Browsing by Author "Schinkel, M"

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    Incidence of seropositive myasthenia gravis in Cape Town and South Africa
    (2007) Bateman, K J; Heckmann, J M; Little, F; Schinkel, M
    Background. Myasthenia gravis (MG) is a treatable autoimmune disease characterised by fatiguable weakness of skeletal muscles. More than 85% of MG patients have antibodies to the acetylcholine receptor (AChR) at the neuromuscular junction or are seropositive for MG (SPMG). In the developed world the incidence of MG has increased, particularly among older individuals, but no epidemiological studies have been done on SPMG in Africa. Objectives. To determine the annual incidence rate (IR) of SPMG in the Cape Town (CT) municipality, and the crude annual IR of SPMG for the whole of South Africa (SA). Methods. Positive AChR antibody tests were identified between 1 January 2003 and 1 January 2005 for patients living in CT, and the age- and sex-specific incidences were calculated. To determine the national crude annual IR over the same period, positive assays were identified from the laboratories that process AChR assays for SA. National Census 2001 population statistics formed the denominators. Results. There were 65 positive assays in CT, and 230 nationwide. Based on these figures the annual IR for CT was 11.2 per million per year (95% confidence interval (CI) 8.7 - 14.3), and for South Africa 2.6 per million / year (95% CI 2.2 - 2.9). After a questionnaire response from CT neurologists regarding the routine use of the AChR antibody assay, the annual IR for CT was adjusted to 12.6 per million (95% CI 9.9 - 15.9) to incorporate those presumed to have SPMG without a confirmatory test. In CT, the IR in females was 15.3 per million / year (95% CI 11.2 - 20.4), and in males, 6.8 per million / year (95% CI 4.1 - 10.7). The CT IRs for blacks, coloureds and whites were not statistically different after adjusting for age and gender. The IR of SPMG in CT was 6 times greater in those presenting after the age of 50 years than in those with earlier disease onset (95% CI 3.7 - 9.7). Conclusions. The annual IR of SPMG in CT is much the same as rates recorded recently in other developed countries, but the rest of SA has a much lower IR. A preponderance of MG starting after the age of 50 years reflects a worldwide trend, although the CT data showed a relatively lower-than-expected incidence for older males. IRs for SPMG vary widely in different regions in SA; this is likely to be related to differences in regional health care delivery, and underdiagnosis.
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    Sensitisation to three cockroach species in Southern Africa
    (2005) Lopata, A L; Jeebhay, M; Groenewald, M; Manjra, A; Du Toit, G; Sibanda, E N; Calvert, J; Lee, S; Schinkel, M; Fenemore, B; Motala, C; Potter, P C
    Cockroaches are important allergen sources in many countries, especially in the tropics. Cockroaches produce several allergens that are major risk factors for rhinitis and asthma. Worldwide, the prevalence of cockroach sensitivity varies between 30% and 70%.Geographical differences exist with regard to cockroach allergen exposure and sensitivity within countries and between countries. No data are available for Africa in this regard. Currently the diagnosis of cockroach sensitivity in southern Africa relies mainly on the detection of specific IgE to Blatella germanica (German cockroach), while a number of other species are found close to human dwellings. The aim of this study was to investigate the prevalence and distribution of sensitisation to three different cockroach species among subjects residing in four different geographical regions in southern Africa. Strong IgE reactivity particular to B. germanica was found among subjects residing in Pretoria and Harare. By contrast strong IgE responses to other cockroach species, Periplaneta americana and Blatta orientalis, were observed in subjects living in Cape Town and Durban. The levels of specific IgE antibodies to all three cockroach species appeared to be higher in Cape Town than those from the other three cities investigated. Monosensitivity to all three cockroach species was observed and minimal cross-reactivity to house-dust mite. These data show that allergy to P. americana and B. orientalis are an important diagnostic consideration in temperate and coastal regions of southern Africa, whereas sensitisation to B. germanica appears to predominate in regions of higher altitude such as Pretoria and Harare.