Last data update: Apr 28, 2025. (Total: 49156 publications since 2009)
Records 1-18 (of 18 Records) |
Query Trace: Awuor AO[original query] |
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Association between low maternal serum aflatoxin B1 exposure and adverse pregnancy outcomes in Mombasa, Kenya, 2017-2019: A nested matched case-control study
Osoro E , Awuor AO , Inwani I , Mugo C , Hunsperger E , Verani JR , Nduati R , Kinuthia J , Okutoyi L , Mwaengo D , Maugo B , Otieno NA , Mirieri H , Ombok C , Nyawanda B , Agogo GO , Ngere I , Zitomer NC , Rybak ME , Munyua P , Njenga K , Widdowson MA . Matern Child Nutr 2024 e13688 We examined the association between serum aflatoxin B1-lysine adduct (AFB1-lys) levels in pregnant women and adverse pregnancy outcomes (low birthweight, miscarriage and stillbirth) through a nested matched case-control study of pregnant women enroled at ≤28 weeks' gestation in Mombasa, Kenya, from 2017 to 2019. Cases comprised women with an adverse birth outcome, defined as either delivery of a singleton infant weighing <2500 g, or a miscarriage, or a stillbirth, while controls were women who delivered a singleton live infant with a birthweight of ≥2500 g. Cases were matched to controls at a ratio of 1:2 based on maternal age at enrolment, gestational age at enrolment and study site. The primary exposure was serum AFB1-lys. The study included 125 cases and 250 controls. The median gestation age when serum samples were collected was 23.0 weeks (interquartile range [IQR]: 18.1-26.0) and 23.5 (IQR: 18.1-26.5) among cases and controls, respectively. Of the 375 tested sera, 145 (38.7%) had detectable serum AFB1-lys: 36.0% in cases and 40.0% in controls. AFB1-lys adduct levels were not associated with adverse birth outcomes on multivariable analysis. Mid-upper arm circumference was associated with a 6% lower odds of adverse birth outcome for every unit increase (p = 0.023). Two-fifths of pregnant women had detectable levels of aflatoxin midway through pregnancy. However, we did not detect an association with adverse pregnancy outcomes, likely because of low serum AFB1-lys levels and low power, restricting meaningful comparison. More research is needed to understand the public health risk of aflatoxin in pregnant women to unborn children. |
Histo-Blood Group Antigen Null Phenotypes Associated With a Decreased Risk of Clinical Rotavirus Vaccine Failure Among Children <2 Years of Age Participating in the Vaccine Impact on Diarrhea in Africa (VIDA) Study in Kenya, Mali, and the Gambia
Schwartz LM , Oshinsky J , Reymann M , Esona MD , Bowen MD , Jahangir Hossain M , Zaman SMA , Jones JCM , Antonio M , Badji H , Sarwar G , Sow SO , Sanogo D , Keita AM , Tamboura B , Traoré A , Onwuchekwa U , Omore R , Verani JR , Awuor AO , Ochieng JB , Juma J , Ogwel B , Parashar UD , Tate JE , Kasumba IN , Tennant SM , Neuzil KM , Rowhani-Rahbar A , Elizabeth Halloran M , Atmar RL , Pasetti MF , Kotloff KL . Clin Infect Dis 2023 76 S153-s161 ![]() ![]() BACKGROUND: Previously studied risk factors for rotavirus vaccine failure have not fully explained reduced rotavirus vaccine effectiveness in low-income settings. We assessed the relationship between histo-blood group antigen (HBGA) phenotypes and clinical rotavirus vaccine failure among children <2 years of age participating in the Vaccine Impact on Diarrhea in Africa Study in 3 sub-Saharan African countries. METHODS: Saliva was collected and tested for HBGA phenotype in children who received rotavirus vaccine. The association between secretor and Lewis phenotypes and rotavirus vaccine failure was examined overall and by infecting rotavirus genotype using conditional logistic regression in 218 rotavirus-positive cases with moderate-to-severe diarrhea and 297 matched healthy controls. RESULTS: Both nonsecretor and Lewis-negative phenotypes (null phenotypes) were associated with decreased rotavirus vaccine failure across all sites (matched odds ratio, 0.30 [95% confidence interval: 0.16-0.56] or 0.39 [0.25-0.62], respectively]. A similar decrease in risk against rotavirus vaccine failure among null HBGA phenotypes was observed for cases with P[8] and P[4] infection and their matched controls. While we found no statistically significant association between null HBGA phenotypes and vaccine failure among P[6] infections, the matched odds ratio point estimate for Lewis-negative individuals was >4. CONCLUSIONS: Our study demonstrated a significant relationship between null HBGA phenotypes and decreased rotavirus vaccine failure in a population with P[8] as the most common infecting genotype. Further studies are needed in populations with a large burden of P[6] rotavirus diarrhea to understand the role of host genetics in reduced rotavirus vaccine effectiveness. |
Antibiotic-prescribing practices for management of childhood diarrhea in 3 Sub-Saharan African countries: Findings from the vaccine impact on diarrhea in Africa (vida) study, 2015-2018
