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1.
Bull World Health Organ ; 98(12): 859-868, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33293746

RESUMO

Objective: To determine the regional- and district-level newborn prevalence of sickle cell trait and disease, and the prevalence of haemoglobin variants and genetic modifiers of sickle cell disease, in the nine regions of north-western United Republic of Tanzania. Methods: We repurposed dried blood spot samples from children (aged 0-24 months) born to mothers living with human immunodeficiency virus (HIV), collected as part of the HIV Early Infant Diagnosis programme, for sickle cell diagnosis. We performed isoelectric focusing to determine whether samples had normal haemoglobin, sickle cell trait, sickle cell disease or a rare haemoglobin variant. We shipped samples diagnosed as disease or variant to Cincinnati Children's Hospital in the United States of America for deoxyribonucleic-acid-based analyses to determine the prevalence of α-thalassaemia, glucose-6-phosphate dehydrogenase (G6PD) deficiency or fetal haemoglobin genetic modifiers. Findings: We analysed a total of 17 200 specimens during February 2017-May 2018. We observed a prevalence of sickle cell trait and disease of 20.3% (3492/17 200) and 1.2% (210/17 200), respectively. District-level trait varied from 8.6% (5/58) to 28.1% (77/274). Among confirmed sickle cell disease specimens, we noted 42.7% (61/143) had 1-gene deletion and 14.7% (21/143) had 2-gene deletion α-thalassaemia trait. We documented G6PD A- deficiency in 19.2% (14/73) of males. Conclusion: Our calculated prevalence is twice as high as previously reported and reinforces the need for enhanced sickle cell diagnostic services. Our district-level data will inform public health policy, allowing screening and disease-modifying hydroxyurea therapy to be focused on high-prevalence areas, until universal newborn screening is available.

2.
Trop Med Int Health ; 2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-33151598

RESUMO

OBJECTIVE: Sickle cell disease is an important public health issue that is increasingly recognized as a substantial contributor to morbidity and early childhood mortality in sub-Saharan Africa. We aimed to provide information from large-scale, long-term sickle cell screening efforts in Africa. METHODS: We used nationally representative data from the centralized public health laboratory database in Uganda to examine epidemiological trends in sickle cell screening over a five-year period, comparing age and geographic adjustments to prevalence among different testing cohorts of children aged 0-24 months, and calculating screening coverage within high-burden districts. RESULTS: A total of 324,356 children aged 0-24 months were screened for sickle cell trait and disease from February 2014 to March 2019. A high national burden of sickle cell disease (0.9%) was confirmed among a cohort of samples co-tested with HIV. In the cohort of samples referred specifically for sickle cell testing, the overall prevalence of sickle cell disease was 9.7% and particularly elevated in high-burden districts where focused screening occurred. The majority of children were screened before age 4 months, but the sickle specific cohort had a larger proportion of affected children tested between age 5-9 months, coincident with onset of disease signs and symptoms. Successful screening coverage of sickle cell disease births was achieved in several high-burden districts. CONCLUSIONS: Examination and analysis of national sickle cell screening trends in Uganda documents the successes of focused screening strategies as an important step toward universal screening. With this evidence and increased healthcare provider knowledge, Uganda can optimize sickle cell diagnosis and management across the country.

3.
Pediatr Blood Cancer ; 66(8): e27807, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31094093

RESUMO

BACKGROUND: The Uganda Sickle Surveillance Study provided evidence for a large sickle burden among HIV-exposed infants in Uganda. To date, however, no large scale screening program has been developed for Central or East Africa. METHODS: A 3-year targeted sickle cell screening project in Uganda was designed by the Ministry of Health to (1) determine sickle cell trait and disease prevalence within high-burden districts, (2) document the prevalence among HIV-exposed and nonexposed children, (3) confirm previously suggested HIV comorbidity, and (4) estimate the co-inheritance of known genetic modifiers of sickle cell disease. RESULTS: A total of 163 334 dried blood spot samples collected between April 2015 and March 2018 were analyzed, including 112 352 samples within the HIV Early Infant Diagnosis program. A high burden with >1% sickle cell disease was found within targeted East Central and Mid-Northern districts, in both HIV-exposed and nonexposed children. Based on crude birth-rate data, 236 905 sickle cell trait births and 16 695 sickle cell disease births will occur annually in Uganda. Compared to sickle cell disease without HIV, the odds ratio of having sickle cell disease plus HIV was 0.50 (95% confidence interval = 0.40-0.64, P < .0001). Alpha-thalassemia trait and G6PD deficiency were common with sickle cell disease, but with different geospatial distribution. CONCLUSIONS: High sickle cell burden and potential HIV comorbidity are confirmed in Uganda. Genetic modifiers are common and likely influence laboratory and clinical phenotypes. These prospective data document that targeted sickle cell screening is feasible and effective in Uganda, and support development of district-level comprehensive care programs.


