Publications

effect of beta-propiolactone on routine biochemical investigations.		1985	4079681
[experimental evaluation of the pathogenicity of lassa virus variants].	pathogenicity for guinea pigs and white mice of various lassa virus variants: native, having had 1 passage in vero cell culture and 4 passages in newborn white mouse brain; a virus having gone through 10 passages in vero cells and 8 mouse brain passages (variant no. 10); a small-plaque clone derived from variant no. 10 by the method of plaque-to-plaque cloning (variant no. 11k), was studied. both the native virus and variant no. 10 were found to be similarly pathogenic for susceptible laboratory ...	1985	4060702
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
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
possible approaches to a vaccine against lassa fever.		1984	6464128
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
effect of environmental factors on aerosol-induced lassa virus infection.	previous studies suggested that the most frequent means of transmission of lassa virus was by either direct or indirect contact with infectious material. aerosol stability and respiratory infectivity of the josiah strain of lassa virus were assessed to determine the effect of environmental factors on aerosol-induced infection. the stability of the virus in aerosol, particularly at low relative humidity (30% rh), plus the ability of the virus to infect guinea pigs and monkeys via the respiratory ...	1984	6512508
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
[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
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
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
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
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
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
protection of lassa virus-infected guinea pigs with lassa-immune plasma of guinea pig, primate, and human origin.	lassa virus-immune plasma has been used to treat human lassa fever patients; however, criteria for plasma selection were based arbitrarily on available serologic tools and protective efficacy was never directly assessed. to test the validity of plasma therapy for lassa virus infections in an animal model, and to develop biologically relevant criteria for selection of protective immune plasma, inbred, strain 13 guinea pigs were infected with a lethal dose of lassa virus and treated with various l ...	1983	6619814
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
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
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
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
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
lassa fever in children.		1982	7185979
[a patient with lassa fever from the upper volta, diagnosed in the netherlands].		1982	7200196
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
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
physical and chemical methods of inactivating lassa virus.		1982	6122855
inactivating lassa and marburg/ebola viruses.		1982	6123862
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
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
use of betapropionolactone inactivated ebola, marburg and lassa intracellular antigens in immunofluorescent antibody assay.		1982	7049096
[acute and chronic lassa virus infection of vero cells].	acute and persistent infections of vero cells with a cloned lassa virus were studied. after acute infection at a multiplicity of 2 pfu/cell the latent period was 12-16 hrs and the maximum yield of virus particles in the growth medium was obtained 28-32 hours postinfection. a persistently infected cell line was established by inoculating vero cells with the cloned lassa virus followed by subcultivation of the infected cells. the infected cells underwent 36 passages. lassa virus production by the ...	1981	7303630
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
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
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
[further comment on lassa fever].		1981	6914002
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
[effect of certain physico-chemical factors on arenaviruses].		1981	7269531
[effect of ribovirin (virazole) on arenavirus reproduction in cell cultures].		1981	7269532
[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
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
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
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
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
isolated case of lassa fever in zaria, northern nigeria.		1980	6107442
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
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
exotic infectious diseases: lassa fever].		1980	7384424
lassa fever virus: properties and characteristics.		1979	111436
protection of rhesus monkeys from lassa virus by immunisation with closely related arenavirus.		1979	90819
lassa virus antibodies in hospital personnel in western liberia.	the sera of 844 liberian hospital staff memebers were positive for lassa virus (lv) antibodies in a survey using the indirect fluorescent antibody technique (ifat). in two hospitals in lofa county near the sierra leone border, the prevalence, 15.4%, was significantly higher than the 8.4% in seven others. there were near differences between the prevalence among laboratory workers, 15.3%, and other workers, 7.7%, and between midwifery students, 21.2%, and midwives, 4.2%, suggesting their infection ...	1979	382467
