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1.
Emerg Infect Dis ; 30(3): 581-585, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38407189

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) is endemic in dromedaries in Africa, but camel-to-human transmission is limited. Sustained 12-month sampling of dromedaries in a Kenya abattoir hub showed biphasic MERS-CoV incidence; peak detections occurred in October 2022 and February 2023. Dromedary-exposed abattoir workers (7/48) had serologic signs of previous MERS-CoV exposure.


Assuntos
Camelus , Coronavírus da Síndrome Respiratória do Oriente Médio , Humanos , Animais , Quênia/epidemiologia , Incidência , Matadouros
2.
PLoS Pathog ; 18(5): e1010494, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35533147

RESUMO

Depot medroxyprogesterone acetate (DMPA) is an injectable hormonal contraceptive used by millions of women worldwide. However, experimental studies have associated DMPA use with genital epithelial barrier disruption and mucosal influx of human immunodeficiency virus (HIV) target cells. We explored the underlying molecular mechanisms of these findings. Ectocervical biopsies and cervicovaginal lavage (CVL) specimens were collected from HIV-seronegative Kenyan sex workers using DMPA (n = 32) or regularly cycling controls (n = 64). Tissue samples were assessed by RNA-sequencing and quantitative imaging analysis, whereas protein levels were measured in CVL samples. The results suggested a DMPA-associated upregulation of genes involved in immune regulation, including genes associated with cytokine-mediated signaling and neutrophil-mediated immunity. A transcription factor analysis further revealed DMPA-associated upregulation of RELA and NFKB1 which are involved in several immune activation pathways. Several genes significantly downregulated in the DMPA versus the control group were involved in epithelial structure and function, including genes encoding keratins, small proline-rich proteins, and cell-cell adhesion proteins. Pathway analyses indicated DMPA use was associated with immune activation and suppression of epithelium development, including keratinization and cornification processes. The cervicovaginal microbiome composition (Lactobacillus dominant and non-Lactobacillus dominant) had no overall interactional impact on the DMPA associated tissue gene expression. Imaging analysis verified that DMPA use was associated with an impaired epithelial layer as illustrated by staining for the selected epithelial junction proteins E-cadherin, desmoglein-1 and claudin-1. Additional staining for CD4+ cells revealed a more superficial location of these cells in the ectocervical epithelium of DMPA users versus controls. Altered protein levels of SERPINB1 and ITIH2 were further observed in the DMPA group. Identification of specific impaired epithelial barrier structures at the gene expression level, which were verified at the functional level by tissue imaging analysis, illustrates mechanisms by which DMPA adversely may affect the integrity of the genital mucosa.


Assuntos
Anticoncepcionais Femininos , Infecções por HIV , Serpinas , Colo do Útero , Anticoncepcionais Femininos/efeitos adversos , Feminino , Humanos , Quênia , Acetato de Medroxiprogesterona/efeitos adversos
3.
Prostaglandins Other Lipid Mediat ; 174: 106878, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39084323

RESUMO

BACKGROUND: 1.5 million new HIV infections occurred in 2021, suggesting new prevention methods are needed. Inflammation increases the risk for HIV acquisition by attracting HIV target cells to the female genital tract (FGT). In a pilot study, acetylsalicylic acid (ASA/Aspirin) decreased the proportion of FGT HIV target cells by 35 %. However, the mechanism remains unknown. METHODS: Women from Nairobi, Kenya took low-dose ASA (81 mg) daily for 6-weeks. Free oxylipins in the plasma were quantified by high-performance liquid chromatography-tandem mass spectroscopy. RESULTS: Oxylipins from 9 fatty acid substrates were detected, with more than one analyte from 4 substrates reduced post-ASA. Summary analysis found ASA downregulated cyclooxygenase and lipoxygenase but not cytochrome P450 activity with a lower n-6/n-3 oxylipin profile, reflecting reduced inflammation post-ASA. CONCLUSIONS: Inflammation is associated with increased lipoxygenase activity and HIV risk. Our data suggests ASA reduces inflammation through downregulation of oxylipins. Understanding how ASA reduces inflammation may lead to novel HIV prevention approaches.


Assuntos
Aspirina , Infecções por HIV , Oxilipinas , Humanos , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/prevenção & controle , Aspirina/farmacologia , Adulto , Oxilipinas/metabolismo , Oxilipinas/sangue , Lipoxigenase/metabolismo , Inibidores de Lipoxigenase/farmacologia
4.
BMC Infect Dis ; 24(1): 1205, 2024 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-39455953