Awuor AO , Ogwel B , Powell H , Verani JR , Sow SO , Hossain MJ , Ochieng JB , Juma J , Jamka LP , Roose A , Doh S , Deichsel EL , Onwuchekwa U , Keita AM , Antonio M , Jones JCM , Zaman SMA , Badji H , Kasumba IN , Nasrin D , Platts-Mills JA , Houpt ER , Berendes DM , Sugerman CE , Widdowson MA , Tennant SM , Mintz ED , Omore R , Kotloff KL . Clin Infect Dis 2023 76 S32-s40 BACKGROUND: Despite antibiotic prescription being recommended for dysentery and suspected cholera only, diarrhea still triggers unwarranted antibiotic prescription. We evaluated antibiotic-prescribing practices and their predictors among children aged 2-59 months in the Vaccine Impact on Diarrhea in Africa (VIDA) Study performed in The Gambia, Mali, and Kenya. METHODS: VIDA was a prospective case-control study (May 2015-July 2018) among children presenting for care with moderate-to-severe diarrhea (MSD). We defined inappropriate antibiotic use as prescription or use of antibiotics when not indicated by World Health Organization (WHO) guidelines. We used logistic regression to assess factors associated with antibiotic prescription for MSD cases who had no indication for an antibiotic, at each site. RESULTS: VIDA enrolled 4840 cases. Among 1757 (36.3%) who had no apparent indication for antibiotic treatment, 1358 (77.3%) were prescribed antibiotics. In The Gambia, children who presented with a cough (adjusted odds ratio [aOR]: 2.05; 95% confidence interval [95% CI]: 1.21-3.48) were more likely to be prescribed an antibiotic. In Mali, those who presented with dry mouth (aOR: 3.16; 95% CI: 1.02-9.73) were more likely to be prescribed antibiotics. In Kenya, those who presented with a cough (aOR: 2.18; 95% CI: 1.01-4.70), decreased skin turgor (aOR: 2.06; 95% CI: 1.02-4.16), and were very thirsty (aOR: 4.15; 95% CI: 1.78-9.68) were more likely to be prescribed antibiotics. CONCLUSIONS: Antibiotic prescription was associated with signs and symptoms inconsistent with WHO guidelines, suggesting the need for antibiotic stewardship and clinician awareness of diarrhea case-management recommendations in these settings. |
Exploring survey-based water, sanitation, and animal associations with enteric pathogen carriage: Comparing results in a cohort of cases with moderate-to-severe diarrhea to those in controls in the Vaccine Impact on Diarrhea in Africa (VIDA) Study, 2015-2018
Berendes DM , Omore R , Prentice-Mott G , Fagerli K , Kim S , Nasrin D , Powell H , Jahangir Hossain M , Sow SO , Doh S , Jones JCM , Ochieng JB , Juma J , Awuor AO , Ogwel B , Verani JR , Widdowson MA , Kasumba IN , Tennant SM , Roose A , Zaman SMA , Liu J , Sugerman CE , Platts-Mills JA , Houpt ER , Kotloff KL , Mintz ED . Clin Infect Dis 2023 76 S140-s152 BACKGROUND: The magnitude of pediatric enteric pathogen exposures in low-income settings necessitates substantive water and sanitation interventions, including animal feces management. We assessed associations between pediatric enteric pathogen detection and survey-based water, sanitation, and animal characteristics within the Vaccine Impact on Diarrhea in Africa case-control study. METHODS: In The Gambia, Kenya, and Mali, we assessed enteric pathogens in stool of children aged <5 years with moderate-to-severe diarrhea and their matched controls (diarrhea-free in prior 7 days) via the TaqMan Array Card and surveyed caregivers about household drinking water and sanitation conditions and animals living in the compound. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using modified Poisson regression models, stratified for cases and controls and adjusted for age, sex, site, and demographics. RESULTS: Bacterial (cases, 93%; controls, 72%), viral (63%, 56%), and protozoal (50%, 38%) pathogens were commonly detected (cycle threshold <35) in the 4840 cases and 6213 controls. In cases, unimproved sanitation (RR, 1.56; 95% CI, 1.12-2.17), as well as cows (RR, 1.61; 95% CI, 1.16-2.24) and sheep (RR, 1.48; 95% CI, 1.11-1.96) living in the compound, were associated with Shiga toxin-producing Escherichia coli. In controls, fowl (RR, 1.30; 95% CI, 1.15-1.47) were associated with Campylobacter spp. In controls, surface water sources were associated with Cryptosporidium spp., Shigella spp., heat-stable toxin-producing enterotoxigenic E. coli, and Giardia spp. CONCLUSIONS: Findings underscore the importance of enteric pathogen exposure risks from animals alongside more broadly recognized water and sanitation risk factors in children. |
Management of diarrhea in young children in Sub-Saharan Africa: Adherence to world health organization recommendations during the Global Enteric Multisite Study (2007-2011) and the Vaccine Impact of Diarrhea in Africa (VIDA) Study (2015-2018)
