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Biomedical subjects

F G Davies

Publications and source records attributed to F G Davies.

At least 37 records · Page 2Linked to original sources
PubMed1985

The alterations in pathogenicity and immunogenicity of a Kenya sheep and goat pox virus on serial passage in bovine foetal muscle cell cultures.

A Kenyan sheep and goat pox virus was attenuated by serial passage in bovine foetal muscle cell cultures. The pathogenicity of the strain was lost between the 15th and 20th passages. Serum-neutralizing antibody developed after inoculation with passages tested up to the 50th. These passages appeared to protect animals against laboratory challenge by intra-dermal titration. The 18th passage was successfully and extensively used to control the disease under field conditions.

Animal Diseases↗
PubMed1985

A study of the host range and distribution of antibody to Akabane virus (genus bunyavirus, family Bunyaviridae) in Kenya.

Serum neutralizing antibody to Akabane virus (genus bunyavirus, family Bunyaviridae) was found in a high proportion (50-95%) of cattle sampled in Kenya, while sheep and goats had fewer positive (13-33%). Camel and horse sera also contained antibody to the virus (70% and 50% respectively). The antibody was found in animals from the high altitude temperature type of grasslands, drier bushed and wooded grasslands and the semi-desert. No arthrogryposis nor hydranencephaly has been encountered in Kenya which might be related to this widespread virus infection. A wide range of Kenyan wild ruminants had antibody to Akabane virus in their sera, as also did zebra.

Altitude↗
PubMed1985

Rift Valley fever virus (family Bunyaviridae, genus Phlebovirus). Isolations from Diptera collected during an inter-epizootic period in Kenya.

A total of 134 876 Diptera collected in Kenya during a 3-year period were tested in 3383 pools for Rift Valley fever (RVF) virus. Nineteen pools of unengorged mosquitoes were found positive for RVF. All isolations were made from specimens collected at or near the naturally or artificially flooded grassland depressions that serve as the developmental sites for the immature stages of many mosquito species. The isolation of virus from adult male and female A. lineatopennis which had been reared from field-collected larvae and pupae suggests that transovarial transmission of the virus occurs in this species.

Aedes↗
PubMed1985

Rainfall and epizootic Rift Valley fever.

Epizootic Rift Valley fever (RVF) has occurred in Kenya four times over the last 30 years. Widespread, frequent, and persistent rainfall has been a feature of these epizootic periods. A composite statistic, based upon measurements of these rainfall characteristics, is positive during periods of epizootic Rift Valley fever. The heavy rainfall raises the level of the water table in certain areas, flooding the grassland depressions (dambos) that are the habitat of the immature forms of certain ground-pool-breeding mosquitos of the genus Aedes. RVF virus is probably transmitted transovarially in these species, very large numbers of which emerge under these damp conditions. This is when clinical signs of the disease are first seen.

Animals↗
PubMed1982

Observations on the epidemiology of lumpy skin disease in Kenya.

Lumpy skin disease virus strains isolated in Kenya over a period of some 20 years have proved to be serologically identical. They were indistinguishable by indirect fluorescent antibody and serum neutralization test from the South African Neethling and West African serotypes. These two serological methods proved of value in studying the antibody responses to infection. While epizootic spread of LSD has occurred in Kenya, most cases are of a sporadic nature and are thought to be the result of accidental contacts with a maintenance cycle. There is evidence of antibody to LSD in the African buffalo (Syncerus caffer) in those areas where LSD is considered to be enzootic in Kenya, and also in small numbers of domestic cattle. No buffalo or bovine sera contained antibody to cowpox virus. An area enzootic for LSD is proposed and it is suggested that the maintenance cycle involves the buffalo. No antibody was found in the other wild ruminant species examined.

Animals↗
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↗