Africa RISING science, innovations and technologies with scaling potential from ESA-Zambia

United States Agency for International Developmen

Association of Maternal Immunity with Rotavirus Vaccine Immunogenicity in Zambian Infants

IntroductionLive attenuated oral vaccines against rotavirus (RV) have been shown to be less efficacious in children from developing countries. Reasons for this disparity are not fully understood. We assessed the role of maternal factors including breast milk RV-specific IgA, transplacentally acquired infant serum RV-specific IgG and maternal HIV status in seroconversion among Zambian infants routinely immunized with Rotarix™ (RV1).Methods420 mother-child pairs were recruited at infant age 6–12 weeks in Lusaka. Clinical information and samples were collected at baseline and at one month following the second dose of RV1. Determination of breast milk RV-specific IgA and serum RV-specific IgA and IgG was done using standardized ELISA. Seroconversion was defined as a ≥ 4 fold rise in serum IgA titre from baseline to one-month post RV1 dose 2, while seropositivity of IgA was defined as serum titre ≥ 40 and antibody variables were modelled on log-base 2. Logistic regression was used to identify predictors of the odds of seroconversion.ResultsBaseline infant seropositivity was 25.5% (91/357). The seroconversion frequency was 60.2% (130/216). Infants who were IgA seropositive at baseline were less likely to seroconvert compared to their seronegative counterparts (P = 0.04). There was no evidence of an association between maternal HIV status and seroconversion (P = 0.25). Higher titres of breast milk rotavirus-specific IgA were associated with a lower frequency of seroconverson (Nonparametric test for trend Z = -2.84; P<0.01): a two-fold increase in breast milk RV-specific IgA titres was associated with a 22% lower odds of seroconversion (OR = 0.80; 95% CI = 0.68–0.94; P = 0.01). There was seasonal variation in baseline breast milk rotavirus-specific IgA titres, with significantly higher GMTs during the cold dry months (P = 0.01).ConclusionLow immunogenicity of RV1 vaccine could be explained in part by exposure to high antibody titres in breast milk and early exposure to wild-type rotavirus infections. Potential interference of anti-RV specific IgA in breast milk and pre-vaccination serum RV specific-IgA and IgG titres with RV1 seroconversion and effectiveness requires further research

How do farmers and seed producers get information and provide feedback on varieties in the public domain: the case of common bean in eastern Zambia?

A Study conducted by the Zambia Agriculture Research Institute (ZARI) and Seed Control and Certification Institute (SCCI) with the International Center for Tropical Agriculture (CIAT)A study was conducted in 2015 to investigate the channels used by farmers and seed producers to access information on bean varieties in the Eastern Province of Zambia, particularly in Chadiza, Chipata, Lundazi and Vubwi districts. Stakeholders, key informants and a sample of 300 bean-producing households were interviewed. Two focus group discussions (FGDs) were also conducted in Chadzombe and Chiwoko Agricultural Camps to contextualize the survey responses. The 300 households produced beans under rain-fed and irrigated wetland conditions, and also grew maize (87 %) and other legumes such as groundnut (66 %) and soybean (61%). Concerning bean production, the majority of respondents (88%) grew only local varieties while 6 % grew only improved varieties, 6% grew both varieties and the remainder (less than 1 %) were unware whether their varieties of choice were local or improved

