The first case of COVID-19 was reported in Kenya in March 2020 and soon after non-pharmaceutical ... more The first case of COVID-19 was reported in Kenya in March 2020 and soon after non-pharmaceutical interventions (NPIs) were established to control the spread of the disease. The NPIs consisted, and continue to consist, of mitigation measures followed by a period of relaxation of some of the measures. In this paper, we use a deterministic mathematical model to analyze the dynamics of the disease, during the first wave, and relate it to the intervention measures. In the process, we develop a new method for estimating the disease parameters. Our solutions yield a basic reproduction number, R0 = 2.76, which is consistent with other solutions. The results further show that the initial mitigation reduced disease transmission by 40% while the subsequent relaxation increased transmission by 25%. We also propose a mathematical model on how interventions of known magnitudes collectively affect disease transmission rates. The modelled positivity rate curve compares well with observations. If in...
Investment in Africa over the past year with regards to SARS-CoV-2 genotyping has led to a massiv... more Investment in Africa over the past year with regards to SARS-CoV-2 genotyping has led to a massive increase in the number of sequences, exceeding 100,000 genomes generated to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence within their own borders, coupled with a decrease in sequencing turnaround time. Findings from this genomic surveillance underscores the heterogeneous nature of the pandemic but we observe repeated dissemination of SARS-CoV-2 variants within the continent. Sustained investment for genomic surveillance in Africa is needed as the virus continues to evolve, particularly in the low vaccination landscape. These investments are very crucial for preparedness and response for future pathogen outbreaks.One-Sentence SummaryExpanding Africa SARS-CoV-2 sequencing capacity in a fast evolving pandemic.
The effects of genetic variation of cytochrome P450 2B6 (CYP2B6) and constitutive androstane rece... more The effects of genetic variation of cytochrome P450 2B6 (CYP2B6) and constitutive androstane receptor (CAR) on efavirenz (EFV) plasma concentration was evaluated among 312 HIV patients in Nairobi Kenya. The EFV plasma concentration at steady-state were determined using ultra-high-performance liquid chromatography with a tandem quadruple mass spectrometer (LC-MS/MS). Thirteen CYP2B6 (329G>T, 341T>C, 444 G>T/C, 15582C>T, 516G>T, 548T>G, 637T>C, 785A>G, 18492C>T, 835G>C, 1459C>T and 21563C>T) and one CAR (540C>T) single nucleotide polymorphisms (SNPs) were genotyped using real-time polymerase chain reaction. HIV drug resistance mutations were detected using an in-house genotypic assay. The EFV concentration of patients ranged from 4 ng/mL to 332697 ng/mL (median 2739.5 ng/mL, IQR 1878–4891.5 ng/mL). Overall, 22% patients had EFV concentrations beyond therapeutic range of 1000–4000 ng/mL (4.5%% < 1000 ng/mL and 31.7% > 4000 ng/mL). Five SNPs ...
The African Journal of Pharmacology and Therapeutics, 2011
Received: November, 2012 Abstract Published: December, 2012 African Journal of Pharmacology and T... more Received: November, 2012 Abstract Published: December, 2012 African Journal of Pharmacology and Therapeutics Vol. 1 No. 4: MVVR-K2 Symposium 2012 Open Access available at http://journals.uonbi.ac.ke/ajpt
The African Journal of Pharmacology and Therapeutics, 2016
Background : Antimicrobial resistance to cephalosporin, penicillin and aztreonam is mediated by E... more Background : Antimicrobial resistance to cephalosporin, penicillin and aztreonam is mediated by Extended-Spectrum Beta-Lactamases (ESBL) via hydrolysis of antibiotics. The most common bacteria associated with ESBL among the Enterobacteriaceae are Escherichia coli and Klebsiella pneumonia . Pathogenic Escherichia coli is associated with diarrhoea affecting mostly elderly, children under five years and the immunocompromised. There are a number of antibiotic regimens for treatment among them cephalosporins. There is reported increase in microbial resistance to cephalosporin use and the resistance is mediated by either TEM or SHV genes. Objective: To investigate the prevalence of ESBL-producing E. coli and Klebsiella pneumonia from patients presenting with diarrhea in Machakos District Hospital, Kenya. Methods : Bacterial isolates were identified to species level by biochemical methods and tested for sensitivity to twelve different antibiotics including cephalosporins, aminoglycosides a...
Journal of the International Academy of Periodontology, 2018
OBJECTIVE The aim of this study was to investigate the association between IL-1β and IL-1α isofor... more OBJECTIVE The aim of this study was to investigate the association between IL-1β and IL-1α isoforms with chronic periodontitis in two Kenyan ethnic groups, Taitas and Swahilis. METHODS A case-control study in which participants were assessed for dental plaque, gingival inflammation, pocket depth and gingival recession after informed consent. Buccal swab samples were obtained and deoxyribonucleic acid was isolated from the swabs using QIAamp DNA purification protocol followed by polymerase chain reaction amplification using specific primers to IL-1 α rs1800587 (-889) and rs17561 (+4845) and IL-1β (rs16944 (-511) and rs11443624 (+3954). Restriction fragment length polymorphisms were recorded and association with clinical data was assessed. RESULTS Three hundred and ninety participants were recruited; four loci (-511, -889, +3953 and +4845) were analyzed per subject, equivalent to 1560 analysis events. No deviation from Hardy Weinberg equilibrium 1df was observed. Frequency of allele 2...
