1
|
Gumba H, Opiyo M, Musyoki J, Mutunga M, Ngetsa C, Mwarumba S, Mosobo M, Njuguna S, Kai O, Lambisia AW, Kimani D, Cheruiyot R, Kiyuka P, Lewa C, Gicheru E, Tendwa M, Said Mohammed K, Osoti V, Makale J, Tawa B, Odundo C, Cheruiyot W, Nyamu W, Gumbi W, Mwacharo J, Nyamako L, Otieno E, Amadi D, Ouma N, Karia B, Thoya J, Karani A, Mugo D, Gichuki BM, Riako D, Mutua S, Gitonga JN, Ominde K, Wanjiku P, Mutiso A, Mwanzu A, Sein Y, Bartilol B, Mwangi S, Omuoyo DO, Morobe JM, de Laurent ZR, Mitsanze F, Mwakubia A, Rono M, Nyaguara A, Tsofa B, Bejon P, Agoti CN, Ochola-Oyier LI. Maintaining laboratory quality assurance and safety in a pandemic: Experiences from the KEMRI-Wellcome Trust Research Programme laboratory’s COVID-19 response. Wellcome Open Res 2022. [DOI: 10.12688/wellcomeopenres.16704.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Laboratory diagnosis plays a critical role in the containment of a pandemic. Strong laboratory quality management systems (QMS) are essential for laboratory diagnostic services. However, low laboratory capacities in resource-limited countries has made the maintenance of laboratory quality assurance, especially during a pandemic, a daunting task. In this paper, we describe our experience of how we went about providing diagnostic testing services for SARS-CoV-2 through laboratory reorganization, redefining of the laboratory workflow, and training and development of COVID-19 documented procedures, all while maintaining the quality assurance processes during the COVID-19 pandemic at the Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme (KWTRP) laboratory. The KWTRP laboratory managed to respond to the COVID-19 outbreak in Kenya by providing diagnostic testing for the coastal region of the country, while maintaining its research standard quality assurance processes. A COVID-19 team comprising of seven sub-teams with assigned specific responsibilities and an organizational chart with established reporting lines were developed. Additionally, a total of four training sessions were conducted for county Rapid Response Teams (RRTs) and laboratory personnel. A total of 11 documented procedures were developed to support the COVID-19 testing processes, with three for the pre-analytical phases, seven for the analytical phase, and one for the post-analytical phase. With the workflow re-organization, the development of appropriate standard operating procedures, and training, research laboratories can effectively respond to pandemic outbreaks while maintaining research standard QMS procedures.
Collapse
|
2
|
Mohammed KS, de Laurent ZR, Omuoyo DO, Lewa C, Gicheru E, Cheruiyot R, Bartilol B, Mutua S, Musyoki J, Gumba H, Mwacharo J, Riako D, Mwangi SJ, Gichuki BM, Nyamako L, Karani A, Karanja H, Mugo D, Gitonga JN, Njuguna S, Gumbi W, Tawa B, Tendwa M, Cheruiyot W, Sein Y, Nyambu JK, Patta SO, Thani TS, Maitha EK, Kitole B, Mwakinangu MS, Muslih BS, Otieno JO, Nyiro JU, Kiyuka P, Ndwiga L, Wamae K, Kimani D, Makale J, Morobe JM, Osoti V, Lambisia AW, Odundo C, Mwarumba S, Mutunga M, Bejon P, Tsofa B, Agoti CN, Ochola-Oyier LI. An optimization of four SARS-CoV-2 qRT-PCR assays in a Kenyan laboratory to support the national COVID-19 rapid response teams. Wellcome Open Res 2022; 5:162. [PMID: 35330938 PMCID: PMC8921690 DOI: 10.12688/wellcomeopenres.16063.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2022] [Indexed: 11/28/2022] Open
Abstract
Background: The COVID-19 pandemic relies on real-time polymerase chain reaction (qRT-PCR) for the detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), to facilitate roll-out of patient care and infection control measures. There are several qRT-PCR assays with little evidence on their comparability. We report alterations to the developers' recommendations to sustain the testing capability in a resource-limited setting. Methods: We used a SARS-CoV-2 positive control RNA sample to generate several 10-fold dilution series that were used for optimization and comparison of the performance of the four qRT-PCR assays: i) Charité Berlin primer-probe set, ii) European Virus Archive - GLOBAL (EVAg) primer-probe set, iii) DAAN premixed commercial kit and iv) Beijing Genomics Institute (BGI) premixed commercial kit. We adjusted the manufacturer- and protocol-recommended reaction component volumes for these assays and assessed the impact on cycle threshold (Ct) values. Results: The Berlin and EVAg E gene and RdRp assays reported mean Ct values within range of each other across the different titrations and with less than 5% difference. The DAAN premixed kit produced comparable Ct values across the titrations, while the BGI kit improved in performance following a reduction of the reaction components. Conclusion: We achieved a 2.6-fold and 4-fold increase in the number of tests per kit for the commercial kits and the primer-probe sets, respectively. All the assays had optimal performance when the primers and probes were used at 0.375X, except for the Berlin N gene assay. The DAAN kit was a reliable assay for primary screening of SARS-CoV-2 whereas the BGI kit's performance was dependent on the volumes and concentrations of both the reaction buffer and enzyme mix. Our recommendation for SARS-CoV-2 diagnostic testing in resource-limited settings is to optimize the assays available to establish the lowest volume and suitable concentration of reagents required to produce valid results.