[marburg, ebole and lassa virus infections].		1979	574072
lassa fever antibodies in hospital personnel in the plateau state of nigeria.		1979	463337
[lassa fever and marburg disease].		1978	417467
[marburg, lassa and ebola virus as cause of hemorrhagic fever].		1978	352653
a serological survey of lassa fever in liberia.	a serological survey was undertaken at four liberian hospitals in 1974 in which serum samples were taken from 104 health workers and 61 patients. six persons had lassa fever antibodies: four midwives and two students of midwifery. of those persons who had lived in loffa county, 4 of 22 midwives were seropositive whereas none of the other 39 residents were positive (p = 0.014).	1978	310723
biological species in praomys (mastomys) natalensis (smith), a rodent carrier of lassa virus and bubonic plague in africa.	plague has been known from countries surrounding rhodesia from as early as 1935, but was first reported from rhodesia in 1974. part of our investigation of the complex ecosystem involving yersinia pestis is critical assessment of the evolutionary status of natural populations belonging to formal, taxonomic species of implicated rodents. we present data on chromosomal and hemoglobin variation in sympatric populations and laboratory produced hybrids that give unequivocal evidence for at least two ...	1978	677375
decreasing any viral infectivity in blood-smears for malarial parasite examination.		1978	74655
[recent lassa, marbourg and ebola viruses in african tropical viruses. i. semiology--physiopathology--diagnosis--treatment (author's transl)].	three new viruses have been identified in africa during the present decade. they may cause sporadic cases or limited outbreaks, and they are probably endemic in areas which are still ill-defined. severe forms of infection lead to the haemorrhagic syndrome or to hypovolemic shock, the physiopathology of which is being studied. the case-fatality ratio of severe cases is between 30 and 85 per cent. nosocomial outbreaks have been observed, but they can be avoided if appropriate barrier nursing measu ...	1978	569288
arenaviruses in perspective.		1978	204386
[arenaviruses].		1978	206025
pathobiology of lassa fever.		1978	350792
serological survey for the detection of antibodies to lassa virus in india.		1978	659905
[tropical medicine. lassa fever in sierra leone].		1978	652080
[new high-risk infectious diseases].		1978	566498
a neutralization test survey for lassa fever activity in lassa, nigeria.	5-8% of 434 sera collected in lassa village, nigeria, in august 1970 were positive by neutralization test for lassa fever (lf) virus. a second survey in march 1971 found 15 of 47 complete compounds tested in lassa, dille and yuba villages had at least one peron with serologically demonstrable experience with lf virus. 67% of positive compounds had more than one infected member. four of 17 hospital staff sero-converted between august 1970 and march 1971 without symptoms, evidence that subclinical ...	1977	560072
[viral haemorrhagic fever].	two outbreaks of haemorrhagic fever caused by a marburg-like virus occurred in the sudan and zaire from august to november 1976. the inital epidemiological investigations and emergency control measures were carried out by sudanese and zairian health personnel and several of them unfortunately died in the course of their duties. in view of the unusual gravity of the outbreaks and the unknown nature of the agent, assistance was provided by a who team in the sudan and a multinational team in zaire. ...	1977	590991
isolation of an arenavirus closely related to lassa virus from mastomys natalensis in south-east africa.	five unidentified virus strains were recovered from the multimammate mouse ,mastomys natalensis, during the course of studies on arbovirus infections in mozambique. these agents were found to be morphologically and immunologically related to lassa virus. four of 19 sera from mastomys captured in the study area had antibodies to both lassa virus and one of the unidentified strains. although not definitive, the differences noted in results of complement fixation and indirect immunofluorescent test ...	1977	304387
lassa fever: response to an imported case.	in february, 1976, a peace corps worker returned to the united states from sierra leone with an undiagnosed illness later recognized as lassa fever. to assess the risk of transmission and to contain a potential outbreak, we identified 552 contacts as having had exposure to the patient before the start of strict isolation procedures, and maintained intensive surveillance on these contacts for 21 days. at the end of the surveillance period, no illness had developed in contacts. one month later, a ...	1977	895819
[lassa fever].		1976	934650
lassa fever (arenaviruses) as a public health problem.	two "new" virus infections, marburg and lassa fever, now constitute diseases of public health importance in several countries of africa, especially west africa. lassa fever has an insidious onset, is initially difficult to diagnose, has "nonspecific" clinical symptoms which have been confused with yellow fever and typhoid, shows evidence of persistent infection, is tremendously contagious, has a high mortality rate, and in particular exhibits unusual nosocomial propensity. it has also been shown ...	1976	1026322
[prevention of diseases transmissible by airlines].		1976	951060
[epidemiology of lassa fever].		1976	935549