BIOCHEMICAL FACTORS ASSOCIATED WITH CASSAVA RESISTANCE TO WHITEFLY INFESTATION

Cassava ( Manihot esculenta Crantz) an important food security crop, is inflicted by whitefly ( Bemisia tabaci ) worldwide, causing direct damage of up to 80% of yield loss. Although resistance to the pest has been associated with antibiosis, changes that occur in metabolite activity, and their effect on the pest have not been fully elucidated. A study was carried out to evaluate changes in peroxidase, tannin and flavonoid activity in cassava genotypes attacked by B. tabaci in order to contribute to knowledge on whitefly resistance in cassava. Five genotypes showing resistance, and three susceptible, were selected based on whitefly count and leaf damage scores, and assayed for peroxidase, tannin and flavonoid activity. There were significant differences among genotypes for leaf damage (P &lt; 0.01) of three to six months plants. Genotypes CS1-144, UG 120133 and NAM 130 showed low damage scores (&lt; 2.00); but a high damage score (&gt; 2.5) was incurred by UG 130068. All genotypes showed significant (P &lt; 0.05) differences for peroxidase activity, with CS1-144 having a high activity rate three months after planting. The lowest activity was observed in UG 120170, a susceptible genotype. A significant (P &lt; 0.01) negative correlation (r = -0.84) was observed between peroxidase activity and cassava leaf damage scores, as well as between tannin and damage (r = -0.57), indicating that peroxidase and tannin play a part in cassava resistance to B. tabaci.Le manioc ( Manihot esculenta Crantz) qui est une importante culture de s\ue9curit\ue9 alimentaire, est influenc\ue9e par la mouche blanche ( Bemisia tabaci ) sur le plan mondial, \ue0 travers des dommages directs allant jusqu\u2019\ue0 80% de perte du rendement. Par ailleurs, la r\ue9sistance \ue0 la peste a \ue9t\ue9 associ\ue9e \ue0 l\u2019antibiose, des changements qui apparaissent dans l\u2019activit\ue9 m\ue9tabolique, et leur effet sur la peste n\u2019ont pas encore \ue9t\ue9 compl\ue8tement \ue9lucid\ue9s. Une \ue9tude a \ue9t\ue9 entreprise pour \ue9valuer les changements d\u2019activit\ue9 en peroxydase, tannin et flavono\uefde dans les g\ue9notypes du manioc attaqu\ue9s par B. tabaci dans le but de contribuer au savoir sur la r\ue9sistance du\ua0manioc. Cinq g\ue9notypes, montrant r\ue9sistance, et trois susceptibles, \ue9taient s\ue9lectionn\ue9s sur la base du nombre de la mouche blanche et les sores de dommages et analys\ue9s pour l\u2019activit\ue9 en peroxydase, tannin and flavono\uefdes. Il y avait de diff\ue9rences significatives entre les g\ue9notypes pour les dommages caus\ue9s sur les feuilles (P&lt; 0,01) des plantes de trois \ue0 six mois. Les g\ue9notypes CS1-144, UG 120133 et NAM 130 ont montr\ue9 de faibles scores de dommage (&lt; 2,00); mais un score \ue9lev\ue9 de dommage (&gt; 2,5) \ue9tait re\ue7u par UG 130068. Tous les g\ue9notypes ont montr\ue9 de diff\ue9rences significatives (P &lt; 0,05) pour l\u2019activit\ue9 de peroxydase, avec CS1-144 ayant un taux d\u2019activit\ue9 \ue9lev\ue9 trois mois apr\ue8s la plantation. La faible activit\ue9 \ue9tait observ\ue9e sur UG 120170, un g\ue9notype susceptible. Une corr\ue9lation significative (P &lt; 0,01) et n\ue9gative (r = -0,84) \ue9tait observ\ue9e entre l\u2019activit\ue9 de peroxydase et les scores de dommages sur les feuilles de manioc, ainsi que entre tannin et dommage (r = -0,57), indiquant que peroxydase et tannin jouent une part de r\uf4le dans la r\ue9sistance du manioc au B. tabaci

Experiences of Justice-Involved People Transitioning to HIV Care in the Community After Prison Release in Lusaka, Zambia: A Qualitative Study

Introduction: In sub-Saharan Africa (SSA), incarcerated people experience a higher HIV burden than the general population. While access to HIV care and treatment for incarcerated people living with HIV (PLHIV) in SSA has improved in some cases, little is known about their transition to and post-release experience with care in the community. To address this gap, we conducted a qualitative study to describe factors that may influence post-release HIV care continuity in Zambia. Methods: In March-December 2018, we recruited study participants from a larger prospective cohort study following incarcerated and newly released PLHIV at 5 correctional facilities in 2 provinces in Zambia. We interviewed 50 participants immediately before release; 27 (54%) participated in a second interview approximately 6 months post-release. Demographic and psychosocial data were collected through a structured survey. Results: The pre-release setting was strongly influenced by the highly structured prison environment and assumptions about life post-release. Participants reported accessible HIV services, a destigmatizing environment, and strong informal social supports built through comradery among people facing the same trying detention conditions. Contrary to their pre-release expectations, during the immediate post-release period, participants struggled to negotiate the health system while dealing with unexpected stressors. Long-term engagement in HIV care was possible for participants with strong family support and a high level of self-efficacy. Conclusion: Our study highlights that recently released PLHIV in Zambia face acute challenges in meeting their basic subsistence needs, as well as social isolation, which can derail linkage to and retention in community HIV care. Releasees are unprepared to face these challenges due to a lack of community support services. To improve HIV care continuity in this population, new transitional care models are needed that develop client self-efficacy, facilitate health system navigation, and pragmatically address structural and psychosocial barriers like poverty, gender inequality, and substance use