Collapse
Affiliation(s)
| | | | | | - Clement Lewa
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | | | | | - Horace Gumba
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Debra Riako
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Lydia Nyamako
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Angela Karani
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Henry Karanja
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Daisy Mugo
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Susan Njuguna
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Wilson Gumbi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Brian Tawa
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Yiakon Sein
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - John K. Nyambu
- Department Of Health Services, Taita-Taveta County Government, Taita-Taveta, Kenya
| | - Shem O. Patta
- Department Of Health Services, Mombasa County Government, Mombasa, Kenya
| | | | | | | | | | | | | | | | | | | | - Kevin Wamae
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | - Victor Osoti
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Calleb Odundo
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK
| | | | | | | |
Collapse
|
3
|
Gumba H, Opiyo M, Musyoki J, Mutunga M, Ngetsa C, Mwarumba S, Mosobo M, Njuguna S, Kai O, Lambisia AW, Kimani D, Cheruiyot R, Kiyuka P, Lewa C, Gicheru E, Tendwa M, Said Mohammed K, Osoti V, Makale J, Tawa B, Odundo C, Cheruiyot W, Nyamu W, Gumbi W, Mwacharo J, Nyamako L, Otieno E, Amadi D, Ouma N, Karia B, Thoya J, Karani A, Mugo D, Gichuki BM, Riako D, Mutua S, Gitonga JN, Ominde K, Wanjiku P, Mutiso A, Mwanzu A, Sein Y, Bartilol B, Mwangi S, Omuoyo DO, Morobe JM, de Laurent ZR, Mitsanze F, Mwakubia A, Rono M, Nyaguara A, Tsofa B, Bejon P, Agoti CN, Ochola-Oyier LI. Maintaining laboratory quality assurance and safety in a pandemic: Experiences from the KEMRI-Wellcome Trust Research Programme laboratory’s COVID-19 response. Wellcome Open Res 2021. [DOI: 10.12688/wellcomeopenres.16704.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Laboratory diagnosis plays a critical role in the containment of a pandemic. Strong laboratory quality management systems (QMS) are essential for laboratory diagnostic services. However, low laboratory capacities in resource-limited countries has made the maintenance of laboratory quality assurance, especially during a pandemic, a daunting task. In this paper, we describe our experience of how we went about providing diagnostic testing services for SARS-CoV-2 through laboratory reorganization, redefining of the laboratory workflow, and training and development of COVID-19 documented procedures, all while maintaining the quality assurance processes during the COVID-19 pandemic at the Kenya Medical Research Institute (KEMRI) Wellcome Trust Research Programme (KWTRP) laboratory. The KWTRP laboratory managed to respond to the COVID-19 outbreak in Kenya by providing diagnostic testing for the coastal region of the country, while maintaining its research standard quality assurance processes. A COVID-19 team comprising of seven sub-teams with assigned specific responsibilities and an organizational chart with established reporting lines were developed. Additionally, a total of four training sessions were conducted for county Rapid Response Teams (RRTs) and laboratory personnel. A total of 11 documented procedures were developed to support the COVID-19 testing processes, with three for the pre-analytical phases, seven for the analytical phase, and one for the post-analytical phase. With the workflow re-organization, the development of appropriate standard operating procedures, and training, research laboratories can effectively respond to pandemic outbreaks while maintaining research standard QMS procedures.
Collapse
|
4
|
Agoti CN, Mutunga M, Lambisia AW, Kimani D, Cheruiyot R, Kiyuka P, Lewa C, Gicheru E, Tendwa M, Said Mohammed K, Osoti V, Makale J, Tawa B, Odundo C, Cheruiyot W, Nyamu W, Gumbi W, Mwacharo J, Nyamako L, Otieno E, Amadi D, Thoya J, Karani A, Mugo D, Musyoki J, Gumba H, Mwarumba S, M. Gichuki B, Njuguna S, Riako D, Mutua S, Gitonga JN, Sein Y, Bartilol B, Mwangi SJ, O. Omuoyo D, M. Morobe J, de Laurent ZR, Bejon P, Ochola-Oyier LI, Tsofa B. Pooled testing conserves SARS-CoV-2 laboratory resources and improves test turn-around time: experience on the Kenyan Coast. Wellcome Open Res 2021; 5:186. [PMID: 33134555 PMCID: PMC7590893 DOI: 10.12688/wellcomeopenres.16113.2] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2020] [Indexed: 12/15/2022] Open
Abstract
Background. International recommendations for the control of the coronavirus disease 2019 (COVID-19) pandemic emphasize the central role of laboratory testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent, at scale. The availability of testing reagents, laboratory equipment and qualified staff are important bottlenecks to achieving this. Elsewhere, pooled testing (i.e. combining multiple samples in the same reaction) has been suggested to increase testing capacities in the pandemic period. Methods. We discuss our experience with SARS-CoV-2 pooled testing using real-time reverse transcription polymerase chain reaction (RT-PCR) on the Kenyan Coast. Results. In mid-May, 2020, our RT-PCR testing capacity for SARS-CoV-2 was improved by ~100% as a result of adoption of a six-sample pooled testing strategy. This was accompanied with a concomitant saving of ~50% of SARS-CoV-2 laboratory test kits at both the RNA extraction and RT-PCR stages. However, pooled testing came with a slight decline of test sensitivity. The RT-PCR cycle threshold value (ΔCt) was ~1.59 higher for samples tested in pools compared to samples tested singly. Conclusions. Pooled testing is a useful strategy to increase SARS-CoV-2 laboratory testing capacity especially in low-income settings.
