Publications by authors named "Chilyabanyama O"

Diarrhoeagenic (DEC) significantly contributes to the burden of diarrhoea among children. Currently, there is no approved vaccine against DEC, but several vaccines against the enterotoxigenic (ETEC) pathotype are in advanced clinical trial stages, including the ETVAX vaccine, undergoing evaluation in Zambia. This study reports on the reactivity of antibodies from ETVAX vaccine and placebo recipients in a phase I clinical trial to proteins derived from (DEC) other than ETEC.

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Article Synopsis
  • Diarrhoea significantly impacts childhood health in developing countries, particularly in Lusaka, Zambia, where a study aimed to identify the specific diarrhoeagenic pathotypes affecting children.
  • Over an 8-month period, 590 stool samples were collected from children aged 0-3 years with diarrhoea, revealing that 76.1% tested positive for diarrhoeagenic pathogens.
  • The most common pathogens identified were enteropathogenic (45.4%), enteroaggregative (39.5%), and enterotoxigenic (29.7%), with a notable finding that over half of the positive samples contained multiple virulent combinations, emphasizing the need for early preventive measures for childhood diarrhoea.
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Background: Rotavirus gastroenteritis remains a leading cause of morbidity and mortality despite the introduction of vaccines. Research shows there are several factors contributing to the reduced efficacy of rotavirus vaccines in low- and middle-income settings. Proposed factors include environmental enteric dysfunction (EED), malnutrition, and immune dysfunction.

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  • The study examined the presence of Epstein-Barr virus (EBV) DNA in the cerebrospinal fluid (CSF) of 470 adults living with HIV in Zambia who showed neurological symptoms, finding that 28.9% tested positive for EBV DNA.
  • Key associations with EBV positivity included younger age, shorter HIV duration, and specific CSF findings like low glucose and high protein and white blood cell levels.
  • Despite the high EBV detection rate, the study concluded that EBV DNA load in CSF and blood had limited clinical significance and was not linked to patient mortality.
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Background: Enterotoxigenic Escherichia coli (ETEC) is an important cause of moderate to severe diarrhoea in children for which there is no licensed vaccine. We evaluated ETVAX®, an oral, inactivated ETEC vaccine containing four E. coli strains over-expressing the major colonization factors CFA/I, CS3, CS5, and CS6, a toxoid (LCTBA) and double mutant heat-labile enterotoxin (dmLT) adjuvant for safety, tolerability, and immunogenicity.

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  • Live-attenuated oral rotavirus vaccines like ROTARIX have reduced diarrhoea and infant mortality but show reduced effectiveness in low-income countries.
  • A study in Zambia with 135 mother-infant pairs assessed the impact of maternal and infant histo-blood group antigen (HBGA) profiles on the vaccine's effectiveness, focusing on seroconversion and IgA antibody levels.
  • Results indicated that while early infant HBGA profiles did not significantly affect vaccine responses, infant HBGA profiles were linked to increased immunogenicity at 12 months, highlighting the need for further research to improve vaccine efficacy for young children.
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Developing a broadly protective vaccine covering most ETEC variants has been elusive. The most clinically advanced candidate yet is an oral inactivated ETEC vaccine (ETVAX). We report on the use of a proteome microarray for the assessment of cross-reactivity of anti-ETVAX IgG antibodies against over 4000 ETEC antigens and proteins.

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Background: Shigella is a leading cause of bacterial diarrhea morbidity and mortality affecting mainly children under five in the developing world. In Zambia, Shigella has a high prevalence of 34.7% in children with diarrhea and an attributable fraction of 6.

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  • The study investigates how Histo-blood group antigens (HBGAs) affect the immune response to the oral cholera vaccine in a cholera-endemic region of Zambia.
  • The research involves a cohort of 223 adults who were vaccinated and tracked for four years, focusing on serum antibody levels and saliva analysis for HBGA types.
  • The findings reveal no significant differences in immune responses based on ABO blood types or secretor status, suggesting that these factors do not influence the effectiveness of the cholera vaccine.
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Simply detecting Epstein-Barr virus deoxyribonucleic acid (EBV-DNA) is insufficient to diagnose EBV-associated diseases. The current literature around EBV-DNA detection from cerebrospinal fluid (CSF) in human immunodeficiency virus (HIV)-positive non-lymphoma patients was systematically reviewed and a meta-analysis reporting the estimated pooled prevalence in this population when PCR methods are employed, targeting different sequence segments within the EBV genome, was conducted. Using a combination of three key concepts-Epstein-Barr virus detection, central nervous system disease, and human cerebrospinal fluid-and their MeSH terms, the PubMed database was searched.

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Background: Under-five mortality is a matter of serious concern for child health as well as the social development of any country. The paper aimed to find the accuracy of machine learning models in predicting under-five mortality and identify the most significant factors associated with under-five mortality.

Method: The data was taken from the National Family Health Survey (NFHS-IV) of Uttar Pradesh.

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Background: Diarrhoeal disease remains a leading cause of death among children mostly in low and middle-income countries. Factors contributing to disease severity are complex and there is currently no consensus on a scoring tool for use in community-based studies.

Methods: Data were collected during a passive surveillance system in an outpatient health facility in Lusaka, Zambia from March 2019 to July 2019.