Deichsel EL , Keita AM , Verani JR , Powell H , Jamka LP , Hossain MJ , Jones JCM , Omore R , Awuor AO , Sow SO , Sanogo D , Tapia MD , Neuzil KM , Kotloff KL . Clin Infect Dis 2023 76 S23-s31 BACKGROUND: Reducing diarrhea-related morbidity and mortality is a global priority, particularly in low-resource settings. We assessed adherence to diarrhea case management indicators in the Global Enteric Multisite Study (GEMS) and Vaccine Impact of Diarrhea in Africa (VIDA) study. METHODS: GEMS (2007-2010) and VIDA (2015-2018) were age-stratified case-control studies of moderate-to-severe diarrhea (MSD) in children aged <5 years. In this case-only analysis, we included children enrolled in The Gambia, Kenya, and Mali. A case with no dehydration received adherent care at home if they were offered more than usual fluids and at least the same as usual to eat. Children with diarrhea and some dehydration are to receive oral rehydration salts (ORS) in the facility. The recommendation for severe dehydration is to receive ORS and intravenous fluids in the facility. Adherent care in the facility included a zinc prescription independent of dehydration severity. RESULTS: For home-based management of children with MSD and no signs of dehydration, 16.6% in GEMS and 15.6% in VIDA were adherent to guidelines. Adherence to guidelines in the facility was likewise low during GEMS (some dehydration, 18.5%; severe dehydration, 5.5%). The adherence to facility-based rehydration and zinc guidelines improved during VIDA to 37.9% of those with some dehydration and 8.0% of children with severe dehydration. CONCLUSIONS: At research sites in The Gambia, Kenya, and Mali, suboptimal adherence to diarrhea case management guidelines for children aged <5 years was observed. Opportunities exist for improvement in case management for children with diarrhea in low-resource settings. |
Clinical and epidemiologic features of cryptosporidium-associated diarrheal disease among young children living in Sub-Saharan Africa: The Vaccine Impact on Diarrhea in Africa (VIDA) Study
Hossain MJ , Powell H , Sow SO , Omore R , Roose A , Jones JCM , Zaman SMA , Badji H , Sarwar G , Kasumba IN , Onwuchekwa U , Doh S , Awuor AO , Ochieng JB , Verani JR , Liu J , Tennant SM , Nasrin D , Jamka LP , Liang Y , Howie SRC , Antonio M , Houpt ER , Kotloff KL . Clin Infect Dis 2023 76 S97-s105 ![]() BACKGROUND: As part of the Vaccine Impact on Diarrhea in Africa (VIDA) Study, we examined the prevalence, clinical presentation, and seasonality of Cryptosporidium in children to understand its relative burden after the introduction of rotavirus vaccine. METHODS: VIDA was a 3-year, age-stratified, matched case-control study of medically attended acute moderate-to-severe diarrhea (MSD) in children aged 0-59 months residing in censused populations at sites in Kenya, Mali, and The Gambia. Clinical and epidemiologic data were collected at enrollment, and a stool sample was tested for enteropathogens by quantitative PCR. An algorithm was created based on the organism's cycle threshold (Ct) and association with MSD to identify the subset of Cryptosporidium PCR-positive (Ct <35) cases most likely to be attributed to MSD. Clinical outcomes were assessed at 2-3 months after enrollment. RESULTS: One thousand one hundred six (22.9%) cases of MSD and 873 controls (18.1%) were PCR positive for Cryptosporidium; 465 cases (42.0%) were considered attributable to Cryptosporidium, mostly among children 6-23 months. Cryptosporidium infections peaked in The Gambia and Mali during the rainy season, while in Kenya they did not have clear seasonality. Compared with cases with watery MSD who had a negative PCR for Cryptosporidium, cases with watery MSD attributed to Cryptosporidium were less frequently dehydrated but appeared more severely ill using a modified Vesikari scale (38.1% vs 27.0%; P < 0.001), likely due to higher rates of hospitalization and intravenous fluid administration, higher prevalence of being wasted or very thin very thin (23.4% vs 14.7%; P < 0.001), and having severe acute malnutrition (midupper arm circumference <115 mm, 7.7% vs 2.5%; P < 0.001). On follow-up, Cryptosporidium-attributed cases had more prolonged and persistent episodes (43.2% vs 32.7%; P <0 .001) and linear growth faltering (change in height-for-age z score between enrollment and follow-up: -0.29 vs -0.17; P < 0.001). CONCLUSIONS: The burden of Cryptosporidium remains high among young children in sub-Saharan Africa. Its propensity to cause illness and further impact children longer term by compromising nutritional status early in life calls for special attention to enable appropriate management of clinical and nutritional consequences. |
Shigella in Africa: New insights from the Vaccine Impact on Diarrhea in Africa (VIDA) Study
Kasumba IN , Badji H , Powell H , Hossain MJ , Omore R , Sow SO , Verani JR , Platts-Mills JA , Widdowson MA , Zaman SMA , Jones J , Sen S , Permala-Booth J , Nasrin S , Roose A , Nasrin D , Ochieng JB , Juma J , Doh S , Jones JCM , Antonio M , Awuor AO , Sugerman CE , Watson N , Focht C , Liu J , Houpt E , Kotloff KL , Tennant SM . Clin Infect Dis 2023 76 S66-s76 BACKGROUND: We evaluated the burden of Shigella spp from children aged 0-59 months with medically attended moderate-to-severe diarrhea and matched controls at sites in Mali, The Gambia, and Kenya participating in the Vaccine Impact on Diarrhea in Africa (VIDA) study from 2015 to 2018. METHODS: Shigella spp were identified using coprocultures and serotyping in addition to quantitative polymerase chain reaction (qPCR). Episode-specific attributable fractions (AFe) for Shigella were calculated using Shigella DNA quantity; cases with AFe ≥0.5 were considered to have shigellosis. RESULTS: The prevalence of Shigella was determined to