Collapse
Affiliation(s)
- Charles N. Agoti
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
- Department of Biomedical Sciences, Pwani University, Kilifi, Kenya
| | - Martin Mutunga
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Arnold W. Lambisia
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Domtila Kimani
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Robinson Cheruiyot
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Patience Kiyuka
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Clement Lewa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Elijah Gicheru
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Metrine Tendwa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Khadija Said Mohammed
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Victor Osoti
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Johnstone Makale
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Brian Tawa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Calleb Odundo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Wesley Cheruiyot
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Wilfred Nyamu
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Wilson Gumbi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Jedidah Mwacharo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Lydia Nyamako
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Edward Otieno
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - David Amadi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Janet Thoya
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Angela Karani
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Daisy Mugo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Jennifer Musyoki
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Horace Gumba
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Salim Mwarumba
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Bonface M. Gichuki
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Susan Njuguna
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Debra Riako
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Shadrack Mutua
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - John N. Gitonga
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Yiakon Sein
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Brian Bartilol
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Shaban J. Mwangi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Donwilliams O. Omuoyo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - John M. Morobe
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Zaydah R. de Laurent
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Philip Bejon
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
- Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK
| | - Lynette Isabella Ochola-Oyier
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Benjamin Tsofa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| |
Collapse
|
5
|
Kariuki SN, Marin-Menendez A, Introini V, Ravenhill BJ, Lin YC, Macharia A, Makale J, Tendwa M, Nyamu W, Kotar J, Carrasquilla M, Rowe JA, Rockett K, Kwiatkowski D, Weekes MP, Cicuta P, Williams TN, Rayner JC. Red blood cell tension protects against severe malaria in the Dantu blood group. Nature 2020; 585:579-583. [PMID: 32939086 PMCID: PMC7116803 DOI: 10.1038/s41586-020-2726-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 06/19/2020] [Indexed: 01/06/2023]
Abstract
Malaria has had a major effect on the human genome, with many protective polymorphisms-such as the sickle-cell trait-having been selected to high frequencies in malaria-endemic regions1,2. The blood group variant Dantu provides 74% protection against all forms of severe malaria in homozygous individuals3-5, a similar degree of protection to that afforded by the sickle-cell trait and considerably greater than that offered by the best malaria vaccine. Until now, however, the protective mechanism has been unknown. Here we demonstrate the effect of Dantu on the ability of the merozoite form of the malaria parasite Plasmodium falciparum to invade red blood cells (RBCs). We find that Dantu is associated with extensive changes to the repertoire of proteins found on the RBC surface, but, unexpectedly, inhibition of invasion does not correlate with specific RBC-parasite receptor-ligand interactions. By following invasion using video microscopy, we find a strong link between RBC tension and merozoite invasion, and identify a tension threshold above which invasion rarely occurs, even in non-Dantu RBCs. Dantu RBCs have higher average tension than non-Dantu RBCs, meaning that a greater proportion resist invasion. These findings provide both an explanation for the protective effect of Dantu, and fresh insight into why the efficiency of P. falciparum invasion might vary across the heterogenous populations of RBCs found both within and between individuals.
Collapse
Affiliation(s)
- Silvia N Kariuki
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Viola Introini
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Benjamin J Ravenhill
- Cambridge Institute for Medical Research, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Yen-Chun Lin
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | - Alex Macharia
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Johnstone Makale
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Metrine Tendwa
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Wilfred Nyamu
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Jurij Kotar
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
| | | | - J Alexandra Rowe
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Kirk Rockett
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Dominic Kwiatkowski
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Big Data Institute, University of Oxford, Oxford, UK
| | - Michael P Weekes
- Cambridge Institute for Medical Research, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Pietro Cicuta
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Thomas N Williams
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
- Institute of Global Health Innovation, Imperial College London, London, UK.
- Department of Infectious Disease, Imperial College London, London, UK.
| | - Julian C Rayner
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK.
