| epidemiologic investigations of the 1969 epidemic of venezuelan encephalitis in ecuador. | an epizoodemic of venezuelan equine encephalitis (vee), subtype i variant b, occurred in ecuador during the rainy and hot season of 1969. in this paper, a general description of the epidemic is given and virus isolations from humans are reported. a serologic survey was performed in order to determine the extension of the epidemic along the coastal zone of the country. it is not clear whether the higher antibody rate in older people was because they were at greater risk of infection or was the re ... | 1975 | 906 |
| ecologic studies of venezuelan encephalitis virus and isolations of nepuyo and patois viruses during 1968-1973 at a marsh habitat near the epicenter of the 1969 outbreak in guatemala. | ecologic studies of venezuelan encephalitis (ve) virus at a marsh habitat near the epicenter of the 1969 outbreak in guatemala revealed that the virus was enzootic there. ve virus was isolated yearly during 1968-1973 from sentinel hamsters exposed during the rainy seasons and from mosquitoes collected during july and august 1970. hamsters yielded 41 strains of ve virus and virus was detected within 2 km of the edge of the marsh, in its interior, and at its western extreme 18 km from the central ... | 1976 | 3981 |
| studies of possible movement of venezuelan encephalitis virus from an enzootic focus in guatemala during 1971-1974. | during the wet seasons of 1972 and possibly 1971, sentinel horses became infected by venezuelan encephalitis (ve) virus in a temporally and geographically progressive manner inland from an enzootic marsh focus of virus on the pacific couast of southeastern guatemala. during the wet seasons of 1972 and 1973, ve virus was detected by sentinel horses (and a sentinel hamster in 1972) in a small woods 10 km north of the marsh, but virus was undetectable there during the dry seasons of 1973 and 1974 a ... | 1976 | 3982 |
| equine viral encephalitis. | the most important neurotropic viral infections of the horse are the arthropod-borne encephalitides. these include venezuelan encephalitis (ve), eastern encephalitis (ee) and western encephalitis (we), which are found in the americas, and japanese b encephalitis which occurs in the far east. all the viruses cause encephalitis in man. between 1969 and 1972 an epidemic of ve occurred in central america. in 1971 the disease was reported in texas, where it was brought under control by the vaccinatio ... | 1976 | 4301 |
| search for epizootic-like venezuelan encephalitis virus at enzootic habitats in guatemala during 1969-1971. | seventy-four strains of venezuelan encephalitis (ve) virus recovered from sentinel hamsters or mosquitoes at enzootic habitats in guatemala in the two years following the 1969 epidemic-equine epizootic were examined for ability to produce small plaques in vero african green monkey kidney cell cultures, like isolates obtained during the epizootic. (a) one strain recovered from a sentinel hamster in late october 1969 at an enzootic habitat near the epicenter of the hemagglutination-inhibition (hi) ... | 1976 | 7138 |
| search for persistent epizootic venezuelan encephalitis virus in guatemala, el salvador and nicaragua during 1970-1975. | evidence was sought during 1970-1975 of persistence of equine-virulent venezuelan encephalitis (ve) virus in regions of central america that were heavily involved in the epidemic-equine epizootic of 1969. (a) four sentinel horses were exposed in an arid, upland region of the atlantic drainage of guatemala during august-october 1970, but no horse became infected. (b) the epicenter region of the 1969 outbreak, in southwestern guatemala and southwestern el salvador, was studied during july 1970-feb ... | 1976 | 7139 |
| arbovirus surveillance in six states during 1972. | a virus surveillance project was established and maintained during 1972 along 10 major river drainages in six states. mosquitoes, biting flies, and blood specimens from sentinel equines were collected during 83 field trip visits to 141 arthropod collecting sites and 22 sentinel locations from april into december 1972. there were 173,074 mosquitoes tested and 303 arboviruses isolated from 11 of 41 species. from 13,388 biting flies tested, 8 arbovirus isolations were obtained in 1 of 5 species. th ... | 1976 | 7148 |
| the effect of combination of different inducers on the refractory state in interferon production. | a second injection of 100 mug poly (ri) poly (rc) per mouse at 6 and 24 hours after the first injection stimulated additional peaks of interferon production. the dynamics of the process of accumulation and disappearance of interferon was similar to that after a single injection of poly (ri). poly (rc). injection of the above dose 12 hours after the first injection induced no interferon production as it apparently coincided with the refractory state in interferon production. after pretreatment of ... | 1976 | 7936 |
| the dynamics of development of cell resistance to viruses induced by synthetic polynucleotides. | the dynamics of interaction of complexes of synthetic polynucleotides (polyinosinic and polycitidylic acid--poly (ri)-poly (rc), and polyguanylic and polycytidylic acid--poly (rg)-poly (rc)) with cells as well as the dynamics of interferon accumulation and development of antiviral effect against some rna viruses were studied in primary chick embryo cell (cec) cultures. four phases were observed in the development of the antiviral effect of synthetic polynucleotides: adsorption, increase, marked ... | 1976 | 7937 |
| properties of virions and ribonucleoproteins of venezuelan equine encephalomyelitis virus. | the physicochemical properties of venezuelan equine encephalomyelitis (vee) virus and of its ribonucleoprotein (rnp) were studied. upon purification in a discontinuous or linear sucrose gradient, the losses of infectivity were small (25%), and 96% of cellular proteins were removed. the purified virus was homogeneous with respect of sedimentation rate (s20, w = 265 s). the cscl gradient was unsuitable for purification of infectious virus because the latter was destroyed at high cscl concentration ... | 1977 | 18919 |
| mosquito-virus relationships of american encephalitides. | | 1978 | 24407 |