RESUMO

BACKGROUND: The emergence and persistence of multidrug-resistant (MDR) Salmonella Typhi (S. Typhi) infections is a significant global health problem. The carrier state of typhoid makes it prudent to conduct routine surveillance for both acute cases and carriers especially those caused by MDR S. Typhi. We report on the prevalence of MDR S. Typhi, resistance phenotypes and antimicrobial resistance genes detected in symptomatic and asymptomatic children living in informal settlements in Nairobi, Kenya. METHODS: 215 archived presumed S. Typhi isolates from stool samples provided by children ≤ 16 years collected from 2013 to 2018 were revived in May, 2022 and confirmed using culture and antisera serotyping. The Kirby Bauer disc diffusion technique was used to test the S. Typhi against 14 antibiotics. The MDR S. Typhi (resistant to ampicillin, chloramphenicol and sulfamethoxazole trimethoprim) which in addition were also resistant to either a cephalosporin or a fluoroquinolone were analyzed for Beta lactams and quinolone resistance genes using polymerase chain reaction. RESULTS: A total of 215 isolates were confirmed to be positively S. Typhi; of these, 105 (49%) and 110 (51%) were from symptomatic and asymptomatic children respectively. On average, S. Typhi resistance from asymptomatic and symptomatic children against 1st line drugs was observed at; 77% &70%, ampicillin; 60% & 64%, sulfamethoxazole-trimethoprim, and 45% & 54%, chloramphenicol respectively. Multi drug resistance was observed in 90 (42%) of the isolates, of these, 44 (49%) were isolated from symptomatic and 46 (51%) from asymptomatic children. Fifteen resistance phenotypes (p) were observed with, ampicillin/chloramphenicol/sulfamethoxazole-trimethoprim/nalidixic acid (amp/chl/sxt/na) as the most common among the symptomatic 43/90 (48%) and asymptomatic 55/90 (61%) children. The blaTEM-D, AMR genes were detected in 37/44 (84%) S. Typhi isolates, out of this 18 (49%) were from symptomatic while 19 (51%) were from asymptomatic children respectively. CONCLUSION: The carriage of MDR S. Typhi among the asymptomatic children is concerning as they can act as potential transmitters of the typhoid disease to unsuspecting children. These study findings highlight the need for continued surveillance of antimicrobial resistance and mass immunization of children living in these urban informal areas.


Assuntos
Antibacterianos , Farmacorresistência Bacteriana Múltipla , Salmonella typhi , Febre Tifoide , Humanos , Quênia/epidemiologia , Salmonella typhi/genética , Salmonella typhi/efeitos dos fármacos , Salmonella typhi/isolamento & purificação , Criança , Farmacorresistência Bacteriana Múltipla/genética , Febre Tifoide/microbiologia , Febre Tifoide/epidemiologia , Pré-Escolar , Antibacterianos/farmacologia , Masculino , Adolescente , Feminino , Lactente , Testes de Sensibilidade Microbiana , Fezes/microbiologia , Prevalência , Portador Sadio/microbiologia , Portador Sadio/epidemiologia
5.
J Infect Dis ; 225(7): 1151-1161, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32780807

RESUMO

BACKGROUND: The hormonal contraceptive depot medroxyprogesterone acetate (DMPA) may be associated with an increased risk of acquiring human immunodeficiency virus (HIV). We hypothesize that DMPA use influences the ectocervical tissue architecture and HIV target cell localization. METHODS: Quantitative image analysis workflows were developed to assess ectocervical tissue samples collected from DMPA users and control subjects not using hormonal contraception. RESULTS: Compared to controls, the DMPA group exhibited a significantly thinner apical ectocervical epithelial layer and a higher proportion of CD4+CCR5+ cells with a more superficial location. This localization corresponded to an area with a nonintact E-cadherin net structure. CD4+Langerin+ cells were also more superficially located in the DMPA group, although fewer in number compared to the controls. Natural plasma progesterone levels did not correlate with any of these parameters, whereas estradiol levels were positively correlated with E-cadherin expression and a more basal location for HIV target cells of the control group. CONCLUSIONS: DMPA users have a less robust epithelial layer and a more apical distribution of HIV target cells in the human ectocervix, which could confer a higher risk of HIV infection. Our results highlight the importance of assessing intact genital tissue samples to gain insights into HIV susceptibility factors.


Assuntos
Anticoncepcionais Femininos , Infecções por HIV , Colo do Útero/metabolismo , Anticoncepcionais Femininos/efeitos adversos , Feminino , HIV , Humanos , Acetato de Medroxiprogesterona/efeitos adversos
6.
J Infect Dis ; 219(6): 856-866, 2019 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-30383238

RESUMO

BACKGROUND: Inflammation and immune activation are key factors in sexual transmission of human immunodeficiency virus (HIV). We sought to define the impact of hormonal cycling on the mucosal immune environment and HIV risk in sex workers with a natural menstrual cycle. METHODS: We compared soluble mucosal immune factors and cervical mononuclear cells during hormone titer-defined phases of the menstrual cycle among 37 sex workers from Nairobi, Kenya. Systemic and mucosal samples were collected 14 days apart to distinguish the follicular and luteal phases of the menstrual cycle, and phases were confirmed by hormone measurements. Vaginal concentrations of 19 immune modulators and cervical T-cell activation markers were measured. RESULTS: The follicular phase signature was characterized by an elevated CCL2 level, decreased interleukin 1α and interleukin 1ß cervical concentrations, and a significant increase in the proportion of CD4+ T cells that expressed CD69. The genital concentration of CCL2 was the best marker to distinguish the follicular from the luteal phase in univariate and multivariate analyses and remained independent of elevated genital inflammation and bacterial vaginosis. CONCLUSION: The follicular phase of the menstrual cycle was associated with an elevated CCL2 level and retention of resident memory CD4+ T cells, which has implications for increased susceptibility to HIV infection.


