Search PubMed⌕ Search

Biomedical subjects

R E Shope

Publications and source records attributed to R E Shope.

At least 37 records · Page 2Linked to original sources
PubMed1997

Serologic evidence of Jamestown Canyon virus infection in white-tailed deer populations from Connecticut.

We determined the prevalence and distribution of Jamestown Canyon (JC) virus antibody in white-tailed deer (Odocoileus virginianus) populations in Connecticut, USA. Sera were collected from hunter-killed deer during 1993. Antibody to JC virus was detected by enzyme-linked immunosorbent assay (ELISA) in 92 (21%) of 446 deer sera, and was uniformly distributed among geographic sites. Twenty-one ELISA-positive sera were tested and confirmed positive by plaque reduction neutralization testing. This represents the first serologic evidence of JC virus in a reservoir host population from the northeastern United States. No cross-reactivity was seen with California encephalitis, Keystone, or snowshoe hare viruses, but a varying degree of cross-reactivity was obtained with Guaroa, Jerry Slough, La-Crosse, San Angelo, and trivittatus viruses. We conclude from this investigation and previous isolations of JC virus from mosquitoes in the state that JC virus occurs enzootically in Connecticut.

Animals↗
PubMed1997

Concepts of control of Japanese encephalitis and dengue.

Japanese encephalitis and dengue are mosquito-borne virus diseases of major human disease importance to the Asian region. Our current knowledge of their distribution and transmission cycles is reviewed, the classical approaches to their control are discussed. The development of live attenuated vaccines for both disease offers possible elimination of human epidemics through combined use of vaccine and mosquito control.

Animals↗
PubMed1996

Genetic variation in yellow fever virus: duplication in the 3' noncoding region of strains from Africa.

The nucleotide sequences of three regions of the genomes of 13 yellow fever (YF) virus isolates were determined to define genetic variation and evolution of the virus. Phylogenetic trees generated from sequences of either the 5' terminal 1320 nucleotides of the genome, 754 nucleotides from the NS4A and NS4B genes, or the 3' terminal 511 nucleotides were very similar and contained minor differences. Overall, these results suggested that there were at least four major genotypes of YF virus, including one in Central/East Africa, one in West Africa, and two in South America. Examination of the 3' noncoding region (3'NCR) showed that only West African strains had a 3'NCR of 511 nucleotides while strains from Central/East Africa and South America had shorter 3'NCRs (443-469 nucleotides) due to the absence of YF specific repeat sequences (RYFs). Central/East African strains have two RYFs and West African strains have three RYFs while South American strains only have one copy of the RYF. It is speculated that duplication of the RYF took place in West Africa subsequent to the presumed introduction of YF virus into South America. Thus, both tick-borne (Mandl et al., J. Virol. 65, 4070-4077, 1991 and Wallner et al., Virology 213, 169-178, 1995) and mosquito-borne flaviviruses have variable 3'NCRs.

Africa↗
PubMed1996

Enzyme-linked immunosorbent assay using recombinant antigens for serodiagnosis of Japanese encephalitis.

Recombinant Japanese encephalitis (JE) virus proteins were evaluated as antigens for serodiagnosis of JE using an enzyme-linked immunosorbent assay (ELISA). The premembrane/membrane (prM/M) and envelope (E) proteins of JE virus were expressed in HeLa cells infected with a recombinant vaccinia virus that encodes the JE virus prM and E genes and were released from cells in a particulate form. The particulate antigens were partially purified from culture fluid from the infected cells by precipitation of particles with polyethylene glycol and then dissociated from the particles with 0.1% Triton X-100. This antigen preparation was used to evaluate one preimmune and two postvaccination sera from 20 volunteers given three inoculations of the commercial JE vaccine (Biken vaccine) by a conventional ELISA. The results from this assay correlated with neutralization data. The results of an IgM capture ELISA carried out with the recombinant antigen also correlated with the results of an existing IgM capture ELISA performed with JE virus-infected mouse brain, when tested with 29 serum and 13 cerebrospinal fluid samples from JE patients. These results indicated that recombinant JE virus antigens are useful for ELISA as an antigenically equivalent, highly productive, and safe alternative to authentic JE virus antigens.