| comparative analysis of interferon and antiviral protein messenger rnas. | a comparative analysis of interferon and antiviral protein messenger rnas was carried out. differences in their biological activities and sedimentation coefficients were found. in rna preparations from superinduced cells (cells treated with poly(i).poly(c) and antimetabolites) and from cells treated with interferon, messenger rnas possesing interferon and antiviral activities were detected. the results suggest the existence of two types of mrna (for interferon and antiviral protein, respectively ... | 1979 | 35956 |
| a microprecipitation test for rapid detection and identification of venezuelan, eastern and western equine encephalomyelitis viruses. | the development of a new diagnostic procedure for the identification of venezvelan, eastern and western equine encephalomyelitis (vee, eee, wee) viruses is described. the procedure utilizes virus precipitation with reference fluorescein-conjugated gamma globulin, followed by cellulose acetate electrophoresis. clinical specimens containing varying concentrations of virus yielded, in primary duck embryo cell culture, sufficient virus for detection within 22 to 44 hours. identification of vee, eee ... | 1975 | 46134 |
| letter: increased potency of killed vee (tc-83) vaccine in mice previously infected with eee virus. | | 1975 | 49960 |
| [determination of arbovirus group affiliation in the indirect hemagglutination reaction]. | a dry polyvalent erythrocyte immunoglobulin diagnostic preparation for arboviruses of group b may be prepared to be used in the indirect hemagglutination test. the preparation detects antigens of arboviruses of this group in the tissue culture fluid and in suckling mouse brain tissue treated with sucrose-acetone. the test with group b arbovirus antigens is inhibited specifically by the homologous polyvalent immune gamma globulin. inhibition of hemagglutination by species-specific immune globulin ... | 1975 | 54999 |
| specific in vitro lymphocyte transformation with venezuelan equine encephalitis virus. | | 1976 | 57835 |
| immunochemical and oligonucleotide fingerprint analyses of venezuelan equine encephalomyelitis complex viruses. | rna oligonucleotide fingerprint analyses indicate that the genome rna obtained from trinidad donkey (trd) venezuelan equine encephalomyelitis (vee) virus serotype i a, its vaccine strain derivative tc-83, and the vee i b virus isolate ptf-39, have almost identical patterns of characteristic ribonuclease t1 resistant oligonucleotides. the tc-83 strain and the i b isolate can, on the basis of these analyses, be considered as variants of the trd virus and categorized as i ab serotypes. comparisons ... | 1979 | 90115 |
| neutralizing antibody responses of humans and mice to vaccination with venezuelan encephalitis (tc-83) virus. | laboratory workers were vaccinated with venezuelan encephalitis virus, strain tc-83. after 2 to 3 years, they were bled, and their sera were tested for neutralizing antibody to all known venezuelan encephalitis subtypes and varieties. the results indicated higher titers to epizootic than to enzootic venezuelan encephalitis viruses and suggested that individuals vaccinated with tc-83 do not produce significant neutralizing antibody to heterologous subtypes. mice vaccinated, bled, and tested in a ... | 1979 | 93607 |
| [nonspecificity of antiviral protein action]. | the authors studied the antiviral activity of the informative rna of antiviral protein (m-rna avp) isolated from the cells following superinduction of interferon in them for the purpose of ascertaining the action specificity of the product of their translation--avp. following the administration of m-ran avp a marked (from 1 to 5 lg pfu/mil) reduction of the infectious titres was observed in the homologous and heterologous cells. rna preparations from control (noninduced) cells possessed a weak ( ... | 1978 | 96890 |
| protective and toxic effects of a nuclease-resistant derivative of polyriboinosinic-polyribocytidylic acid on venezuelan equine encephalomyelitis virus in rhesus monkeys. | polyriboinosinic-polyribocytidylic acid, stabilized with poly-l-lysine and carboxymethylcellulose (poly iclc), favorably alters the pathogenesis of venezuelan equine encephalomyelitis virus infection in rhesus monkeys by decreasing the number of infected monkey that become detectably viremic and by delaying the onset of viremia in the remaining monkeys. poly iclc is known to induce high circulating levels of interferon in primates, and the interferon system is assumed to be the mechanism by whic ... | 1979 | 109544 |
| [comparative antiviral and interferonogenic activity of natural and synthetic interferon inducers in vitro and in vivo]. | biological activities of the rna replicative form of phage f2, a natural interferon inductor and poly-i -- poly-c, a synthetic polyribonucleotide complex were studied comparatively. differences in the comparative interferonogenic and antiviral activity of the inductors were as dependent on the type of the cell system. it was shown that deae-dextran increased the interferon-inducing activity of rff2 in the cell culture by 4 to 8 times. the dynamics of the interferonogenic and antiviral activity o ... | 1979 | 110250 |
| adjuvant effects of low doses of a nuclease-resistant derivative of polyinosinic acid . polycytidylic acid on antibody responses of monkeys to inactivated venezuelan equine encephalomyelitis virus vaccine. | polyriboinosinic.polyribocytidylic acid [poly(i).poly(c)] stabilized with poly-l-lysine and carboxymethylcellulose [poly(iclc)] has been previously shown to be a compound with marked adjuvant activity when given in high doses with inactivated venezuelan equine encephalomyelitis (vee) virus vaccine. this study investigated the effects of much lower doses of poly(iclc) on the magnitude and kinetics of the primary and secondary humoral antibody responses of rhesus monkeys to inactivated vee virus v ... | 1979 | 110688 |
| [stimulation of interferon production]. | data on the effect of some factors on interferon production in vitro are presented the kinetics of interferon synthesis in response to superinduction was similar to the respective curve of the effect of uv-radiation on the cell. possible similarity in the effect of these factors on the mechanisms controlling interferon production is noted. an increase in interferon synthesis under the effect of ascorbic acid in cells of chick embryo fibroblast and l-929 was found. combined use of the inductors p ... | 1979 | 114105 |