Assuntos
Colo do Útero/imunologia , Infecções por HIV/imunologia , Ciclo Menstrual/imunologia , Vagina/imunologia , Biomarcadores/análise , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Colo do Útero/citologia , Quimiocina CCL2/análise , Feminino , Infecções por HIV/transmissão , Humanos , Quênia , Profissionais do Sexo , Vagina/citologia , Vaginose Bacteriana/imunologia
7.
Clin Infect Dis ; 68(10): 1675-1683, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-30407498

RESUMO

BACKGROUND: Genital immunology is a key determinant of human immunodeficiency virus (HIV) susceptibility. Both factors are modulated by bacterial vaginosis (BV) and, to some extent, by Lactobacillus iners, the genital Lactobacillus spp. that predominates in African, Caribbean, and other Black (ACB) women. We conducted a clinical trial to assess the impact of oral metronidazole treatment on the genital immune parameters of HIV acquisition risks in Kenyan women with BV. METHODS: The primary endpoint was ex vivo cervical CD4+ T-cell HIV susceptibility after 1 month; secondary endpoints included genital cytokine/chemokine levels, cervical immune cell populations, and the composition of the cervico-vaginal microbiota by 16S ribosomal RNA gene amplicon sequencing. RESULTS: BV resolved (Nugent score ≤ 3) at 1 month in 20/45 participants, and cervical CD4+ T-cell HIV entry was moderately reduced in all participants, regardless of treatment outcome. Resolution of BV and reduced abundances of BV-associated gram-negative taxa correlated with reduced genital interleukin (IL)-1α/ß. However, BV resolution and the concomitant colonization by Lactobacillus iners substantially increased several genital chemokines associated with HIV acquisition, including interferon-γ inducible protein (IP)-10, macrophage inflammatory protein (MIP)-3α, and monokine induced by gamma interferon (MIG). In an independent cohort of ACB women, most of whom were BV-free, vaginal chemokines were again closely linked with L. iners abundance, though not other Lactobacillus spp. CONCLUSIONS: BV treatment reduced genital CD4+ T-cell HIV susceptibility and IL-1 levels, but dramatically increased the genital chemokines that may enhance HIV susceptibility; the latter effect was related to the restoration of an Lactobacillus iners-dominated microbiota. Further studies are needed before treatment of asymptomatic BV can be recommended for HIV prevention in ACB communities.


Assuntos
Colo do Útero/imunologia , Suscetibilidade a Doenças/virologia , Metronidazol/uso terapêutico , Microbiota/efeitos dos fármacos , Vagina/imunologia , Vagina/microbiologia , Vaginose Bacteriana/tratamento farmacológico , Administração Oral , Adulto , Linfócitos T CD4-Positivos/virologia , Células Cultivadas , Citocinas/imunologia , Feminino , HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Humanos , Estudos Longitudinais , Pessoa de Meia-Idade , Estudos Prospectivos , RNA Ribossômico 16S/genética , Fatores de Risco , Vaginose Bacteriana/imunologia , Adulto Jovem
8.
BMC Public Health ; 19(1): 372, 2019 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-30943975

RESUMO

BACKGROUND: Over the last decade, the Kenyan HIV treatment program has grown exponentially, with improved survival among people living with HIV (PLHIV). In the same period, noncommunicable diseases (NCDs) have become a leading contributor to disease burden. We sought to characterize the burden of four major NCDs (cardiovascular diseases, cancer, chronic respiratory diseases and diabetes mellitus) among adult PLHIV in Kenya. METHODS: We conducted a nationally representative retrospective medical chart review of HIV-infected adults aged ≥15 years enrolled in HIV care in Kenya from October 1, 2003 through September 30, 2013. We estimated proportions of four NCD categories among PLHIV at enrollment into HIV care, and during subsequent HIV care visits. We compared proportions and assessed distributions of co-morbidities using the Chi-Square test. We calculated NCD incidence rates and their confidence intervals in assessing cofactors for developing NCDs. RESULTS: We analyzed 3170 records of HIV-infected patients; 2115 (66.3%) were from women. Slightly over half (51.1%) of patient records were from PLHIVs aged above 35 years. Close to two-thirds (63.9%) of PLHIVs were on ART. Proportion of any documented NCD among PLHIV was 11.5% (95% confidence interval [CI] 9.3, 14.1), with elevated blood pressure as the most common NCD 343 (87.5%) among PLHIV with a diagnosed NCD. Despite this observation, only 17 (4.9%) patients had a corresponding documented diagnosis of hypertension in their medical record. Overall NCD incidence rates for men and women were (42.3 per 1000 person years [95% CI 35.8, 50.1] and 31.6 [95% CI 27.7, 36.1], respectively. Compared to women, the incidence rate ratio for men developing an NCD was 1.3 [95% CI 1.1, 1.7], p = 0.0082). No differences in NCD incidence rates were seen by marital or employment status. At one year of follow up 43.8% of PLHIV not on ART had been diagnosed with an NCD compared to 3.7% of patients on ART; at five years the proportions with a diagnosed NCD were 88.8 and 39.2% (p < 0.001), respectively. CONCLUSIONS: PLHIV in Kenya have a high prevalence of NCD diagnoses. In the absence of systematic, effective screening, NCD burden is likely underestimated in this population. Systematic screening and treatment for NCDs using standard guidelines should be integrated into HIV care and treatment programs in sub-Saharan Africa.