- Cambridge Institute for Medical Research, School of Clinical Medicine, University of Cambridge, Cambridge, UK.
| |
Collapse
|
6
|
Agoti CN, Mutunga M, Lambisia AW, Kimani D, Cheruiyot R, Kiyuka P, Lewa C, Gicheru E, Tendwa M, Said Mohammed K, Osoti V, Makale J, Tawa B, Odundo C, Cheruiyot W, Nyamu W, Gumbi W, Mwacharo J, Nyamako L, Otieno E, Amadi D, Thoya J, Karani A, Mugo D, Musyoki J, Gumba H, Mwarumba S, M. Gichuki B, Njuguna S, Riako D, Mutua S, Gitonga JN, Sein Y, Bartilol B, Mwangi SJ, O. Omuoyo D, M. Morobe J, de Laurent ZR, Bejon P, Ochola-Oyier LI, Tsofa B. Pooled testing conserves SARS-CoV-2 laboratory resources and improves test turn-around time: experience on the Kenyan Coast. Wellcome Open Res 2020; 5:186. [PMID: 33134555 PMCID: PMC7590893 DOI: 10.12688/wellcomeopenres.16113.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2020] [Indexed: 12/15/2022] Open
Abstract
Background. International recommendations for the control of the coronavirus disease 2019 (COVID-19) pandemic emphasize the central role of laboratory testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent, at scale. The availability of testing reagents, laboratory equipment and qualified staff are important bottlenecks to achieving this. Elsewhere, pooled testing (i.e. combining multiple samples in the same reaction) has been suggested to increase testing capacities in the pandemic period. Methods. We discuss our experience with SARS-CoV-2 pooled testing using real-time reverse transcription polymerase chain reaction (RT-PCR) on the Kenyan Coast. Results. In mid-May, 2020, our RT-PCR testing capacity for SARS-CoV-2 was improved by ~100% as a result of adoption of a six-sample pooled testing strategy. This was accompanied with a concomitant saving of ~50% of SARS-CoV-2 laboratory test kits at both the RNA extraction and RT-PCR stages. However, pooled testing came with a slight decline of test sensitivity. The RT-PCR cycle threshold value (ΔCt) was ~1.59 higher for samples tested in pools compared to samples tested singly. Conclusions. Pooled testing is a useful strategy to increase SARS-CoV-2 laboratory testing capacity especially in low-income settings.
Collapse
Affiliation(s)
- Charles N. Agoti
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
- Department of Biomedical Sciences, Pwani University, Kilifi, Kenya
| | - Martin Mutunga
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Arnold W. Lambisia
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Domtila Kimani
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Robinson Cheruiyot
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Patience Kiyuka
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Clement Lewa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Elijah Gicheru
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Metrine Tendwa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Khadija Said Mohammed
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Victor Osoti
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Johnstone Makale
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Brian Tawa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Calleb Odundo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Wesley Cheruiyot
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Wilfred Nyamu
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Wilson Gumbi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Jedidah Mwacharo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Lydia Nyamako
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Edward Otieno
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - David Amadi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Janet Thoya
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Angela Karani
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Daisy Mugo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Jennifer Musyoki
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Horace Gumba
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Salim Mwarumba
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Bonface M. Gichuki
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Susan Njuguna
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Debra Riako
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Shadrack Mutua
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - John N. Gitonga
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Yiakon Sein
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Brian Bartilol
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Shaban J. Mwangi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Donwilliams O. Omuoyo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - John M. Morobe
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Zaydah R. de Laurent
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Philip Bejon
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
- Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK
| | - Lynette Isabella Ochola-Oyier
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| | - Benjamin Tsofa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Centre for Geographic Medicine Research, Kilifi, Kenya
| |
Collapse
|
7
|
Mohammed KS, de Laurent ZR, Omuoyo DO, Lewa C, Gicheru E, Cheruiyot R, Bartilol B, Mutua S, Musyoki J, Gumba H, Mwacharo J, Riako D, Mwangi SJ, Gichuki BM, Nyamako L, Karani A, Karanja H, Mugo D, Gitonga JN, Njuguna S, Gumbi W, Tawa B, Tendwa M, Cheruiyot W, Sein Y, Nyambu JK, Patta SO, Thani TS, Maitha EK, Kitole B, Mwakinangu MS, Muslih BS, Otieno JO, Nyiro JU, Kiyuka P, Ndwiga L, Wamae K, Kimani D, Makale J, Morobe JM, Osoti V, Lambisia AW, Odundo C, Mwarumba S, Mutunga M, Bejon P, Tsofa B, Agoti CN, Ochola-Oyier LI. An optimisation of four SARS-CoV-2 qRT-PCR assays in a Kenyan laboratory to support the national COVID-19 rapid response teams. Wellcome Open Res 2020; 5:162. [PMID: 35330938 PMCID: PMC8921690 DOI: 10.12688/wellcomeopenres.16063.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2020] [Indexed: 05/13/2024] Open
Abstract
Background: The global COVID-19 outbreak relies on a quantitative real-time polymerase chain reaction (qRT-PCR) for the detection of severe acute respiratory syndrome coronavirus (SARS-CoV-2), to facilitate the roll-out of patient care and infection control measures. There are several qRT-PCR assays with little evidence on their comparability. We report alterations to the developers' recommendations to sustain the testing capability in our setting, where the supply of testing reagents is limited. Methods: Standards generated from a serially-diluted positive control and previously identified positive/negative samples were used to determine the optimal volumes of the qRT-PCR reagents and to evaluate the validity and performance of four assays: Charité Berlin and European Virus Archive - GLOBAL (EVAg) primer-probe sets, and DAAN and Beijing Genomics Institute (BGI) premixed commercial kits. A multiplex and singleplex RT-PCR kit was used with the two primer-probe sets and the recommended assay volumes of the two premixed kits were altered. Results: In comparison to the multiplex RT-PCR kit, the singleplex RT-PCR kit combined with the primer-probe sets yielded consistent cycle threshold (Ct) values across the different titrations tested. The DAAN premixed kit produced comparable Ct values across the titrations, while the BGI kit showed incomparable Ct values and inconsistent results between batches using the manufacturer's recommended volumes. Conclusion: We achieved a 2.5-fold and 4-fold increase in the number of tests/kit for the premixed kits and the primer-probe sets, respectively. The primer-probe set assays were reliable and consistent, and we preferred a combination of an EVAg and a Berlin target. Any inconclusive result was repeated by different individuals following the same protocol. DAAN was a consistent and reliable assay even at lower concentrations from the stated recommendations. BGI in contrast, required dilution to improve its performance and was hence an assay that was used in combination with EVAg or Berlin targets.
