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E P Gibbs

Publications and source records attributed to E P Gibbs.

At least 19 recordsLinked to original sources
PubMed1992

Epidemiology of bluetongue viruses in the American tropics. Regional Bluetongue Team.

A study of the epidemiology of bluetongue viruses is in progress with the collaboration of 11 Central American and Caribbean countries. To date, over 200 bluetongue virus isolates have been obtained from cattle and sheep in sentinel groups distributed in the participating countries. Bluetongue serotypes identified include 1, 3, 6, and 12, virus types not previously recorded in the Western Hemisphere. Although the clinical impact of bluetongue virus infections in this hyperendemic environment appears to be minimal, the ubiquity of infection causes restrictions on the export of ruminant livestock and germ plasm. The stability of the Caribbean region ecosystem and the long-range implications of the interface with the northern temperate bluetongue virus ecosystem are reviewed.

Animals↗
PubMed1992

Evaluation of Culicoides insignis (Diptera: Ceratopogonidae) as a vector of bluetongue virus.

Based upon epidemiological evidence, Culicoides insignis Lutz is a probable biological vector of bluetongue viruses (BTV) in South Florida, the Caribbean Region and Central America. The vector potential of this species for BTV was evaluated in the laboratory in a series of experiments using insects caught in the field. Although there was great variation in the percentage of flies that fed from any one catch, it was demonstrated that C. insignis became infected after membrane feeding on a mixture of blood and virus. The infection rates ranged from 20 to 62.5%. Following intrathoracic inoculation, BTV replicated to high titres in C. insignis. Such flies were also shown to be capable of transmitting BTV to susceptible sheep and embryonated chicken eggs. This series of experiments provides the first conclusive evidence that C. insignis is a biological vector of bluetongue virus. This is the first proven vector of BTV in the neotropics.

Animals↗
PubMed1991

Isolation and molecular characterization of the swinepox virus thymidine kinase gene.

Swinepox virus (SPV), the only member of the Suipoxvirus genus, shows little antigenic relatedness or DNA homology to members of the other poxvirus genera. A SPV thymidine kinase (TK) gene was detected and mapped to the left end of the HindIII G fragment using degenerate oligonucleotide probes. Cloning and sequencing of a 1.8-kb HindIII-BamHI fragment containing the SPV TK gene revealed an open reading frame (ORF) of 181 amino acids yielding a predicted polypeptide of Mr 20.6 kDa with significant homology to both poxvirus and vertebrate thymidine kinases. Comparison with other TK protein sequences showed that the SPV thymidine kinase was closely related to the TK genes of avipoxviruses (52.0%) and vertebrates (57.1-59.7%). The TK gene from African swine fever virus (ASF) showed little homology (30.5%) to the SPV TK gene suggesting that these two viruses are not closely related though they share many biochemical features and infect a single, common mammalian host (swine). The SPV TK gene, like that of other poxviruses, is transcribed early, and when cloned into a TK- strain of vaccinia converted the virus to a TK+ phenotype. BUdRR mutants of SPV contained frameshift, deletion, and missense mutations in the TK ORF.

Amino Acid Sequence↗
PubMed1991

Seroepidemiology of Bivens Arm virus infections of cattle in Florida, St. Croix and Puerto Rico.

Bivens Arm virus (BAV) is a newly discovered rhabdovirus infecting cattle and water buffalo in Florida. The virus is classified as a member of the Tibrogargan group, members of which have hitherto been found only in Australasia. They are considered to be transmitted by Culicoides species. Bivens Arm virus was first isolated from Culicoides insignis which suggests that BAV is also transmitted by this genus. A serological survey of two small groups of cattle raised in St. Croix and Puerto Rico, in the Caribbean, established that antibody to BAV, or a closely related virus, exists on both island. A retrospective analysis of seroconversions to BAV in sentinel calves in Florida, relative to populations of potential Culicoides vectors, failed to demonstrate any statistically significant correlation.

Animals↗
PubMed1990

Culicoides spp. (Diptera: Ceratopogonidae) associated with cattle in St. Croix, Virgin Islands, and their relevance to bluetongue virus.

Potential biting midge vectors were collected at two sites on St. Croix as part of an ongoing study on the epidemiology of bluetongue viruses in the Caribbean region. Six species of Culicoides were trapped in a New Jersey light trap (mean = 173 biting midges/trap night) near cattle on a dairy farm. C. furens (Poey) and C. insignis Lutz were the predominant phototactic species, and C. pusillus Lutz, C. trilineatus Fox, C. jamaicensis Edwards, and C. phlebotomus (Williston) were collected less frequently. Four species of Culicoides were aspirated from bovine bait during the morning and evening crepuscular periods with a modified car vacuum. C. furens was aspirated primarily from the ventral portions of the bovine host, whereas C. insignis and C. pusillus were collected principally from the dorsum, and C. trilineatus was collected equally from all aspects. At least one individual of each of these aspirated species was blood engorged. Because C. furens, C. insignis, C. pusillus, and C. trilineatus were most abundant and feed on cattle, they deserve further consideration as vectors of bluetongue virus on St. Croix.

