| expression of lassa virus nucleocapsid protein segments in bacteria: purification of high-level expression products and their application in antibody detection. | the lassa virus nucleocapsid protein gene and segments from it were expressed in escherichia coli under the control of the lac promoter in puc-based plasmids. expression of the near full-length protein [amino acid (aa) residues 12-570] fused to an n-terminal sequence of vector-derived 6 aa was not particularly efficient, and neither was that of a smaller n-terminal segment (aa 6-201) which was also fused at its c terminus to the remainder of the lacz gene product. by contrast, the c-terminal 370 ... | 1987 | 3315857 |
| studies of the coagulation system in arenaviral hemorrhagic fever: experimental infection of strain 13 guinea pigs with pichinde virus. | significant coagulation abnormalities were associated with experimental infection of strain 13 guinea pigs with pichinde virus, an arenavirus related to the virulent human pathogens junin, machupo, and lassa viruses. infected animals developed decreased activity of multiple coagulation factors, decreased antithrombin iii levels, high levels of fibrin-fibrinogen degradation products, impaired platelet function, and thrombocytopenia. testing for the presence of a coagulation inhibitor revealed a p ... | 1987 | 3030150 |
| early diagnosis of human lassa fever by elisa detection of antigen and antibody. | sequential serum samples, beginning on the day of hospital admission, from three patients with lassa fever were tested for the presence of lassa-virus antigens and antibodies by means of an enzyme-linked immunosorbent assay. lassa-virus antigens were detected in the first serum sample from each patient, thus providing an early definitive diagnosis. in contrast, seroconversion was not detectable by elisa or indirect fluorescent antibody techniques until 3 days or more after admission. the antigen ... | 1985 | 2857321 |
| [dynamics of antigen and antibody accumulation in adult mice, infected with lassa virus]. | | 1989 | 2658319 |
| modifications to indirect immunofluorescence tests on lassa, marburg, and ebola material. | | 1983 | 6131336 |
| reproduction of lassa virus in different cell cultures. | sierra leone strain of lassa virus was growing to high titres of 10(5)-10(6) plaque forming units (pfu) per ml in vero, l and swine kidney cell lines as well as in diploid human cells and primary human embryo kidney cells. as many as 80% of the cells became infected as demonstrated by the immunofluorescence (if) technique. in bhk-21, cv-1, hela, fl, hep-2 and dog kidney cell lines, the virus reproduced to lower titres (10(4)-10(5) pfu per ml), whereas in primary chick embryo fibroblasts it did n ... | 1983 | 6138991 |
| indirect solid-phase immunosorbent assay for detection of arenavirus antigens and antibodies. | indirect enzyme-linked immunosorbent assay (elisa) and solid-phase radioimmunoassay (spria) using either anti-human or anti-mouse igg labelled with horseradish peroxidase and 125i, respectively, were developed for the detection of junin, machupo, tacaribe, amapari, tamiami, lassa and lcm arena-viruses. both methods allow high sensitivity detection of arena-virus antigens and antibodies. | 1984 | 6148001 |
| monoclonal antibodies to lymphocytic choriomeningitis virus react with pathogenic arenaviruses. | certain arenaviruses have become widely recognized as important human pathogens, the most notable among these being lassa virus, the causative agent of lassa fever. two other members of the group, junin and machupo virus, are the aetiological agents of argentine and bolivian haemorrhagic fevers, respectively. all these agents share both morphological features and to varying degrees serological cross-reactivity with other non-pathogenic arenaviruses. despite the evident clinical importance of the ... | 1980 | 6160402 |
| [inhibition of the accumulation of the lassa virus in vero cells by immune gamma globulin and complement]. | specific inhibition of lassa virus replication in vero cells was found to be better achieved with immune gamma globulin in combination with complement than with gamma globulin alone. according to the authors, the inhibitory effect of these preparations is due to the cyto-destructive action of antibodies and complement on the infected cells. | 1984 | 6208692 |
| new emerging viral zoonoses. | new developments in the field of viral transmission from animal to man can be divided into four areas of study. first are the new viral zoonoses such as diseases caused by rotaviruses, lassa virus and the animal orthopox viruses which will be more prevalent after the cessation of mandatory vaccination against smallpox. secondly are the numerous ubiquitous viruses, such as adeno and herpesviruses, which in healthy animals lead only to clinically inapparent infections. a typical example of the thi ... | 1980 | 6254232 |
| pathogenesis of a pichinde virus strain adapted to produce lethal infections in guinea pigs. | a model for studying the pathogenesis of virulent arenavirus infection was developed by adapting pichinde virus to produce lethal infections of inbred guinea pigs. this adapted pichinde virus retained low virulence for primates, thus potentially reducing the biohazard to investigators. whereas all inbred (strain 13) guinea pigs were infected and killed by 3 plaque-forming units or more of adapted pichinde virus injected subcutaneously, outbred (hartley strain) guinea pigs were relatively resista ... | 1981 | 6265367 |
| experimental infection of rhesus monkeys with lassa virus and a closely related arenavirus, mozambique virus. | as a model for the pathogenesis of lassa fever in humans, nine rhesus monkeys were inoculated with lassa virus. three monkeys had had a previous asymptomatic experimental infection with mozambique virus, a closely related arenavirus; these monkeys were protected from illness and viremia and manifested only mild pathologic lesions. the other animals developed severe disease and viremia. at necropsy, hepatocellular necrosis, interstitial pneumonia, a unique pulmonary arteritis, adrenal gland necro ... | 1982 | 6286795 |
| ribonucleic acids of machupo and lassa viruses. | sucrose gradient velocity centrifugation, polyacrylamide gel electrophoresis and rna-rna hybridization were used to characterize lassa and machupo virion rnas as well as virus-specific rnas from cells infected with pichinde and machupo viruses. five rna species: 30-31s, 28s, 22-24s, 18s and 4-6s have been detected in lassa, machupo, and pichinde virion rnas. among them 28s, 18s and 4-6s rnas cosediment and comigrate with respectively cell rnas. rnase resistance analyses suggest the presence of e ... | 1984 | 6320777 |