Collapse
Affiliation(s)
| | | | | | - Clement Lewa
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | | | | | - Horace Gumba
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Debra Riako
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Lydia Nyamako
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Angela Karani
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Henry Karanja
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Daisy Mugo
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Susan Njuguna
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Wilson Gumbi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Brian Tawa
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Yiakon Sein
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - John K. Nyambu
- Department Of Health Services, Taita-Taveta County Government, Taita-Taveta, Kenya
| | - Shem O. Patta
- Department Of Health Services, Mombasa County Government, Mombasa, Kenya
| | | | | | | | | | | | | | | | | | | | - Kevin Wamae
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | - Victor Osoti
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Calleb Odundo
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, University of Oxford, Oxford, UK
| | | | | | | |
Collapse
|
8
|
Macharia AW, Mochamah G, Uyoga S, Ndila CM, Nyutu G, Tendwa M, Nyatichi E, Makale J, Ware RE, Williams TN. β-Thalassemia pathogenic variants in a cohort of children from the East African coast. Mol Genet Genomic Med 2020; 8:e1294. [PMID: 32394645 PMCID: PMC7336762 DOI: 10.1002/mgg3.1294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 04/09/2020] [Accepted: 04/11/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND β-Thalassemia is rare in sub-Saharan Africa. Previous studies have suggested that it is limited to specific parts of West Africa. Based on hemoglobin A2 (HbA2 ) concentrations measured by HPLC, we recently speculated that β-thalassemia might also be present on the East African coast of Kenya. Here, we follow this up using molecular methods. METHODS We used raised hemoglobin A2 (HbA2 ) values (> 4.0% of total Hb) to target all HbAA members of a cohort study in Kilifi, Kenya, for HBB sequencing for β-thalassemia (n = 99) together with a sample of HbAA subjects with lower HbA2 levels. Because HbA2 values are artifactually raised in subjects carrying sickle hemoglobin (HbS) we sequenced all participants with an HPLC pattern showing HbS without HbA (n = 116) and a sample with a pattern showing both HbA and HbS. RESULTS Overall, we identified 83 carriers of four separate β-thalassemia pathogenic variants: three β0 -thalassemia [CD22 (GAA→TAA), initiation codon (ATG→ACG), and IVS1-3' end del 25bp] and one β+ -thalassemia pathogenic variants (IVS-I-110 (G→A)). We estimated the minimum allele frequency of all variants combined within the study population at 0.3%. CONCLUSIONS β-Thalassemia is present in Kilifi, Kenya, an observation that has implications for the diagnosis and clinical care of children from the East Africa region.
Collapse
Affiliation(s)
| | | | - Sophie Uyoga
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
| | | | - Gideon Nyutu
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
| | | | | | | | - Russell E. Ware
- Cincinnati Children’s Hospital Medical CenterCincinnatiOHUSA
| | - Thomas N. Williams
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
- Department of MedicineImperial CollegeSt Mary’s HospitalLondonUK
| |
Collapse
|
9
|
Uyoga S, Macharia AW, Mochamah G, Ndila CM, Nyutu G, Makale J, Tendwa M, Nyatichi E, Ojal J, Otiende M, Shebe M, Awuondo KO, Mturi N, Peshu N, Tsofa B, Maitland K, Scott JAG, Williams TN. The epidemiology of sickle cell disease in children recruited in infancy in Kilifi, Kenya: a prospective cohort study. Lancet Glob Health 2019; 7:e1458-e1466. [PMID: 31451441 PMCID: PMC7024980 DOI: 10.1016/s2214-109x(19)30328-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 07/02/2019] [Accepted: 07/05/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Sickle cell disease is the most common severe monogenic disorder in humans. In Africa, 50-90% of children born with sickle cell disease die before they reach their fifth birthday. In this study, we aimed to describe the comparative incidence of specific clinical outcomes among children aged between birth and 5 years with and without sickle cell disease, who were resident within the Kilifi area of Kenya. METHODS This prospective cohort study was done on members of the Kilifi Genetic Birth Cohort Study (KGBCS) on the Indian Ocean coast of Kenya. Recruitment to the study was facilitated through the Kilifi Health and Demographic Surveillance System (KHDSS), which covers a resident population of 260 000 people, and was undertaken between Jan 1, 2006, and April 30, 2011. All children who were born within the KHDSS area and who were aged 3-12 months during the recruitment period were eligible for inclusion. Participants were tested for sickle cell disease and followed up for survival status and disease-specific admission to Kilifi County Hospital by passive surveillance until their fifth birthday. Children with sickle cell disease were offered confirmatory testing and care at a dedicated outpatient clinic. FINDINGS 15 737 infants were recruited successfully to the KGBCS, and 128 (0·8%) of these infants had sickle cell disease, of whom 70 (54·7%) enrolled at the outpatient clinic within 12 months of recruitment. Mortality was higher in children with sickle cell disease (58 per 1000 person-years of observation, 95% CI 40-86) than in those without