Animals↗
PubMed1996

The S RNA genomic sequences of Inkoo, San Angelo, Serra do Navio, South River and Tahyna bunyaviruses.

The complete nucleotide sequences of the small (S) genomic RNA segments of five California (CAL) serogroup bunyaviruses (two Inkoo virus strains, San Angelo virus, Serra do Navio virus, South River virus and Tahyna virus) were determined. In agreement with previously published data concerning CAL serogroup viruses, the nucleocapsid (N) and non-structural (NSs) proteins were encoded in over-lapping open reading frames (ORFs). All N protein ORFs were 708 nucleotides in length and encoded a 235 amino-acid gene product. The NSs ORFs were either 279 or 294 nucleotides in length, which would encode 92 or 97 amino-acid proteins, respectively. Comparative analysis of the nucleotide sequences and amino acids corresponding to the nucleocapsid protein resulted in a predicted relationship among these viruses that generally agreed with those determined by serology. The only exception was Inkoo virus, where comparisons based on the S RNA sequence and partial M RNA sequence suggest that this virus is more similar to Jamestown Canyon virus of the Melao complex than it is to viruses such as Tahyna and La Crosse viruses of the California encephalitis complex.

Amino Acid Sequence↗
PubMed1995

Double-subgenomic Sindbis virus recombinants expressing immunogenic proteins of Japanese encephalitis virus induce significant protection in mice against lethal JEV infection.

A series of double-subgenomic Sindbis virus (dsSIN) recombinants that express cassettes encoding the immunogenic proteins of Japanese encephalitis virus (JEV) [prM-E, prM-E-NS1, NS1-NS2A, 80%E (encodes the amino-terminal 80% part of E), and NS1] were constructed and analyzed for their ability to confer protective immunity in mice against lethal challenge with neurovirulent JEV. The cassettes were introduced into both 5' [second subgenomic promoter of the vector precedes the SIN structural open reading frame (SP-ORF)] and 3' (the promoter follows the SP-ORF) dsSIN vectors. The longest cassette (prM-E-NS1) was 3.2 kb in length, which is remarkable for such a small vector virus as SIN (SIN genome is roughly 11.8 kb in length). The level of expression of JEV proteins appeared similar for both 5' and 3' recombinants. In general, the stability of the recombinants obtained was found to be low (expression was lost following one to five passages at low multiplicity of infection, depending on the recombinant). However, 5' recombinants containing longer cassettes (prM-E-NS1, prM-E, NS1-NS2A) were more stable than the corresponding 3' recombinants. Intraperitoneal inoculation of mice with 10(7) PFU of dsSIN-JEV recombinants induced antibodies against JEV proteins and low titers of JEV-neutralizing antibodies were produced by mice inoculated with recombinants expressing 80%E, prM-E, and prM-E-NS1. A single immunization of mice with the dsSIN-prM-E or dsSIN-prM-E-NS1 recombinants provided 40-65% protection against peripheral lethal challenge with 10(4) LD50 of neurovirulent JEV. The results demonstrate that genetically engineered togaviruses can be successfully used as vaccine vectors.

Animals↗
PubMed1995

Characterization of a highly attenuated Japanese encephalitis virus generated from molecularly cloned cDNA.

Six recombinant Japanese encephalitis virus (JEV) isolates were recovered from infectious RNAs transcribed by T7 RNA polymerase from molecularly cloned cDNA templates. Three of the recombinant viruses had characteristics similar to the wild-type parent virus, JaOArS982. The other 3 recombinant viruses exhibited an attenuated phenotype in mice. An avirulent recombinant virus, IC47, was characterized and compared with the wild-type parent virus and a virulent recombinant virus, IC37. IC47 produced smaller plaques than parent or IC37 viruses and exhibited no viremia or neuroinvasion in young adult mice inoculated subcutaneously and no mortality when inoculated intracerebrally. IC47 was also immunogenic and protective in the murine model. The probable basis for attenuation, revealed by nucleotide sequence analysis, was a single amino acid substitution at position 138 (Glu to Lys) in the E protein.

Animals↗
PubMed1995

Sensitive and specific colorimetric dot assay to detect eastern equine encephalomyelitis viral RNA in mosquitoes (Diptera: Culicidae) after polymerase chain reaction amplification.