| detection of lassa virus antigens and lassa virus-specific immunoglobulins g and m by enzyme-linked immunosorbent assay. | rapid diagnosis of lassa fever is desirable for the timely therapeutic intervention and implementation of strict quarantine procedures both in west africa field hospitals where the disease is endemic and at international crossroads. an enzyme-linked immunosorbent assay (elisa) to measure lassa virus antigens in viremic sera was developed in which experimentally infected monkeys were used as a model for the human disease. in this test, lassa virus antigens in test sera were captured in wells of m ... | 1984 | 6386846 |
| endemic lassa fever in liberia. ii. serological and virological findings in hospital patients. | patients admitted with fever to four liberian hospitals were tested for lassa fever (lf) by means of the indirect fluorescent antibody technique and by virus isolation. the incidence of lf and presumptive lf among consecutive febrile adult patients was 14% and 17% in two hospitals located in the interior; no cases of lf were found among 24 consecutive patients in a hospital near the coast. in the three inland hospitals the incidence of confirmed or presumptive lf among the patients in whom the d ... | 1984 | 6390808 |
| endemic lassa fever in liberia. v. distribution of lassa virus activity in liberia: hospital staff surveys. | serological testing of hospital personnel by the indirect fluorescent antibody (ifa) technique was used to indicate the distribution of lassa virus (lv) activity in liberia. determination of the places of origin of the staff members as well as the sites of the hospitals indicated that lv is active in throughout liberia. prevalences of ifa varied from 3.8% at the j. j. dossen hospital on the coast in the south-east to 22.3, 23.5 and 40.4% in lofa county hospitals inland in the north-west. rises i ... | 1984 | 6398529 |
| endemic lassa fever in liberia. vi. village serological surveys for evidence of lassa virus activity in lofa county, liberia. | six villages in lofa county, north-west liberia, and one near the coast were surveyed for the presence of indirect fluorescent antibodies (ifa) to lassa virus (lv). prevalences were similar among males and females, and among various age groups. the prevalence of ifa positive sera, 6.4%, in two roadside villages was significantly higher than in two matched villages "in the bush", 1.9%. it was also higher in gbanwei, a roadside village which did not maintain traditional sanitary measures, than in ... | 1984 | 6398530 |
| structural and cell-associated proteins of lassa virus. | lassa virus was purified from culture fluids of infected cv-1 monkey kidney cells and its structural proteins analysed by polyacrylamide gel electrophoresis. stained gels showed a typical arenavirus profile, with a prominent protein of molecular weight 60000, corresponding to the nucleocapsid protein n, and two faint broad bands with molecular weights of 45000 and 38000, the envelope glycoproteins g1 and g2. g1 and g2 were shown to be glycosylated by their ability to bind concanavalin a to nitro ... | 1983 | 6405010 |
| antibodies against haemorrhagic fever viruses in kenya populations. | human sera from lodwar (77 sera), nzoia (841 sera), masinga (251 sera), laisamis (174 sera) and the malindi/kilifi area (556 sera) in kenya were tested by indirect immunofluorescence for antibodies against marburg, ebola (zaire and sudan strains), congo haemorrhagic fever, rift valley fever and lassa viruses. antibodies against ebola virus, particularly the zaire strain, were detected in all regions and were, over-all, more abundant than antibodies against the other antigens. ebola and marburg a ... | 1983 | 6419422 |
| physicochemical inactivation of lassa, ebola, and marburg viruses and effect on clinical laboratory analyses. | clinical specimens from patients infected with lassa, ebola, or marburg virus may present a serious biohazard to laboratory workers. we have examined the effects of heat, alteration of ph, and gamma radiation on these viruses in human blood and on the electrolytes, enzymes, and coagulation factors measured in laboratory tests that are important in the care of an infected patient. heating serum at 60 degrees c for 1 h reduced high titers of these viruses to noninfectious levels without altering t ... | 1984 | 6490832 |
| viral haemorrhagic fever surveillance in kenya, 1980-1981. | following two cases of marburg virus disease in kenya in 1980, viral haemorrhagic fever surveillance was undertaken in western kenya. over a 21-month period investigations, including virus isolation attempts, patient and contact serology, visits to areas where suspected cases occurred, interviewing family members and neighbours of suspected cases and following up any additional illnesses in these areas, were carried out. during the study two cases were found that were likely to have been ebola h ... | 1983 | 6684336 |
| passive antibody therapy of lassa fever in cynomolgus monkeys: importance of neutralizing antibody and lassa virus strain. | lassa virus-infected cynomolgus monkeys were passively immunized with immune plasma of primate or human origin to gain insight into criteria for plasma selection and administration to human lassa fever patients. protective efficacy was correlated with neutralizing antibody concentrations, expressed as a log10 neutralization index (lni). convalescent lassa-immune monkey plasma was titrated for protective efficacy in monkeys by intravenous inoculation with dilutions of plasma on the day of subcuta ... | 1984 | 6715049 |
| enhanced treatment of lassa fever by immune plasma combined with ribavirin in cynomolgus monkeys. | lassa virus-infected cynomolgus monkeys were treated with lassa virus-immune monkey serum containing a high concentration of neutralizing antibody, the antiviral drug ribavirin, or a combination of ribavirin plus immune serum at various times after infection. when treatment was initiated early (day 0 or 4), either ribavirin (30 mg/kg of body weight per day) or immune serum alone protected monkeys. however, when the initial treatment was delayed until day 7, only four of eight ribavirin-treated a ... | 1984 | 6715898 |