Assuntos
Doenças Cardiovasculares , Diabetes Mellitus , Infecções por HIV/epidemiologia , Neoplasias , Doenças não Transmissíveis/epidemiologia , Doenças Respiratórias , Adolescente , Adulto , Idoso , Doenças Cardiovasculares/epidemiologia , Comorbidade , Atenção à Saúde , Diabetes Mellitus/epidemiologia , Feminino , HIV , Infecções por HIV/complicações , Humanos , Hipertensão/epidemiologia , Quênia/epidemiologia , Masculino , Programas de Rastreamento , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Prevalência , Doenças Respiratórias/epidemiologia , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
9.
BMC Infect Dis ; 16: 101, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26932656

RESUMO

BACKGROUND: Viral hepatitis is a major concern worldwide, with hepatitis A (HAV) and E (HEV) viruses showing sporadic outbreaks while hepatitis B (HBV) and C (HCV) viruses are associated with chronic hepatitis, cirrhosis and hepatocellular carcinoma. The present study determined the proportion, geographic distribution and molecular characterization of hepatitis viruses among patients seeking medical services at hospitals throughout Kenya. METHODS: Patients presenting with jaundice at four selected hospitals were recruited (n = 389). Sera were tested for the presence of antibody to hepatitis viruses A through E, and HBV surface antigen (HBsAg). Nucleic acid from anti-HAV IgM antibody and HBsAg positive samples was extracted, amplified and sequenced. RESULTS: Chronic HBV infection was the leading cause of morbidity among patients with symptoms of liver disease seeking medical help. Incident HCV, HEV and HDV infection were not detected among the patients in this study, while the proportion of acute HAV was low; HAV IgM positivity was observed in 6.3 % of patients and sequencing revealed that all cases belonged to genotype 1B. HCV seropositivity upon initial screening was 3.9 % but none were confirmed positive by a supplementary immunoblot assay. There was no serological evidence of HDV and acute HEV infection (anti-HEV IgM). HBsAg was found in 50.6 % of the patients and 2.3 % were positive for IgM antibody to the core protein, indicating probable acute infection. HBV genotype A was predominant (90.3 %) followed by D (9.7 %) among HBV DNA positive specimens. Full genome analysis showed HBV/D isolates having similarity to both D4 and D6 subgenotypes and D/E recombinant reference sequences. Two recombinant sequences demonstrated > 4 % nucleotide divergence from other previously known D/E recombinants. CONCLUSIONS: HBV is highly prevalent among patients seeking care for symptoms consistent with hepatitis, compared to the general population. Molecular characterization of HBV isolates indicated recombinant strains that may give rise to new circulating variants. There is a need to document the prevalence, clinical manifestation and distribution of the variants observed. HAV genotype 1B, prevalent in Africa, was observed; however, the absence of HCV, HDV and acute HEV in this study does not rule out their presence in Kenya.


Assuntos
Hepatite B/epidemiologia , Icterícia/virologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Hepatite B/complicações , Hepatite B/diagnóstico , Hepatite Viral Humana/complicações , Hepatite Viral Humana/diagnóstico , Hepatite Viral Humana/epidemiologia , Humanos , Quênia/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Prospectivos , Estudos Soroepidemiológicos , Adulto Jovem
10.
Retrovirology ; 12: 17, 2015 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-25810006

RESUMO

BACKGROUND: LAG-3 is a potent negative regulator of the immune response but its impact in HIV infection in poorly understood. Unlike exhaustion markers such as PD-1, Tim-3, 2B4 and CD160, LAG-3 is poorly expressed on bulk and antigen-specific T cells during chronic HIV infection and its expression on innate lymphocyte subsets is not well understood. The aim of this study was to assess LAG-3 expression and association with cellular dysfunction on T cells, NK cells and iNKT cells among a cohort of healthy and HIV-infected female sex workers in Nairobi, Kenya. RESULTS: Ex vivo LAG-3 expression was measured by multiparametric flow cytometry, and plasma cytokine/chemokine concentrations measured by bead array. Although LAG-3 expression on bulk T cells was significantly increased among HIV-infected women, the proportion of cells expressing the marker was extremely low. In contrast, LAG-3 was more highly expressed on NK and iNKT cells and was not reduced among women treated with ART. To assess the functional impact of LAG-3 on iNKT cells, iNKT cytokine production was measured in response to lipid (αGalCer) and PMA/Io stimulation by both flow cytometry and cytokine bead array. iNKT cytokine production is profoundly altered by both HIV infection and treatment, and LAG-3, but not PD-1, expression is associated with a reduction in iNKT IFNγ production. CONCLUSIONS: LAG-3 does not appear to mediate T cell exhaustion in this African population, but is instead expressed on innate lymphocyte subsets including iNKT cells. HIV infection alters iNKT cytokine production patterns and LAG-3 expression is uniquely associated with iNKT dysfunction. The continued expression of LAG-3 during treatment suggests it may contribute to the lack of innate immune reconstitution commonly observed during ART.