be 359 of 4840 (7.4%) cases and 83 of 6213 (1.3%) controls by culture, and 1641 of 4836 (33.9%) cases and 1084 of 4846 (22.4%) controls by qPCR (cycle threshold <35); shigellosis was higher in The Gambia (30.8%) than in Mali (9.3%) and Kenya (18.7%). Bloody diarrhea attributed to Shigella was more common in 24- to 59-month-old children (50.1%) than 0- to 11-month-old infants (39.5%). The Shigella flexneri serogroup predominated among cases (67.6% of isolates), followed by Shigella sonnei (18.2%), Shigella boydii (11.8%), and Shigella dysenteriae (2.3%). The most frequent S. flexneri serotypes were 2a (40.6%), 1b (18.8%), 6 (17.5%), 3a (9.0%), and 4a (5.1%). Drug-specific resistance among 353 (98.3%) Shigella cases with AMR data was as follows: trimethoprim-sulfamethoxazole (94.9%), ampicillin (48.4%), nalidixic acid (1.7%), ceftriaxone (0.3%), azithromycin (0.3%), and ciprofloxacin (0.0%). CONCLUSIONS: A high prevalence of shigellosis continues in sub-Saharan Africa. Strains are highly resistant to commonly used antibiotics while remaining susceptible to ciprofloxacin, ceftriaxone, and azithromycin. |
Prevalence, clinical severity, and seasonality of adenovirus 40/41, astrovirus, sapovirus, and rotavirus among young children with moderate-to-severe diarrhea: Results from the Vaccine Impact on Diarrhea in Africa (VIDA) Study
Keita AM , Doh S , Sow SO , Powell H , Omore R , Jahangir Hossain M , Ogwel B , Ochieng JB , Jones JCM , Zaman SMA , Awuor AO , Juma J , Nasrin D , Liu J , Traoré A , Onwuchekwa U , Badji H , Sarwar G , Antonio M , Houpt ER , Tennant SM , Kasumba IN , Jamka LP , Roose A , Platts-Mills JA , Verani JR , Tate JE , Parashar UD , Neuzil KM , Kotloff KL . Clin Infect Dis 2023 76 S123-s131 ![]() BACKGROUND: While rotavirus causes severe diarrheal disease in children aged <5 years, data on other viral causes in sub-Saharan Africa are limited. METHODS: In the Vaccine Impact on Diarrhea in Africa study (2015-2018), we analyzed stool from children aged 0-59 months with moderate-to-severe diarrhea (MSD) and without diarrhea (controls) in Kenya, Mali, and The Gambia using quantitative polymerase chain reaction. We derived the attributable fraction (AFe) based on the association between MSD and the pathogen, accounting for other pathogens, site, and age. A pathogen was attributable if the AFe was ≥0.5.The severity of attributable MSD was defined by a modified Vesikari score (mVS). Monthly cases were plotted against temperature and rainfall to assess seasonality. RESULTS: Among 4840 MSD cases, proportions attributed to rotavirus, adenovirus 40/41, astrovirus, and sapovirus were 12.6%, 2.7%, 2.9%, and 1.9%, respectively. Attributable rotavirus, adenovirus 40/41, and astrovirus MSD cases occurred at all sites, with mVS of 11, 10, and 7, respectively. MSD cases attributable to sapovirus occurred in Kenya, with mVS of 9. Astrovirus and adenovirus 40/41 peaked during the rainy season in The Gambia, while rotavirus peaked during the dry season in Mali and The Gambia. CONCLUSIONS: In sub-Saharan Africa, rotavirus was the most common cause of MSD; adenovirus 40/41, astrovirus, and sapovirus contributed to a lesser extent among children aged <5 years. Rotavirus- and adenovirus 40/41-attributable MSD were most severe. Seasonality varied by pathogen and location. Efforts to increase the coverage of rotavirus vaccines and to improve prevention and treatment for childhood diarrhea should continue. |
Moderate-to-severe diarrhea and stunting among children younger than 5 years: Findings from the Vaccine Impact on Diarrhea in Africa (VIDA) Study
Nasrin D , Liang Y , Powell H , Casanova IG , Sow SO , Hossain MJ , Omore R , Sanogo D , Tamboura B , Zaman SMA , Antonio M , Jones JCM , Awuor AO , Kasumba IN , Ochieng JB , Badji H , Verani JR , Widdowson MA , Roose A , Jamka LP , Tennant SM , Ramakrishnan U , Kotloff KL . Clin Infect Dis 2023 76 S41-s48 BACKGROUND: Stunting affects >20% of children <5 years old worldwide and disproportionately impacts underserved communities. The Vaccine Impact on Diarrhea in Africa (VIDA) Study examined the association between an episode of moderate-to-severe diarrhea (MSD) and the risk of subsequent stunting in children <5 years living in 3 sub-Saharan African countries. METHODS: In this prospective, matched, case-control study among children <5 years, data were collected over 36 months from 2 groups. "Children with MSD" visited a health center within 7 days of illness onset experiencing ≥3 loose stools/day plus sunken eyes, poor skin turgor, dysentery, intravenous rehydration, or hospitalization. "Children without MSD" were enrolled from the community within 14 days of the index MSD child; they were diarrhea-free during the previous 7 days and were matched to the index case by age, sex, and residence. Using generalized linear mixed-effects models, we estimated the effect of an MSD episode on odds of being stunted, defined as height-for-age z-scores <-2, at a follow-up visit 2-3 months post-enrollment. RESULTS: The proportion of stunting at enrollment was similar when 4603 children with MSD and 5976 children without MSD were compared (21.8% vs 21.3%; P = .504). Among children not stunted at enrollment, those with MSD had 30% higher odds of being stunted at follow-up than children without MSD after controlling for age, sex, study site, and socioeconomic status (adjusted OR: 1.30; 95% CI: 1.05-1.62: P = .018). CONCLUSIONS: Children <5 years in sub-Saharan Africa without stunting experienced an increased likelihood of stunting during 2-3 months following an episode of MSD. Strategies for control of early childhood diarrhea should be integrated into programs intended to reduce childhood stunting. |