| pathogenesis of lassa virus infection in guinea pigs. | a rodent model for human lassa fever was developed which uses inbred (strain 13) and outbred (hartley) guinea pigs. strain 13 guinea pigs were uniformly susceptible to lethal infection by 2 or more pfu of lassa virus strain josiah. in contrast, no more than 30% of the hartley guinea pigs died regardless of the virus dose. in lethally infected strain 13 guinea pigs, peak titers of virus (10(7) to 10(8) pfu) occurred in the spleen and lymph nodes at 8 to 9 days, in the salivary glands at 11 days, ... | 1982 | 6749685 |
| viral haemorrhagic fever antibodies in zimbabwe schoolchildren. | | 1982 | 6761909 |
| lassa virus infection of rhesus monkeys: pathogenesis and treatment with ribavirin. | rhesus monkeys were experimentally infected with lassa virus to establish their suitability as a nonhuman primate model for the human disease and to test the protective efficacy of ribavirin, an antiviral drug. six of 10 untreated control monkeys died after subcutaneous inoculation of 10(6.1) plaque-forming units of lassa virus (strain josiah). infectivity titrations of tissue homogenates from the six dead monkeys indicated significant replication in all tissues tested except the central nervous ... | 1980 | 6768812 |
| effect of storage temperature on the stability of lassa virus complement-fixing antigen. | inactivated lassa virus complement-fixing antigen is normally prepared as a wet frozen antigen, and shipped in dry ice from the center for disease control, atlanta, georgia, usa, to other laboratories not equipped for handling live lassa virus. however, with this antigen there is a considerable loss of potency during shipping. in the search for a more stable antigen, inactivated lassa antigen was lyophilized and subjected to different storage temperatures. lyophilization did not significantly af ... | 1980 | 6772319 |
| marburg, ebola and rift valley fever virus antibodies in east african primates. | sera from 464 primates held at four institutes in kenya were tested by indirect immunofluorescence for the presence of antibodies against marburg, ebola, congo haemorrhagic fever, rift valley fever and lassa viruses. four of 136 vervet monkeys were positive for marburg virus antibodies and three of 184 baboons had antibodies against ebola virus. one baboon was positive for marburg virus antibodies. two vervet monkeys, three baboons and one grivet monkey (of 56 tested) had antibodies against rift ... | 1982 | 6810518 |
| a case of lassa fever: clinical and virological findings. | five days after arriving in london from jos a young nigerian women developed a severe and prolonged illness that proved to be lassa fever. virus was not detected in urine during the first three weeks but then appeared and reached a peak during the sixth week, with continuing excretion for 67 days after the onset of illness. laboratory investigations showed evidence of extensive tissue damage and disturbance of clotting, but there was no serious bleeding and she eventually made a complete recover ... | 1982 | 6812716 |
| case-control study of mastomys natalensis and humans in lassa virus-infected households in sierra leone. | lassa virus infection and antibodies were studied in households where lassa fever cases occurred, and compared to those in nearest neighbor houses and "far" houses located across the village from case houses. seventy-nine percent of all rodents caught in the houses were mastomys, the natural reservoir of lassa virus. rodent infection was not randomly distributed, but rather focal. thirty-nine percent of the mastomys in case houses were viremic, compared to 3.7% in control houses. human antibody ... | 1983 | 6881432 |
| [further comment on lassa fever]. | | 1981 | 6914002 |
| preparation and use of erythrocyte-globulin conjugates to lassa virus in reversed passive hemagglutination and inhibition. | conditions were defined for functional covalent coupling of anti-lassa virus globulins to glutaraldehyde-fixed chicken erythrocytes. tolylene-2,4-diisocyanate in a reaction mixture containing not more than 0.01 m nacl produced uniformly good conjugates which were used in reversed passive hemagglutination (rph) and reversed passive hemagglutination inhibition (rphi) tests to detect lassa virus antigens in infected cell cultures and specific antigens in vero cell cultures. identical results were o ... | 1980 | 7000810 |
| a comparison of indirect immunofluorescence and electron microscopy for the diagnosis of some haemorrhagic viruses in cell cultures. | yellow fever, dengue (types 1, 2 and 4), chikungunya, rift valley fever, ebola, marburg, and lassa viruses were inoculated into susceptible cell cultures and daily investigated by indirect immunofluorescence (ifa) and electron microscopy (em) with a view to achieve an early detection-identification of these agents. compared to the other cell lines tested (vero, bhk-21 and aedes albopictus), cv-1 cells were found to be more sensitive. viral antigens were detected by ifa from a few hours post inoc ... | 1981 | 7024293 |
| preparation of polyvalent viral immunofluorescent intracellular antigens and use in human serosurveys. | a method is described for preparation of polyvalent antigens for use in rapid screening for immunofluorescent antibodies to lassa, marburg, and ebola viruses. the technique uses mixtures of specifically infected vero cells placed on teflon-templated microscopy slides. it was found to be as sensitive as the use of monovalent antigens for detection and quantitation of antibodies to these highly hazardous human pathogens. | 1981 | 7031084 |
| recovery of a lassa-related arenavirus in zimbabwe. | immunofluorescent antibodies to "mozambique" virus, a close relative of lassa virus, were found in 11 of 55 mastomys natalensis and 1 of 13 aethomys chrysophilus rodents captured near que que and chiredzi, zimbabwe. six strains of mozambique virus, identified by use of specific monoclonal antibodies to the agent, were recovered from visceral tissues of m. natalensis rodents. all mastomys having virus or antibodies to this agent were of the chromosomal form 2n = 32 (m. natalensis). these data ext ... | 1981 | 7034562 |
| use of betapropionolactone inactivated ebola, marburg and lassa intracellular antigens in immunofluorescent antibody assay. | | 1982 | 7049096 |
