Browsing by Author "Shibemba A"

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Clinical performance of digital cervicography and cytology for cervical cancer screening in HIV-infected women in Lusaka, Zambia.
(2014-Oct-01) Bateman AC; Parham GP; Sahasrabuddhe VV; Mwanahamuntu MH; Kapambwe S; Katundu K; Nkole T; Mulundika J; Pfaendler KS; Hicks ML; Shibemba A; Vermund SH; Stringer JS; Chibwesha CJ; *Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; †University of North Carolina at Chapel Hill, Chapel Hill, NC; ‡University Teaching Hospital, Lusaka, Zambia; §Vanderbilt University, Nashville, TN; ‖University of Cincinnati, Cincinnati, OH; and ¶Michigan Cancer Institute, Pontiac, MI.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
Although there is a growing literature on the clinical performance of visual inspection with acetic acid in HIV-infected women, to the best of our knowledge, none have studied visual inspection with acetic acid enhanced by digital cervicography. We estimated clinical performance of cervicography and cytology to detect cervical intraepithelial neoplasia grade 2 or worse. Sensitivity and specificity of cervicography were 84% [95% confidence interval (CI): 72 to 91) and 58% (95% CI: 52 to 64). At the high-grade squamous intraepithelial lesion or worse cutoff for cytology, sensitivity and specificity were 61% (95% CI: 48 to 72) and 58% (95% CI: 52 to 64). In our study, cervicography seems to be as good as cytology in HIV-infected women.
Identification of human papillomaviruses from formalin-fixed, paraffin-embedded pre-cancer and invasive cervical cancer specimens in Zambia: a cross-sectional study.
(2015-Jan-16) Bateman AC; Katundu K; Polepole P; Shibemba A; Mwanahamuntu M; Dittmer DP; Parham GP; Chibwesha CJ; Centre for Infectious Disease Research in Zambia, Plot 5032 Great North Road, Lusaka, Zambia. bateman.allen@gmail.com.; Centre for Infectious Disease Research in Zambia, Plot 5032 Great North Road, Lusaka, Zambia. professorparham@gmail.com.; University of Zambia Teaching Hospital, Lusaka, Zambia. mulindim@gmail.com.; Centre for Infectious Disease Research in Zambia, Plot 5032 Great North Road, Lusaka, Zambia. mulindim@gmail.com.; Department of Obstetrics and Gynecology, UNC School of Medicine, UNC, Chapel Hill, North Carolina, USA. Carla.Chibwesha@cidrz.org.; Department of Obstetrics and Gynecology, UNC School of Medicine, UNC, Chapel Hill, North Carolina, USA. professorparham@gmail.com.; Department of Medicine, UNC School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. bateman.allen@gmail.com.; Centre for Infectious Disease Research in Zambia, Plot 5032 Great North Road, Lusaka, Zambia. Carla.Chibwesha@cidrz.org.; Centre for Infectious Disease Research in Zambia, Plot 5032 Great North Road, Lusaka, Zambia. Katundu.Katundu@cidrz.org.; University of Zambia Teaching Hospital, Lusaka, Zambia. poleman1981@gmail.com.; University of Zambia Teaching Hospital, Lusaka, Zambia. professorparham@gmail.com.; University of Zambia Teaching Hospital, Lusaka, Zambia. shibemba@yahoo.com.; Program in Global Oncology, UNC Lineberger Comprehensive Cancer Center and School of Medicine, UNC, Chapel Hill, North Carolina, USA. dirk_dittmer@med.unc.edu.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
BACKGROUND: The most common human papillomavirus (HPV) genotypes isolated from cervical cancer in select African countries are HPV-16, HPV-18, HPV-35, and HPV-45, but the most common genotypes in Zambia are unknown. The overall objective of this study was to assess the potential impact of current HPV vaccines in preventing cervical cancer in Zambia, by determining the combined prevalence of HPV-16 and/or HPV-18 in invasive cervical cancer (ICC) and high-grade pre-cancer [cervical intraepithelial neoplasia 2 or 3 (CIN2/3)] cases. FINDINGS: We compared DNA extraction techniques to determine which assay performs well in the Zambian context, where unbuffered formalin is used to fix specimens. We then tested specimens with the Abbott RealTime High-Risk HPV test to estimate the prevalence of HPV-16/18 in formalin-fixed, paraffin-embedded ICC and CIN2/3 specimens. DNA extraction using heat (without xylene) was more successful than xylene-based extraction. Over 80% of specimens tested using heat extraction and the Abbott RealTime HPV test were positive for HPV. HPV-16 and/or HPV-18 were identified in 65/93 (69.9%) ICC specimens positive for HPV and in 38/65 (58.5%) CIN2/3 specimens positive for HPV. CONCLUSIONS: To our knowledge this is the first report to identify HPV genotypes in cervical cancers in Zambia. A combined HPV-16/18 prevalence of 69.9% in ICC specimens suggests that current vaccines will be highly protective against cervical cancer in Zambia.
Three transmission events of Vibrio cholerae O1 into Lusaka, Zambia.
(2021-Jun-14) Mwaba J; Debes AK; Murt KN; Shea P; Simuyandi M; Laban N; Kazimbaya K; Chisenga C; Li S; Almeida M; Meisel JS; Shibemba A; Kantenga T; Mukonka V; Kwenda G; Sack DA; Chilengi R; Stine OC; Johns Hopkins Bloomberg School of Public Health, MD, Baltimore, USA.; Zambia National Public Health Institute, Lusaka, Zambia.; Department of Biomedical Sciences, University of Zambia School of Health Sciences, Lusaka, Zambia.; Department of Pathology and Microbiology, University Teaching Hospitals, Lusaka, Zambia.; University of Maryland School of Medicine, Baltimore, MD, USA.; University of Maryland, College Park, College Park, MD, USA.; University of Maryland School of Medicine, Baltimore, MD, USA. cstine@som.umaryland.edu.; Université Paris-Saclay, INRAE, MGP, 78350, Jouy-en-Josas, France.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
BACKGROUND: Cholera has been present and recurring in Zambia since 1977. However, there is a paucity of data on genetic relatedness and diversity of the Vibrio cholerae isolates responsible for these outbreaks. Understanding whether the outbreaks are seeded from existing local isolates or if the outbreaks represent separate transmission events can inform public health decisions. RESULTS: Seventy-two V. cholerae isolates from outbreaks in 2009/2010, 2016, and 2017/2018 in Zambia were characterized using multilocus variable number tandem repeat analysis (MLVA) and whole genome sequencing (WGS). The isolates had eight distinct MLVA genotypes that clustered into three MLVA clonal complexes (CCs). Each CC contained isolates from only one outbreak. The results from WGS revealed both clustered and dispersed single nucleotide variants. The genetic relatedness of isolates based on WGS was consistent with the MLVA, each CC was a distinct genetic lineage and had nearest neighbors from other East African countries. In Lusaka, isolates from the same outbreak were more closely related to themselves and isolates from other countries than to isolates from other outbreaks in other years. CONCLUSIONS: Our observations are consistent with i) the presence of random mutation and alternative mechanisms of nucleotide variation, and ii) three separate transmission events of V. cholerae into Lusaka, Zambia. We suggest that locally, case-area targeted invention strategies and regionally, well-coordinated plans be in place to effectively control future cholera outbreaks.