Stunting following moderate-to-severe diarrhea among children aged <5 years in Africa before and after rotavirus vaccine introduction: A comparison of the global enteric multicenter study and the Vaccine Impact on Diarrhea in Africa (VIDA) Study
Nasrin D , Liang Y , Verani JR , Powell H , Sow SO , Omore R , Hossain MJ , Doh S , Zaman SMA , Jones JCM , Awuor AO , Kasumba IN , Tennant SM , Ramakrishnan U , Kotloff KL . Clin Infect Dis 2023 76 S49-s57 BACKGROUND: Studies conducted before rotavirus vaccine introduction found that moderate-to-severe diarrhea (MSD) in children aged <5 years was associated with stunting at follow-up. It is unknown whether the reduction in rotavirus-associated MSD following vaccine introduction decreased the risk of stunting. METHODS: The Global Enteric Multicenter Study (GEMS) and the Vaccine Impact on Diarrhea in Africa (VIDA) study, two comparable matched case-control studies, were conducted during 2007-2011 and 2015-2018, respectively. We analyzed data from 3 African sites where rotavirus vaccine was introduced after GEMS and before starting VIDA. Children with acute MSD (<7 days onset) were enrolled from a health center and children without MSD (diarrhea-free for ≥7 days) were enrolled at home within 14 days of the index MSD case. The odds of being stunted at a follow-up visit 2-3 months after enrollment for an episode of MSD was compared between GEMS and VIDA using mixed-effects logistic regression models controlling for age, sex, study site, and socioeconomic status. RESULTS: We analyzed data from 8808 children from GEMS and 10 579 from VIDA. Among those who were not stunted at enrollment in GEMS, 8.6% with MSD and 6.4% without MSD became stunted during the follow-up period. In VIDA, 8.0% with MSD and 5.5% children without MSD developed stunting. An episode of MSD was associated with higher odds of being stunted at follow-up compared with children without MSD in both studies (adjusted odds ratio [aOR], 1.31; 95% confidence interval [CI]: 1.04-1.64 in GEMS and aOR, 1.30; 95% CI: 1.04-1.61 in VIDA). However, the magnitude of association was not significantly different between GEMS and VIDA (P = .965). CONCLUSIONS: The association of MSD with subsequent stunting among children aged <5 years in sub-Saharan Africa did not change after rotavirus vaccine introduction. Focused strategies are needed for prevention of specific diarrheal pathogens that cause childhood stunting. |
Epidemiology of enteroaggregative, enteropathogenic, and shiga toxin-producing escherichia coli among children aged <5 years in 3 countries in Africa, 2015-2018: Vaccine Impact on Diarrhea in Africa (VIDA) Study
Ochieng JB , Powell H , Sugerman CE , Omore R , Ogwel B , Juma J , Awuor AO , Sow SO , Sanogo D , Onwuchekwa U , Keita AM , Traoré A , Badji H , Hossain MJ , Jones JCM , Kasumba IN , Nasrin D , Roose A , Liang Y , Jamka LP , Antonio M , Platts-Mills JA , Liu J , Houpt ER , Mintz ED , Hunsperger E , Onyango CO , Strockbine N , Widdowson MA , Verani JR , Tennant SM , Kotloff KL . Clin Infect Dis 2023 76 S77-s86 ![]() BACKGROUND: To address knowledge gaps regarding diarrheagenic Escherichia coli (DEC) in Africa, we assessed the clinical and epidemiological features of enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), and Shiga toxin-producing E. coli (STEC) positive children with moderate-to-severe diarrhea (MSD) in Mali, The Gambia, and Kenya. METHODS: Between May 2015 and July 2018, children aged 0-59 months with medically attended MSD and matched controls without diarrhea were enrolled. Stools were tested conventionally using culture and multiplex polymerase chain reaction (PCR), and by quantitative PCR (qPCR). We assessed DEC detection by site, age, clinical characteristics, and enteric coinfection. RESULTS: Among 4840 children with MSD and 6213 matched controls enrolled, 4836 cases and 1 control per case were tested using qPCR. Of the DEC detected with TAC, 61.1% were EAEC, 25.3% atypical EPEC (aEPEC), 22.4% typical EPEC (tEPEC), and 7.2% STEC. Detection was higher in controls than in MSD cases for EAEC (63.9% vs 58.3%, P < .01), aEPEC (27.3% vs 23.3%, P < .01), and STEC (9.3% vs 5.1%, P < .01). EAEC and tEPEC were more frequent in children aged <23 months, aEPEC was similar across age strata, and STEC increased with age. No association between nutritional status at follow-up and DEC pathotypes was found. DEC coinfection with Shigella/enteroinvasive E. coli was more common among cases (P < .01). CONCLUSIONS: No significant association was detected between EAEC, tEPEC, aEPEC, or STEC and MSD using either conventional assay or TAC. Genomic analysis may provide a better definition of the virulence factors associated with diarrheal disease. |