| the binding of staphylococcal protein a by the sera of different animal species. | the capacity of purified immunoglobulin or serum to bind (125i)-labeled staphylococcal protein a (spa) was measured by means of an immunofiltration assay that facilitated the examination of large numbers of sera and required only a minute quantity of each. sera from 80 species, including humans, laboratory animals, domestic animals, and a variety of african mammals were examined. a wide interspecies variation in the spa-binding capacity of serum immunoglobulins was confirmed. only small variatio ... | 1982 | 7061862 |
| [factors affecting plaque formation by lassa virus in vero cells]. | the method of porterfield and allison was adapted for titration of the infectious activity of lassa virus by the plaque formation in vero cells. the virus was cloned, and the effect of the time of adsorption, ph, temperature, as well as polycations (dead-dextran, protamine sulphate) dimethylsuphoxide (dmso), and trypsin added during adsorption or into the agar overlay on the effectiveness of plaque production by lassa virus (virus titres, plaque size) were studied. the optimal adsorption time wa ... | 1982 | 7072230 |
| pathologic and virologic study of fatal lassa fever in man. | postmortem examination of 21 virologically documented cases of lassa fever, including 6 complete autopsies, was performed as part of a field study of community-acquired lassa fever in sierra leone. the most consistently observed lesions were hepatocellular, adrenal, and splenic necrosis and adrenal cytoplasmic inclusions. neither these lesions, nor other milder and less constantly observed lesions such as myocarditis, renal tubular injury, and interstitial pneumonia, appeared severe enough to ex ... | 1982 | 7081389 |
| pathology of lassa virus infection in the rhesus monkey. | the clinical signs and gross and microscopic lesions of lassa virus infection in the rhesus monkey are described. of 17 monkeys infected with lassa virus, nine died or were killed when moribund. the clinical signs were lethargy, aphagia, constipation, fever, conjunctivitis, and skin rash. pulmonary congestion, pleural effusion, pericardial edema, hydropericardium, and a few visceral hemorrhages were present grossly. major microscopic lesions were necrotizing hepatitis and interstitial pneumonia. ... | 1982 | 7125056 |
| inactivation of lassa, marburg, and ebola viruses by gamma irradiation. | because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. the infectivity of lassa, marburg, and ebola viruses was inactivated without altering the immunological activity after radiation with co60 gamma rays. at 4 degrees c, lassa virus was the most difficult to inactivate with a rate of 5.3 x 10(-6) log 50% tissue culture infective dose per rad of co60 radiation, as compared with 6.8 x 10(-6) log 5 ... | 1982 | 7153317 |
| haemorrhagic fever in gabon. i. incidence of lassa, ebola and marburg viruses in haut-ogooué. | a serological enquiry aimed at determining the incidence of infection with lassa, ebola and marburg viruses was conducted on the human population of the region of haut-ogooué (gabon) and on primates. the results, obtained by the indirect immunofluorescence technique, showed that more than 6% of the human population had had contact with ebola virus but no antibodies against marburg or lassa viruses were found. most sera reacted to an ebola antigen from a zairian strain, but showed little or no re ... | 1982 | 7164137 |
| glycoprotein detection in nitrocellulose transfers of electrophoretically separated protein mixtures using concanavalin a and peroxidase: application to arenavirus and flavivirus proteins. | | 1982 | 7165111 |
| lassa fever in children. | | 1982 | 7185979 |
| [a patient with lassa fever from the upper volta, diagnosed in the netherlands]. | | 1982 | 7200196 |
| clinical observations in 42 patients with lassa fever. | under continuous observation of several months, 42 patients from the eastern province of sierra leone, liberia (lofa county), and neighbouring guinea were identified as lassa fever cases by indirect immunofluorescent antibody technique, indicating that the disease is endemic in these areas. the clinical course varied from mild disease to severe illness with haemorrhagic disorders. the fatality rate was 14%. the occurrence of only two possible secondary cases suggests that person-to-person spread ... | 1980 | 7233535 |
| [accumulation of certain arenaviruses in transplantable vero and bhk-21 cells]. | production of lassa and machupo viruses in vero and bhk-21 cells was studied in relation to various conditions of the infected cell cultivation and as a function of different multiplicities of infection. the highest titers (expressed in pfu/ml) were obtained when the cells were grown in roller bottles with daily changes of the medium. the maximum titer in lassa virus-infected cells was over 10(6), in machupo virus-infected cells over 10(7). the effect of the autointerfering factor on the growth ... | 1981 | 7269524 |
| [effect of certain physico-chemical factors on arenaviruses]. | | 1981 | 7269531 |
| [effect of ribovirin (virazole) on arenavirus reproduction in cell cultures]. | | 1981 | 7269532 |
| exotic infectious diseases: lassa fever]. | | 1980 | 7384424 |
| [the localization and preliminary characteristics of antigenic sites (b epitopes) in the nucleocapsid protein of the lassa virus]. | nucleocapsid protein of lassa virus contains 4 epitope sites. three of them were localized in amino acid position 123-1 27, 337-346, and 518-527. monoclonal antibody 1108 specific to lassa virus np-protein reacted with 123-127 synthetic peptide in solid-phase elisa and precipitated nucleocapsid proteins of machupo, tacaribe, and mopeia arenaviruses in rip. | 1993 | 7521097 |
| [study of certain indicators of immunity upon infecting cba/calac line mice with lassa virus]. | some immunity parameters (interferon, tumor necrosis factor, interleukin 1, etc.) were studied in cba/calac mice infected with lassa virus. the results permit a hypothesis that a pathologic inflammatory reaction is responsible for the death of animals in experimental lassa fever. one of the components of this reaction is endogenous shock involving a manifest production of immune response mediators, such as interferon, interleukin 1. and tumor necrosis factor. | 1994 | 7536373 |
| from the centers for disease control and prevention. update: management of patients with suspected viral hemorrhagic fever--united states. | | 1995 | 7616624 |
