81 research outputs found

    Cytokine expression in malaria-infected non-human primate placentas

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    Malaria parasites are known to mediate the induction of inflammatory immune responses at the maternal-foetal interface during placental malaria (PM) leading to adverse consequences like pre-term deliveries and abortions. Immunological events that take place within the malaria-infected placental micro-environment leading to retarded foetal growth and disruption of pregnancies are among the critical parameters that are still in need of further elucidation. The establishment of more animal models for studying placental malaria can provide novel ways of circumventing problems experienced during placental malaria research in humans such as inaccurate estimation of gestational ages. Using the newly established olive baboon (Papio anubis)-Plasmodium knowlesi (P. knowlesi) H strain model of placental malaria, experiments were carried out to determine placental cytokine profiles underlying the immunopathogenesis of placental malaria. Four pregnant olive baboons were infected with blood stage P. knowlesi H strain parasites on the one fiftieth day of gestation while four other uninfected pregnant olive baboons were maintained as uninfected controls. After nine days of infection, placentas were extracted from all the eight baboons through cesarean surgery and used for the processing of placental plasma and sera samples for cytokine sandwich enzyme linked immunosorbent assays (ELISA). Results indicated that the occurrence of placental malaria was associated with elevated concentrations of tumour necrosis factor alpha (TNF-{\alpha}) and interleukin 12 (IL-12). Increased levels of IL-4, IL-6 and IL-10 and interferon gamma (IFN-{\gamma}) levels were detected in uninfected placentas. These findings match previous reports regarding immunity during PM thereby demonstrating the reliability of the olive baboon-P. knowlesi model for use in further studies.Comment: Open Veterinary Journal 1st June 2012. Seven pages, Three Figures. arXiv admin note: text overlap with arXiv:1201.323

    Tomato Production Characteristics, Biotic Constraints and their Management Practices by Farmers in Bungoma County, Kenya

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    Tomato (Solanum lycopersicum L.) is an important crop in Bungoma County, Kenya. Its production is constrained by arthropod pests and diseases which make farmers rely heavily on synthetic chemicals to control them. To support the development of effective integrated pest and disease management strategies on tomato, a survey was carried out in Sirisia, Bumula and Mt. Elgon sub-counties. A total of 90 randomly selected farmers in the region were interviewed using a structured questionnaire. Data collected included demographic characteristics of farmers, tomato varieties, farm size, prevalence of pests, diseases and their management practices. Majority of the respondents were male with 89.7% in Mt. Elgon. Most of the respondents had primary education. The varieties of tomato grown were Rio-grande, Kilele, Carl-J, Money-maker, Safari and Onyx. The average farm size ranged from 0.25 to 1.0 hectare with 80.4% in Sirisia. Most prevalent pests affecting tomato were Frankliniella occidentalis (58.6%) and Bemisia tabaci (35%) while the most reported disease was Ralstonia solanacearum (75%). The chemicals used against pests included Imidacloprid (24.4%), Alpha-Cypermethrin (20.7%) and Lambda-cyhalothrin (20%). Farmers controlled diseases using Metalaxyl-M, Mancozeb, Propineb and Carbendazim. Out of the total ninety respondents in the region, only 2.4% in Sirisia used bio-pesticides. At least 60%, 22% and 20.7% of respondents in Bumula, Sirisia and Mt. Elgon, respectively used more than one chemical. About 10% of respondents in Bumula and 6.9% in Mt. Elgon applied chemicals twice a week. In Sirisia, about 53.6% reported that the chemicals used effectively controlled the pests and diseases compared to Bumula (61%) and Mt. Elgon (58.6%) who reported that they were ineffective. The main source of advice on crop protection was Agrovet shops. The findings revealed that pest and diseases limited tomato production in the region. The study therefore recommends increased awareness on proper use of chemicals and use of safer alternatives such as bio-pesticides to reduce on pesticide residues and the production cost. Future studies on the level of synthetic chemical residues in tomatoes produced in the region should be conducted. Keywords: Bio-pesticides, chemicals, diseases, pests, tomato. DOI: 10.7176/JNSR/9-12-07 Publication date:June 30th 201

    In vitro and in vivo antileishmanial efficacy of a combination therapy of diminazene and artesunate against Leishmania donovani in BALB /c mice