Norovirus disease among children <5 years in 3 Sub-Saharan African countries: Findings from the Vaccine Impact on Diarrhea in Africa (VIDA) Study, 2015-2018
Omore R , Powell H , Sow SO , Jahangir Hossain M , Ogwel B , Doh S , Ochieng JB , Jones JCM , Zaman SMA , Awuor AO , Juma J , Kasumba IN , Roose A , Jamka LP , Nasrin D , Liu J , Keita AM , Traoré A , Onwuchekwa U , Badji H , Sarwar G , Antonio M , Sugerman CE , Mintz ED , Houpt ER , Verani JR , Widdowson MA , Tennant SM , Platts-Mills JA , Tate JE , Parashar UD , Kotloff KL . Clin Infect Dis 2023 76 S114-s122 ![]() BACKGROUND: To address a paucity of data from sub-Saharan Africa, we examined the prevalence, severity, and seasonality of norovirus genogroup II (NVII) among children <5 years old in The Gambia, Kenya, and Mali following rotavirus vaccine introduction. METHODS: Population-based surveillance was conducted to capture medically-attended moderate-to-severe diarrhea (MSD) cases, defined as a child 0-59 months old passing ≥3 loose stools in a 24-hour period with ≥1 of the following: sunken eyes, poor skin turgor, dysentery, intravenous rehydration, or hospitalization within 7 days of diarrhea onset. Diarrhea-free matched controls randomly selected from a censused population were enrolled at home. Stools from cases and controls were tested for enteropathogens, including norovirus and rotavirus, by TaqMan quantitative polymerase chain reaction (PCR) and conventional reverse transcription PCR. We used multiple logistic regression to derive adjusted attributable fractions (AFe) for each pathogen causing MSD, which takes into consideration the prevalence in both cases and controls, for each site and age. A pathogen was considered etiologic if AFe was ≥0.5. In further analyses focusing on the predominant NVII strains, we compared rotavirus and NVII severity using a 20-point modified Vesikari score and examined seasonal fluctuations. RESULTS: From May 2015 to July 2018, we enrolled 4840 MSD cases and 6213 controls. NVI was attributed to only 1 MSD episode. NVII was attributed to 185 (3.8%) of all MSD episodes and was the sole attributable pathogen in 139 (2.9%); peaking (36.0%) at age 6-8 months with majority (61.2%) aged 6-11 months. MSD cases whose episodes were attributed to NVII alone compared with rotavirus alone were younger (median age, 8 vs 12 months, P < .0001) and had less severe illness (median Vesikari severity score, 9 vs 11, P = .0003) but equally likely to be dehydrated. NVII occurred year-round at all study sites. CONCLUSIONS: Infants aged 6-11 months bear the greatest burden of norovirus disease, with NVII predominating. An early infant vaccine schedule and rigorous adherence to guidelines recommended for management of dehydrating diarrhea may offer substantial benefit in these African settings. |
Prevalence of aflatoxins in dietary staples in the border county of Busia, Western Kenya
Awuor AO , Thuita FM , Okoth SD . Afr J Food Agric Nutr Dev 2020 20 (7) 17045-17062 Aflatoxins, secondary metabolites of some Aspergillus fungi, are of public health importance. They are major contaminants of cereals and tubers. Data on prevalence of aflatoxin contamination of sorghum, millet and cassava in Busia County are limited. The extent of aflatoxin contamination in dietary staples in Busia County were assessed and potential sources associated with the contamination evaluated. A tool designed to collect sociodemographic profile, food sources and storage locations and vessels and food consumption habits of respondents was loaded onto an Open Data Kit and used in 3 subcounties. Quantitative data were analyzed using SAS version 15 software. Maize, millet, sorghum, cassava and groundnut samples were collected from 469 households. Competitive Enzyme-linked Immunosorbent Assay method was used to determine total aflatoxin levels in food samples. Sixty-eight percent of the maize samples were sourced from the market. Approximately 75% of maize samples were stored in polypropylene sacks. Samples of all five foods had detectable levels of aflatoxin. Overall, maize had the highest level of contamination (mean 100 ppb; SD 252.9; range 1-1584 ppb) with about a third of maize samples above the East African Community regulatory limits (10 ppb). The levels of aflatoxin ranged from 0.3 to 740 ppb in sorghum, 0.5 to 15 ppb in cassava, from 0.5 to 12 ppb in millet and from 0.1 to 2.8 ppb in groundnuts. The odds of contamination above 10 ppb for market-sourced maize was 1.2 times higher than homegrown maize (OR 1.185, CI 0.554, 2.534). Sorghum stored in buckets had a 12.81 likelihood of having higher than allowable limits of aflatoxin (OR 12.82, CI 2.566, 63.992) than when stored in polypropylene sacks. Aflatoxin is prevalent in the dietary staples consumed in households within Busia County. Residents are at risk of chronic exposure to aflatoxin. Enhanced market surveillance within the county is recommended. |
Human aflatoxin exposure in Uganda: Estimates from a subset of the 2011 Uganda AIDS indicator survey (UAIS)