| cross-protection against lymphocytic choriomeningitis virus mediated by a cd4+ t-cell clone specific for an envelope glycoprotein epitope of lassa virus. | recombinant vaccinia virus expressing the lassa virus (lv) envelope glycoprotein precursor, v-lsgpc, was used to study the basis of lv-induced cross-protective immunity against the closely related arenavirus lymphocytic choriomeningitis virus (lcmv). c3h/hej mice primed with v-lsgpc developed neither circulating antibodies nor cd8+ cytotoxic t cells specific for lcmv, yet they resisted a normally lethal lcmv challenge. spleen cells from such mice gave a proliferative response to lcmv in vitro th ... | 1993 | 7684468 |
| update: management of patients with suspected viral hemorrhagic fever--united states. | in 1988, cdc published guidelines for managing patients with suspected viral hemorrhagic fever (vhf) (1). pending a comprehensive review of the 1988 guidelines, this notice provides interim recommendations that update the 1988 guidelines for healthcare settings in the united states. this update applies to four viruses that cause syndromes of vhf: lassa, marburg, ebola, and congo-crimean hemorrhagic fever viruses; although the risk and/or mode of nosocomial transmission differs for each of these ... | 1995 | 7783731 |
| [an evaluation of the possibility of obtaining an inactivated vaccine against lassa fever]. | | 1994 | 7879553 |
| [research with the marburg, lassa and ebola viruses]. | | 1993 | 8059520 |
| [serological evidence of lassa virus circulation in the republic of guinea]. | seroepidemiological investigations in guinea were carried out to estimate the areas of lassa virus circulation. the recombinant protein of lassa virus nucleocapsid was used as the antigen to analyse blood sera by elisa. in some regions, from 30 to 54.9% of the population had antibodies to lassa virus, but in others only 6-7%. | 1993 | 8073741 |
| haemorrhagic fever virus activity in equatorial africa: distribution and prevalence of filovirus reactive antibody in the central african republic. | seroepidemiological surveys were conducted to determine the frequency and distribution of haemorrhagic fever virus (hfv) activity in the central african republic. human serum specimens (4295) were collected from 5 ecologically distinct zones. serological evidence of hfv activity was found in all the zones. the filovirus antibody prevalence (24.4%, 1051/4295) was greater than the combined prevalence for lassa virus, rift valley fever virus and crimean-congo hfv antibody (1.1%, 45/4295; p < 0.01). ... | 1993 | 8266402 |
| [a trial to produce an inactivated lassa fever vaccine]. | a single and double immunization of papio hamadryas monkeys with an inactivated concentrated purified adsorbed preparation of lassa virus in doses of 0.5-1.0 and 1.1-2.1 mg by protein, respectively, protected the animals against the development of the disease and occurrence of viremia after an intramuscular challenge with 0.4 pfu dose. upon aerogenic infection of monkeys protection of 50% of the animals was achieved by a single immunization with the inactivated preparation in a dose 1.1 mg by pr ... | 1993 | 8303891 |
| lassa virus activity in guinea: distribution of human antiviral antibody defined using enzyme-linked immunosorbent assay with recombinant antigen. | more than 3,100 households in 27 selected villages distributed in the main geographic regions of guinea were surveyed for the presence of lassa virus-specific igg antibodies (lva), using an enzyme-linked immunosorbent assay (elisa) with lassa virus nucleocapsid protein expressed in insect cells infected with a recombinant baculovirus as antigen. the highest prevalence of lva (25-55%) was found among inhabitants of tropical secondary forest (areas near gueckedou, yomou, and lola) and guinea savan ... | 1993 | 8355019 |
| evaluation of the polymerase chain reaction for diagnosis of lassa virus infection. | we evaluated the polymerase chain reaction (pcr) and hybridization procedures for diagnosis of lassa fever. primers were derived from a region of the small rna segment of lassa virus coding for the glycoprotein. serum samples stored for a 14-year period from patients in sierra leone, west africa were examined retrospectively. blinded samples were then tested prospectively. eighty-eight virus isolation-negative control sera were negative by pcr and hybridization. in the retrospective study, virus ... | 1993 | 8357084 |
| hunting of peridomestic rodents and consumption of their meat as possible risk factors for rodent-to-human transmission of lassa virus in the republic of guinea. | in this population-based study, we correlated possible risk factors for rodent-to-human transmission of lassa virus with markers of lassa fever in two different regions of the republic of guinea (prefectures of pita and gueckedou). antibody prevalence was 2.6% (6 of 232) in pita compared with 14.0% (105 of 751) in gueckedou, with up to 35.0% seropositivity in selected villages of the higher prevalence area. we observed three major risk factors in gueckedou favoring lassa virus transmission: rode ... | 1996 | 9025695 |
| the lassa fever virus l gene: nucleotide sequence, comparison, and precipitation of a predicted 250 kda protein with monospecific antiserum. | the large (l) rna segment of lassa fever virus (las) encodes a putative rna-dependent rna polymerase (rdrp or l protein). similar to other arenaviruses, the las l protein is encoded on the genome-complementary strand and is predicted to be 2218 amino acids in length (253 kda). it has an unusually large non-coding region adjacent to its translation start site. the las l protein contains six motifs of conserved amino acids that have been found among arenavirus l proteins and core rdrp of other seg ... | 1997 | 9049403 |
| [false-positive reactions in laboratory diagnosis of lassa, marburg, and ebola viral hemorrhagic fevers and aids]. | sera of normal subjects and aids patients living in minsk and odessa were tested for antibodies to hazardous viral infections lassa, marburg, and ebola. four to 16% of examinees were seropositive to ebola virus, 0.8 to 2.3% to lassa, and up to 0.8% to marburg virus. common b-epitopes were found in viruses belonging to different families: lassa, ebola, and hiv. antibodies specific to these viruses antigens were found in the reference sera to influenza a and b, respiratory syncytial virus, and ade ... | 1997 | 9182402 |
| [development and study of immunoglobulins against lassa fever]. | the authors validate the use of horses as producers of immune antiserum to lassa virus. specific immunoglobulin with at least 1:512 titer of virus neutralizing antibodies to lassa virus was obtained from the serum of immunized horses by kohn's alcohol method. the resultant preparation does not differ from the heterologous commercial immunoglobulins. preclinical studies of immunoglobulin against lassa virus demonstrated its safety and high specific activity. the strategy of treating with the immu ... | 1997 | 9182403 |