failure to prove arenavirus infection among the small mammals from an endemic area of korean hemorrhagic nephrosonephritis.	in the light of recent knowledge on a complex of diseases caused by a new group of viruses, arenaviruses, virological studies largely directed toward small field mammals were undertaken during 1973-1974 aiming at etiological clarification of korean hemorrhagic nephrosonephritis (khnn). specimens were collected in an endemic area of khnn located north to northeast of seoul. virus isolation tests with 299 urine specimens and 131 mite pools recovered from small mammals and 14 acute stage sera from ...	1976	12383
lassa fever.		1976	958983
lassa fever.		1976	1264786
[lassa fever].		1975	1102478
experimental lassa virus infection in the squirrel monkey.	experimental lassa virus infection was investigated in a nonhuman primate in order to elucidate the target organs of the viral infection and the course of pathologic events. four squirrel monkeys (saimiri scirreus) were inoculated intramuscularly with lassa virus and sacrificed for organ titrations and histopathology, one each day, on days 7, 12, 14, and 28 after inoculation. the animals showed a variable clinical course, with an incubation period of 8 to 18 days. the virus was demonstrated to b ...	1975	1163630
unrecognized diseases in africa. ii. lassa fever.		1975	1165154
haemorrhagic fevers.		1975	1169820
lassa virus hepatitis. observations on a fatal case from the 1972 sierra leone epidemic.	during a recent outbreak of lassa fever in sierre leone, a 20-year-old woman developed an acute febrile disease with tonsillar exudates and hemorrhagic manifestations. lassa virus was isolated in cell cultures from pharyngeal secretions and pleural fluid and was identified by complement fixation. typical arenavirus particles were observed in these infected cell cultures. in a liver biopsy specimen, diffuse hepatocellular damage and focal necroses were evident, with a spectrum of liver cell chang ...	1975	1227472
[problems of clinical diagnosis and therapy of a new arena virus infection (lassa fever)].		1975	1229576
[viral hemorrhagic fever in man].		1975	1103342
letter: imported diseases.		1975	1109675
editorial: lassa fever.		1975	1111738
letter: lassa fever.		1975	1115977
[lassa fever].		1975	1118049
lassa virus infection in mastomys natalensis in sierra leone. gross and microscopic findings in infected and uninfected animals.	pathological examinations of 28 wild-caught mastomys natalensis from sierra leone, 14 of which were positive for lassa virus by tissue culture, are reported. the high frequency of neoplastic and degenerative diseases observed among older animals in closed colonies of m. natalensis were not observed in the wild animals studied. this is probably a reflection of the age distribution of the study population, since the life expectancy of wild mastomys is less than a year. inflammatory lesions were no ...	1975	1085221
diagnosis of lassa fever and the isolation and management of patients.	the clinical spectrum of lassa fever is described and discussed in terms of the possible pathophysiological events involved. early diagnosis is essential to permit prompt isolation of the potentially infectious patient. lassa fever may be suspected on clinical grounds, but specific early diagnosis depends upon isolation of the virus. virus isolation is best accomplished from serum obtained during the first 2 weeks of illness. the patterns of viraemia and virus excretion described in this paper a ...	1975	1085225
handling patients with suspected lassa fever entering great britain.	a special isolation unit has been created at the hospital for tropical diseases, london, for the reception of patients arriving in great britain from west africa with suspected lassa fever. the management of such patients and the operation of the unit are described. experience during the first eighteen months of operation has been very satisfactory and valuable lessons have been learned concerning the diagnosis and treatment of lassa fever and the nursing of patients.	1975	1085226
arenavirus chemotherapy--retrospect and prospect.	two groups of compounds, identifiable by structural similarity, have been found to interfere with the in vitro replication of arenaviruses. all 4 members of the benzimidazole group contain dipolar fused benzene and 5-membered nitrogen-containing rings and share potential chelating ability through the different bidentate structures formed with their side-chains. the biological activity of one of these compounds, metisazone, has been shown to depend on the presence of divalent metals of the first ...	1975	1085227
the arenaviruses: some priorities for future research.	in this paper lassa virus is used as a model in pinpointing priorities for future research on the arenaviruses. suggestions for specific investigations and public health measures cover the detection of lassa virus infection, the pathology and therapy of the disease, and its prevention and control.	1975	1085230
arenavirus taxonomy: a review.	despite a late beginning, the construction of the arenavirus taxon and its placement in the scheme of the international committee on taxonomy of viruses has now been completed. the bringing together of the member viruses has already provided valuable indications of promising laboratory and field study approaches; in the future this classification will contribute further to our understanding of the natural history and disease processes of the human pathogens of the group.	1975	182395