| clonal analysis of mammalian cell cultures persistently infected with japanese encephalitis virus. | more than 200 cells were cloned from populations of mammalian cells persistently infected with japanese encephalitis virus. only four cloned cultures contained cells that had viral antigen measurable by immunofluorescence and that released infectious virus, yet all clones harbored virus-specific rna. superinfection of cloned cells with wild-type japanese encephalitis virus did not produce cytopathic effects, but resulted in production of viral antigen and infectious virus in formerly nonproducin ... | 1979 | 117119 |
| biochemical and antigenic comparison of the envelope glycoproteins of venezuelan equine encephalomyelitis virus strains. | pulse-chase experiments after synchronous initiation of translation indicate that the larger venzuelan equine encephalomyelitis (vee) virus membrane glycoprotein e2, is derived by proteolytic cleavage of the precursor, pe2. the structural proteins of vee virus strains representing each of the antigenic subtypes and varieties have been compared by discontinuous sds-polyacrylamide gel electrophoresis. nucleocapsid proteins of all isolates were similar in size (mol. wt. 35 to 36 x 10(3). the mol. w ... | 1979 | 119035 |
| tetracycline-mediated photodynamic inactivation of animal viruses. | demethylchlortetracycline (dmct), doxycycline and, to a lesser extent, chlortetracycline were capable of mediating the in vitro photoinactivation of venezuelan equine encephalitis (vee) virus. other tetracyclines tested were found to be inactive in this respect. however, no correlation between chemical structure and photosensitizing activity could be established. the photoinactivation of vee virus by dmct proceeds through a photodynamic mechanism as shown by the absolute requirement of o2 for th ... | 1979 | 120411 |
| [evaluation of the serological reponse of cattle infected naturally and experimentally with venezuelan equine encephalitis virus]. | | 1979 | 154334 |
| response of irradiated mice to live-virus (tc-83) immunization. | studies were conducted to determine the effects of sublethal, acute, total-body irradiation (600 r) on the immune response of mice to a replicating antigen. irradiation was performed at varying times (0 to 21 days) prior to immunization with attenuated venezuelan equine encephalomyelitis virus, tc-83. development of protective immunity was studied by inoculating subgroups of irradiated mice with virulent venezuelan equine encephalomyelitis virus on days 1 through 28 after immunization. irradiati ... | 1975 | 163795 |
| paramagnetic spin label interactions with the envelope of a group a arbovirus. lipid organization. | electron paramagnetic resonance observations were made on nitroxide spin- labeled molecules which were bound to the tc-83 vaccine strain of venezuelan equine-encephalomyelitis virus. paramagnetic resonance parameters derived from the observations and their dependence on sample temperature were similar but not identical to those which have been reported for these labels dissolved in lipid bilayer membranes of mammalian and bacterial origin. the data has a mechanical rigidity substantially greater ... | 1975 | 166687 |
| wildlife and environmental health: raccoons as indicators of zoonoses and pollutants in southeastern united states. | inasmuch as terrestrial fauna are an integral part of our natural environment and are directly exposed to disease and pollutants, it follows that certain wild populations could serve to detect subtle alterations within ecosystems. a collection of studies on raccoons is presented to stimulate other researchers to develop the potential of our wildlife resources as monitors of environmental health. raccoons have been used as serologic sentinels for st louis encephalitis and venezuelan equine enceph ... | 1975 | 170239 |
| murine oncornavirus activation in the pancreas during infection with venezuelan equine encephalitis virus. | electron microscopic studies of the pancreases of 3-week-old icr swiss mice infected with venezuelan equine encephalitis virus and killed 6 days post inoculation (at which time they were moribund) indicated significantly more type-c particles than were found in uninfected controls. this phenomenon was apparently possible because of the microanatomy of the pancreas, in which interstital spaces allowed accumulation of virus particles. | 1975 | 171430 |
| host immune responses after administration of inactivated venezuelan equine encephalomyelitis virus vaccines. ii. kinetics of neutralizing antibody responses in donors and adoptively immunized recipients. | lymphoid cell responses to immunization with various formalin-inactivated venezuelan equine encephalomyelitis (vee) virus vaccines were monitored in mice by assessment of the development of both the neutralizing antibody response in sera of spleen cell donors and the adoptive neutralizing antibody response induced by spleen cell transfer in recipients. donors immunized intraperitoneally with formalin-inactivated vee vaccine (a single dose or a dose on three consecutive days) developed early seru ... | 1976 | 181497 |
| [superinduction of interferon and and a study of its messenger rna]. | combined use of interferon inductor poly-ic and antibiotics (cycloheximide and actinomycin d) provided a significant increase (up to 1000 times) in interferon production by chick, mouse, monkey and human cells. messenger rna with matrix activity for interferon (mrna-if) was isolated from superinduced cells. on translation of mrna-if in homogenous and heterogenous cells the specificity of interferons produced was determined by the type of the cells from which mrna-if was isolated. sedimentation a ... | 1977 | 192141 |
| virus-induced diabetes mellitus. | | 1977 | 196570 |
| [isolation and characteristics of messenger rna for antiviral protein]. | experimental data on the induction and isolation of functionally active mrna's for antiviral protein (avp) from interferon-treated cells are presented. the dynamics of mrna-avp translation in homologous cells and sedimentational distribution of the total and poly(a)-containing preparation of mrna-avp in sucrose density gradients were studied. | 1977 | 200010 |
| viral infections in pregnancy. | the responsibility of the physician for viral infections in pregnancy has changed dramatically in the last 15 years. genital herpes infections have become much more frequent, and the recognition of these infections in women near term is particularly important. cytomegaloviruses have been found to be the most commom cause of congenital infection, but no satisfactory methods are available for prevention or treatment. varicella is now recognized as a teratogen when infection occurs in the first 4 m ... | 1978 | 208810 |