| [development and study of properties of immunoglobulins against lassa fever]. | a horse may serve the producer of immune antiserum to lassa virus. specific immunoglobulin with at least 1:512 titer of virus-neutralizing antibodies to lassa fever was obtained by alcohol sedimentation after cohn from the blood serum of immunized horses. the preparation does not differ from heterologous commercial immunoglobulins. preclinical studies of immunoglobulin to lassa fever demonstrated its safety and a high specific activity. the agent can be injected both alone and in combination wit ... | 1997 | 9304297 |
| a survey for antibodies to lassa virus among health workers in nigeria. | a study was conducted among 552 health workers at 6 health facilities in nigeria. lassa virus immunoglobulin (ig) g antibody was detected in 12.3%, using an enzyme-linked immunosorbent assay. antibody prevalence in the 6 health centres ranged from 1.2% to 27.3%. prevalences were higher in primary and secondary health facilities than in tertiary centres. seroprevalences ranged from 1.7% to 23.7% among different occupational groups of health workers; the highest observed antibody prevalence was am ... | 1997 | 9373625 |
| phylogenetic analysis of the arenaviridae: patterns of virus evolution and evidence for cospeciation between arenaviruses and their rodent hosts. | viruses of the arenaviridae cause hemorrhagic fevers and neurologic disease in humans. historically, the arenaviruses have been divided into two complexes (lasv-lcmv, tacaribe) through the use of antigenic typing. the phylogeny of the arenaviridae as a whole has not been estimated previously due to a lack of sequence data for all members of the family. in this study, nucleocapsid protein gene sequence data were obtained for all currently known arenaviruses and used to estimate, for the first tim ... | 1997 | 9417890 |
| the investigation of emerging and re-emerging viral diseases: a paradign. | emerging virus infections are defined as previously nonthreatening viruses that can decimate new populations by finding fresh hosts and vectors--often with the help of humans who introduce new species into virgen environment, several etiologic agents of these diseases, some of the interacting factors that contribute to their development and the role of molecular medicine in their understanding is discussed. | 1997 | 9419931 |
| an arenavirus ring (zinc-binding) protein binds the oncoprotein promyelocyte leukemia protein (pml) and relocates pml nuclear bodies to the cytoplasm. | the promyelocytic leukemia protein (pml) forms nuclear bodies which are altered in some disease conditions. we report that the cytoplasmic rna virus lymphocytic choriomeningitis virus (lcmv) influences the distribution of pml bodies. in cells infected with lcmv, the z protein and pml form large bodies primarily in the cytoplasm. transient transfection studies indicate that z alone is sufficient to redistribute pml to the cytoplasm and that pml and z colocalize. coimmunoprecipitation studies show ... | 1998 | 9420283 |
| replicon-helper systems from attenuated venezuelan equine encephalitis virus: expression of heterologous genes in vitro and immunization against heterologous pathogens in vivo. | a replicon vaccine vector system was developed from an attenuated strain of venezuelan equine encephalitis virus (vee). the replicon rna consists of the cis-acting 5' and 3' ends of the vee genome, the complete nonstructural protein gene region, and the subgenomic 26s promoter. the genes encoding the vee structural proteins were replaced with the influenza virus hemagglutinin (ha) or the lassa virus nucleocapsid (n) gene, and upon transfection into eukaryotic cells by electroporation, these repl ... | 1997 | 9434729 |
| [viral hemorrhagic fever--ebola hemorrhagic fever, marburg disease and lassa fever]. | viral hemorrhagic fevers include ebola hemorrhagic fever, marburg disease and lassa fever. the etiologic agents of the diseases, ebola virus, marburg virus and lassa virus, respectively, are categorized as viruses with biosafety level 4, because of their high mortality, high transmissibility and the lack of effective vaccines and therapeutic measures. ebola and marburg viruses are members of the filoviridae family and easily distinguishable from viruses of other families by the characteristic mo ... | 1998 | 9721531 |
| identification of alpha-dystroglycan as a receptor for lymphocytic choriomeningitis virus and lassa fever virus. | a peripheral membrane protein that is interactive with lymphocytic choriomeningitis virus (lcmv) was purified from cells permissive to infection. tryptic peptides from this protein were determined to be alpha-dystroglycan (alpha-dg). several strains of lcmv and other arenaviruses, including lassa fever virus (lfv), oliveros, and mobala, bound to purified alpha-dg protein. soluble alpha-dg blocked both lcmv and lfv infection. cells bearing a null mutation of the gene encoding dg were resistant to ... | 1998 | 9851928 |
| a welcome mat for leprosy and lassa fever. | | 1998 | 9874652 |
| lassa fever: implications of t-cell immunity for vaccine development. | lassa fever is a re-emerging viral hemorrhagic fever, which causes significant human morbidity in endemic regions of west africa. attempts to vaccinate against this virus in animal models including non-human primates have revealed that eliciting a strong cellular immune response protects from clinical disease, but not infection, in the absence of measurable neutralizing antibodies. as there is renewed interest in developing a vaccine against lassa fever for use in humans, several questions shoul ... | 1999 | 10486929 |
| lassa and mopeia virus replication in human monocytes/macrophages and in endothelial cells: different effects on il-8 and tnf-alpha gene expression. | cells of the mononuclear and endothelial lineages are targets for viruses which cause hemorrhagic fevers (hf) such as the filoviruses marburg and ebola, and the arenaviruses lassa and junin. a recent model of marburg hf pathogenesis proposes that virus directly causes endothelial cell damage and macrophage release of tnf-alpha which increases the permeability of endothelial monolayers [feldmann et al. , 1996]. we show that lassa virus replicates in human monocytes/macrophages and endothelial cel ... | 1999 | 10534741 |
