Eradication of poliomyelitis in South Africa.

An international campaign under the leadership of the World Health Organisation is underway to eradicate polio from the world by the year 2000. South Africa may already be free of polio. However, to ensure eradication we need to move from a polio control programme to a polio eradication programme. This necessitates the institution of a surveillance programme for acute flaccid paralysis (AFP) and improvement of the delivery of polio vaccine. All children with AFP (including those with suspected Guillain-Barré syndrome) should be investigated with stool culture to exclude polio. Primary care services need strengthening so that oral polio vaccine coverage greater than 90% is achieved in all regions by all authorities. Outbreak response activities need to be developed. Consideration needs to be given to national immunisation days and mopping-up activities.

Laboratory surveillance of viral meningitis by examination of cerebrospinal fluid in Cape Town, 1981-9.

Nine years accumulated laboratory data derived from the culture of the cerebrospinal fluid of 11,360 aseptic meningitis cases were retrospectively reviewed to establish the epidemiology of viral meningitis in Cape Town. Virus was isolated from 3406 of the cases (91% enteroviruses and 9% mumps). Five major summer viral meningitis episodes were documented: two of echovirus 4 (706 and 445 cases), echovirus 9 (223), coxsackie A9 (104) and one of unidentified enterovirus (324 cases--probably echo 9). Although coxsackie B was endemic, clusters of one or other type were dominant at any one time. Mumps was endemic. Sixty-two percent of all viral cases were < 5 years old. The median ages of 4 and 5 years in echoviruses 9 and 4 (the epidemic strains) contrasted with that of 1 year in coxsackie B (with many cases < 3 months old). Mumps peaked at 3-4 years of age. Males dominated overall, particularly in mumps.

Factors influencing the accumulation in fibrous plaques of lipid derived from low density lipoprotein. I. Relation between fibrin and immobilization of apo B-containing lipoprotein.

The lipid that accumulates in some fibrous atherosclerotic lesions appears to be derived from plasma low density lipoprotein (LDL). An early stage in lipid accumulation may be immobilization of a fraction of the LDL, and this is released by incubation with proteolytic enzymes, of which the most effective is the fibrinolytic enzyme, plasmin. We have examined the relationship between release of fibrin degradation products (FDP) and LDL in controlled plasmin incubations of 42 samples of normal intima and atherosclerotic lesions from aortas of 10 patients. In three patients (group 1) no LDL was released from any of the 11 tissue samples although they comprised lesions as well as normal intima. In 2 more patients (group 2) LDL was consistently low. However, in 5 patients (group 3) substantial amounts of LDL were released from all 21 tissue samples, and there was a significant correlation between the amounts of FDP and LDL (P less than 0.001). In spite of this correlation there were marked differences in the ratio FDP/LDL, but analysis by SDS-polyacrylamide gel electrophoresis and immuno blotting of the FDP released showed no consistent pattern related to LDL binding. Although the ratio FDP/LDL showed a 4-fold range, in 6 lesions subjected to successive 2-h incubations with plasmin the ratio within each lesion remained constant, supporting the concept that fibrin and LDL are linked.

Fate of fibrinogen in human arterial intima.

Fibrinogen and fibrinogen/fibrin-related antigen (total FRA) was measured in human normal intima and different types of atherosclerotic lesions and mural thrombi. The amount showed marked variation between groups of tissue samples, but within each group there was a significant correlation between levels of total FRA and low density lipoprotein (LDL), suggesting that some common factor must influence their influx or retention. The total FRA were analyzed by gradient sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting with antisera to whole fibrinogen and fragments D and E, and fibrinopeptide A (FPA). All intimal samples (but not thrombi) contained fragment X, the first product of plasmin digestion of fibrinogen, but fragment Y was present in only half the samples, and no core-fragment E containing FPA was detected in any sample, suggesting that fibrinogenolysis is limited. By contrast, all samples contained fragment E, which was negative for FPA, so presumably derived from fibrin; they also contained fragments D-dimer and DY, which are characteristic degradation products of cross-linked fibrin. There were no differences between samples obtained during reconstructive vascular surgery and samples obtained at autopsy, so the patterns appear to represent the steady state. This implies that within the intima there is continuous formation of cross-linked fibrin and continuous fibrinolysis, both processes generating fragments that may have atherogenic properties.

Two new genome types of adenovirus 7c.

Adenovirus type 7 is the type most frequently associated with serious disease. Eighteen different genome types of adenovirus type 7 had been reported up to October 1986. The genome type Ad7c, based on the restriction enzyme profiles of SmaI and BamHI, has been reported from Europe prior to 1969 and more recently from South Africa. Here, we report two new genome types of adenovirus 7 c that have not previously been identified and that have been isolated in South Africa between 1975 and 1986 from children with postmeasles pneumonia. The two new genome types differ from the prototype Ad7c virus in having two (Ad7c1) or one (Ad7c2) extra cleavage sites for the restriction endonuclease EcoRI. These sites have been located at 3.68kb and 5.32kb from the left terminus of the genome map published for the prototype Ad7c strain. A strain resembling the prototype Ad7c was also isolated in 1986 from a case of post measles pneumonia.