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    The in vitro and in vivo activity of diminazene (Dim), artesunate (Art) and combination of Dim and Art (Dim-Art) against Leishmania donovani was compared to reference drug; amphotericin B. IC50 of Dim-Art was found to be 2.28±0.24μ2.28 \pm 0.24 \mu g/mL while those of Dim and Art were 9.16±0.3μ9.16 \pm 0.3 \mu g/mL and 4.64±0.48μ4.64 \pm 0.48 \mu g/mL respectively. The IC50 for Amphot B was 0.16±0.32μ0.16 \pm 0.32 \mu g/mL against stationary-phase promastigotes. In vivo evaluation in the L. donovani BALB/c mice model indicated that treatments with the combined drug therapy at doses of 12.5 mg/kg for 28 consecutive days significantly (p<0.001p < 0.001) reduced parasite burden in the spleen as compared to the single drug treatments given at the same dosages. Although parasite burden was slightly lower (p<0.05p < 0.05) in the Amphot B group than in the Dim-Art treatment group, the present study demonstrates the positive advantage and the potential use of the combined therapy of Dim-Art over the constituent drugs, Dim or Art when used alone. Further evaluation is recommended to determine the most efficacious combination ratio of the two compounds.Comment: 4 Pages, 3 Figure

    Impact of COVID-19 on mortality in coastal Kenya: a longitudinal open cohort study

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    The mortality impact of COVID-19 in Africa remains controversial because most countries lack vital registration. We analysed excess mortality in Kilifi Health and Demographic Surveillance System, Kenya, using 9 years of baseline data. SARS-CoV-2 seroprevalence studies suggest most adults here were infected before May 2022. During 5 waves of COVID-19 (April 2020-May 2022) an overall excess mortality of 4.8% (95% PI 1.2%, 9.4%) concealed a significant excess (11.6%, 95% PI 5.9%, 18.9%) among older adults ( ≥ 65 years) and a deficit among children aged 1–14 years (−7.7%, 95% PI −20.9%, 6.9%). The excess mortality rate for January 2020-December 2021, age-standardised to the Kenyan population, was 27.4/100,000 person-years (95% CI 23.2-31.6). In Coastal Kenya, excess mortality during the pandemic was substantially lower than in most high-income countries but the significant excess mortality in older adults emphasizes the value of achieving high vaccine coverage in this risk group

    Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Kenyan blood donors.

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    The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Africa is poorly described. The first case of SARS-CoV-2 in Kenya was reported on 12 March 2020, and an overwhelming number of cases and deaths were expected, but by 31 July 2020, there were only 20,636 cases and 341 deaths. However, the extent of SARS-CoV-2 exposure in the community remains unknown. We determined the prevalence of anti-SARS-CoV-2 immunoglobulin G among blood donors in Kenya in April-June 2020. Crude seroprevalence was 5.6% (174 of 3098). Population-weighted, test-performance-adjusted national seroprevalence was 4.3% (95% confidence interval, 2.9 to 5.8%) and was highest in urban counties Mombasa (8.0%), Nairobi (7.3%), and Kisumu (5.5%). SARS-CoV-2 exposure is more extensive than indicated by case-based surveillance, and these results will help guide the pandemic response in Kenya and across Africa

    The evolving SARS-CoV-2 epidemic in Africa: insights from rapidly expanding genomic surveillance

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    Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern—particularly Alpha, Beta, Delta, and Omicron—on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    The evolving SARS-CoV-2 epidemic in Africa: insights from rapidly expanding genomic surveillance

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    Investment in SARS-CoV-2 sequencing in Africa over the past year has led to a major increase in the number of sequences generated, now exceeding 100,000 genomes, used to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence domestically, and highlight that local sequencing enables faster turnaround time and more regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and shed light on the distinct dispersal dynamics of Variants of Concern, particularly Alpha, Beta, Delta, and Omicron, on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve, while the continent faces many emerging and re-emerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    May Measurement Month 2018: a pragmatic global screening campaign to raise awareness of blood pressure by the International Society of Hypertension

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    Aims Raised blood pressure (BP) is the biggest contributor to mortality and disease burden worldwide and fewer than half of those with hypertension are aware of it. May Measurement Month (MMM) is a global campaign set up in 2017, to raise awareness of high BP and as a pragmatic solution to a lack of formal screening worldwide. The 2018 campaign was expanded, aiming to include more participants and countries. Methods and results Eighty-nine countries participated in MMM 2018. Volunteers (≥18 years) were recruited through opportunistic sampling at a variety of screening sites. Each participant had three BP measurements and completed a questionnaire on demographic, lifestyle, and environmental factors. Hypertension was defined as a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, or taking antihypertensive medication. In total, 74.9% of screenees provided three BP readings. Multiple imputation using chained equations was used to impute missing readings. 1 504 963 individuals (mean age 45.3 years; 52.4% female) were screened. After multiple imputation, 502 079 (33.4%) individuals had hypertension, of whom 59.5% were aware of their diagnosis and 55.3% were taking antihypertensive medication. Of those on medication, 60.0% were controlled and of all hypertensives, 33.2% were controlled. We detected 224 285 individuals with untreated hypertension and 111 214 individuals with inadequately treated (systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg) hypertension. Conclusion May Measurement Month expanded significantly compared with 2017, including more participants in more countries. The campaign identified over 335 000 adults with untreated or inadequately treated hypertension. In the absence of systematic screening programmes, MMM was effective at raising awareness at least among these individuals at risk
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