| unsafe injections in the developing world and transmission of bloodborne pathogens: a review. | unsafe injections are suspected to occur routinely in developing countries. we carried out a literature review to quantify the prevalence of unsafe injections and to assess the disease burden of bloodborne infections attributable to this practice. quantitative information on injection use and unsafe injections (defined as the reuse of syringe or needle between patients without sterilization) was obtained by reviewing the published literature and unpublished who reports. the transmissibility of h ... | 1999 | 10593026 |
| characterization of human cd4(+) t-cell clones recognizing conserved and variable epitopes of the lassa virus nucleoprotein. | t cells must play the major role in controlling acute human lassa virus infection, because patients recover from acute lassa fever in the absence of a measurable neutralizing antibody response. t cells alone seem to protect animals from a lethal lassa virus challenge, because after experimental vaccination no neutralizing antibodies are detectable. in order to study human t-cell reactivity to single lassa virus proteins, the nucleoprotein (np) of lassa virus, strain josiah, was cloned, expressed ... | 2000 | 10666248 |
| effective vaccine for lassa fever. | lassa fever has been estimated to cause 5,000 deaths annually in west africa. recently, war in the zone where lassa fever is hyperendemic has severely impeded control and treatment. vaccination is the most viable control measure. there is no correlation between antibody levels and outcome in human patients, and inactivated vaccines produce high titers of antibodies to all viral proteins but do not prevent virus replication and death in nonhuman primates. accordingly, we vaccinated 44 macaques wi ... | 2000 | 10888616 |
| [introduction to sterilization and disinfection of medical wastes contaminated with human virus]. | in this paper, we describe sterilization and disinfection of medical wastes contaminated with blood borne-virus, such as ebola virus, marburg virus, crimean-congo hemorrhagic fever virus, lassa virus, hepatitis b virus and human immunodeficiency virus. | 2000 | 10901040 |
| [lassa fever]. | a 22-year-old female german student was admitted with fever of unknown origin for 5 days to the hospital of her hometown immediately after returning from a 7-week journey under simple conditions through 4 west african countries. after exclusion of malaria and typhoid and nonrespondence to antibiosis, she was transferred on the 4th day to the department of tropical medicine in würzburg. after the clinical assumption of lassa fever, the virus was confirmed by pcr within 3 hours (bernhard nocht ins ... | 2000 | 10935419 |
| imported lassa fever in germany: molecular characterization of a new lassa virus strain. | we describe the isolation and characterization of a new lassa virus strain imported into germany by a traveler who had visited ghana, côte d'ivoire, and burkina faso. this strain, designated "av," originated from a region in west africa where lassa fever has not been reported. viral s rna isolated from the patient's serum was amplified and sequenced. a long-range reverse transcription polymerase chain reaction allowed amplification of the full-length (3.4 kb) s rna. the coding sequences of strai ... | 2000 | 10998376 |
| experimental study on the possibility of treatment of some hemorrhagic fevers. | after intracerebral challenge with 100 pfu of lassa virus (strain josiah), all infected mice (cba/calac) died (control group). production of pro-inflammatory cytokines (il-1beta, tnf-alpha) significantly increased in the blood of these mice during the infection. for neutralization of increasing concentrations of these cytokines recombinant il-1ra was used intraperitonealy at a dose 100 microg kg(-1), everyday, within 5 days from the third day after the challenge. injections of il-1ra decreased t ... | 2000 | 11000462 |
| preliminary study on potential circulation of arenaviruses in the rodent population of nakhon pathom province, thailand and their medical importance in an evoluting environment. | preliminary serological investigations were prefered to detect evidence of arenavirus infection in rodents. the study examined virus antibody in 367 rodents trapped in 6 different geographical areas of nakhon pathom province, thailand from february-march, 1998. the overall seroprevalence among rodents was 13.3%, mostly in bandicota savilei (35.7%) and rattus norvegicus (31.5%). between ecology, behavior and sex of the rodents, seroprevalence was not significantly different (p>0.05), however the ... | 2000 | 11023066 |
| identification of a novel consensus sequence at the cleavage site of the lassa virus glycoprotein. | the lassa virus glycoprotein consists of an amino-terminal and a carboxy-terminal cleavage fragment designated gp-1 and gp-2, respectively, that are derived by proteolysis from the precursor gp-c. the membrane-anchored gp-2 obtained from purified virions of the josiah strain revealed the n-terminal tripeptide gtf(262) when analyzed by edman degradation. upstream of this site, gp-c contains the tetrapeptide sequence rrll(259), which is conserved in all lassa virus isolates published to date. syst ... | 2000 | 11070044 |
| [production of immune mediators, induced by lassa virus, in a human mononuclear cell culture]. | infection of human mononuclear cells with lassa virus leads to production of inflammatory cytokines (tumor necrosis factor and interleukin-1). these cytokines cause expression of adhesion receptors icam-1 and vcam-1 by human endothelial cells. mitogen-induced cell proliferation was not suppressed 1 h after infection of human mononuclear cells with lassa virus in a dose of 0.01 pfu/cell. the capacity of cells to proliferation in response to mitogen stimulation decreased significantly only 4 h aft ... | 2000 | 11200643 |
| [conformational changes in lassa viral proteins when exposed to antibodies and complement]. | addition of the complement to the antigen in lassa virus elisa stimulated the sensitivity and specificity of the assay. the effect depended on the mouse ig subclasses. elisa plate sensitization with igg2a and igg2b increased the sensitivity of elisa 8-16 times. protein footprinting data suggest that the complement c1q component stimulates antibody-induced conformation changes of the antigen. | 2000 | 11200644 |