Zitomer NC , Awuor AO , Widdowson MA , Daniel JH , Sternberg MR , Rybak ME , Mbidde EK . Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2020 38 (1) 1-12 Aflatoxins are carcinogenic mycotoxins that contaminate a variety of crops worldwide. Acute exposure can cause liver failure, and chronic exposure can lead to stunting in children and liver cancer in adults. We estimated aflatoxin exposure across Uganda by measuring a serum biomarker of aflatoxin exposure in a subsample from the 2011 Uganda AIDS Indicator Survey, a nationally representative survey of HIV prevalence, and examined its association with geographic, demographic, and socioeconomic variables. We analysed a subsample of 985 serum specimens selected among HIV-negative participants from 10 survey-defined geographic regions for serum aflatoxin B1-lysine (AFB1-lys) by use of isotope dilution LC-MS/MS and calculated results normalised to serum albumin. We used statistical techniques for censored data to estimate geometric means (GMs), standard deviations, and percentiles. We detected serum AFB1-lys in 71.7% of specimens (LOD = 0.5 pg/mg albumin). Unadjusted GM AFB1-lys (pg/mg albumin) was 1.33 (95% CI: 1.21-1.47). Serum AFB1-lys was higher in males (GM: 1.57; 95% CI: 1.38-1.80) vs. females (GM: 1.12; 95% CI: 0.97-1.30) (P = .0019), and higher in persons residing in urban settings (GM: 2.83; 95% CI: 2.37-3.37) vs. rural (GM: 1.10; 95% CI: 0.99-1.23) (P < .0001). When we used a multivariable censored regression model to assess confounding and interactions among variables we found that survey region, gender, age, occupation, distance to marketplace, and number of meals per day were statistically significant predictors of aflatoxin exposure. While not nationally representative, our findings provide an improved understanding of the widespread burden of aflatoxin exposure throughout Uganda and identify key geographic, demographic, and socioeconomic factors that may modulate aflatoxin exposure risk. |
Water, sanitation, and hygiene characteristics among HIV-positive households participating in the Global Enteric Multicenter Study in Rural Western Kenya, 2008-2012
Schilling KA , Awuor AO , Rajasingham A , Moke F , Omore R , Amollo M , Farag TH , Nasrin D , Nataro JP , Kotloff KL , Levine MM , Ayers T , Laserson K , Blackstock A , Rothenberg R , Stauber CE , Mintz ED , Breiman RF , O'Reilly CE . Am J Trop Med Hyg 2018 99 (4) 905-915 Diarrheal illness, a common occurrence among people living with human immunodeficiency virus (PLHIV), is largely preventable through access to safe drinking water quality, sanitation, and hygiene (WASH) facilities. We examined WASH characteristics among households with and without HIV-positive residents enrolled in the Global Enteric Multicenter Study (GEMS) in rural Western Kenya. Using univariable logistic regression, we examined differences between HIV-positive and HIV-negative households in regard to WASH practices. Among HIV-positive households, we explored the relationship between the length of time knowing their HIV status and GEMS enrollment. No statistically significant differences were apparent in the WASH characteristics among HIV-positive and HIV-negative households. However, we found differences in the WASH characteristics among HIV-positive households who were aware of their HIV status >/= 30 days before enrollment compared with HIV-positive households who found out their status < 30 days before enrollment or thereafter. Significantly more households aware of their HIV-positive status before enrollment reported treating their drinking water (odds ratio [OR] confidence interval [CI]: 2.34 [1.12, 4.86]) and using effective water treatment methods (OR [CI]: 9.6 [3.09, 29.86]), and had better drinking water storage practices. This suggests that within this region of Kenya, HIV programs are effective in promoting the importance of practicing positive WASH-related behaviors among PLHIV. |
Evaluation of efficacy, acceptability and palatability of calcium montmorillonite clay used to reduce aflatoxin B1 dietary exposure in a crossover study in Kenya
Awuor AO , Montgomery J , Yard E , Martin C , Daniel J , Zitomer N , Rybak M , Lewis L , Phillips T , Romoser A , Elmore S , Oyugi E , Amwayi S , Bii C , Vulule J . Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2016 34 (1) 93-102 Acute aflatoxin exposure can cause death and disease (aflatoxicosis) in humans. Aflatoxicosis fatality rates have been documented to be as high as 40% in Kenya. The inclusion in the diet of calcium silicate 100 (ACCS100), a calcium montmorillonite clay, may reduce aflatoxin bioavailability; thus potentially decreasing the risk of aflatoxicosis. We investigated the efficacy, acceptability, and palatability of ACCS100 in a population in Kenya with recurring aflatoxicosis outbreaks. Healthy adult participants were enrolled in this double-blinded, cross-over clinical trial in 2014. Following informed consent, participants (n=50) were randomized to receive either ACCS100 (3g/day) or placebo (3g/day) for seven days. Treatments were switched following a five-day washout period. Urine samples were collected daily and assessed for urinary