Animals↗
PubMed1990

Bluetongue epidemiology in the Caribbean region: serological and entomological evidence from a pilot study in Barbados.

Variation in the percentage of lambs seroconverting to bluetongue viruses was seen between sites and years in Barbados. Transmission at some sites was nearly absent whereas all lambs at one site became seropositive. The agar gel immunodiffusion test for bluetongue gave consistent results in series of serum samples from 112 of 121 sentinel lambs. Collections of biting midges in association with sheep yielded six species: Culicoides insignis Lutz, C. pusillus Lutz, C. phlebotomus (Williston), C. furens (Poey), C. jamaicensis Edwards and C. trilineatus Fox. The first two species comprised 92% of those caught during a sentinel lamb study and were the predominant species trapped for virus isolation. No viruses were recovered from 5517 C. insignis, 614 C. pusillus, three C. trilineatus and two C. furens placed into pools during two brief intensive trapping operations.

Animals↗
PubMed1990

Serologic survey for transmissible gastroenteritis virus neutralizing antibodies in selected feral and domestic swine sera in the southern United States.

Serum samples collected from feral and domestic swine (Sus scrofa) in Florida and feral swine in Georgia and Texas were assayed by plaque reduction for their virus neutralizing (VN) antibodies against the porcine transmissible gastroenteritis virus (TGE). None of 560 samples collected from feral swine contained VN antibodies for TGE virus, but experimentally infected feral swine seroconverted. None of 665 samples from domestic swine contained TGE-VN antibodies. These results indicate feral swine are not a significant reservoir for TGE virus in southern states, but are capable of becoming infected and developing VN antibodies against TGE.

Animals↗
PubMed1990

Epidemiologic study of bluetongue viruses in Central America and the Caribbean: 1986-1988. Regional Bluetongue Team.

Results of a prospective serologic and virologic study of ruminant livestock in Central America and the Caribbean islands revealed bluetongue virus (BTV) to be enzootic in the 9 countries participating in the study. Bluetongue virus serotypes 1, 3, 6, and 12 were isolated from sentinel animals. To the authors' knowledge, these are the first isolations of BTV from the region studied and the first isolations of these serotypes in the Western Hemisphere. Clinical disease attributable to BTV infection was not observed in sentinel animals. The incidence pattern, with respect to age and geographic location, was determined. The need to evaluate the epizootiologic features or arthropod-borne viruses (arboviruses) on a regional ecologic basis is stressed.

Animals↗
PubMed1989

Bivens arm virus: a new rhabdovirus isolated from Culicoides insignis in Florida and related to Tibrogargan virus of Australia.

During field studies in 1981 on the transmission of bluetongue viruses in ruminants in Florida, a virus was isolated from Culicoides insignis collected near water buffalo (Bubalus bubalis) recently imported from Trinidad. Electron microscopy showed that this isolate, for which the name Bivens Arm virus is proposed, has rhabdovirus morphology. Serologic comparisons were made with recognized rhabdoviruses from terrestrial vertebrates and hematophagous arthropods. Indirect fluorescent antibody, complement fixation and neutralization tests indicated antigenic reactivity between Bivens Arm virus and two rhabdoviruses found only in Australia, Tibrogargan and Coastal Plains viruses. The Australian isolates cause subclinical infections in cattle and water buffalo and are believed to be transmitted by Culicoides. Initially, it was thought that Bivens Arm virus may have been introduced to Florida with the water buffalo from Trinidad, but a serologic survey of cattle serum, collected before the importation of the buffalo revealed antibody to the virus in cattle on farms located in diverse areas of Florida.

Animals↗
PubMed1989

Bluetongue epidemiology in the Caribbean region: serological and entomological findings from a pilot sentinel system in Trinidad and Tobago.

When monitored by the agar gel immunodiffusion test for antibody to bluetongue viruses, a sentinel flock of twenty-five lambs remained seropositive through the year, whereas in a sentinel herd of twenty calves only two individuals seroconverted and these became negative again within 2 months. A light trap operated with the calf herd yielded high numbers of Culicoides insignis Lutz (over 18,000 per trap night) along with C. filariferus Hoffman, C. pusillus Lutz, C. leopoldi Ortiz, C. foxi Ortiz, C. limai Barretto, C. diabolicus Hoffman and C. guyanensis Floch and Abonnenc. Culicoides were trapped at the sheep station which had housed the lambs 3 years following the sentinel study. No virus was isolated from pools of C. insignis, C. filariferus and C. pusillus. Six other species were collected in insufficient numbers to warrant attempted virus isolations.