| mucosal immunization with salmonella typhimurium expressing lassa virus nucleocapsid protein cross-protects mice from lethal challenge with lymphocytic choriomeningitis virus. | lassa fever virus (las) is transmitted to man by rodent carriers and is fatal in a third of untreated cases. our goal is to provide immune protection from lassa fever by mucosal vaccination. | 2001 | 11437313 |
| lassa fever encephalopathy: lassa virus in cerebrospinal fluid but not in serum. | the pathogenesis of neurologic complications of lassa fever is poorly understood. a nigerian patient had fever, disorientation, seizures, and blood-brain barrier dysfunction, and lassa virus was found in cerebrospinal fluid (csf) but not in serum. the concentration of lassa virus rna in csf corresponded to 1 x 10(3) pfu/ml, as determined by a quantitative real-time polymerase chain reaction assay. to characterize the lassa virus in csf, the 3.5-kb s rna was sequenced. in the s rna coding sequenc ... | 2001 | 11443561 |
| antibodies to lassa virus z protein and nucleoprotein co-occur in human sera from lassa fever endemic regions. | it is not known whether the small 11-kda z protein of lassa virus is immunogenic during human lassa virus infection. to obtain evidence for the existence of an antibody response and to test the suitability of these antibodies for serosurveys, sera from lassa fever endemic regions (guinea and nigeria, n = 75) were tested for co-reactivity to z protein and nucleoprotein (np). sera from a non-endemic region (uganda, n = 50) served as a specificity control. z protein and np were expressed in escheri ... | 2001 | 11599793 |
| the lassa virus glycoprotein precursor gp-c is proteolytically processed by subtilase ski-1/s1p. | the surface glycoprotein of the lassa virus, a member of the arenaviridae family, is synthesized as a 76-kda precursor (gp-c) that is posttranslationally cleaved into an n-terminal 44-kda subunit and a c-terminal membrane-anchored 36-kda subunit. cleavage occurs at the c-terminal end of the unusual recognition motif r-r-l-l. we show here that gp-c is cleaved in the endoplasmic reticulum by the cellular subtilase ski-1/s1p, an enzyme that has so far been observed to be involved in cholesterol met ... | 2001 | 11606739 |
| individual and bivalent vaccines based on alphavirus replicons protect guinea pigs against infection with lassa and ebola viruses. | lassa and ebola viruses cause acute, often fatal, hemorrhagic fever diseases, for which no effective vaccines are currently available. although lethal human disease outbreaks have been confined so far to sub-saharan africa, they also pose significant epidemiological concern worldwide as demonstrated by several instances of accidental importation of the viruses into north america and europe. in the present study, we developed experimental individual vaccines for lassa virus and bivalent vaccines ... | 2001 | 11689649 |
| interaction of lyssaviruses with the low-affinity nerve-growth factor receptor p75ntr. | the low-affinity nerve-growth factor receptor p75ntr interacts in vitro with the rabies virus (rv) glycoprotein and serves as a receptor for rv. the lyssavirus genus comprises seven genotypes (gts) of rabies and rabies-related viruses. the ability of p75ntr to interact with the glycoprotein of representative lyssaviruses from each gt was investigated. this investigation was based on a specific binding assay between bsr cells infected with a lyssavirus and spodoptera frugiperda (sf21) cells expre ... | 2001 | 11714960 |
| [microbiological surveillance: viral hemorrhagic fever in central african republic: current serological data in man]. | an investigation was conducted between 1994 and 1997 in forested areas of the central african republic (car) to determine the seroprevalence of igg antibodies against several haemorrhagic fever viruses present in the region. sera were obtained from 1762 individuals in two groups (pygmy and bantu locuted populations) living in 4 forested areas in the south of the country. sera were tested for igg antibodies against ebola, marburg, rift valley fever (rvf), yellow fever (yf) and hantaviruses by enz ... | 2000 | 11775321 |
| self-assembly properties of a model ring domain. | ring domains act in a variety of essential cellular processes but have no general function ascribed to them. here, we observe that purified arenaviral protein z, constituted almost entirely by its ring domain, self-assembles in vitro into spherical structures that resemble functional bodies formed by z in infected cells. by using a variety of biophysical methods we provide a thermodynamic and kinetic framework for the ring-dependent self-assembly of z. assembly appears coupled to substantial con ... | 2002 | 11792829 |
| monitoring of clinical and laboratory data in two cases of imported lassa fever. | during 2000, four cases of fatal lassa fever were imported from africa to europe. in two patients, consecutive serum samples were available for monitoring of virus load and cytokine levels in addition to standard laboratory data. both patients had non-specific early clinical symptoms including high fever. patient 1 developed multi-organ failure and died of hemorrhagic shock on day 15 of illness, while patient 2 died of respiratory failure due to aspiration without hemorrhage on day 16. ribavirin ... | 2002 | 11825774 |
| recent advances in vaccines against viral haemorrhagic fevers. | development of vaccines against viral haemorrhagic fevers is a public health priority. recent advances in our knowledge of pathogenesis and of the immune responses elicited by these viruses emphasize the crucial role of the immune system in the control of infection, but also its probable involvement in pathogenesis. several vaccine candidates against viral haemorrhagic fevers have been evaluated in animals during the past year. together, these data suggest that a vaccine approach against viral h ... | 2001 | 11964870 |
| new world arenavirus clade c, but not clade a and b viruses, utilizes alpha-dystroglycan as its major receptor. | alpha-dystroglycan (alpha-dg) has been identified as a major receptor for lymphocytic choriomeningitis virus (lcmv) and lassa virus, two old world arenaviruses. the situation with new world arenaviruses is less clear: previous studies demonstrated that oliveros virus also exhibited high-affinity binding to alpha-dg but that guanarito virus did not. to extend these initial studies, several additional old and new world arenaviruses were screened for entry into mouse embryonic stem cells possessing ... | 2002 | 11967329 |
| lassa fever. | | 2002 | 11987809 |