Assuntos
Antígenos CD/metabolismo , Citocinas/metabolismo , Infecções por HIV/imunologia , HIV-1/imunologia , Interações Hospedeiro-Patógeno , Células T Matadoras Naturais/imunologia , Receptor de Morte Celular Programada 1/metabolismo , Adulto , Estudos de Coortes , Feminino , Expressão Gênica , Voluntários Saudáveis , Humanos , Quênia , Pessoa de Meia-Idade , Profissionais do Sexo , Regulação para Cima , Proteína do Gene 3 de Ativação de Linfócitos
11.
Trop Anim Health Prod ; 47(1): 247-9, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25326718

RESUMO

Peste des petits ruminants virus that causes a highly infectious and often fatal disease of sheep and goats is confirmed by various diagnostic techniques among them being isolation of the virus from cell culture systems, viral ribonucleic acid (RNA) detection by molecular assays, and viral antigen detection by immunocapture enzyme-linked immunosorbent assay (IC ELISA), immunohistochemistry (IHC), and AGAR gel test. Whereas most of the confirmatory diagnostic procedures require pathological samples to be stored frozen to preserve integrity of the peste des petits ruminants (PPR) virus RNA, samples for IHC tests are preserved in 10% formalin. In this study, nine formalin-fixed pathological samples from three goats suspected of PPR were processed for extraction of PPR viral RNA and analyzed for detection with real-time reverse transcription-polymerase chain reaction (qRT-PCR) assay. The results showed that five out of the nine tested samples returned positive for presences PPR viral genome. This study has established that field pathological samples of PPR-suspected cases, collected and stored in 10% formalin for up 2 years, could be used for PPR virus RNA extraction for disease virus confirmation.


Assuntos
Doenças das Cabras/virologia , Peste dos Pequenos Ruminantes/diagnóstico , Vírus da Peste dos Pequenos Ruminantes/isolamento & purificação , Animais , Ensaio de Imunoadsorção Enzimática/veterinária , Formaldeído/química , Doenças das Cabras/diagnóstico , Cabras/virologia , Imuno-Histoquímica , RNA Viral , Reação em Cadeia da Polimerase em Tempo Real , Fixação de Tecidos
12.
Curr Microbiol ; 68(1): 64-70, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23982202

RESUMO

Over the last decade, cholera outbreaks have become common in some parts of Kenya. The most recent cholera outbreak occurred in Coastal and Lake Victoria region during January 2009 and May 2010, where a total of 11,769 cases and 274 deaths were reported by the Ministry of Public Health and Sanitation. The objective of this study is to isolate Vibrio cholerae bacteriophages from the environmental waters of the Lake Victoria region of Kenya with potential for use as a biocontrol for cholera outbreaks. Water samples from wells, ponds, sewage effluent, boreholes, rivers, and lakes of the Lake Victoria region of Kenya were enriched for 48 h at 37 °C in broth containing a an environmental strain of V. cholerae. Bacteriophages were isolated from 5 out of the 42 environmental water samples taken. Isolated phages produced tiny, round, and clear plaques suggesting that these phages were lytic to V. cholerae. Transmission electron microscope examination revealed that all the nine phages belonged to the family Myoviridae, with typical icosahedral heads, long contractile tails, and fibers. Head had an average diameter of 88.3 nm and tail of length and width 84.9 and 16.1 nm, respectively. Vibriophages isolated from the Lake Victoria region of Kenya have been characterized and the isolated phages may have a potential to be used as antibacterial agents to control pathogenic V. cholerae bacteria in water reservoirs.


Assuntos
Bacteriófagos/isolamento & purificação , Lagos/microbiologia , Vibrio cholerae/virologia , Microbiologia da Água , Bacteriófagos/patogenicidade , Bacteriófagos/ultraestrutura , Quênia
13.
PLoS One ; 19(8): e0308318, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39116080

RESUMO

Initial transmission of severe acute respiratory syndrome virus-2 (SARS-CoV-2) was highest in densely populated regions of Kenya. Transmission gradually trickled down to the less densely populated, remote and underserved regions such as the pastoral regions of Kajiado County which are characterized by poor healthcare systems. Molecular assays that were pivotal for COVID-19 diagnosis were not available in these regions. Serology is an alternative method for retrospectively tracking the transmission of SARS-CoV-2 in such populations. Dry blood spots (DBS) were prepared from consenting patients attending six health facilities in Kajiado County from March 2020 to March 2022. Upon elution, we conducted an enzyme-linked immunosorbent assay (ELISA) for the detection of SARS-Cov-2 IgG antibodies. Of the 908 DBSs we analyzed, 706 (78%) were from female participants. The overall seropositivity to SARS-Cov-2 antibodies was 7.3% (95% CI 5.7-9.1). The elderly (over 60 years) and male participants had a high likelihood of testing positive for SAR-CoV-2 infections. Mashuru (15.6%, 14/90) and Meto (15%, 19/127) health facilities registered the highest proportion of seropositive participants. Evidence of SARS-CoV-2 transmission among pastoralists in the remote and underserved regions of Kajiado County was established by DBS sampling and serologic testing.