| [comparative analysis of the action of an interferon inducer in in vitro and in vivo systems]. | investigation of interferon inductor (poly ic) in vitro (chick embryon fibroblasts) and in vivo (mice) showed that the main parameters of the preparation effect, i. e. induction of interferon and development of resistance to viruses are as a whole quite comparable. the phenomenon of hyporeactivity in the both systems was reproduced on repeated use of the inductor. at the same time significant differences in the stimulating effect of deae-dextran were registered. the merits and demerits of the in ... | 1978 | 209734 |
| [enzymatic and ultrastructural changes in isolated liver mitochondria from mice infected with several group a arboviruses]. | inoculation of white mice of varying body mass with pathologic strains of eastern and venezuelan equine encephalomyelitis viruses and their attenuated variants (dnc-20/6 and no. 2621), promising as vaccine candidates, resulted in an increase of enzymatic activity and ultrastructural changes of isolated mitochondria from livers of the animals. the attenuated strains of the viruses were shown to induce temporary changes in both aspects of the study which became normal by the end of the study. ther ... | 1978 | 211733 |
| [antiviral activity of interferon and its inducers in human lymphoblastoid and somatic cells]. | the antiviral effect of interferon inductors, such as poly-i--poly-c, phage f2 rna replicative form and low molecular inductor gsn and their influence on cellular dna synthesis were studied in the cultures of lymphoblastoid (inplanting lines raji namalva) and somatic human cells. the semliki forest virus used as the test organism multiplicated well in cells raji accumulating up to 9 lg bou/ml. the two-strand rna was less active in the lymphoid cells than in the somatic ones. gsn was 10 times mor ... | 1979 | 220908 |
| ten clinical cases of human infection with venezuelan equine encephalomyelitis virus, subtype i-d. | the clinical and laboratory findings in ten humans infected with venezuelan equine encephalitis virus, subtype i-d, are described in this report. clinical and laboratory data indicate that, in contrast to equine infections, human infection with these enzootic virus strains (i-d) is similar to human infection with epizootic strains (i-abc). in most cases there was an abrupt onset of fever, muscle pain, and vomiting. virus was recovered from sera obtained during the first 3 days of illness. lympho ... | 1979 | 222156 |
| [viral interaction with stimulated and nonstimulated human tonsil cells]. | interferon induction and the course of infection with paramyxovirus (newcastle disease virus) and alphaviruses (venezuelan equine encephalomyelitis, sindbis, semliki forest viruses) in human tonsillar cell cultures were studied in comparison with continuous burkitt lymphoma, raji, and nawalva cells. the virus inducers stimulated production of dozens and hundreds iu50/ml of interferon in tonsillar cell cultures. no virus replication could be detected either in intact or phytohemagglutinin-stimula ... | 1979 | 230646 |
| persistence in humans of antibody after immunization with four alphavirus vaccines. | immunization with attenuated vee virus vaccine resulted in persistence of neutralizing antibody for 12 years. immunization with inactivated wee vaccine converted 83% of the subjects, killed eee vaccine converted 27% and killed chikungunya vaccine induced no significant titers. antibody formed as a result of immunization with inactivated vaccines was of short duration, i.e. less than 1 year. attenuated vee was responsible for some heterologous antibody rises to the other three alphaviruses. among ... | 1979 | 233418 |
| epidemic venezuelan equine encephalitis in north america: a summary of virus-vector-host relationships. | | 1975 | 235211 |
| epidemic venezuelan equine encephalitis in north america in 1971: vector studies. | a major epidemic of venezuelan equine encephalitis occurred in south texas in the summer of 1971. more than 1500 equines died of vee in texas, and 110 human cases with no deaths were reported. vector studies in south texas and northern tamaulipas revealed that the overall mosquito infection rates during the peak of the epidemic were about 1:100, one of the highest rates observed for a major epidemic. mosquito infection rates of this magnitude could easily explain the intensity of vee outbreaks i ... | 1975 | 235212 |
| arbovirus vector ecology studies in mexico during the 1972 venezuelan equine encephalitis outbreak. | virus vector studies were conducted in the states of durango, chihuahua, and tamaulipas, mexico, in june and july 1972. apparently only a low level of venzuelan equine encephalitis (vee) virus transmission to equines occured at the time of the study, and the infection was restricted to areas which had not experienced overt activity during the preceding year. the low level of infection was associated with a scarcity of mosquitoes. the ib (epidemic) strain of vee virus was isolated from two pools ... | 1975 | 235213 |
| ecologic studies of venezuelan encephalitis virus in peru during 1970-1971. | venezuelan encephalitis (ve) virus has intermittently produced epidemics and equine epizootics on the dry pacific coastal plain of peru since at least the 1930's. however, evidence that the virus exists in the amazon region of peru to the east of the andes mountains was not obtained until antibodies were found in human sera collected in 1965, and 10 strains of the virus were isolated in a forest near the city of iquitos, peru during february and march 1971. eight strains came from mosquitoes and ... | 1975 | 235838 |
| antigenic and biologic characteristics of venezuelan encephalitis virus strains including a possible new subtype, isolated from the amazon region of peru in 1971. | nine strains of venezuelan encephalitis (ve) virus isolated from the amazon region of peru in 1971 were identified as antigenic subtype i based on plaque-reduction neutralization tests with four and 20 units of antibody. a tenth strain, 71d1252, was possibly a new subtype, but was related to subtypes i and iii. hemagglutinins of each strain made from infected mouse brains had optimals phs of 6.2 and 6.4. nine strains were pathogenic for adult hamsters and adult mice, but strain 71d1252 inapparen ... | 1975 | 235839 |