sickle cell disease (2·4 per 1000 person-years of observation, 2·0-2·8; adjusted incidence rate ratio [IRR] 23·1, 95% CI 15·1-35·3). Among children with sickle cell disease, mortality was lower in those who enrolled at the clinic (adjusted IRR 0·26, 95% CI 0·11-0·62) and in those with higher levels of haemoglobin F (HbF; adjusted IRR 0·40, 0·17-0·94). The incidence of admission to hospital was also higher in children with sickle cell disease than in children without sickle cell disease (210 per 1000 person-years of observation, 95% CI 174-253, vs 43 per 1000 person-years of observation, 42-45; adjusted IRR 4·80, 95% CI 3·84-6·15). The most common reason for admission to hospital among those with sickle cell disease was severe anaemia (incidence 48 per 1000 person-years of observation, 95% CI 32-71). Admission to hospital was lower in those with a recruitment HbF level above the median (IRR 0·43, 95% CI 0·24-0·78; p=0·005) and those who were homozygous for α-thalassaemia (0·07, 0·01-0·83; p=0·035). INTERPRETATION Although morbidity and mortality were high in young children with sickle cell disease in this Kenyan cohort, both were reduced by early diagnosis and supportive care. The emphasis must now move towards early detection and prevention of long-term complications of sickle cell disease. FUNDING Wellcome Trust.
Collapse
Affiliation(s)
- Sophie Uyoga
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | - Gideon Nyutu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | | | - John Ojal
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mark Otiende
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | | | - Neema Mturi
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Norbert Peshu
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Kathryn Maitland
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; Faculty of Medicine, Imperial College, St Mary's Hospital, London, UK
| | - J Anthony G Scott
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; London School of Hygiene & Tropical Medicine, London, UK; INDEPTH Network, Accra, Ghana
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya; London School of Hygiene & Tropical Medicine, London, UK; INDEPTH Network, Accra, Ghana.
| |
Collapse
|
10
|
Macharia AW, Uyoga S, Ndila C, Nyutu G, Makale J, Tendwa M, Nyatichi E, Ojal J, Atkinson S, Williams TN. The population dynamics of hemoglobins A, A 2, F and S in the context of the hemoglobinopathies HbS and α-thalassemia in Kenyan infants. Haematologica 2018; 104:e184-e186. [PMID: 30467202 DOI: 10.3324/haematol.2018.199596] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Alex W Macharia
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Sophie Uyoga
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Carolyne Ndila
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Gideon Nyutu
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Johnstone Makale
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Metrine Tendwa
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Emily Nyatichi
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - John Ojal
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Sarah Atkinson
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Paediatrics, John Radcliffe Hospital, Oxford, UK
| | - Thomas N Williams
- Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.,Department of Medicine, Imperial College, St Mary's Hospital, London, UK
| |
Collapse
|
11
|
Macharia AW, Mochamah G, Uyoga S, Ndila CM, Nyutu G, Makale J, Tendwa M, Nyatichi E, Ojal J, Shebe M, Awuondo KO, Mturi N, Peshu N, Tsofa B, Scott JAG, Maitland K, Williams TN. The clinical epidemiology of sickle cell anemia In Africa. Am J Hematol 2018; 93:363-370. [PMID: 29168218 PMCID: PMC6175377 DOI: 10.1002/ajh.24986] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 11/20/2017] [Indexed: 12/17/2022]
Abstract
Sickle cell anemia (SCA) is the commonest severe monogenic disorders of humans. The disease has been highly characterized in high‐income countries but not in sub‐Saharan Africa where SCA is most prevalent. We conducted a retrospective cohort study of all children 0–13 years admitted from within a defined study area to Kilifi County Hospital in Kenya over a five‐year period. Children were genotyped for SCA retrospectively and incidence rates calculated with reference to population data. Overall, 576 of 18,873 (3.1%) admissions had SCA of whom the majority (399; 69.3%) were previously undiagnosed. The incidence of all‐cause hospital admission was 57.2/100 person years of observation (PYO; 95%CI 52.6–62.1) in children with SCA and 3.7/100 PYO (95%CI 3.7–3.8) in those without SCA (IRR 15.3; 95%CI 14.1–16.6). Rates were higher for the majority of syndromic diagnoses at all ages beyond the neonatal period, being especially high for severe anemia (hemoglobin <50 g/L; IRR 58.8; 95%CI 50.3–68.7), stroke (IRR 486; 95%CI 68.4–3,450), bacteremia (IRR 23.4; 95%CI 17.4–31.4), and for bone (IRR 607; 95%CI 284–1,300), and joint (IRR 80.9; 95%CI 18.1–362) infections. The use of an algorithm based on just five clinical features would have identified approximately half of all SCA cases among hospital‐admitted children with a number needed to test to identify each affected patient of only fourteen. Our study illustrates the clinical epidemiology of SCA in a malaria‐endemic environment without specific interventions. The targeted testing of hospital‐admitted children using the Kilifi Algorithm provides a pragmatic approach to early diagnosis in high‐prevalence countries where newborn screening is unavailable.
