Epizootology of wildebeest-derived malignant catarrhal fever : possible transmission among cows and their calves in the north-western Transvaal

The investigation involved 52 cases of wildebeest-derived malignant catarrhal fever in 1986 and 1989 in a herd of cattle kept in camps adjacent to a game farm harbouring a herd of approximately 330 blue wildebeest (Connochaetes taurinus). In the outbreaks, 34 cows and 18 calves died as result of the disease. The exceptionally high incidence of the disease in both cows and their calves, the low incidence in calves of unaffected cows, the relatively short period between the death of cows and their calves as well as the occurrence of the disease in 2 calves born after their mothers had been moved away from wildebeest, are indicative of transmission among cows and calves. The death of at least 6 calves within 6 weeks of birth is ascribed to intra-uterine infection while some calves that survived longer may have acquired the infection from other cattle or from wildebeest.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Antibodies against some viruses of domestic animals in southern African wild animals

Twenty-four species of South African wild animals were tested for the presence of antibodies against the viruses of 16 common diseases of domestic animals. Positive results were obtained for African horsesickness, equine encephalosis, equid herpes virus-1, infectious bovine rhinotracheitis,AIIerton disease (Herpes mammillitis), lumpy skin disease, parainfluenza, encephalomyocarditis, bluetongue, Wesselsbron disease, bovine ephemeral fever, and Akabane disease complex. No antibodies could be demonstrated against the viruses of equine influenza, equine infectious anaemia, equine viral arteritis and Rift Valley fever. The negative results substantiate observations that the latter diseases, with the exception of equine viral arteritis, are absent in South Africa. The number of animal species found positive for a specific virus, ranged from 0-16. No antibodies were found in crocodiles and warthogs, whereas antibodies against Wesselsbron and bovid herpes virus-1 were present in 16 species. Antibodies against viruses of horses were found almost exclusively in zebras and, although elephants reacted to African horsesickness, no neutralizing antibodies against it could be demonstrated in their sera. Zebras were also found to be positive for Wesselsbron and Akabane, which are usually regarded as viruses of ruminants. Antibodies against most viruses were encountered in all vegetation zones in South Africa but, as a rule, most viruses were more prevalent in the highrainfall zone in KwaZulu-Natal.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Acid production by flavivirus-infected Vero and Cer cell cultures

VERO and CER cell cultures infected with flaviviruses produce more acid than non-infected control cultures. Acid production is dependent on the presence of glucose. This phenomenon can be utilized for the titration of flaviviruses.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.am201

Some factors governing the entry of Culicoides spp. (Diptera: Ceratopogonidae) into stables

The entry of Culicoides species into stables was examined by comparing the numbers of midges caught with identical light-traps under different conditions. The comparison was made between collections made inside an empty stable, a regularly cleaned stable and a dirty stable and those made outside the stables in a sleeping space open on two sides. The work was first done in the presence of cattle and sheep in adjoining paddocks and then repeated in their absence. A positive correlation was found between the numbers of C. imicola females caught out of doors and inside a clean stable. Removal of the cattle and sheep resulted in a reduction in the numbers of C. imicola caught inside and outside the stables. In contrast, the numbers of Culicoides spp. that prefer to feed on birds was not affected by the removal of the cattle and sheep. Their entry into the stable was proportionate to the size of the entrances into the sleeping space and the size of the stable door and presumably occurs passively. On the other hand, the numbers of C. imicola females entering the same stables were somewhat enhanced by the presence of horses inside the stables and by odours associated with dirty stables.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Circulation of African horsesickness virus in zebra (Equus burchelli) in the Kruger National Park, South Africa, as measured by the prevalence of type specific antibodies

In the Kruger National Park 75% of zebra foals are born in October-March and they lose their passive immunity against African horsesickness virus (AHSV) when they are 5-6 months old. One month later infection with different serotypes of AHSV amounts to 31% and thereafter infections increase rapidly to almost 100% before the foals are 12 months old. The capability of zebra to maintain AHSV is clearly illustrated by the continuing infections during every month of the year with a peak period in winter. This peak is ascribed to the presence of large numbers of susceptible foals in the presence of active Culicoides species.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

The role played by wildlife in the epizootiology of rabies in South Africa and South-West Africa

The role played by wildlife in the perpetuation of rabies is discussed in the light of information obtained during a routine examination of specimens at the Veterinary Research Institute, Onderstepoort, during the 10-year period, 1967-1976. In the course of the investigation, 9 additional hosts of rabies were confirmed and 4 rabies areas identified. The chief disseminators in 2 of these areas were found to be the dog (Canis familiaris) and the black-backed jackal (C. mesomelas); in the third area, the yellow mongoose (Cynictis penicillata), and in the fourth Genetta and Felis spp., including the domestic cat (Felis catis). It was noted that the domestic cat is of less importance in those areas where dogs and jackals are the chief disseminators.This article has been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-Format

Flaviviruses in South Africa : diagnostic procedures

Employing rabbit immune serum, 10 flaviviruses known to be present in South Africa could be divided into 5 serological subgroups. The subgroups conform to the general pattern described for the group. Sera from experimentally infected calves and lambs were monospecific in neutralization tests, but cross-reacted in haemagglutination inhibition tests. These results suggest that sheep and cattle sera from the field can best be tested by microneutralization tests. The greater sensitivity of embryonated hen's eggs for some viruses and of one-day-old mice for other viruses necessitates the employment of both systems for the isolation of flaviviruses from field specimens.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

A study of the pathology of lumpy skin disease in cattle

Microscopic lesions in cattle infected with the virus of the Neethling form of lumpy skin disease comprised a granulomatous reaction in the dermis and hypodermis which extended to the surrounding tissue. During the early stages of the lesions a vasculitis and lymphangitis with concomitant thrombosis and infarction resulted in necrosis and oedema. A hallmark of the acute to subacute stages of the lesions was the presence of intracytoplasmic eosinophilic inclusions in various cell types. The inclusions consisted of the viroplasm which was identified as aggregates of electron-dense, finely granular to fibrillar deposits in which membrane-enclosed virions and occasional groups of tubular structures were observed. Various cytopathogenic changes were observed in cells exhibiting viral proliferation. The morphogenesis of the virions is discussed in relation to the cytopathogenic changes.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Bluetongue virus as a cause of hydranencephaly in cattle

Hydranencephaly was produced in a foetus and a calf by intra-uterine infection with an attenuated Type 10 bluetongue virus. Laparotomy was performed on the respective dams and the foetust:s, respectively 126 days and 138 days old, were inoculated intramuscularly through the uterine wall with 1 ml of a virus suspension containing 5 x 10³ tissue culture infective doses. The younger foetus was aborted on Day 262, while the other one was born alive on Day 273. Both foetuses showed marked hydranencephaly.The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentyation PDF-Format

Attenuation of turkey meningo-encephalitis virus in BHK21 cells

Turkey meningo-encephalitis virus was adapted to BHK21 cell culture. Cytopathic effects were characterized by rounding and detachment of cells within 48 hours. Attenuation was achieved by 41 successive passages in BHK21 cell cultures. Turkeys and Japanese quail ( Coturnix coturnix japonica),kept under laboratory conditions and inoculated with the attenuated virus, did not develop symptoms of turkey meningo-encephalitis but reacted by the production of haemagglutination inhibition antibody. They resisted intracerebral challenge with pathogenic strains of turkey meningo-encephalitis virus.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format