A sensitive and specific colorimetric dot assay following polymerase chain reaction (PCR) method has been developed to detect 0.1 pg of eastern equine encephalomyelitis viral (EEEV) RNA. The assay is 250-fold more sensitive than analysis by electrophoresis and is based on converting a 291-nucleotide sequence of the viral coat protein amino terminus into a double-stranded DNA (dsDNA) and amplifying the DNA using a specific primer pair and PCR. The amplified complementary DNA (cDNA) is denatured adsorbed onto a nylon strip, baked, and detected with a digoxigenin-labeled probe. Dots with viral cDNA are stained dark red, whereas controls do not stain or stain lightly. The assay is very specific and sensitive and detects only EEEV. RNA of Venezuelan equine encephalitis, St. Louis encephalitis, Keystone, Flanders, Tensaw, and western equine encephalitis viruses were not detected. EEEV (Ten Broeck) RNA was detected at the 10-ng level, indicating that the prototype we used may have different nucleotides in the region where the primer pair binds. The PCR amplified EEEV cDNA that was 92% homologous to the consensus sequence of EEEV. The detection of EEEV in the liver of an infected Emu bird and in field-collected mosquitoes from Florida and Massachusetts that were analyzed concurrently as blind samples by tissue culture plaque assay and by PCR dot analysis proved that the assay is sensitive and can be used to detect infected mosquitoes. The assay can detect at least 1 infected mosquito in a pool of 1,000 uninfected mosquitoes.

Animals↗
PubMed1994

Recombinant vaccinia viruses co-expressing dengue-1 glycoproteins prM and E induce neutralizing antibodies in mice.

Four recombinant vaccinia viruses expressing different portions of the dengue type 1 virus (DEN-1) genome (C-prM-E-NS1-NS2A-NS2B; prM-E; prM-E-NS1-NS2A-NS2B; or NS1-NS2A) were constructed in order to establish the most immunogenic configuration of DEN-1 proteins. Both recombinants producing prM and E in the absence of C induced the synthesis of extracellular forms of E in vitro. Mice inoculated with these two recombinants produced DEN-1 neutralizing (NEUT) and haemagglutination inhibiting (HAI) antibodies. The other two recombinant vaccinia viruses, which did not induce the production of extracellular forms of E, did not induce E-specific immune responses. These results support our previous studies on the design of flavivirus-vaccinia vaccine candidates by showing the importance of co-expressing prM and E in order to induce the synthesis of extracellular E and to elicit NEUT and HAI antibodies.

Animals↗
PubMed1994

Avipox virus-vectored Japanese encephalitis virus vaccines: use as vaccine candidates in combination with purified subunit immunogens.

An avipox virus, canarypox (ALVAC), which is naturally host-range restricted, was used to construct recombinants encoding the Japanese encephalitis virus (JEV) prM, E and NS1 genes (vCP107) and prM and E genes (vCP140). Mice immunized with these recombinant viruses produced JEV neutralizing antibodies and were protected from lethal JEV challenge. Protection was also observed in mice immunized with a subunit vaccine candidate, consisting of extracellular particles (EPs; RNA-free subviral membrane vesicles containing prM/M and E proteins) derived from HeLa cell cultures infected with a JEV-vaccinia recombinant. Mice primed with vCP107 and boosted with EPs had higher antibody levels than mice immunized twice with EPs alone, although the levels were comparable to that obtained in mice immunized twice with the recombinant virus. Mice immunized with a mixture of recombinant virus (vCP107) plus EPs had neutralizing antibody titres higher than mice immunized with the recombinant virus or EPs alone.

Animals↗
PubMed1994

Description of Guanarito virus (Arenaviridae: Arenavirus), the etiologic agent of Venezuelan hemorrhagic fever.