Assuntos
Anemia Falciforme/diagnóstico , Genes Modificadores , Deficiência de Glucosefosfato Desidrogenase/diagnóstico , Infecções por HIV/diagnóstico , Programas de Rastreamento/métodos , Talassemia alfa/diagnóstico , Anemia Falciforme/complicações , Anemia Falciforme/epidemiologia , Anemia Falciforme/genética , Pré-Escolar , Comorbidade , Feminino , Seguimentos , Deficiência de Glucosefosfato Desidrogenase/complicações , Deficiência de Glucosefosfato Desidrogenase/epidemiologia , Deficiência de Glucosefosfato Desidrogenase/genética , HIV/genética , HIV/isolamento & purificação , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Infecções por HIV/genética , Humanos , Lactente , Recém-Nascido , Masculino , Prevalência , Prognóstico , Estudos Prospectivos , Talassemia alfa/complicações , Talassemia alfa/epidemiologia , Talassemia alfa/genética
5.
Semin Hematol ; 55(2): 102-112, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-30616806

RESUMO

The vast majority of the world's population of children and adults with sickle cell disease (SCD) are born in low-resource settings, particularly in sub-Saharan Africa, the Caribbean, the Middle East, and India. As a result numerous well-established, cost-effective, and evidence-based strategies for managing SCD such as newborn screening, early education, vaccinations, screening for stroke prevention, and treatments with safe transfusions and hydroxyurea are often unavailable, leading to substantial morbidity and increased mortality. Collaborations between high-income countries and these low-resource settings (North-South partnerships) have been advocated, with the goal of improving clinical care. Based on directives promulgated by the World Health Organization, we have developed a strategy of developing prospective research programs that focus on training, capacity building, and local data collection. This strategy involves consideration of important guiding principles, full partnerships, proper planning, and financial issues before program launch, after which rigorous program management is required for full effect and long-term sustainability. Ultimately these collaborative research programs should help create national guidelines and lead to improved clinical care for all children and adults with SCD.


Assuntos
Anemia Falciforme/terapia , Cooperação Internacional , Área Carente de Assistência Médica , Pesquisa Médica Translacional/organização & administração , Assistência à Saúde/organização & administração , Assistência à Saúde/normas , Saúde Global/normas , Humanos , Estudos Prospectivos , Pesquisa Médica Translacional/normas
7.
Lancet Glob Health ; 4(3): e195-200, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26833239

RESUMO

BACKGROUND: Sickle cell disease contributes substantially to mortality in children younger than 5 years in sub-Saharan Africa. In Uganda, 20,000 babies per year are thought to be born with sickle cell disease, but accurate data are not available. We did the cross-sectional Uganda Sickle Surveillance Study to assess the burden of disease. METHODS: The primary objective of the study was to calculate prevalence of sickle cell trait and disease. We obtained punch samples from dried blood spots routinely collected from HIV-exposed infants in ten regions and 112 districts across Uganda for the national Early Infant Diagnosis programme. Haemoglobin electrophoresis by isoelectric focusing was done on all samples to identify those from babies with sickle trait or disease. FINDINGS: Between February, 2014, and March, 2015, 99,243 dried blood spots were analysed and results were available for 97,631. The overall number of children with sickle cell trait was 12,979 (13·3%) and with disease was 716 (0·7%). Sickle cell numbers ranged from 631 (4·6%) for trait and 23 (0·2%) for disease of 13,649 in the South Western region to 1306 (19·8%) for trait and 96 (1·5%) for disease of 6581 in the East Central region. Sickle cell trait was seen in all districts. The lowest prevalence was less than 3·0% in two districts. Eight districts had prevalence greater than 20·0%, with the highest being 23·9%. Sickle cell disease was less common in children older than 12 months or who were HIV positive, which is consistent with comorbidity and early mortality. INTERPRETATION: Prevalence of sickle cell trait and disease were high in Uganda, with notable variation between regions and districts. The data will help to inform national strategies for sickle cell disease, including neonatal screening. FUNDING: Cincinnati Children's Research Foundation.


Assuntos
Anemia Falciforme/epidemiologia , Criança , Pré-Escolar , Comorbidade , Estudos Transversais , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Prevalência , Traço Falciforme/epidemiologia , Uganda/epidemiologia
8.
Blood Adv ; 1(1): 93-100, 2016 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-29296698

RESUMO

The Uganda Sickle Surveillance Study analyzed dried blood spots that were collected from almost 100 000 infants and young children from all 10 regions and 112 districts in the Republic of Uganda, with the primary objective of determining the prevalence of sickle cell trait and disease. An overall prevalence of 13.3% sickle cell trait and 0.7% sickle cell disease was recently reported. The isoelectric focusing electrophoresis technique coincidentally revealed numerous hemoglobin (Hb) variants (defined as an electrophoresis band that was not Hb A, Hb F, Hb S, or Hb C) with an overall country-wide prevalence of 0.5%, but with considerable geographic variability, being highest in the northwest regions and districts. To elucidate these Hb variants, the original isoelectric focusing (IEF) gels were reviewed to identify and locate the variant samples; corresponding dried blood spots were retrieved for further testing. Subsequent DNA-based investigation of 5 predominant isoelectric focusing patterns identified 2 α-globin variants (Hb Stanleyville II, Asn78Lys; Hb G-Pest, Asp74Asn), 1 ß-globin variant (Hb O-Arab, Glu121Lys), and 2 fusion globin variants (Hb P-Nilotic, ß31-δ50; Hb Kenya, Aγ81Leu-ß86Ala). Compound heterozygotes containing an Hb variant plus Hb S were also identified, including both Hb S/O-Arab and HbS/Kenya. Regional differences in the types and prevalence of these hemoglobin variants likely reflect tribal ancestries and migration patterns. Algorithms are proposed to characterize these Hb variants, which will be helpful for emerging neonatal hemoglobinopathy screening programs that are under way in sub-Saharan Africa.

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