonstrates a pathological role for the cellular immune response in this experimental model. as regards ats treatment, 3 schedules were employed, the most efficient being daily 0.01 ml/g weight doses from day -1 to day +9, then +12, +14 and +16, taking day ...19901966503
[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
long-term protection against argentine hemorrhagic fever in tacaribe virus infected marmosets: virologic and histopathologic findings.tacaribe virus may represent a better alternative than attenuated strains of junin virus (jv) for immunization against argentine hemorrhagic fever (ahf) because of possible risk of persistent infection of disease associated with live, attenuated strains. callithrix jacchus marmosets, which suffer 100% mortality if inoculated with the pathogenic xj strain of jv, were used to evaluate possible tacaribe virus persistence, subclinical, or long-term disease and the duration of protection against chal ...19882832541
evaluation of an enzyme-linked immunosorbent assay for quantitation of antibodies to junin virus in human enzyme-linked immunosorbent assay (elisa) was evaluated for the quantitation of anti-junin virus (jv) antibodies, in 83 selected cases of argentine haemorrhagic fever (ahf). serum samples were studied in two groups to facilitate comparative analysis; the first group was elisa with indirect immunofluorescence (if) test, in the second elisa with plaque reduction neutralization test (print). from the results obtained by using elisa and if on the same serum samples, a clear tendency of elisa to d ...19882836465
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
junin virus-induced delayed-type hypersensitivity suppression in adult mice.junin virus (jv) infection of suckling mice leads to lethal meningoencephalitis consistent with a delayed-type hypersensitivity (dth)-like immune response. in contrast, there are no central nervous system (cns) alterations, and high antibody titers are induced in resistant adult mice. as a possible explanation, jv infection in adult mice may provoke dth depression. thus in this work we study the alterations induced by jv in the immune response of adult mice by using sheep red blood cells (srbc) ...19882839614
toward a vaccine against argentine hemorrhagic fever.a vaccine against argentine hemorrhagic fever, the "mal de los rastrojos" of the pampas, has been a dream of physicians and scientists involved with the disease since its recognition in the 1950s. several killed and live immunogens have been produced and tested in pursuit of this goal, none of which has proved suitable for widespread human use. recently, a new live-attenuated junin virus vaccine, candid #1, was developed through a cooperative international effort. testing conducted to date indic ...19911654168
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
mortality induced by adoptive immunity in junin virus-infected athymic mice.the effect of normal or sensitized spleen cell transfer from syngeneic euthymic mice to junin virus-infected suckling athymic mice was studied. transfer was performed 1 or 7 days after infection. in both cases, an acute lethal disease developed 6-11 days after transfer. the mortality reached 100% in all infected groups receiving normal or sensitized splenocytes, while it was negligible for different control groups of athymic mice. transfer of normal or sensitized splenocytes was unable to signif ...19882842272
viral strain dependent differences in experimental argentine hemorrhagic fever (junin virus) infection of guinea pigs.guinea pigs infected with low-passage junin virus of human origin showed viral strain dependent differences in mortality, ld50, time to death, and in viral spread and distribution. different junin strains appeared to cause at least two broad patterns of argentine hemorrhagic fever in guinea pigs. a number of strains of junin virus caused a viscerotropic type of illness in which virus replicated predominantly in lymph nodes, spleen, and bone marrow. with the most severe visceral forms of argentin ...19882846464
molecular organization of junin virus s rna: complete nucleotide sequence, relationship with other members of the arenaviridae and unusual secondary this study, overlapping cdna clones covering the entire s rna molecule of junin virus, an arenavirus that causes argentine haemorrhagic fever, were generated. the complete sequence of this 3400 nucleotide rna was determined using the dideoxynucleotide chain termination method. the nucleocapsid protein (n) and the glycoprotein precursor (gpc) genes were identified as two non-overlapping open reading frames of opposite polarity, encoding primary translation products of 564 and 481 amino acids, ...19911654373
experimental infection of suckling mice with a host range mutant of junin virus.experimental infection of three mouse strains with a non-pathogenic mutant of junin virus named cl67 was compared with respect to the parental xjcl3 strain. after intracerebral (ic) or intraperitoneal inoculation, xjcl3 was highly virulent for 2 day-old c3h/hej, of1, and balb/cj mouse strains, whereas its derivative cl67 was attenuated. survival of the cl67-infected mouse was associated with a restricted replication at the site of inoculation which would impair spread of virus. thus, the reduced ...19911658215
microgeographic distribution of allele frequencies in populations of calomys laucha (rodentia, cricetidae).the microgeographic differentiation of allelic frequencies was analysed in two population samples of calomys laucha, collected in a grid set in cultivated fields at laguna larga (córdoba province, argentina). one of the samples (n = 79) was obtained in may (autumn), when the population density is at a maximum, and the other (n = 85) in november (spring), at the onset of reproductive activity. fst values for the november sample show significant differences between the six groups over which the sa ...19911880049
protection of guinea pigs against experimental argentine hemorrhagic fever by purified human igg: importance of elimination of infected cells.antibody-containing plasma from patients recovered from argentine hemorrhagic fever (ahf) is of proven value in treatment of the acute disease, but the possibility of transmitting blood-borne organisms such as hiv and hepatitis virus detracts from this approach. purified human immune plasma fractions igg1,2,4, igg1,2,3,4 and f(ab')2 neutralized junin virus in vitro. igg1,2,3,4 and igg1,2,4 lysed (in the presence of complement) cells infected with junin virus, and protected infected guinea pigs f ...19901965845
[heterogeneity in the virulence of viral subpopulations derived from an attenuated strain of junin virus]. 19872854292
[association of the infection of the thymus and bone marrow with the establishment of persistent infection with junin virus in 2 genera of rodents].junin virus infection of immune system organs was correlated with persistence establishment in the mouse and rat. rockland mice under 24 or at 72 and 120 h of age received 10(4) pfu of junin virus xj strain by ic route. separately, two groups of mice under 24 h old were infected with the same dose of xj or xjcl3 strain by the same route respectively. results showed that higher thymus virus titer correlated with greater survival. in turn, the former also seemed to correlate with decreasing age at ...19852829274
[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
antiviral effect of ribavirin on junin virus replication in vitro.the effect of ribavirin (1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamide) on the replication in vitro of junin virus, the causative agent of argentine hemorrhagic fever (ahf), was examined. a concentration as low as 3.12 micrograms/ml of the drug inhibited the cytopathic effect observed five days post-infection (pi) on vero cells. on the other hand, a concentration of 25 micrograms/ml reduced the virus yield and specific antigen formation to undetectable levels. this same concentration of ri ...19862825242
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