The surface growth and activity ofNitrobacter.

The effect of surface attachment on oxidation of nitrite to nitrate byNitrobacter was studied in batch culture, on glass coverslips, and in continuous culture on glass beads and anion exchange resin beads in an air-lift column fermenter. In batch culture, the surfaces stimulated specific growth rate, while in continuous culture, activity of attached cells was less than that of freely suspended cells. Nitrate productivity, free cell productivity, and attached cell concentration increased exponentially at the same specific rate, termed the colonization rate, and nitrate productivity was found to be a convenient estimate of biomass concentration. Permanent attachment was mediated by production of slime material. Surface growth resulted in multiple steady states and the ability to respond quickly to changes in dilution rate. The air-lift column fermenter system provided a convenient system for the study of growth and activity of attached cells and was most suitable when using ion exchange resins as a substratum for attachment.

Mitogenic activity in human atherosclerotic lesions.

Focal smooth muscle cell proliferation is a key event in atherogenesis, but the stimulating factors are unknown, and there is little information on the occurrence of growth promoting factors in the arterial wall. We have tested extracts of human aortic intima for stimulation of DNA synthesis, using the chick chorioallantoic membrane (CAM) assay in an attempt to avoid artifacts arising with cultured cells. Consistently high levels of stimulation were obtained with early proliferative (gelatinous) lesions (mean DNA synthesis 188% of control, n = 6) and slightly more advanced transitional lesions (mean 160%, n = 4); results with mature fibrous plaques were variable (range 120-182%, n = 3). Significant stimulation was also given by four of eleven samples of apparently lesion-free intima. Intima contains fibrinogen and a range of fibrinogen and fibrin degradation products (FRA) and preliminary fractionation experiments suggest that activity may reside in the FRA fraction. Serum does not stimulate DNA synthesis in the CAM; extract activity was retained in FRA-containing fractions after removal of most serum proteins by affinity chromatography, but was mainly lost from serum protein-containing fractions after removal of FRA.

Human cytomegalovirus infection.

Human cytomegalovirus (CMV) infection is a very common lifelong infection in South Africa, with intermittent periods of silent reactivation. Infection is spread by intimate contact with infected body fluids (urine, saliva, milk, semen and blood) and most commonly takes place silently in childhood. Clinical disease is rare but may be associated with one or more of the following: (i) a large dose of virus; (ii) a primary infection; and (iii) infection at a time of poor or impaired cellular immunity (developing fetus, after organ transplantation). CMV is an important but rare cause of congenital disease involving especially hearing and neurological deficits. It is often found after organ transplantation but its precise role is not clear. Interpretation of cytomegalovirus tests in connection with an undiagnosed illness is rendered very difficult by the ubiquitous, silently reactivating nature of the virus in both health and disease. An aetiological role is easily assumed but not easily proved.

Lymphosarcoma in a cat.

Feline leukaemia virus (FeLV) antigen was detected in a cat from Cape Town which was subjected to euthanasia after a long history of upper respiratory infection and progressive emaciation. Based on the necropsy findings and subsequent histopathological examinations, a diagnosis of lymphosarcoma was made. It is regarded as likely that this tumour was caused by infection with FeLV.

Aspergillus hypersensitivity in asthmatics in Cape Town.

An analysis of skin prick reactions in 500 consecutive patients referred for investigation and management of asthma showed that 240 patients had multiple positive reactions. Of these patients 46% had positive reactions to Aspergillus and they differed from patients with multiple positive reactions excluding Aspergillus by having onset of asthma at a younger age and being more atopic. Precipitins to Aspergillus were present in the serum of twenty-six of seventy-one consecutive patients in whom these were looked for. Thirteen of the patients with positive precipitins had chest radiograph shadows compatible with allergic bronchopulmonary aspergillosis (ABPA) and in eight of these there was sufficient evidence to make a diagnosis of ABPA. These results were obtained in a region where ABPA had never been previously recognized and they highlight the importance of routine skin prick testing with Aspergillus antigen and of awareness of ABPA in making this diagnosis.

Electron microscopic study of the distribution of the Australia antigen in individual sera of 50 serologically positive blood donors and two patients with serum hepatitis.

The distribution of the morphological types of Australia antigen in 50 blood donors and two patients with serum hepatitis is described.The significance of the high incidence of immune complexes and Dane particles in these persistent carriers is discussed.