Assuntos
Anticorpos Antivirais , COVID-19 , SARS-CoV-2 , Humanos , COVID-19/epidemiologia , COVID-19/transmissão , COVID-19/diagnóstico , Feminino , Masculino , Quênia/epidemiologia , Adulto , Pessoa de Meia-Idade , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , Adolescente , Anticorpos Antivirais/sangue , Adulto Jovem , Imunoglobulina G/sangue , Criança , Idoso , Pré-Escolar , Estudos Retrospectivos , Ensaio de Imunoadsorção Enzimática , Lactente
14.
BMC Complement Altern Med ; 13: 285, 2013 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-24160735

RESUMO

BACKGROUND: The Quinine tree (Rauvolfia caffra) is used as a medicinal plant among traditional communities in many countries to manage tumors and other diseases associated with oxidative stress. To validate indigenous knowledge and possibly position this herb for technology uptake and utilization, we established the level of antioxidant activity in R. caffra, and probed for the presence of associated phytochemicals. METHODS: Antioxidant activity was determined on 1,1-diphenyl-2-picrylhydrazyl (DPPH) while major phytochemicals were identified by multiple tests on methanol fractions. RESULTS: R. caffra showed promise as a cure, with antioxidant activity comparable to the commercially used drug quercetin (R. caffra = 79.7% ±1.9; quercetin = 82.6% ± 2.0). However, we found two phytochemicals with possible antagonistic effect: co-occurrence of alkaloids and saponins significantly reduced antioxidant activity (alkaloids only = 63%; alkaloids plus saponins = 15%; steroids, terpenoids and cardiac glycosides = 82%), thus alkaloids and saponins should be exclusive to each other in drug formulations. CONCLUSIONS: Antagonistic relationship among phytochemicals would affect the efficacy of crude extracts as used in traditional medicine. Unlike in herbal medicine, use of modern biotechnology in extraction, purification and design of optimal combinations will ensure efficient drug formulations with optimum bioactivity and minimum toxicity. Metabolic pathway engineering under a controlled environment may optimize availability of desired compounds.


Assuntos
Extratos Vegetais/química , Plantas Medicinais/química , Rauwolfia/química , Saponinas/química , Alcaloides/química , Alcaloides/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Biotecnologia , Interações Medicamentosas , Medicina Tradicional , Fitoterapia , Extratos Vegetais/farmacologia , Saponinas/farmacologia , Árvores/química
15.
PLoS One ; 18(8): e0287738, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37531383

RESUMO

BACKGROUND: In the context of the current COVID-19 pandemic, there is still limited information about how people suffering from autoimmune diseases respond to the different COVID vaccines. The fact that they are taking an immunosuppressant or other drugs that aim to decrease the immune system activities, such as hydroxychloroquine (HCQ), could also impact their ability to respond to a COVID vaccine and vaccines in general. METHODS: Heathy donors were given 200mg of HCQ daily for 6-weeks to assess HCQs impact on the systemic T cells and humoral immune response. Peripheral blood mononuclear cells (PBMC) and plasma were obtained at baseline and 6-weeks after starting daily HCQ. Flow cytometry assays were designed to determine changes in T cell activation and T cell responses. Bead array multiplex were used to analyse antibodies and cytokine levels before and after HCQ intake. RESULTS: As anticipated, HCQ treatment decreased ex vivo T cell activation. We observed a decrease in CD4+CD161- expressing CCR5 (p = 0.015) and CD69 (p = 0.004) as well as in CD8+CCR5+ (p = 0.003), CD8+CD161+CCR5+ (p = 0.002) and CD8+CD161+CD95+ (p = 0.004). Additionally, HCQ decreased the proportion of Th17 expressing CD29 (p = 0.019), a subset associated with persistent inflammation. The proportion of T regulatory cells expressing the inhibitory molecule TIGIT was also reduced by HCQ (p = 0.003). As well, T cells from people on HCQ were less responsive to activation and cytokine production following stimulation with recall antigens and memory T cells were less likely to produce both IFNγ and TNFα following stimulation. CONCLUSION: This study shows HCQ is associated with lower T cell activation and decreased T cell cytokine production. While this study was not performed with the intent of looking at COVID vaccine response, it does provide important information about the changes in immune response that may occur in patient taking HCQ as a treatment for their autoimmune disease.