Genetic diversity and population structure of Peronosclerospora sorghi isolates of Sorghum in Uganda

Sorghum is the third most important staple cereal crop in Uganda after maize and millet. Downy mildew disease is one of the most devastating fungal diseases which limits the production and productivity of the crop. The disease is caused by an obligate fungus, Peronosclerospora sorghi (Weston & Uppal) with varying symptoms. Information on the genetic diversity and population structure of P.sorghi in sorghum is imperative for the screening and selection for resistant genotypes and further monitoring possible mutant(s) of the pathogen. Isolates of P. sorghi infecting sorghum are difficult to discriminate when morphological descriptors are used. The use of molecular markers is efficient, and reliably precised for characterizing P. sorghi isolates. This study was undertaken to assess the level of genetic diversity and population structure that exist in P. sorghi isolates in Uganda. A total of 195 P. sorghi isolates, sampled from 13 different geographic populations from 10 different regions (agro-ecological zones) was used. Eleven (11) molecular markers, comprising of four Random amplified microsatellite (RAM) and seven (7) Inter-Simple Sequence Repeat (ISSR) markers were used in this study. The analysis of molecular variation (AMOVA) based on 11 microsatellite markers showed significant (P < 0.001) intra-population (88.9 %, PhiPT = 0.111) and inter-population (8.4 %, PhiPR = 0.083) genetic variation, while the genetic variation among regions (2.7 %, PhiRT = 0.022) was not significant. The highest genetic similarity value (0.987 = 98.7 %) was recorded between Pader and Lira populations and the lowest genetic similarity (0.913 = 91.3 %) was observed between Namutumba and Arua populations. The mean Nei's genetic diversity index (H) and Shannon Information Index (I) were 0.308 and 0.471 respectively. Seven distinct cluster groups were formed from the 195 P. sorghi isolates based on their genetic similarity. Mantel test revealed no association between genetic differentiation and geographical distance (R2 = 0.0026, p = 0.02) within the 13 geographic populations

Effects of maize residue and mineral nitrogen applications on maize yield in conservation-agriculture-based cropping systems of Southern Africa

Conservation agriculture (CA) and no-till (NT)-based cropping systems could address soil degradation and fertility decline in southern Africa. A multi-location and multi-year experiment was carried out between 2008 and 2014 to assess the effects of different levels of maize residue biomass (0, 2, 4, 6 and 8 t ha−1) and nitrogen (N) fertilizer (0, 30, 90 kg ha−1) on maize performance under no-tillage. In some sites, different (N) fertilizer levels were superimposed to test their effects on maize grain yield and leaf chlorophyll content under different maize residue biomass levels. The different residue levels had no significant effect on maize yield in most growing seasons. Maize residue cover increased grain yield in eight out of 39 site-years across the sites used. However, in some sites, maize yield decreased with increases in residue level in cropping seasons that had average to above average rainfall. At a few sites maize yield increased with increase in residue level. Seasonal rainfall pattern influenced the effect of different residue levels on grain yield at most sites. Nitrogen fertilizer increased maize yield regardless of the residue level applied. This study demonstrates that mulching with maize residues in CA/NT systems results in limited maize yield gains – at least within the first 6 years in different agro-ecological conditions of southern Africa

Biocompatibility of Biomaterials for Nanoencapsulation: Current Approaches.

Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed

Universal combination antiretroviral regimens to prevent mother-to-child transmission of HIV in rural Zambia: a two-round cross-sectional study

To evaluate if a pilot programme to prevent mother-to-child transmission (PMTCT) of the human immunodeficiency virus (HIV) was associated with changes in early childhood survival at the population level in rural Zambia