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Background: Enterotoxigenic Escherichia coli (ETEC) is one of the top aetiologic agents of diarrhea in children under the age of 5 in low-middle income countries (LMICs). The lack of point of care diagnostic tools for routine ETEC diagnosis results in limited data regarding the actual burden and epidemiology in the endemic areas. We evaluated performance of the novel Rapid LAMP based Diagnostic Test (RLDT) for detection of ETEC in stool as a point of care diagnostic assay in a resource-limited setting.

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Stunting is a global public health issue. We sought to train and evaluate machine learning (ML) classification algorithms on the Zambia Demographic Health Survey (ZDHS) dataset to predict stunting among children under the age of five in Zambia. We applied Logistic regression (LR), Random Forest (RF), SV classification (SVC), XG Boost (XgB) and Naïve Bayes (NB) algorithms to predict the probability of stunting among children under five years of age, on the 2018 ZDHS dataset.

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Cellular immunity against rotavirus in children is incompletely understood. This review describes the current understanding of T-cell immunity to rotavirus in children. A systematic literature search was conducted in Embase, MEDLINE, Web of Science, and Global Health databases using a combination of "t-cell", "rotavirus" and "child" keywords to extract data from relevant articles published from January 1973 to March 2020.

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Introduction: In cholera endemic areas, the periodicity of cholera outbreaks remains unpredictable, making it difficult to organize preventive efforts. Lack of data on duration of protection conferred by oral cholera vaccines further makes it difficult to determine when to deploy preemptive vaccination. We report on the immunogenicity and waning of immunity to Shanchol™ in Lukanga Swamps.

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Background: We set out to assess the impact of human immunodeficiency virus (HIV) and micronutrient deficiency as indicated by serum retinol levels on the immune responses to Oral Cholera Vaccine (Shanchol™) in a cohort of participants in Lukanga Swamps, Zambia. Cholera remains endemic in Zambia with vaccines being the only effective preventive measures. However, the effect of these vaccines on populations living with HIV has not been widely documented.

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Emerging and re-emerging mosquito-borne viral diseases are a threat to global health. This systematic review aimed to investigate the available evidence of mosquito-borne viral pathogens reported in Zambia. A search of literature was conducted in PubMed and Google Scholar for articles published from 1 January 1930 to 30 June 2020 using a combination of keywords.

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Background: Impaired growth among infants remains one of the leading nutrition problems globally. In this study, we aimed to compare the growth trajectory rate and evaluate growth trajectory characteristics among children, who are HIV exposed uninfected (HEU) and HIV unexposed uninfected (HUU), under two years in Zambia.

Method: Our study used data from the ROVAS II study (PACTR201804003096919), an open-label randomized control trial of two verses three doses of live, attenuated, oral RotarixTM administered 6 &10 weeks or at 6 &10 weeks plus an additional dose at 9 months of age, conducted at George clinic in Lusaka, Zambia.

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Introduction: Shigellosis, is a leading cause of moderate-to-severe diarrhoea and related mortality in young children in low and middle income countries (LMICs). Knowledge on naturally acquired immunity can support the development of Shigella candidate vaccines mostly needed in LMICs. We aimed to quantify Shigella-specific antibodies of maternal origin and those naturally acquired in Zambian infants.

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Background: Despite an otherwise robust national antenatal clinic program, maternal and congenital syphilis remains an important public health issue in Zambia. This case series reports the clinical presentation of seven infants diagnosed with congenital syphilis in Lusaka, Zambia.

Case Presentations: The cases in this series were incidental findings from a cohort of infants enrolled in a rotavirus vaccine immunogenicity study recruiting infants at 6 weeks of age.

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Setting: Peri-urban health facilities providing HIV and TB care in Zambia.

Objective: To evaluate 1) the impact of Xpert MTB/RIF on time-to-diagnosis, treatment initiation, and outcomes among adult people living with HIV (PLHIV) on antiretroviral therapy (ART); and 2) the diagnostic performance of Xpert and Determine™ TB-LAM Ag assays.

Design: Quasi-experimental study design with the first cohort evaluated per standard-of-care (SOC; first sputum tested using smear microscopy) and the second cohort per an algorithm using Xpert as initial test (intervention phase; IP).

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Introduction: The re-emergence of vector borne diseases affecting millions of people in recent years has drawn attention to arboviruses globally. Here, we report on the sero-prevalence of chikungunya virus (CHIKV), dengue virus (DENV), mayaro virus (MAYV) and zika virus (ZIKV) in a swamp community in Zambia.

Methods: We collected blood and saliva samples from residents of Lukanga swamps in 2016 during a mass-cholera vaccination campaign.

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Prognosis among those who are HIV infected has improved but long-term retention is challenging. Health systems may benefit from routinely measuring patient satisfaction which is a potential driver of engagement in HIV care, but it is not often measured in Africa, and Zambia in particular. This study aims to internally validate a patient satisfaction tool, assess satisfaction among patients previously lost-to-follow up (LTFU) from HIV care in Lusaka province and to measure association between patient satisfaction with their original clinic and re-engagement in HIV care.

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Article Synopsis
  • In 2016, Zambia's Ministry of Health initiated a cholera outbreak response by vaccinating high-risk populations with a single dose of the Shancol oral cholera vaccine to control the disease's spread.
  • A study conducted in 2017 analyzed the costs associated with cholera illness and evaluated the cost-effectiveness of the vaccination campaign in Lusaka, using patient interviews and health facility financial records.
  • The results indicated that the average cost per vaccine was $1.72, with treatment costs for hospitalized patients varying widely; the analysis showed that the cost per case averted ranged from $369 to $532, highlighting the campaign's overall economic impact.
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