The mechanical transmission of hepatitis B virus by the common bedbug (Cimex lectularius L.) in South Africa

Tests for both hepatitis B surface antigen (HBsAg) and hepatitis e antigen (HBeAg) were carried out on wild-caught and laboratory-colonized bedbugs (Cimex lectularius L.), the latter after hepatitis B virus (HBV)-positive blood-meals. Positivity for both antigens was interpreted as an indication of HBV infectivity. Of 22 pools in which were tested 211 bugs collected in the northern Transvaal, 18 were HBsAg-positive and 17 HBeAg-positive, with estimated infection rates of 156,7 and 137.7 per 1000 bugs respectively. Passage of HBV in bugs, allowing an extrinsic incubation period of 57-69 days, resulted in 19 out of 25 bugs being positive for HBsAg after the first passage; only a small number of these were positive for HBeAg. After the second passage all bugs tested were HBsAg-negative, showing that the virus had disappeared. Tests on the salivary glands and carcass of each bug at intervals up to 31 days after an infective meal showed a positivity rate of 98% (HBsAg) and 17% (HBeAg) for carcasses and 20% (HBsAg) and 0% (HBeAg) for salivary glands. Attempts to detect HBV particles in the salivary glands by electron microscopy failed. Bugs were shown to continue to excrete HBsAg in their faeces up to the 42nd day, and both HBsAg and HBeAg together up to the 30th day. HBsAg particles were only detected by electron microscopy in faeces hal1lested on the 10th day. The results as a whole· indicate that no biological mUltiplication of virus occurs in C. lectularius but that mechanical transmission from inseCts to man could occur by: (i) contamination of a person when crushing infective bugs; (ii) contamination from infected faeces; and (iii) infection by bite due to regurgitation or interrupted feeding

Further observations on the ultrastructure of ephemeral fever virus

Electron microscope observations on ephemeral fever virus showed that the electron-dense material was helical in structure, that probably two strands 4 nm in diameter formed a limb approx. 17 nm in diameter with one complete turn of the helix occupying 10 nm. A proposed model of the virus is illustrated.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format..mn201

Electron microscopic study of the information of bluetongue virus

BHK 21 cells infected with bluetongue virus were sampled at various stages during a single cycle of viral replication, sectioned and studied with the electron microscope. Stages in development of the virus have been recorded including initial penetration into the cell and eventual exit from the cell of mature particles. This study indicates that bluetongue virus essentially has no envelope. Successive characteristics shown by the cells include: (1) appearance of dense inclusion bodies; (2) swelling of the endoplasmic reticulum; (3) the appearance of masses of fine filaments m the cytoplasm; (4) the presence of mitochondria containing dense inclusion bodies; (5) the appearance of bundles of tubular elements; (6) the presence of irregular, dense bodies containing virus particles and (7) incipient and mature virus particles.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

An investigation of the occurrence of sv40 antibodies in South Africa

We developed an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to simian virus 40 (SV40) in human serum. We then used the ELISA to test for anti-SV40 antibodies in healthy inviduals and patients suffering from cancer and renal diseases. The aim of the study was to determine the presence of antibodies against SV40 in sera of individuals who received the South African poliovirus vaccines from 1958 to the present. Detecting such antibodies could give an indication of whether any of the poliovirus vaccines used in South Africa were ever contaminated with the SV40 or not. A total of 5/164 samples were repeatedly positive for SV40 antibodies by the ELISA. Four of the samples were from the healthy population group and the remaining 1 (1/64) was from the patient group. An SV40 antibody-blocking assay and a Western blot were used as additional confirmation for the SV40 antibodies, whereas the Western blot assay developed a single common band on all 5 samples

Electron microscopic and serological studies on simian virus S.A. 11 and the "related" O agent

Electron microscopic and serological studies carried out on Simian virus S.A. 11 and the O agent in MK2 cells have indicated that these viruses differ considerably. While S.A. 11 virus is associated with vesicles of the rough endoplasmic reticulum, with viral inclusion bodies and with membranous elements, O agent shows no such relationships but occurs in vacuoles and in crystalline array in the cytoplasmic matrix. No cross neutralization could be demonstrated.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 the final presentation PDF-format

Electron microscopic studies on reovirus type 1 in BHK 21 cells

BHK 21 cells infected with reovirus Type 1 were sampled at various stages during a single cycle of virus replication, sectioned and studied with the electron microscope. Attention is drawn to cytopathic characteristics shown by the infected cell which are absent from uninfected cells. On the basis of similarities with bluetongue virus it is suggested that the nucleic acid moiety of the virus particles may be incompletely inserted in the capsid. This may be due to incomplete coiling up of the nucleic acid before condensation of the capsid around the nucleic acid or incomplete packing in of the nucleic acid into a preformed capsid or possible leaking out of the nucleic acid from the formed virus particle.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Variation in morphology of ephemeral fever virus

Electron microscope studies on the three ephemeral fever virus (EFV) strains EFVl, EFV13 (South Africa) and Japanese bovine epizootic fever (BEF) virus (Strain YHK) showed that the normally cone-shaped South African EFV, may, under certain circumstances, appear bullet-shaped while the Japanese EFV which is usually bullet-shaped may appear as a cone. These findings suggest that ephemeral fever virus is pleomorphic.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 the final presentation PDF-format

Mechanism of envelopment of herpesvirus by the nuclear envelope

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 the final presentation PDF-format.Meat Board of the Republic of South Afric

Formation of Wallal virus in cell culture

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 the final presentation PDF-format.Winston Churchill Memorial Trus

Visualization of the extracapsid coat in certain bluetongue-type viruses

Electron microscopic studies employing the negative staining technique have demonstrated an extracapsid coat in Corriparta, Eubenangee, D'Aguilar, Warrego, Mitchell R, Wallal and M9/71 viruses. These observations are substantiated by the fact that coated and uncoated virus particles exhibit different diameters.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 the final presentation PDF-format.Winston Churchill Memorial Trus