This paper characterizes Guanarito virus, the etiologic agent of Venezuelan hemorrhagic fever. Based on its morphology and antigenic properties, Guanarito virus appears to be a new member of the Tacaribe complex of the genus Arenavirus, family Arenaviridae. Complement fixation and indirect fluorescent antibody tests showed that Guanarito virus and its antiserum are broadly cross-reactive with other members of the Tacaribe complex, but it can be differentiated from other members of the complex by neutralization test. Guanarito virus causes mortality in suckling mice and adult guinea pigs, but not in adult mice. Inoculated rhesus monkeys developed viremia and became ill; however, they subsequently recovered and responded with production of antibody. To date, all isolates of Guanarito virus have come from sick persons or wild rodents living within a single geographic focus in the central plains of Venezuela.

Adult↗
PubMed1994

Mosquito and arbovirus surveillance in Connecticut, 1991-1992.

A surveillance program for mosquito-borne arboviruses was conducted in Connecticut following an epizootic of eastern equine encephalitis (EEE) in horses and domestic birds during 1990. Mosquito trapping was done weekly using CO2-baited miniature light traps at 12 freshwater swamp sites that were located mostly in the southeastern portion of the state. Trapping was conducted from June 27 to October 11, 1991 and from June 2 to September 30, 1992. Totals of 7,435 (1991) and 13,912 (1992) adult female mosquitoes representing 21 species in 7 genera were collected and assayed for arboviruses. Virus isolates were identified by ELISA using reference antibody of California encephalitis, EEE, Highlands J (HJ), Jamestown Canyon (JC), LaCrosse, and St. Louis encephalitis viruses. Culiseta melanura was the most common species trapped each year, followed by Aedes canadensis, Aedes cinereus, and Coquillettidia perturbans. The most abundant univoltine snowmelt species was Aedes abserratus. Three isolates positive for JC virus were obtained from Ae. abserratus, Ae. canadensis (new state record), and Ae. cinereus (new state record) that were collected from 2 different sites in June (1992) and July (1991 and 1992). Six isolates positive for HJ virus were made from Cs. melanura and one isolate from Ae. cinereus (new host record) collected in mid- to late September, 1992 from 3 locations. Based on repeated virus isolations in this and other studies, high field infection rates, and its relative abundance, Ae. abserratus appears to be a principal vector of JC in Connecticut. However, the prevalence and importance of JC as a human disease in the state are unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Aedes↗
PubMed1994

Epidemiology of arboviral infections.

OBJECTIVE: To review the current state of knowledge regarding the epidemiology of arboviruses. DATA SOURCES: Computerized literature searches, identification of papers through review of article bibliographies, and Yale Arbovirus Research Unit, USA. STUDY SELECTION: Articles documenting research pertaining to the epidemiology of arboviruses with emphasis on factors that increase or decrease the spread of these infections. DATA EXTRACTION: The review articles were extracted independently by the authors. DATA SYNTHESIS: Arboviral infections are a global health problem accounting for significant morbidity and mortality in human and animal populations. They belong to the families Togaviridae, Flaviviridae, Bunyaviridae, Reoviridae, and Rhabdoviridae, and are transmitted to humans and domestic animals by the bite of infected arthropods. Rodents and birds are significant vertebrate hosts, while humans are usually not involved in the maintenance and spread of most arboviruses. Ecologic changes and human behavior are important in the spread of these infections. Clinical features range from mild fevers to fatal encephalitis. Surveillance, immunization, and vector control are important methods of prevention. CONCLUSION: It appears that the distribution and spread of arboviruses is greatly influenced by human behavior and ecologic changes in the environment. Awareness regarding these and other factors, such as travel history, history of bites of arthropods, concurrent epidemic pattern in the community, and knowledge of surveillance data are useful ways of identifying these infections. Future research may be directed toward methodical search for new arboviruses and their relation to human and animal disease.

Animals↗
PubMed1993

Recurrence of Rift Valley fever in Egypt.

Rift Valley fever (RVF) has been recorded in man and in domestic animals in Egypt after a 12-year absence. Human infections were first noted in the Aswan Governorate in late May, 1993. Only cases of ocular disease, an infrequent and late manifestation, were reported. Of 41 cases, 35 were tested serologically and 27 (77%) had RVF virus-specific IgM antibodies. An estimated 600-1500 infections occurred in the region. Abortions in cattle and buffalo were seen concurrently and antibodies to RVFV were present in 39% of domestic livestock, presumably unvaccinated. RVFV was isolated from an aborted water buffalo fetus.

Abortion, Veterinary↗