Browsing by Author "Havyarimana, Enock"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Open Access
    Blood pressure variation and its association with outdoor temperature among adults with hypertension in a primary care setting in South Africa
    (2018) Havyarimana, Enock; Bobrow, Kirsten; Levitt, Naomi
    Rationale – There is limited evidence about the effect of climate on blood pressure management of people living with and cared for hypertension in Sub-Sahara Africa. We investigate the relationship between outdoor temperature and blood pressure in a primary care setting with limited control of indoor climate in Cape Town, South Africa. Method – The study uses blood pressure data from 2494 participants screened and enrolled for entry in the SMS-text Adherence (StAR) trial study. Participants’ data were matched with outdoor temperature and air quality data using the nearest hour of enrolment. Individuals were included in this study if they were recruited during the study’s screening period (June 2012 to November 2014) and the clinic’s operating hours (7h00 and 17h00). Result - 72% of participants enrolled for the trial were female and had a BMI of 31 kg/m2 . There was an inter-subject variation of blood pressure between participants enrolled in winter and spring. Those enrolled in winter (June – July) and in the morning (07h00-10h00) when temperatures were generally low, had a higher mean blood pressure compared to those enrolled during spring (September - November) and in the afternoons (≥13h00). Mean outdoor temperature during the trial period was 16.7°C (min: 3.7°C –max: 30.7°C) with lowest temperatures recorded in June. Both outdoor temperature and blood pressure were found to be associated with nitrogen dioxide (NO2) and sulphur dioxide and (SO2) and therefore may be confounded by them. In a multivariate analysis controlling for air pollution, humidity and several leading cardiovascular risk factors, it was observed that a 10°C increase in outdoor temperature was associated with 7.5mmHg (95% CI: 3, 82 - 11, 18) change in systolic blood pressure. This association is modified by age, BMI and the time of the day. Those 65 years and older, with a low BMI and those enrolled in the morning (7h00 – 10h00) had the greatest change in blood pressure due to outdoor temperature Conclusion –The study shows an inverse association between outdoor temperature and clinic-based blood pressure in a primary care setting in South Africa. Given the fact that clinic-based blood pressure measures are used to direct the management of hypertension, greater attention needs to be given to environmental factors which may affect it. This may become of greater clinical relevance with changes in the climate and extreme weather patterns, including extensive smog
  • No Thumbnail Available
    Item
    Open Access
    Cervicovaginal Human Papillomavirus Genomes, Microbiota Composition and Cytokine Concentrations in South African Adolescents
    (Multidisciplinary Digital Publishing Institute, 2023-03-15) Happel, Anna-Ursula; Balle, Christina; Havyarimana, Enock; Brown, Bryan; Maust, Brandon S.; Feng, Colin; Yi, Byung H.; Gill, Katherine; Bekker, Linda-Gail; Passmore, Jo-Ann S.; Jaspan, Heather B.; Varsani, Arvind
    The interaction between cervicovaginal virome, bacteriome and genital inflammation has not been extensively investigated. We assessed the vaginal DNA virome from 33 South African adolescents (15–19 years old) using shotgun DNA sequencing of purified virions. We present analyses of eukaryote-infecting DNA viruses, with a focus on human papillomavirus (HPV) genomes and relate these to the vaginal bacterial microbiota (assessed by 16S rRNA gene sequencing) and cytokines (assessed by Luminex). The DNA virome included single-stranded (Anelloviridae, Genomoviridae) and double-stranded DNA viruses (Adenoviridae, Alloherpesviridae, Herpesviridae, Marseilleviridae, Mimiviridae, Polyomaviridae, Poxviridae). We identified 110 unique, complete HPV genomes within two genera (Alphapapillomavirus and Gammapapillomavirus) representing 40 HPV types and 12 species. Of the 40 HPV types identified, 35 showed positive co-infection patterns with at least one other type, mainly HPV-16. HPV-35, a high-risk genotype currently not targeted by available vaccines, was the most prevalent HPV type identified in this cohort. Bacterial taxa commonly associated with bacterial vaginosis also correlated with the presence of HPV. Bacterial vaginosis, rather than HPV, was associated with increased genital inflammation. This study lays the foundation for future work characterizing the vaginal virome and its role in women’s health.
  • Thumbnail Image
    Item
    Open Access
    Disruption of maternal gut microbiota during gestation alters offspring microbiota and immunity
    (BioMed Central, 2018-07-07) Nyangahu, Donald D; Lennard, Katie S; Brown, Bryan P; Darby, Matthew G; Wendoh, Jerome M; Havyarimana, Enock; Smith, Peter; Butcher, James; Stintzi, Alain; Mulder, Nicola; Horsnell, William; Jaspan, Heather B
    Background: Early life microbiota is an important determinant of immune and metabolic development and may have lasting consequences. The maternal gut microbiota during pregnancy or breastfeeding is important for defining infant gut microbiota. We hypothesized that maternal gut microbiota during pregnancy and breastfeeding is a critical determinant of infant immunity. To test this, pregnant BALB/c dams were fed vancomycin for 5 days prior to delivery (gestation; Mg), 14 days postpartum during nursing (Mn), or during gestation and nursing (Mgn), or no vancomycin (Mc). We analyzed adaptive immunity and gut microbiota in dams and pups at various times after delivery. Results In addition to direct alterations to maternal gut microbial composition, pup gut microbiota displayed lower α-diversity and distinct community clusters according to timing of maternal vancomycin. Vancomycin was undetectable in maternal and offspring sera, therefore the observed changes in the microbiota of stomach contents (as a proxy for breastmilk) and pup gut signify an indirect mechanism through which maternal intestinal microbiota influences extra-intestinal and neonatal commensal colonization. These effects on microbiota influenced both maternal and offspring immunity. Maternal immunity was altered, as demonstrated by significantly higher levels of both total IgG and IgM in Mgn and Mn breastmilk when compared to Mc. In pups, lymphocyte numbers in the spleens of Pg and Pn were significantly increased compared to Pc. This increase in cellularity was in part attributable to elevated numbers of both CD4+ T cells and B cells, most notable Follicular B cells. Conclusion Our results indicate that perturbations to maternal gut microbiota dictate neonatal adaptive immunity.