| accelerated host metabolism of l-thyroxine during acute infection: role of the leukocyte and peripheral leukocytosis. | metabolism of thyroid hormones is accelerated during acute infection in man and in experimental animals. the pathogenetic mechanisms mediating this phenomenon are uncertain, but activated leukocytes of the infected host have been implicated as potentially important sites of hormone degradation. the present studies were conducted in an attempt to assess the in vivo contribution of leukocytes and peripheral leukocytosis to the enhancement of l-thyroxine (t4) clearance seen during infection, and to ... | 1975 | 236322 |
| serologic evidence of venezuelan equine encephalitis in some wild and domestic populations of southern texas. | more than 2,500 sera from approximately 30 wild and domestic species in southern texas were tested for neutralizing antibodies to venezuelan equine encephalitis (vee). virus isolations were also attempted from blood and tissue samples of many of the wild specimens. vee neutralizing substances were present in a variety of species collected prior to the 1971 epizootic, suggesting that vee was present and perhaps enzootic in this area before the recent epizootic. serologic results of this study sug ... | 1975 | 238050 |
| correlation between virus-cell receptor properties of alphaviruses in vitro and virulence in vivo. | virulent and avirulent clones of venezuelan, western, and eastern equine encephalitis viruses were examined for their in vitro attachment characteristics to the surface of cultured cell monolayers. these attachment characteristics were correlated with in vivo plasma clearance rates and virulence. for the clones investigated, avirulence correlated in vitro with attachment ph optima close to physiologic ph and in vivo with a rapid clearance from plasma. conversely, virulent clones had lower in vit ... | 1979 | 295182 |
| host immune responses after administration of inactivated venezuelan equine encephalomyelitis virus vaccines--iii. kinetics for neutralizing antibody immunoglobulin class responses in donors and adoptively-immunized recipients. | c57b16 mice were immunized with either live, attenuated tc-83 strain vee virus vaccine or formalin-inactivated vee vaccine combined with bordetella pertussis. the kinetics of specific donor and adoptively-immunized recipient anti-vee neutralizing antibody responses were studied. donor mice immunized with either live or inactivated vee virus vaccine combined with potent adjuvants develop specific anti-vee igm and igg responses as early as 7 days post-immunization. anti-vee igm antibody responses ... | 1979 | 318539 |
| induction of the interferon protein in vivo: viral inducers. | | 1977 | 358477 |
| [immunofluorescence method of study of biosynthesis of human interferon]. | the method of fluorescent antibody (mfa) has first been used for the study of regularities of human interferon biosynthesis in superinduced cells. the dynamics of the appearance and accumulation of interferon in individual cells and the dependence of these processes upon the time elapsing since the termination of superinduction were determined. clear-cut inverse relationship between the interferon content in cells (mfa) and the interferon content in the culture fluid (titrations of biological ac ... | 1978 | 373250 |
| protective effects of supplemental vitamin e against infection. | vitamin e supplementation (dl-alpha-tocopheryl acetate except where noted) in excess of requirement significantly increased humoral immune response or disease resistance. mice immunized with sheep red blood cells or tetanus toxoid and fed the supplemental vitamin demonstrated increased plaque-forming cells (pfc) and hemagglutinin (ha) titers. a vitamin e deficiency resulted in decreased pfc and little igg which was partially corrected by n,n-diphenyl-p-phenylenediamine but not as effectively as ... | 1979 | 376353 |
| venezuelan encephalitis virus-induced alterations in carbohydrate metabolism in geneticaly diabetic mice. | | 1979 | 381078 |
| detection of antibodies to alphaviruses by enzyme-linked immunosorbent assay. | cell culture-derived antigens detected antibodies to alphaviruses in human sera with the enzyme-linked immunosorbent assay technique. results correlated with those from hemagglutination inhibition and neutralization tests. | 1979 | 393723 |
| survival of arboviruses in trypanosome-infected triatomines. | the potential of triatomines to maintain arboviruses was demonstrated by the ability of rhodinius prolixus with experimentally punctured abdomen to harbor venezuelan equine encephalitis (vee) virus for at least 4 months and st. louis encephalitis virus for 1 month. at 30 days after infection vee virus was found at low titers in trypanosoma cruzi-infected r. prolixus and at moderate titers in t. rangeli-infected r. neglectus. transmission of vee virus by bite of punctured bugs was successful 2 we ... | 1977 | 403822 |
| inactivated venezuelan equine encephalomyelitis virus vaccine complexed with specific antibody: enhanced primary immune response and altered pattern of antibody class elicited. | complexes of formalinized venezuelan equine encephalomyelitis (vee) virus vaccine and specific igg formed at antigen-antibody equivalence enhanced the immune responses of rhesus monkeys (macaca mulatta). the predomonant class of antibody elicited by complexes was igg. in contrast, lower titers of antibody and a more biphasic (igg-igm) response were observed after exposure of monkeys to the vaccine alone. in comparison to the response of monkeys primed with antigen, a more rapid secondary respons ... | 1977 | 404363 |
| vascular clearance of venezuelan equine encephalomyelitis viruses as a correlate to virulence for rhesus monkeys. | the epizootic trinidad donkey strain of venezuelan equime encephalomyelitis virus (vee) was cleared slowly from the circulation of rhesus monkeys following intravenous inoculation, while the live, attenuated vaccine strain, tc-83, was cleared rapidly. the efficent clearance of tc-83 vaccine may be a factor in the lower viremia and benign course of tc-83 virus infection in rhesus monkeys. | 1977 | 411457 |
| congenital cerebral and ocular malformations induced in rhesus monkeys by venezuelan equine encephalitis virus. | rhesus monkey fetuses were inoculated with venezuelan equine encephalitis (vee) vaccine virus by the direct intracerebral route at approximately 100 days gestation to determine possible teratogenicity of the virus. congenital micrencephaly, hydrocephalus and cataracts were found in all animals and porencephaly in 67 percent of the cases. the virus replicated in the brain and other organs of the fetus. vee vaccine virus is teratogenic for non-human primates and must be considered a potential tera ... | 1977 | 413204 |