Collapse
Affiliation(s)
| | | | - Sophie Uyoga
- KEMRI/Wellcome Trust Research Programme, Kilifi; Kenya
| | | | - Gideon Nyutu
- KEMRI/Wellcome Trust Research Programme, Kilifi; Kenya
| | | | | | | | - John Ojal
- KEMRI/Wellcome Trust Research Programme, Kilifi; Kenya
| | | | | | - Neema Mturi
- KEMRI/Wellcome Trust Research Programme, Kilifi; Kenya
| | - Norbert Peshu
- KEMRI/Wellcome Trust Research Programme, Kilifi; Kenya
| | | | - J. Anthony G. Scott
- KEMRI/Wellcome Trust Research Programme, Kilifi; Kenya
- London School of Hygiene and Tropical Medicine; London WC1E 7HT United Kingdom
- INDEPTH Network; Accra Ghana
| | - Kathryn Maitland
- KEMRI/Wellcome Trust Research Programme, Kilifi; Kenya
- Faculty of Medicine; Imperial College, St Mary's Hospital; London W21NY United Kingdom
| | - Thomas N. Williams
- KEMRI/Wellcome Trust Research Programme, Kilifi; Kenya
- INDEPTH Network; Accra Ghana
- Faculty of Medicine; Imperial College, St Mary's Hospital; London W21NY United Kingdom
| |
Collapse
|
12
|
Etyang AO, Khayeka-Wandabwa C, Kapesa S, Muthumbi E, Odipo E, Wamukoya M, Ngomi N, Haregu T, Kyobutungi C, Tendwa M, Makale J, Macharia A, Cruickshank JK, Smeeth L, Scott JAG, Williams TN. Blood Pressure and Arterial Stiffness in Kenyan Adolescents With α +Thalassemia. J Am Heart Assoc 2017; 6:JAHA.117.005613. [PMID: 28381468 PMCID: PMC5533038 DOI: 10.1161/jaha.117.005613] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background Recent studies have discovered that α‐globin is expressed in blood vessel walls where it plays a role in regulating vascular tone. We tested the hypothesis that blood pressure (BP) might differ between normal individuals and those with α+thalassemia, in whom the production of α‐globin is reduced. Methods and Results The study was conducted in Nairobi, Kenya, among 938 adolescents aged 11 to 17 years. Twenty‐four‐hour ambulatory BP monitoring and arterial stiffness measurements were performed using an arteriograph device. We genotyped for α+thalassemia by polymerase chain reaction. Complete data for analysis were available for 623 subjects; 223 (36%) were heterozygous (−α/αα) and 47 (8%) were homozygous (−α/−α) for α+thalassemia whereas the remaining 353 (55%) were normal (αα/αα). Mean 24‐hour systolic BP ±SD was 118±12 mm Hg in αα/αα, 117±11 mm Hg in −α/αα, and 118±11 mm Hg in −α/−α subjects, respectively. Mean 24‐hour diastolic BP ±SD in these groups was 64±8, 63±7, and 65±8 mm Hg, respectively. Mean pulse wave velocity (PWV)±SD was 7±0.8, 7±0.8, and 7±0.7 ms−1, respectively. No differences were observed in PWV and any of the 24‐hour ambulatory BP monitoring‐derived measures between those with and without α+thalassemia. Conclusions These data suggest that the presence of α+thalassemia does not affect BP and/or arterial stiffness in Kenyan adolescents.
