Masters Degrees (Medical Virology)

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Browsing Masters Degrees (Medical Virology) by Subject "Blood donors -- South Africa -- Western Cape"

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    Prevalence and risks of Hepatitis E virus infection in blood donors from the Western Cape, South Africa
    (Stellenbosch : Stellenbosch University, 2016-03) Lopes, Tatum; Andersson, Monique I.; Preiser, Wolfgang; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Pathology. Medical Virology.
    ENGLISH ABSTRACT: Hepatitis E virus (HEV) is an important cause of enterically transmitted acute hepatitis worldwide and is a locally acquired disease in both developing and developed nations. Different genotypes in these two regions display the different characteristics of this interesting infection. HEV is classified into four major genotypes and it can present as two contrasting clinical entities. HEV genotypes 1 (HEV1) and 2 (HEV 2) are related to waterborne transmission and poor sanitation. Whereas genotypes 3 (HEV3) and 4 (HEV4) are associated with zoonotic transmission mainly through pigs, wild boar and deer. HEV infections in Africa are thought to be caused by HEV1 and HEV2. The seroprevalence of HEV has been described in Southern Africa, but all more than 10 years ago when assays were not well developed. South Africa has three HEV reports, describing a hospital outbreak, and the seroprevalence in specific communities of South Africa. The seroprevalence from these studies ranged from 2% to 10.7% however no genotyping was done. Researchers have reported evidence of direct and indirect transfusion-transmitted HEV infection being a potential risk to recipients of blood transfusions. Asymptomatic HEV infections in blood donors increase the likelihood that blood or blood products are contaminated with HEV viral particles. Hence, there is a greater chance of infecting high-risk recipient groups with compromised immune systems. Therefore, the main aim of this study was to determine the prevalence of past and active HEV infection in blood donors from the Western Cape. We also investigated which risk factors are associated with infection. Our study population consisted of 10,250 blood donors that were tested as two sub-studies. For study group 1 we recruited 250 donors to complete an HEV risk questionnaire. Thereafter these donors were tested using an indirect Wantai ELISA (Fortress Diagnostics) for anti-HEV IgG detection. Statistical analysis was done to determine which demographics and risk factors were associated with past HEV infection. In addition, to this, their plasma donations were pooled, prior to extraction and amplified with an in-house real-time reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) to detect HEV RNA. The 10,000 blood donors of study group 2 were tested as individual donations using a commercial Procleix HEV nucleic acid testing (NAT) assay to qualitatively detect HEV RNA by transcription-mediated amplification (TMA). Thereafter repeat-reactive donations were quantified using our in-house real-time RT-qPCR. The total anti-HEV IgG seroprevalence of our study was found to be 42.4% in blood donors (study group 1). Risk analysis revealed that eating turkey (p=0.001) and organ meat (p=0.026) and canoeing (p=0.017) were significantly associated with past HEV infection. Whereas direct contact with rabbits (p=0.045) or chickens (p=0.020) were statistically significantly different means of HEV exposure associated with HEV3 and HEV4. Furthermore, we found that the total HEV RNA prevalence was 0.009% (1/10,250). Studies are needed to further assess the risk of HEV blood-borne transmission and to understand the epidemiology of HEV in our setting.