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- Nyokabi, Ndungu S., et al.
(författare)
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The role of power relationships, trust and social networks in shaping milk quality in Kenya
- 2023
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Ingår i: NJAS: Impact in Agricultural and Life Sciences. - : Taylor & Francis. - 2768-5241. ; 95:1
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to examine social networks in dairy value chains (DVCs) in Kenya and understand how DVC actors' power relationships and trust influence their behaviour regarding milk quality. We conducted a stakeholder analysis using the Net-Map tool in Laikipia, Nakuru and Nyandarua counties in Kenya. VisuaLyzer software was used to analyse the social networks. Thematic content analysis of the discussions, recorded during the mapping exercise, was undertaken using ATLAS.ti. Formal DVC had more actors and dense social networks characterised by vertical and horizontal integration, high levels of power asymmetries between actors, limited trust and short-term contractual arrangements. Informal DVC was characterised by fewer actors and less dense social networks, low levels of power asymmetries between actors and a high level of trust due to the existence of reciprocal personal relationships. Milk was perceived to be of higher quality in the formal value chain reflecting top-down enforcement of milk standards, bottom-up collective action, power asymmetries and contractual relationships. Poor milk quality management in the informal DVC underscores the need for powerful actors, e.g. regulatory agencies, and buyers such as processors, to influence other DVC actors' behavioural change. Understanding and leveraging DVC social networks and actors' power and addressing power asymmetries and enhancing trust between actors will increase compliance with milk quality standards. There is an urgent imperative to design policies and interventions which empower DVC actors, by providing economic incentives, enhancing their skills and knowledge and their access to infrastructure which facilitates milk quality improvement.
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- Fwambah, Lynn, et al.
(författare)
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Exposure to common infections may shape basal immunity and potentially HIV-1 acquisition amongst a high-risk population in Coastal Kenya
- 2023
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Ingår i: Frontiers in Immunology. - 1664-3224. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The impact of exposure to endemic infections on basal immunity and susceptibility to HIV-1 acquisition remains uncertain. We hypothesized that exposure to infections such as cytomegalovirus (CMV), malaria and sexually transmitted infections (STIs) in high-risk individuals may modulate immunity and subsequently increase susceptibility to HIV-1 acquisition. Methods: A case-control study nested in an HIV-1 negative high-risk cohort from Coastal Kenya was used. Cases were defined as volunteers who tested HIV-1 positive during follow-up and had a plasma sample collected 3 ± 2 months prior to the estimated date of HIV-1 infection. Controls were individuals who remained HIV-1 negative during the follow-up and were matched 2:1 to cases by sex, age, risk group and follow-up time. STI screening was performed using microscopic and serologic tests. HIV-1 pre-infection plasma samples were used to determined exposure to CMV and malaria using enzyme-linked immunosorbent assays and to quantify forty-one cytokines and soluble factors using multiplexing assays. Multiplexing data were analyzed using principal component analysis. Associations between cytokines and soluble factors with subsequent HIV-1 acquisition were determined using conditional logistic regression models. Results and discussion: Overall, samples from 47 cases and 94 controls were analyzed. While exposure to malaria (p=0.675) and CMV (p=0.470) were not associated with HIV-1 acquisition, exposure to STIs was (48% [95% CI, 33.3 – 63] vs. 26% [95% CI, 17.3 – 35.9]. Ten analytes were significantly altered in cases compared to controls and were clustered into four principal components: PC1 (VEGF, MIP-1β, VEGF-C and IL-4), PC2 (MCP-1, IL-2 and IL-12p70), PC3 (VEGF-D) and PC4 (Eotaxin-3). PC1, which is suggestive of a Th2-modulatory pathway, was significantly associated with HIV-1 acquisition after controlling for STIs (adjusted odds ratio, (95% CI), p-value: 1.51 [1.14 – 2.00], p=0.004). Elevation of Th2-associated pathways may dampen responses involved in viral immunity, leading to enhanced susceptibility to HIV-1 acquisition. Immunomodulatory interventions aimed at inhibiting activation of Th2-associated pathways may be an additional strategy to STI control for HIV-1 prevention and may reduce dampening of immune responses to vaccination.
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- Hassan, Amin S, et al.
(författare)
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A Stronger Innate Immune Response During Hyperacute HIV-1 Infection is associated with ACUTE retroviral syndrome
- 2021
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1537-6591 .- 1058-4838. ; 73:5, s. 832-841
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Acute retroviral syndrome (ARS) is associated with HIV-1 subtype and disease progression, but the underlying immunopathological pathways are poorly understood. We aimed to elucidate associations between innate immune responses during hyperacute HIV-1 infection (hAHI) and ARS.METHODS: Plasma samples obtained from volunteers (≥18.0 years) before and during hAHI, defined as HIV-1 antibody negative and RNA or p24 antigen positive from Kenya, Rwanda, Uganda, Zambia and Sweden were analysed. Forty soluble innate immune markers were measured using multiplexed assays. Immune responses were differentiated into volunteers with stronger and comparatively weaker responses using principal component analysis. Presence or absence of ARS was defined based on eleven symptoms using latent class analysis. Logistic regression was used to determine associations between immune responses and ARS.RESULTS: Of 55 volunteers, 31 (56%) had ARS. Volunteers with stronger immune responses (n=36 [65%]) had increased odds of ARS which was independent of HIV-1 subtype, age, and risk group (adjusted odds ratio, 7.1 [95% CI: 1.7-28.8], p=0.003). IP-10 was fourteen-fold higher during hAHI, elevated in seven of the eleven symptoms, and independently associated with ARS. IP-10 threshold >466.0 pg/mL differentiated stronger immune responses with a sensitivity of 84.2% (95% CI: 60.4-96.6) and specificity of 100.0% (95% CI: 90.3-100.0).CONCLUSIONS: A stronger innate immune response during hAHI was associated with ARS. Plasma IP-10 may be a candidate biomarker of stronger innate immunity. Our findings provide further insights on innate immune responses in regulating ARS and may inform the design of vaccine candidates harnessing innate immunity.
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- Ndungu, Nelly, et al.
(författare)
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Can the shape of the wing help in the identification of African stingless bee species? (Hymenoptera: Apidae: Meliponini) : Wing geometric morphometrics: a tool for african stingless bee taxonomy
- 2023
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Ingår i: International Journal of Tropical Insect Science. - : Springer Science and Business Media LLC. - 1742-7584 .- 1742-7592. ; 43:2, s. 749-759
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Tidskriftsartikel (refereegranskat)abstract
- Stingless bees are important pollinators of wild and cultivated plants, and they produce medicinal honey. However, their taxonomy and systematics are still debated and would benefit a continent-wide revision. Here, we explore the potential of wing shape in delineation and classification of Afrotropical Meliponini using geometric morphometrics. We sampled 749 specimens from nine countries of sub-Saharan Africa, belonging to the genera Meliponula (n = 8), Dactylurina (n = 2) and Plebeina (n = 1). Specimens collected from Kenya were used as standards to assess similar species collected from other eight African countries. Eleven landmarks were plotted on the right forewing of each specimen to conduct multivariate analyses and group/specimen classification. Our results show that seven out of eleven African stingless bee species were reliably discriminated using wing shape, however, there was overlap in the remaining four species, namely Meliponula cameroonensis, Meliponula ferruginea, Meliponula togoensis and Meliponula erythra. In conclusion geometric morphometrics represent a promising taxonomic tool that can be applied to identify African stingless bee species.
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