| [preparation and characteristics of temperature-sensitive mutants of the venezuelan equine encephalomyelitis virus]. | fifteen ts mutants of venezuelan equine encephalomyelitis (vee) virus have been produced and studied. two of them were isolated from a virus population grown in the presence of 5-fluorouracyl and 13 from a virus suspension treated with nitrous acid. the efficiency of plating 40 degrees/35 degrees of various mutants varied from 2 x 10(-2) to 6 x 10(-6). three ts mutants had rna- phenotype (rna synthesis at a nonpermissive temperature was 1.5-3.3% of that of the wild type), 11 ts mutants had rna+ ... | 1979 | 433244 |
| studies on immunity to alphaviruses in foals. | | 1979 | 453684 |
| [interaction of venezuelan equine encephalitis virus ts-mutants with cells]. | an acute infection of hela cell cultures with a ts mutant of venezuelan equine encephalomyelitis (vee) virus may have different outcomes ranging from formation of a chronic virus-carrier state to complete elimination of virus from the culture. one of the possibilities is also a short-time carrier state (up to 10 passages) of the virus genome apparently existing in the form of dna-provirus. the carrier state of virus genetic material in this case is indicated by the infectivity of cellular dna an ... | 1979 | 462926 |
| further observations on infections of guinea pigs with venezuelan encephalitis virus strains. | guinea pigs from a guatemalan colony died after subcutaneous inoculating of moderately small doses of equine-benign strains of venezuelan encephalitis (ve) virus of hemagglutination-inhibition subtype i-e from enzootic habitats in mexico and guatemala. thus these guinea pigs were unlike english short hair and inbred 13 guinea pigs, which usually survive infections with equine-benign ve strains of subtype i-e. we therefore caution others that not all strains of guinea pigs can be used to evaluate ... | 1979 | 464194 |
| interaction of alphaviruses with human peripheral leukocytes: in vitro replication of venezuelan equine encephalomyelitis virus in monocyte cultures. | human peripheral blood leukocytes (pbl) were examined for their ability to support growth of several group a arboviruses in vitro. cells were refractory to infection with eastern (eee) and western (wee) equine encephalitis viruses, whereas venezuelan equine encephalomyelitis (vee) virus was shown to infect and replicate to a substantially high titer. when pbl were fractionated into purified subpopulations, only the monocytes were susceptible to predictive vee virus infection. lymphocytes treated ... | 1979 | 468371 |
| central nervous system alterations as sequelae of venezuelan equine encephalitis virus infection in the rat. | alterations of the central nervous system (cns) in rats surviving acute infection with a virulent strain of venezuelan equine encephalitis (vee) virus were studied by light and electron microscopy. cavitary necrosis of the cerebral cortex, macrophage activity and degenerative axonal changes were considered to be sequelae of the lesions induced during the acute phase of the infection. mononuclear cell infiltrates of the neuropil, 3 mth after inoculation, were related to the immune response of the ... | 1979 | 469656 |
| [temperature-sensitive mutants of the venezuelan equine encephalomyelitis virus studied in the complementation test]. | investigation of 15 ts mutants of venezuelan equine encephalomyelitis (vee) virus by complementation tests permitted to divide these mutants into 5 complementation groups and to distinguish unclassifiable mutants. mutants of 2 groups had rna+/- or rna- phenotype, i. e. had defects in rna synthesis. mutants in the other 3 groups had the rna+ phenotype, and the temperature-sensitive defect of these mutants was in later stages of virus reproduction. | 1979 | 483775 |
| transmission of venezuelan encephalitis virus by naturally infected culex (melanoconion) opisthopus. | during august 1977 two of 975 culex (melanoconion) opisthopus collected from an enzootic marsh habitat on the pacific coast of guatemala transmitted ve virus to hamsters. eight ve strains were isolated from cu. opisthopus. the minimal level of ve infection in this species during july-august 1977 at la avellana, guatemala was 1/128 (8/1,021), and the prevalence of cu. (mel.) opisthopus transmitting ve virus was 1/487 (2/975). this mosquito was the predominant species attacking humans at that time ... | 1979 | 507283 |
| study of ve virus and isolation of sle, ee, group c, and guama group arboviruses in the amazon region of peru, 1975. | | 1979 | 519080 |
| multi-factorial specification of virus-host interactions: studies with strains of venezuelan equine encephalomyelitis virus in mice. | mice of different ages were infected i.p. or i.c. by 23 different strains of vee virus. the course of the virus host interaction was specified in terms of the efficiency of infection, the outcome of infection as lethality or protection and the survival time. these separately quantifiable features all showed several host-maturation events that combine to provide a multifactorial specification of virus-strains and host-responses. this base-line for correlations with the responses of principal host ... | 1979 | 521796 |
| adjuvant effects of the lipid amine cp-20,961. | | 1979 | 522085 |
| evaluation in humans of a new, inactivated vaccine for venezuelan equine encephalitis virus (c-84). | a new, formalin-inactivated vaccine for venezuelan equine encephalitis (vee) virus (c-84), prepared from an attenuated vaccine strain of virus (tc-83), was tested in humans. only occasional, mild, local and systemic reactions were noted in 28 volunteers; no meaningful changes in clinical laboratory values occurred. the vaccine augmented preexisting titers of serum neutralizing antibody to vee virus in seropositive recipients of tc-83 vaccine, and it induced high titers of neutralizing antibody i ... | 1979 | 528788 |
| seroepidemiologic studies in oaxaca, mexico. ii. survey for arbovirus antibody. | a serologic survey was conducted in south-western mexico to obtain information on human experience with arbovirus infections. sera were collected from two semitropical areas along the pacific coast of oaxaca state, two mountain areas above 1,700 meters and the interior valley at 1,500 meters. of the 610 sera tested for group a antibody, 4.9 per cent were positive in the hemagglutination-inhibition (hi) test to venezuelan (ve), 11 per cent to eastern, and none to western encephalitis viruses. in ... | 1979 | 539866 |