Collapse
Affiliation(s)
- Anthony O Etyang
- KEMRI-Wellcome Trust Research Program, Kilifi, Kenya .,London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | | | - Emily Odipo
- KEMRI-Wellcome Trust Research Program, Kilifi, Kenya
| | | | - Nicholas Ngomi
- African Population and Health Research Centre, Nairobi, Kenya
| | - Tilahun Haregu
- African Population and Health Research Centre, Nairobi, Kenya
| | | | | | | | - Alex Macharia
- KEMRI-Wellcome Trust Research Program, Kilifi, Kenya
| | | | - Liam Smeeth
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - J Anthony G Scott
- KEMRI-Wellcome Trust Research Program, Kilifi, Kenya.,London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Program, Kilifi, Kenya.,Imperial College, London, United Kingdom
| |
Collapse
|
13
|
Opi DH, Ochola LB, Tendwa M, Siddondo BR, Ocholla H, Fanjo H, Ghumra A, Ferguson DJP, Rowe JA, Williams TN. Erratum to "Mechanistic Studies of the Negative Epistatic Malaria-protective Interaction Between Sickle Cell Trait and α +thalassemia" [EBioMedicine 1 (2014) 29-36]. EBioMedicine 2015; 2:1001. [PMID: 28087114 PMCID: PMC4563111 DOI: 10.1016/j.ebiom.2015.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/30/2022] Open
Affiliation(s)
- D Herbert Opi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, P.O. Box 230, 80108 Kilifi, Kenya; Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom
| | - Lucy B Ochola
- Kenya Medical Research Institute-Wellcome Trust Research Programme, P.O. Box 230, 80108 Kilifi, Kenya
| | - Metrine Tendwa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, P.O. Box 230, 80108 Kilifi, Kenya
| | - Bethsheba R Siddondo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, P.O. Box 230, 80108 Kilifi, Kenya
| | - Harold Ocholla
- Kenya Medical Research Institute-Wellcome Trust Research Programme, P.O. Box 230, 80108 Kilifi, Kenya
| | - Harry Fanjo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, P.O. Box 230, 80108 Kilifi, Kenya
| | - Ashfaq Ghumra
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom
| | - David J P Ferguson
- Nuffield Department of Clinical Laboratory Science, University of Oxford, John Radcliffe Hospital, OX3 9DU Oxford, United Kingdom
| | - J Alexandra Rowe
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom
| | - Thomas N Williams
- Kenya Medical Research Institute-Wellcome Trust Research Programme, P.O. Box 230, 80108 Kilifi, Kenya; Department of Medicine, Imperial College, St Mary's Hospital, Praed Street, London W21NY, United Kingdom.
| |
Collapse
|
14
|
Opi DH, Ochola LB, Tendwa M, Siddondo BR, Ocholla H, Fanjo H, Ghumra A, Ferguson DJP, Rowe JA, Williams TN. Mechanistic Studies of the Negative Epistatic Malaria-protective Interaction Between Sickle Cell Trait and α +thalassemia. EBioMedicine 2014; 1:29-36. [PMID: 25893206 PMCID: PMC4397954 DOI: 10.1016/j.ebiom.2014.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Background Individually, the red blood cell (RBC) polymorphisms sickle cell trait (HbAS) and α+thalassemia protect against severe Plasmodium falciparum malaria. It has been shown through epidemiological studies that the co-inheritance of both conditions results in a loss of the protection afforded by each, but the biological mechanisms remain unknown. Methods We used RBCs from > 300 donors of various HbAS and α+thalassemia genotype combinations to study the individual and combinatorial effects of these polymorphisms on a range of putative P. falciparum virulence phenotypes in-vitro, using four well-characterized P. falciparum laboratory strains. We studied cytoadhesion of parasitized RBCs (pRBCs) to the endothelial receptors CD36 and ICAM1, rosetting of pRBCs with uninfected RBCs, and pRBC surface expression of the parasite-derived adhesion molecule P. falciparum erythrocyte membrane protein-1 (PfEMP1). Findings We confirmed previous reports that HbAS pRBCs show reduced cytoadhesion, rosetting and PfEMP1 expression levels compared to normal pRBC controls. Furthermore, we found that co-inheritance of HbAS with α+thalassemia consistently reversed these effects, such that pRBCs of mixed genotype showed levels of cytoadhesion, rosetting and PfEMP1 expression that were indistinguishable from those seen in normal pRBCs. However, pRBCs with α+thalassemia alone showed parasite strain-specific effects on adhesion, and no consistent reduction in PfEMP1 expression. Interpretation Our data support the hypothesis that the negative epistasis between HbAS and α+thalassemia observed in epidemiological studies might be explained by host genotype-specific changes in the pRBC-adhesion properties that contribute to parasite sequestration and disease pathogenesis in vivo. The mechanism by which α+thalassemia on its own protects against severe malaria remains unresolved.
Collapse
Affiliation(s)
- D Herbert Opi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, 80108 Kilifi, Kenya ; Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom
| | - Lucy B Ochola
- Kenya Medical Research Institute-Wellcome Trust Research Programme, 80108 Kilifi, Kenya
| | - Metrine Tendwa
- Kenya Medical Research Institute-Wellcome Trust Research Programme, 80108 Kilifi, Kenya
| | - Bethsheba R Siddondo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, 80108 Kilifi, Kenya
| | - Harold Ocholla
- Kenya Medical Research Institute-Wellcome Trust Research Programme, 80108 Kilifi, Kenya
| | - Harry Fanjo
- Kenya Medical Research Institute-Wellcome Trust Research Programme, 80108 Kilifi, Kenya
| | - Ashfaq Ghumra
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom
| | - David J P Ferguson
- Nuffield Department of Clinical Laboratory Science, University of Oxford, John Radcliffe Hospital, OX3 9DU, Oxford, United Kingdom
| | - J Alexandra Rowe
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, EH9 3FL, United Kingdom
| | - Thomas N Williams
- Kenya Medical Research Institute-Wellcome Trust Research Programme, 80108 Kilifi, Kenya ; Department of Medicine, Imperial College, St Mary's Hospital, Praed Street, London W21NY, United Kingdom
| |
Collapse
|