Assuntos
COVID-19 , Hidroxicloroquina , Humanos , Hidroxicloroquina/farmacologia , Hidroxicloroquina/uso terapêutico , Leucócitos Mononucleares , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral , Vacinas contra COVID-19 , Pandemias , Tratamento Farmacológico da COVID-19 , Citocinas
16.
Microbiome ; 11(1): 67, 2023 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-37004130

RESUMO

BACKGROUND: The majority of studies characterizing female genital tract microbiota have focused on luminal organisms, while the presence and impact of tissue-adherent ectocervical microbiota remain incompletely understood. Studies of luminal and tissue-associated bacteria in the gastrointestinal tract suggest that these communities may have distinct roles in health and disease. Here, we performed a multi-omics characterization of paired luminal and tissue samples collected from a cohort of Kenyan female sex workers. RESULTS: We identified a tissue-adherent bacterial microbiome, with a higher alpha diversity than the luminal microbiome, in which dominant genera overall included Gardnerella and Lactobacillus, followed by Prevotella, Atopobium, and Sneathia. About half of the L. iners-dominated luminal samples had a corresponding Gardnerella-dominated tissue microbiome. Broadly, the tissue-adherent microbiome was associated with fewer differentially expressed host genes than the luminal microbiome. Gene set enrichment analysis revealed that L. crispatus-dominated tissue-adherent communities were associated with protein translation and antimicrobial activity, whereas a highly diverse microbial community was associated with epithelial remodeling and pro-inflammatory pathways. Tissue-adherent communities dominated by L. iners and Gardnerella were associated with lower host transcriptional activity. Tissue-adherent microbiomes dominated by Lactobacillus and Gardnerella correlated with host protein profiles associated with epithelial barrier stability, although with a more pro-inflammatory profile for the Gardnerella-dominated microbiome group. Tissue samples with a highly diverse composition had a protein profile representing cell proliferation and pro-inflammatory activity. CONCLUSION: We identified ectocervical tissue-adherent bacterial communities in all study participants of a female sex worker cohort. These communities were distinct from cervicovaginal luminal microbiota in a significant proportion of individuals. We further revealed that bacterial communities at both sites correlated with distinct host gene expression and protein levels. The tissue-adherent bacterial community could possibly act as a reservoir that seed the lumen with less optimal, non-Lactobacillus, bacteria. Video Abstract.


Assuntos
Microbiota , Profissionais do Sexo , Feminino , Humanos , Vagina/microbiologia , Quênia , Microbiota/genética , Bactérias/genética , Lactobacillus/genética , RNA Ribossômico 16S/genética , Expressão Gênica
17.
Front Nutr ; 10: 1166495, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37485389

RESUMO

Background: Nutrition-sensitive livestock interventions have the potential to improve the nutrition of communities that are dependent on livestock for their livelihoods by increasing the availability and access to animal-source foods. These interventions can also boost household income, improving purchasing power for other foods, as well as enhance determinants of health. However, there is a lack of synthesized empirical evidence of the impact and effect of livestock interventions on diets and human nutritional status in Africa. Objective: To review evidence of the effectiveness of nutrition-sensitive livestock interventions in improving diets and nutritional status in children younger than 5 years old and in pregnant and lactating women. Methods: Following PRISMA guidelines, we conducted a systematic review and meta-analysis of published studies reporting on the effect of livestock interventions on maternal and child nutrition in Africa. Data were extracted, synthesized, and summarized qualitatively. Key outcomes were presented in summary tables alongside a narrative summary. Estimation of pooled effects was undertaken for experimental studies with nutritional outcomes of consumption of animal-source foods (ASFs) and minimum dietary diversity (MDD). Fixed effects regression models and pooled effect sizes were computed and reported as odds ratios (ORs) together with their 95% confidence intervals (CI). Results: After the screening, 29 research papers were included in the review, and of these, only 4 were included in the meta-analysis. We found that nutrition-sensitive livestock interventions have a significant positive impact on the consumption of ASFs for children < 5 years (OR = 5.39; 95% CI: 4.43-6.56) and on the likelihood of meeting minimum dietary diversity (OR = 1.89; 95% CI: 1.51-2.37). Additionally, the impact of livestock interventions on stunting, wasting, and being underweight varied depending on the type of intervention and duration of the program/intervention implementation. Therefore, because of this heterogeneity in reporting metrics, the pooled estimates could not be computed. Conclusion: Nutrition-sensitive livestock interventions showed a positive effect in increasing the consumption of ASFs, leading to improved dietary diversity. However, the quality of the evidence is low, and therefore, more randomized controlled studies with consistent and similar reporting metrics are needed to increase the evidence base on how nutrition-sensitive livestock interventions affect child growth outcomes.

18.
Food Nutr Bull ; 44(2_suppl): S119-S123, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37850922

RESUMO

BACKGROUND: Livestock-dependent communities in Africa's drylands disproportionately experience acute malnutrition, especially during drought seasons. We detail the design and implementation of the Livestock for Health (L4H) study aimed at determining the effect of providing livestock feed and nutritional counselling to prevent seasonal spikes of acute malnutrition. METHODS: The L4H study employed a 3-arm cluster randomized controlled trial to compare households in pastoralist settings in northern Kenya receiving livestock feeds during critical dry periods, with or without nutritional counseling, with control households. Over 4 dry seasons, 2019 to 2021, the study collected data on household milk production, consumption patterns, mothers'/children's nutritional status, household socioeconomic status, herd dynamics, and human and animal health status every 6 weeks. RESULTS: L4H recruited 1734 households, with 639, 585, and 510 households assigned to intervention arms 1 and 2 and control arm 3, respectively. From these households, 1734 women and 1748 children younger than 3 years were recruited. In total, 19 419 household visits were completed, obtaining anthropometric measures 9 times on average for each child and mother. Eighty-one households (5%) were lost from the study due to the mother's death, child's death, migration, and withdrawal for other reasons. DISCUSSION: L4H's success in a challenging environment was possible due to strong community engagement, formative studies to inform trial design, collaboration with local authorities, and effective interdisciplinary collaboration. Subsequent manuscripts will report the study findings. TRIAL REGISTRATION: The study was registered October 29, 2020, and is online at ClinicalTrials.gov (ID: NCT04608656).