| radioimmunoassay for quantitation of antibodies to alphaviruses with staphylococcal protein a. | a radioimmunoassay (ria) procedure is described for measuring antibodies to alphaviruses in human and other mammalian sera. the test employed protein abearing staphylococcus aureus as a solid-phase immunoadsorbent for (3)h-labeled viruses complexed with immunoglobulin g. using antibodies produced in humans and guinea pigs, the ria procedure clearly differentiated among antibodies to venezuelan, western, and eastern equine encephalomyelitis viruses. sensitivity of the ria depended on the concentr ... | 1978 | 566768 |
| enzootic and epizootic venezuelan equine encephalomyelitis virus in horses infected by peripheral and intrathecal routes. | forty-five horses were infected peripherally or intrathecally with enzootic or epizootic strains of venezuelan equine encephalomyelitis (vee) virus. low titers of virus appeared in cerebrospinal fluid (csf) after peripheral inoculation of enzootic or epizootic vee virus strains. intrathecal infection with either epizootic or enzootic vee virus produced higher titers of virus in csf than did peripheral infection. in contrast to peripheral infections with enzootic strains, intrathecal infections w ... | 1978 | 580289 |
| comparisons of venezuelan encephalitis virus strains by hemagglutination-inhibition tests with chicken antibodies. | twenty strains of venezuelan encephalitis (ve) virus inoculated intravenously in large doses into roosters produced hemagglutination-inhibition (hi) antibodies detectable in plasmas within 7 to 10 days. no signs of illness occurred, and there was no evidence of viral growth in tissues since blood concentrations of infectious virus steadily decreased after inoculation. hi antibodies in early plasmas were specific for ve virus and did not cross-react significantly with two other north american alp ... | 1977 | 591629 |
| [pathomorphogenesis of experimental infection produced in syrian hamsters by an attenuated strain of venezuelan equine encephalitis virus. 1. acute and subacute phases of the infection]. | | 1977 | 603386 |
| [pathomorphogenesis of experimental infection produced in syrian hamsters by an attenuated strain of venezuelan equine encephalitis virus. 2. histopathologic residual modifications in the brain]. | | 1977 | 603387 |
| study of homologous and heterologous antibody response in california horses vaccinated with attenuated venezuelan equine encephalomyelitis vaccine (strain tc-83). | of 359 horses vaccinated with attenuated venezuelan equine encephalomyelitis (vee) vaccine (strain tc-83), 87% developed hemagglutination-inhibition (hi) antibodies to vee virus within 1 month. blood from a subsample of 101 of the 359 horses was obtained over a 1-year period. within 1 month after vaccination, 84% of the 101 horses had developed vee hi antibodies, 87% had developed vee-neutralizing (nt) antibodies, and 78% had developed vee complement-fixing (cf) antibodies. one year after vaccin ... | 1978 | 637386 |
| production of venezuelan equine encephalitis virus in cells grown on artificial capillaries. | primary cell cultures, a continuous cell line, and a diploid cell line were grown on an artificial capillary system. the cells were subsequently infected with venezuelan equine encephalitis virus, and viral replication was studied. extracellular fluids harvested from this system contained high titers of virus and were relatively free of cell debris. | 1978 | 637540 |
| venezuelan encephalitis virus: in vivo induction of a chromosomal abnormality in hamster bone marrow cells. | this study reports the induction in vivo of aneuploidy in bone marrow cells of the syrian hamster after short-term infection with venezuelan encephalitis virus. | 1978 | 640727 |
| [effect of virulent and anttenuated variants of viruses of american equine encephalomyelitis on the mitotic activity of the cells]. | a comparative study of reproduction of venezuelan and eastern equine encephalomyelitis (vee and eee) viruses in l cell culture showed the disorders of the mitotic activity of the infected cultures to depend on the variant of the inoculated virus and the degree of its attenuation. the highest number of pathological mitosis was observed within 12--24 hours after inoculation of the cultures, the attenuated variants of both the viruses causing lower numbers of pathological mitoses than virulent vari ... | 1978 | 645059 |
| venezuelan encephalitis virus infection in neotropical bats. i. natural infection in a guatemalan enzootic focus. | a serological survey of 939 neotropical bats of 22 species from an enzootic focus of venezuelan encephalitis (ve) virus on the pacific lowlands of guatemala during 1971--1975 revealed ve virus specific antibodies in seven species, three belonging to the genus artibeus. ve virus was isolated from the blood of one uroderma bilobatum. antibody frequency was considerably lower in bats than in terrestrial mammals, and tended to vary within any given species from locality to locality and from year to ... | 1978 | 646021 |
| venezuelan encephalitis virus infection in neotropical bats. ii. experimental infections. | eighty-nine neotropical bats of five species were inoculated subcutaneously with epizootic or enzootic strains of venezuelan encephalitis (ve) virus. viremia was detected in 92.5% of all bats, but no illness attributable to virus infection was observed. detectable viremias averaged slightly over 4 days in artibeus jamaicensis and a. lituratus, and 2.8 days in phyllostomus discolor, and maximal viremia titers in these three species averaged 6.9, 6.6, and 4.6 log10 smicld50 per ml of blood, respec ... | 1978 | 646022 |
| venezuelan encephalitis virus infection in neotropical bats. iii. experimental studies on virus excretion and non-arthropod transmission. | a total of 80 neotropical bats of five species was inoculated with one of four strains of venezuelan encephalitis (ve) virus. virus was detected in the oropharynges of 56% of bats, and most regularly in artibeus jamaicensis (75%). titers of virus in oropharyngeal secretions were occasionally very high (8.5 log10 smicld50/ml in one a. jamaicensis). only 2 of 123 urine samples from 50 bats and 2 of 86 fecal samples from 46 bats yielded ve virus. no contact or aerosol virus transmission from bat to ... | 1978 | 646023 |