HIV-related stigma, lack of disclosure and social support are still hindrances to HIV testing, ca... more HIV-related stigma, lack of disclosure and social support are still hindrances to HIV testing, care, and prevention. We assessed the association of these social-psychological statuses with nevirapine (NVP) and efavirenz (EFV) plasma concentrations among HIV patients in Kenya. Blood samples were obtained from 254 and 312 consenting HIV patients on NVP- and EFV-based first-line antiretroviral therapy (ART), respectively, and a detailed structured questionnaire was administered. The ARV plasma concentration was measured by liquid chromatography-tandem mass spectrometry (LC–MS/MS). There were 68.1% and 65.4% of the patients on NVP and EFV, respectively, who did not feel guilty for being HIV positive. The disclosure rates were approximately 96.1% and 94.6% of patients on NVP and EFV, respectively. Approximately 85% and 78.2% of patients on NVP and EFV, respectively, received social support as much as needed. There were 54.3% and 14.2% compared to 31.7% and 4.5% patients on NVP and EFV, r...
HIV-related stigma, lack of disclosure and social support are still a hindrance to HIV testing, c... more HIV-related stigma, lack of disclosure and social support are still a hindrance to HIV testing, care, and prevention. We evaluated the influence of these socio-phycological status on nevirapine (NVP) and efavirenz (EFV) plasma concentrations among HIV patients in Kenya. Blood samples were obtained from 254 and 312 consenting HIV patients on NVP and EFV based first-line Antiretroviral therapy (ART) respectively and a detailed structured questionnaire was administered. The NVP and EFV plasma level was measured by liquid chromatography - tandem mass spectrometry (LC-MS/MS). The median duration of living with HIV infection was 5 years (IQR = 1–11years) and a median duration since ART initiation was 3 years (IQR = 1–8 years). There were 68.1% and 65.4% of the patients on NVP and EFV respectively who did not feel guilty for being HIV positive. The disclosure rate was about 96.1% and 94.6% of patients on NVP and EFV respectively. About 85% and 78.2% of patients on NVP and EFV respectively ...
The first case of COVID-19 was reported in Kenya in March 2020 and soon after non-pharmaceutical ... more The first case of COVID-19 was reported in Kenya in March 2020 and soon after non-pharmaceutical interventions (NPIs) were established to control the spread of the disease. The NPIs consisted, and continue to consist, of mitigation measures followed by a period of relaxation of some of the measures. In this paper, we use a deterministic mathematical model to analyze the dynamics of the disease, during the first wave, and relate it to the intervention measures. In the process, we develop a new method for estimating the disease parameters. Our solutions yield a basic reproduction number, R0 = 2.76, which is consistent with other solutions. The results further show that the initial mitigation reduced disease transmission by 40% while the subsequent relaxation increased transmission by 25%. We also propose a mathematical model on how interventions of known magnitudes collectively affect disease transmission rates. The modelled positivity rate curve compares well with observations. If in...
Investment in Africa over the past year with regards to SARS-CoV-2 genotyping has led to a massiv... more Investment in Africa over the past year with regards to SARS-CoV-2 genotyping has led to a massive increase in the number of sequences, exceeding 100,000 genomes generated to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence within their own borders, coupled with a decrease in sequencing turnaround time. Findings from this genomic surveillance underscores the heterogeneous nature of the pandemic but we observe repeated dissemination of SARS-CoV-2 variants within the continent. Sustained investment for genomic surveillance in Africa is needed as the virus continues to evolve, particularly in the low vaccination landscape. These investments are very crucial for preparedness and response for future pathogen outbreaks.One-Sentence SummaryExpanding Africa SARS-CoV-2 sequencing capacity in a fast evolving pandemic.
The effects of genetic variation of cytochrome P450 2B6 (CYP2B6) and constitutive androstane rece... more The effects of genetic variation of cytochrome P450 2B6 (CYP2B6) and constitutive androstane receptor (CAR) on efavirenz (EFV) plasma concentration was evaluated among 312 HIV patients in Nairobi Kenya. The EFV plasma concentration at steady-state were determined using ultra-high-performance liquid chromatography with a tandem quadruple mass spectrometer (LC-MS/MS). Thirteen CYP2B6 (329G>T, 341T>C, 444 G>T/C, 15582C>T, 516G>T, 548T>G, 637T>C, 785A>G, 18492C>T, 835G>C, 1459C>T and 21563C>T) and one CAR (540C>T) single nucleotide polymorphisms (SNPs) were genotyped using real-time polymerase chain reaction. HIV drug resistance mutations were detected using an in-house genotypic assay. The EFV concentration of patients ranged from 4 ng/mL to 332697 ng/mL (median 2739.5 ng/mL, IQR 1878–4891.5 ng/mL). Overall, 22% patients had EFV concentrations beyond therapeutic range of 1000–4000 ng/mL (4.5%% < 1000 ng/mL and 31.7% > 4000 ng/mL). Five SNPs ...