aflatoxin M1 (AFM1). Blood samples were collected at the beginning and end of the trial and assessed for aflatoxin B1-lysine adducts from serum albumin (AFB1-lys). AFM1 concentrations in urine; were significantly reduced while taking ACCS100 compared to calcium carbonate placebo (beta=0.49, 95% confidence limit: 0.32-0.75). The 20 day interval included both the placebo and ACCS100 treatments as well as a washout period. There were no statistically significant differences in reported taste, aftertaste, appearance, color, or texture by treatment. There were no statistically significant differences in self-reported adverse events by treatment. Most participants would be willing to take ACCS100 (98%) and give it to their children (98%). ACCS100 was effective, acceptable, and palatable. More work is needed to test ACCS100 among vulnerable populations and to determine if ACCS100 remains effective at the levels of aflatoxin exposure that induce aflatoxicosis. |
Epidemiology, seasonality and factors associated with rotavirus infection among children with moderate-to-severe diarrhea in rural western Kenya, 2008-2012: The Global Enteric Multicenter Study (GEMS)
Omore R , Tate JE , O'Reilly CE , Ayers T , Williamson J , Moke F , Schilling KA , Awuor AO , Jaron P , Ochieng JB , Oundo J , Parashar UD , Parsons MB , Bopp CC , Nasrin D , Farag TH , Kotloff KL , Nataro JP , Panchalingam S , Levine MM , Laserson KF , Nuorti JP , Mintz ED , Breiman RF . PLoS One 2016 11 (8) e0160060 OBJECTIVE: To evaluate factors associated with rotavirus diarrhea and to describe severity of illness among children <5 years old with non-dysenteric, moderate-to-severe diarrhea (MSD) in rural western Kenya. METHODS: We analyzed data from children <5 years old with non-dysenteric MSD enrolled as cases in the Global Enteric Multicenter Study (GEMS) in Kenya. A non-dysenteric MSD case was defined as a child with ≥3 loose stools in 24 hrs. and one or more of the following: sunken eyes, skin tenting, intravenous rehydration, or hospitalization, who sought care at a sentinel health center within 7 days of illness onset. Rotavirus antigens in stool samples were detected by ELISA. Demographic and clinical information was collected at enrollment and during a single follow-up home visit at approximately 60 days. We analyzed diarrhea severity using a GEMS 17 point numerical scoring system adapted from the Vesikari score. We used logistic regression to evaluate factors associated with rotavirus infection. RESULTS: From January 31, 2008 to September 30, 2012, among 1,637 (92%) non-dysenteric MSD cases, rotavirus was detected in stools of 245 (15.0%). Rotavirus-positive compared with negative cases were: younger (median age, 8 vs. 13 months; p<0.0001), had more severe illness (median severity score, 9 vs 8; p<0.0001) and had to be hospitalized more frequently (37/245 [15.1%] vs. 134/1,392 [9.6%]), p <0.013). Independent factors associated with rotavirus infection included age 0-11 months old (aOR = 5.29, 95% CI 3.14-8.89) and presenting with vomiting ≥3 times/24hrs (aOR = 2.58, 95% CI [1.91-3.48]). Rotavirus was detected more commonly in warm and dry months than in the cool and rainy months (142/691 [20%] vs 70/673 [10%]) p<0.0001). CONCLUSIONS: Diarrhea caused by rotavirus is associated with severe symptoms leading to hospitalization. Consistent with other settings, infants had the greatest burden of disease. |
The relationship between distance to water source and moderate-to-severe diarrhea in the Global Enterics Multi-Center Study in Kenya, 2008-2011
Nygren BL , O'Reilly CE , Rajasingham A , Omore R , Ombok M , Awuor AO , Jaron P , Moke F , Vulule J , Laserson K , Farag TH , Nasrin D , Nataro JP , Kotloff KL , Levine MM , Derado G , Ayers TL , Lash RR , Breiman RF , Mintz ED . Am J Trop Med Hyg 2016 94 (5) 1143-9 In the developing world, fetching water for drinking and other household uses is a substantial burden that affects water quantity and quality in the household. We used logistic regression to examine whether reported household water fetching times were a risk factor for moderate-to-severe diarrhea (MSD) using case-control data of 3,359 households from the Global Enterics Multi-Center Study in Kenya in 2009-2011. We collected additional global positioning system (GPS) data for a subset of 254 randomly selected households and compared GPS-based straight line and actual travel path distances to fetching times reported by respondents. GPS-based data were highly correlated with respondent-provided times (Spearman correlation coefficient = 0.81, P < 0.0001). The median estimated one-way distance to water source was 200 m for cases and 171 for controls (Wilcoxon rank sums/Mann-Whitney P = 0.21). A round-trip fetching time of > 30 minutes was reported by 25% of cases versus 15% of controls and was significantly associated with MSD where rainwater was not used in the last 2 weeks (odds ratio = 1.97, 95% confidence interval = 1.56-2.49). These data support the United Nations definition of access to an improved water source being within 30 minutes total round-trip travel time. |
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