| efficacy of trivalent inactivated encephalomyelitis virus vaccine in horses. | twenty-nine horses were vaccinated with a trivalent (venezuelan, eastern, and western) inactivated equine encephalomyelitis virus vaccine. the vaccine purchased for this study was the only one licensed and commercially available in may, 1975. plaque-neutralizing and hemagglutinin-inhibiting antibodies in response to each of the 3 equine encephalomyelitis viruses were determined after vaccination. horses had rising levels of plaque-neutralizing and hemagglutinin-inhibiting antibodies shortly afte ... | 1978 | 646197 |
| venezuelan equine encephalomyelitis virus aggregation and immunogenicity following freeze-drying. | | 1978 | 649621 |
| [antiviral activity of the complexes obtained at different ratios of complementary homopolyribonucleotides]. | antiviral activity of the complexes of synthetic polyribonucleotides, i.e. poly (i).poly (c) and poly (g).poly (c) obtained at non-equimolar ratios of homopolymers was studied. the system of chick embryon fibroblasts and horse venezuellan eguine encephalitis virus served as the model. it was shown that the active and stable complexes poly (i).poly (c) and poly (g).poly (c) were formed at some excess of poly (c), i.e. at the ratio of poly g) or poly (i) to poly (c) equal to 40/60 to 20/80 molar p ... | 1978 | 655685 |
| pathogenesis of a venezuelan encephalitis virus strain lethal for adult white rats. | | 1978 | 670947 |
| isolation of mucambo virus, a member of the venezuelan equine encephalitis virus complex in the state of são paulo, brasil. | | 1978 | 675033 |
| infections of congenitally athymic (nude) and normal mice with avirulent and virulent strains of venezuelan encephalitis virus. | two strains of venezuelan encephalitis virus that are avirulent for normal balb/c mice inoculated subcutaneously were also avirulent for infected congenitally athymic (nude) mice of the same strain. viremias were of similar magnitudes and durations in normal and nude mice. brain concentrations were higher in nude mice with the one avirulent strain tested, although the periods of detectable virus in brains were similar. no lesions were found in brains, spleens, or lymph nodes by ordinary histopat ... | 1978 | 711332 |
| venezuelan equine encephalomyelitis vaccine (strain tc-83): a field study. | in 1971, more than 370 horses in south texas were studied with respect to their clinical, virologic, and neutralizing antibody responses to vaccination with venezuelan equine encephalomyelitis (vee) strain tc-83. this study confirms reported findings that the vaccine used in the 1971 epizootic in the lower rio grande valley of texas was safe and efficacious. vaccinal virus viremia titers were generally below the postulated infection threshold of epizootic vectors. in general, reactions to the va ... | 1978 | 717877 |
| [protein repressor of interferon]. | | 1978 | 749349 |
| virus-induced pancreatic disease by venezuelan encephalitis virus. alterations in glucose tolerance and insulin release. | viral infections have been implicated in the induction of diabetes mellitus in man and laboratory animals. since virus-specific immunofluorescence (fa) is detectable in hamster pancreas during the acute phase of venezuelan encephalitis (ve), experiments were designed to correlate pathologic and virologic events with metabolic studies in ve-infected hamsters. golden syrian hamsters were inoculated s.c. in groups of four to 12 with 100,000 plaque-forming units (pfu) of the vaccine strain (tc-83) o ... | 1976 | 776726 |
| rapid diagnosis of venezuelan equine encephalomyelitis by fluorescence microscopy. | goat venezuelan equine encephalomyelitis (vee) antiserum and normal serum were conjugated and evaluated for staining sensitivity and specificity. cross-staining with either eastern or western equine encephalomyelitis virus-infected cells did not occur. the baby hamster kidney (bhk-21) cell line when combined with highly specific vee conjugate detected 100 medium suckling mouse intracerebral lethal doses (suckling mouse ld-50/ic) of the 1b subtype of vee virus per milliliter of equine tissue susp ... | 1975 | 803352 |
| comparative analyses of members of the venezuelan equine encephalomyelitis virus complex. | polyacrylamide gel electrophoretic examination of viruses selected from the venezuelan equine encephalomyelitis (vee) complex revealed distinct strain to strain differences in profiles of the two virion envelope proteins. the core protein was identical in all viruses tested. we detected five electrophoretic patterns into which the virus strains could be classified and these were designated alpha (alpha), beta (beta), gamma (gamma), delta (delta), and episolon (episolon). isolates representing va ... | 1975 | 803779 |
| venezuelan equine encephalomyelitis virus (veev):strain differentiation and specification of virulence markers. | fourteen strains of veev of diverse origin and antigenicity were classified into five virulence categories according to their efficiency of infection and nature of response in mice. mice of ages up to 30 days represented distinct levels of responsiveness and were suitable for the differentiation of veev strains of highest to lowest virulence. stepwise changes with age of the susceptibility or responsiveness of mice appeared to determined the type of response as predominantly lethal (d), dual or ... | 1975 | 804536 |
| response of sublethally irradiated monkeys to a replicating viral antigen. | temporal effects of exposure to sublethal, total-body x radiation (400 r) on responses to vaccination with attenuated venezuelan equine encephalomyelitis vaccine virus. tc-83, were examined in rhesus monkeys. viremia, often with delayed onset, was prolonged even when irradiation preceded vaccination by 28 days. virus titers were increased, articularly in groups irradiated 4 or 7 days before vaccination. delay in appearance of hemagglutination-inhibition and serum-neutralizing antibody correlated ... | 1975 | 809358 |
| an evaluation of military sentry dogs as a sentinel system to everglades virus (venezuelan equine encephalitis fe3-7c strain). | | 1975 | 812018 |
| multiplication of venezuelan equine encephalitis (mucambo) virus in cultured mosquito cells. | venezuelan equine encephalitis (mucambo) virus was able to multiply at 28degree c in cultured mosquito cells (aedes aegypti and aedes albopictus) without inducing any apparent cytopathology. the kinetics of virus multiplication was similar in mosquito and mammalian (vero) cells. twelve to twenty four hours post-infection, a maximum of 10-50 per cent of the cells were engaged in virus production; however, almost immediately this proportion fell abruptly tending to stabilize in the order of 0.01 t ... | 1975 | 813617 |