The African Journal of Pharmacology and Therapeutics, 2011
Received: November, 2012 Abstract Published: December, 2012 African Journal of Pharmacology and T... more Received: November, 2012 Abstract Published: December, 2012 African Journal of Pharmacology and Therapeutics Vol. 1 No. 4: MVVR-K2 Symposium 2012 Open Access available at http://journals.uonbi.ac.ke/ajpt
The African Journal of Pharmacology and Therapeutics, 2016
Background : Antimicrobial resistance to cephalosporin, penicillin and aztreonam is mediated by E... more Background : Antimicrobial resistance to cephalosporin, penicillin and aztreonam is mediated by Extended-Spectrum Beta-Lactamases (ESBL) via hydrolysis of antibiotics. The most common bacteria associated with ESBL among the Enterobacteriaceae are Escherichia coli and Klebsiella pneumonia . Pathogenic Escherichia coli is associated with diarrhoea affecting mostly elderly, children under five years and the immunocompromised. There are a number of antibiotic regimens for treatment among them cephalosporins. There is reported increase in microbial resistance to cephalosporin use and the resistance is mediated by either TEM or SHV genes. Objective: To investigate the prevalence of ESBL-producing E. coli and Klebsiella pneumonia from patients presenting with diarrhea in Machakos District Hospital, Kenya. Methods : Bacterial isolates were identified to species level by biochemical methods and tested for sensitivity to twelve different antibiotics including cephalosporins, aminoglycosides a...
Journal of the International Academy of Periodontology, 2018
OBJECTIVE The aim of this study was to investigate the association between IL-1β and IL-1α isofor... more OBJECTIVE The aim of this study was to investigate the association between IL-1β and IL-1α isoforms with chronic periodontitis in two Kenyan ethnic groups, Taitas and Swahilis. METHODS A case-control study in which participants were assessed for dental plaque, gingival inflammation, pocket depth and gingival recession after informed consent. Buccal swab samples were obtained and deoxyribonucleic acid was isolated from the swabs using QIAamp DNA purification protocol followed by polymerase chain reaction amplification using specific primers to IL-1 α rs1800587 (-889) and rs17561 (+4845) and IL-1β (rs16944 (-511) and rs11443624 (+3954). Restriction fragment length polymorphisms were recorded and association with clinical data was assessed. RESULTS Three hundred and ninety participants were recruited; four loci (-511, -889, +3953 and +4845) were analyzed per subject, equivalent to 1560 analysis events. No deviation from Hardy Weinberg equilibrium 1df was observed. Frequency of allele 2...
HIV-related stigma, lack of disclosure and social support are still hindrances to HIV testing, ca... more HIV-related stigma, lack of disclosure and social support are still hindrances to HIV testing, care, and prevention. We assessed the association of these social-psychological statuses with nevirapine (NVP) and efavirenz (EFV) plasma concentrations among HIV patients in Kenya. Blood samples were obtained from 254 and 312 consenting HIV patients on NVP- and EFV-based first-line antiretroviral therapy (ART), respectively, and a detailed structured questionnaire was administered. The ARV plasma concentration was measured by liquid chromatography-tandem mass spectrometry (LC–MS/MS). There were 68.1% and 65.4% of the patients on NVP and EFV, respectively, who did not feel guilty for being HIV positive. The disclosure rates were approximately 96.1% and 94.6% of patients on NVP and EFV, respectively. Approximately 85% and 78.2% of patients on NVP and EFV, respectively, received social support as much as needed. There were 54.3% and 14.2% compared to 31.7% and 4.5% patients on NVP and EFV, r...
HIV-related stigma, lack of disclosure and social support are still a hindrance to HIV testing, c... more HIV-related stigma, lack of disclosure and social support are still a hindrance to HIV testing, care, and prevention. We evaluated the influence of these socio-phycological status on nevirapine (NVP) and efavirenz (EFV) plasma concentrations among HIV patients in Kenya. Blood samples were obtained from 254 and 312 consenting HIV patients on NVP and EFV based first-line Antiretroviral therapy (ART) respectively and a detailed structured questionnaire was administered. The NVP and EFV plasma level was measured by liquid chromatography - tandem mass spectrometry (LC-MS/MS). The median duration of living with HIV infection was 5 years (IQR = 1–11years) and a median duration since ART initiation was 3 years (IQR = 1–8 years). There were 68.1% and 65.4% of the patients on NVP and EFV respectively who did not feel guilty for being HIV positive. The disclosure rate was about 96.1% and 94.6% of patients on NVP and EFV respectively. About 85% and 78.2% of patients on NVP and EFV respectively ...
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Papers by Wallace Bulimo