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Biomedical subjects

R E Shope

Publications and source records attributed to R E Shope.

At least 91 records · Page 5Linked to original sources
PubMed1982

Electrophoretic comparison of the genomes of North American bluetongue viruses, one Australian bluetongue virus, and three other related orbiviruses.

The genomes of U.S. bluetongue viruses, an Australian bluetongue virus, and three other related orbiviruses were analyzed by polyacrylamide gel electrophoresis. The genomes were comprised of ten segments of double-stranded (ds) RNA. Estimates of the molecular weights of the dsRNA segments revealed that the U.S. bluetongue serotypes were remarkably similar. Although the dsRNA profiles of the viruses exhibited common segments, each virus had a distinct dsRNA profile. The usefulness of the genome analysis as a diagnostic tool for identification and for epidemiologic studies is discussed.

Arboviruses↗
PubMed1982

Molecular basis of bunyavirus per os infection of mosquitoes: role of the middle-sized RNA segment.

The molecular basis of bunyavirus per os infection of mosquitoes was determined; La Crosse (LaC), snowshoe hare (Ssh), and LaC-Ssh reassortment viruses were compared for their ability to infect Aedes triseriatus, the natural vector of the LaC virus. The viruses were comparable in their ability to infect midgut cells; 115 of 117 (98%) mosquitoes ingesting viruses containing the LaC middle-sized RNa segment and 92/100 (92%) of mosquitoes ingesting viruses containing the Ssh middle-sized RNA segment became infected. However, those viruses containing the LaC middle-sized RNA segments disseminated efficiently (113/115, 98%) from the midgut to infect secondary target organs. Those viruses containing the Ssh middle-sized RNA segment efficiently infected the midgut and large amounts of viral antigen were detected in the midgut cells but antigen was detected in the secondary target organs only in 26% (24/92) of the mosquitoes with midgut infection. Thus, the middle-sized RNA segment seems to be the major determinant for successful dissemination of LaC virus from infected A. triseriatus midgut cells.

Aedes↗
PubMed1982

Detection of La Crosse arbovirus antigen in mosquito pools: application of chromogenic and fluorogenic enzyme immunoassay systems.

An enzyme immunoassay producing either a chromogenic or fluorogenic end product was developed and evaluated for detecting La Crosse viral antigen within mosquito pools. The enzyme immunoassay was found to be sensitive, detecting one infected mosquito within a pool of 100 mosquitoes, and specific, distinguishing between closely related California group viruses. Assays were completed within 5 h after the addition of test samples. La Crosse viral antigen could be readily detected in mosquito pools after seven freeze-thaw cycles.

Aedes↗
PubMed1982

The spread of Rift Valley fever and approaches to its control.

Rift Valley fever (RVF) is primarily a disease of sheep, cattle, other domestic animals, and man; it was believed to be relatively benign for man until 1977 when it spread to Egypt. There it caused enormous losses of sheep and cattle, and thousands of human cases occurred, with nearly 600 reported deaths. Although mosquitos are known to transmit RVF virus in epizootics and epidemics, the reservoir and means of inter-epizootic maintenance are not known. RVF epizootics can be recognized by a combination of observations: abortions and neonatal death in sheep and cattle at times when mosquitos are abundant, accompanied by cases of fever in man, which are complicated in a minority of patients by haemorrhagic fever, encephalitis, and retinitis with blindness. Vaccination of livestock with available killed or live attenuated vaccines should prevent transmission to both human subjects and animals. Although routine quarantine of animals is not deemed a practical measure, movement of animals should be restricted when an epizootic is in progress. Since it is possible that RVF may spread from Africa in the future, serological surveillance in man and animals is recommended in potentially receptive countries of the Mediterranean Basin and South-West Asia to establish baseline data and to familiarize staff with the methods of RVF diagnosis.

Africa↗
PubMed1981

Molecular basis of bunyavirus transmission by mosquitoes: role of the middle-sized RNA segment.

In an examination of the molecular basis of oral transmission of bunyaviruses by mosquitoes., La Crosse (LAC), snowshoe hare (SSH), and LAC-SSH reassortant viruses were compared in their ability to be transmitted to laboratory mice by the natural mosquito vector of LAC virus, Aedes triseriatus. Both LAC virus and the reassortment viruses containing the middle-sized (M) segment from the LAC parent were efficiently transmitted. In contrast, SSH virus and reassortment viruses containing the M RNA from the SSH parent were inefficiently transmitted. Thus, the M RNA segment, which codes for the virion glycoproteins, may be a major determinant of oral transmission of bunyaviruses by mosquitoes.

Aedes↗
PubMed1980

Bunyaviridae.

The family Bunyaviridae comprises over 200 viruses (serotypes, subtypes, and varieties) that infect vertebrates and/or invertebrates. Four genera of viruses have been defined (Bunyavirus, Nairovirus, Phlebovirus, and Uukuvirus). The main characteristics of the member viruses are: (i) the virus particles are for the most part uniformly spherical, 80-110 nm in diameter, and possess a unit membrane envelope from which protrude polypeptide spikes 5-10nm long; (ii) the viruses have three helical nucleocapsids, often in the form of supercoiled circles, each consisting of a single species of single-stranded RNA, major nucleocapsid polypeptide, N, and at least in some cases minor amounts of a large polypeptide which may be a transcriptase component; (iii) the genome is composed of three species of RNA (L, large; M, medium; and S, small), organized in end-hydrogen bonded circular structures; (iv) most viruses have three major virion polypeptides (N, and two surface polypeptides, designated G1 and G2); (v) for at least some member viruses, the virions have been shown to contain an RNA-directed RNA polymerase, believed to be responsible for the synthesis of viral complementary mRNA, so that bunyaviruses are considered to be negative-stranded viruses; (vi) at least some bunyaviruses are capable of heterologous virus genome segment reassortment and can form recombinant viruses at high or low frequency; (vii) viruses appear to mature primarily at smooth membrane surfaces and accumulate in Golgi vesicles and saccules, or nearby; (viii) transovarial, venereal and/or transstadial transmission in arthropods has been shown to occur for some members of the family.

Bunyaviridae↗
PubMed1980

Semen changes in boars after experimental infection with pseudorabies virus.

Two groups of adult boars were inoculated with a field strain of pseudorabies virus (PRV) by intranasal droplet; one group was given 5 x 10(5) median tissue culture infective doses (TCID50), and the other, 5 x 10(6) TCID50. (A third group was maintained as controls.) Ejaculates were examined twice a week for volume, sperm numbers, sperm morphology, and presence of PRV. Severe clinical disease with fever followed administration of the larger virus dose. Death (one boar), testicular degeneration, and transient elevation in spermatozoa with proximal cytoplasmic droplets were seen in different members of this group. The smaller dose resulted in seroconversion, but did not produce signs of disease. In this group, volume, sperm numbers, and sperm morphology did not decline when compared with base-line values or data of control animals. The virus was not isolated from semen. Effects of PRV infection on semen quality in boars seem to be related to the associated clinical signs of systemic disease.

Animals↗