Assuntos
Gado , Desnutrição , Animais , Feminino , Humanos , Lactente , Características da Família , Quênia/epidemiologia , Desnutrição/prevenção & controle , Mães , Pré-Escolar
19.
AIDS ; 37(7): 1065-1075, 2023 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-36928263

RESUMO

BACKGROUND: Persons with HIV (PWH) on antiretroviral therapy (ART) have persistent immune activation associated with increased risk for non-AIDS related diseases. Latent tuberculosis infection (LTBI), endemic in Africa, may contribute to this immune dysregulation. We evaluated the impact of HIV and TB co-infection on plasma pro- and anti-inflammatory cytokines among Kenyan adults. METHODS: We compared data from 221 PWH on long-term ART and 177 HIV-negative adults examining biomarkers of pro-[sCD14, interleukin (IL)-2, IL-6, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), IL-12p70, IL-17A] and anti(IL-4, IL-5, IL-13) inflammatory cytokines, by HIV/LTBI status (HIV+LTBI+, HIV+LTBI-, HIV-LTBI+, HIV-LTBI-). LTBI was diagnosed based on a positive QuantiFERON TB Gold-Plus test in the absence of active TB symptoms. Linear regression was used to evaluate the associations of HIV, LTBI, and HIV/LTBI status with biomarkers adjusting for clinical factors including HIV-specific factors. RESULTS: Half of the participants were women and 52% had LTBI. HIV was independently associated with higher sCD14, IL-15, IL-6, IL-4, IL-5. LTBI was independently associated with higher TNF-α, IL-12p70, IL-17A, IL-4, IL-13 in adjusted models ( P  < 0.05). LTBI status was associated with higher IL-4 and IL-12p70 only among PWH, but not HIV-negative participants ( P  < 0.05 for interactions). In multivariate analysis, only HIV+LTBI+ demonstrated elevated levels of TNF-α, IL-6, IL-12p70, IL-15, IL-17A, IL4, IL-5, IL-13 in comparison to the HIV-LTBI- ( P  < 0.05 for all). The effect of LTBI on cytokines among PWH was independent of CD4 + T-cell count and ART duration. CONCLUSIONS: Despite viral suppression, persons with HIV and LTBI exhibit abnormal cytokine production accompanied by high concentrations of pro- and anti-inflammatory cytokines.


Assuntos
Infecções por HIV , Tuberculose Latente , Adulto , Masculino , Humanos , Feminino , Citocinas , Tuberculose Latente/diagnóstico , Tuberculose Latente/tratamento farmacológico , Interleucina-17 , Interleucina-15/uso terapêutico , Quênia , Fator de Necrose Tumoral alfa , Interleucina-13 , Interleucina-4 , Interleucina-5/uso terapêutico , Interleucina-6 , Receptores de Lipopolissacarídeos , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Biomarcadores , Anti-Inflamatórios
20.
Pan Afr Med J ; 41: 239, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35721652

RESUMO

Introduction: coronaviruses are highly contagious and healthcare workers are at a higher risk of contracting the disease. The objective of this study was to assess the level of knowledge, risk perception, preparedness for coronavirus disease 2019 and vaccine acceptability among healthcare workers in Kenya. Methods: a cross-sectional study was conducted from December 2020 to January 2021. A link to an online self-administered questionnaire was disseminated to health workers across the country. SPSS version 20 was used for data analysis. Bivariate correlation analyses were used to determine associations between variables. P-value of <0.05 was considered statistically significant.Results: a total of 997 participants were enrolled in the study. About half (53%) of the participants were female. The mean age was 36.54 years (SD = 8.31) and 46% of the participants were aged between 31-40 years. The overall knowledge score of health workers for COVID-19 was 80%. Most of the health workers (89%) perceived that they were at high risk of infection. Seventy-two percent of the participants felt that they were either partially or fully prepared to handle patients with COVID-19. Overall, 71% of all health workers would take a vaccine if provided free by the government. Conclusion: health workers´ knowledge on transmission, clinical manifestations and risk factors for development of severe COVID-19 was good. Majority of the health workers perceived the risk of infection with COVID-19 as high and a significant number felt that they were not fully prepared to handle the pandemic. Majority of health workers would take a COVID-19 vaccine.


Assuntos
COVID-19 , Vacinas , Adulto , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Estudos Transversais , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Pessoal de Saúde , Humanos , Quênia/epidemiologia , Masculino , Percepção , SARS-CoV-2
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