Animals↗
PubMed1988

Detection of eastern equine encephalomyelitis virus antigen in equine brain tissue by enzyme-linked immunosorbent assay.

Sensitivity and specificity of an antigen-capture ELISA vs virus isolation in cell culture were evaluated for the detection of eastern equine encephalomyelitis (EEE) virus in the brain tissue of naturally infected equids. Brain specimens from 16 equids with neurologic disease were examined by ELISA and by inoculation onto baby hamster kidney cell cultures. Of 10 brain samples from which virus was isolated in the cell culture bioassay, all were correctly identified as containing EEE virus antigen by ELISA. None of the remaining 6 specimens, without detectable infectious EEE virus, contained detectable antigen. Sensitivity and specificity of the ELISA were 100% with no false-positive or false-negative results. The antigen-capture ELISA was a rapid, sensitive, specific, and simple alternative to a traditional bioassay for the detection of EEE virus.

Alphavirus↗
PubMed1985

Two electropherotypes of bluetongue virus serotype 2 from naturally infected calves.

The first isolation of bluetongue virus (BTV) serotype 2 in the U.S.A. was in 1982 from a sentinel herd of cattle at Ona, Florida. Electrophoretic analysis of genome RNA revealed that all 16 serotype 2 isolates obtained from this focus of infection had one of two electropherotypes (designated Ona A and Ona B). All genome segments of Ona A and Ona B had detectable differences in electrophoretic mobility, with major differences noted for segments 1, 4, 5, 7, 8, 9 and 10. Electrophoretic comparison revealed that Ona A was indistinguishable from the African serotype 2 prototype isolated 23 years earlier. In 1983, Ona B, in the apparent absence of Ona A, was isolated from two additional cattle herds in Florida. These results suggest that Ona B may be a variant of Ona A that evolved as a result of mutation or reassortment with another BTV strain, and may be better adapted to the selective pressures found in southern Florida. Comparison of the electropherotypes of Ona B with two Florida isolates of serotype 13 and 17 and the prototypes of BTV 10, 11, 13 or 17 produced no evidence for reassortment between Ona A and any of these strains as the possible origin of Ona B.

Africa↗
PubMed1985

Orbiviruses from Culicoides in Florida.

Between 1980 and 1983, 45,484 Culicoides spp. collected in Florida near cattle have been examined for orbiviruses by attempted isolation in cell cultures and intravenous (IV) inoculations of embryonated chicken eggs. Bluetongue virus (BTV) serotype 2 was isolated from a pool of Culicoides insignis trapped at Ona. This is the 1st recovery of BTV from this species representing the 2nd new world species of Culicoides from which BT viruses have been isolated. C. insignis is a neotropical form which extends from northern Florida through the Caribbean region and much of South America. If this species is proven capable of biological transmission of BTV, it could help explain the distribution of antibodies to BTV in areas lacking C. variipennis. Epizootic hemorrhagic disease virus (EHDV) serotype 2 was recovered from several pools of C. variipennis collected at 2 beef cattle operations in Florida. No viruses were isolated from the small number of C. arboricola, C. stellifer and C. niger examined.

Animals↗
PubMed1985

Serological observations on the epidemiology of bluetongue virus infections in the Caribbean and Florida.

Serological surveys of cattle, sheep and goats have confirmed that infection with bluetongue virus (BTV) is common in Florida, Puerto Rico and St. Croix in the USA, in the Caribbean countries of Jamaica, St. Kitts/Nevis, Antigua, St. Lucia, Barbados, Grenada, Trinidad and Tobago, and the Bahamas, and in the South American countries of Guyana and Suriname. In most countries, over 50% of ruminant livestock have antibody to BTV as assessed by the bluetongue immunodiffusion (BTID) test. A sentinel animal system operating in Florida and 4 islands in the Caribbean has established that the transmission of BTV is seasonal, with most animals becoming infected in late summer and fall. In Florida, it appears that there may be some years when little virus transmission occurs among cattle. Examination of sera from yearling animals and sentinels in the region for antibody to the range of serotypes of BTV recognized worldwide, has resulted in a) the isolation of BTV type 2 from cattle in Florida - the 1st time this virus has been identified in the Western Hemisphere - and b) the recognition that the range of serotypes of BTV present in the Caribbean may be different from those in the USA. No clinical disease has been associated with BTV during the period of these studies (1979-83).

Animals↗