Land reform in South Africa: effects on land prices and productivity

South Africa’s land redistribution policy (1994-2008) has been widely publicised, and has come under scrutiny of late from the public, private and government spheres, highlighting a need for research in this area. The research examines progress in South Africa’s land redistribution programme in two of KwaZulu-Natal’s district municipalities, Uthungulu and iLembe. Specifically the research investigates whether the government has paid above market prices when purchasing sugarcane farmland for redistribution in these districts. Moreover, it is illustrated how productivity on redistributed farms has been affected with the changes in ownership. To investigate the research questions, reviews of theories pertaining to property rights, land reform and market structures were conducted. Moreover, two cases studies were conducted in the districts of Uthungulu and iLembe, with assistance from the Department of Land Affairs, Inkezo Land Company and the South African Cane Growers Association. The case study data indicate that above ordinary market prices have been paid (2004-2006) by the government for sugarcane farmland in the districts concerned, and further that productivity has been negatively impacted ‘during’ and ‘post‘ transfer, in the majority of cases

Detection, prevalence, and transmission of avian hematozoa in waterfowl at the Arctic/sub-Arctic interface: co-infections, viral interactions, and sources of variation

Background The epidemiology of avian hematozoa at high latitudes is still not well understood, particularly in sub-Arctic and Arctic habitats, where information is limited regarding seasonality and range of transmission, co-infection dynamics with parasitic and viral agents, and possible fitness consequences of infection. Such information is important as climate warming may lead to northward expansion of hematozoa with unknown consequences to northern-breeding avian taxa, particularly populations that may be previously unexposed to blood parasites. Methods We used molecular methods to screen blood samples and cloacal/oropharyngeal swabs collected from 1347 ducks of five species during May-August 2010, in interior Alaska, for the presence of hematozoa, Influenza A Virus (IAV), and IAV antibodies. Using models to account for imperfect detection of parasites, we estimated seasonal variation in prevalence of three parasite genera (Haemoproteus, Plasmodium, Leucocytozoon) and investigated how co-infection with parasites and viruses were related to the probability of infection. Results We detected parasites from each hematozoan genus in adult and juvenile ducks of all species sampled. Seasonal patterns in detection and prevalence varied by parasite genus and species, age, and sex of duck hosts. The probabilities of infection for Haemoproteus and Leucocytozoon parasites were strongly positively correlated, but hematozoa infection was not correlated with IAV infection or serostatus. The probability of Haemoproteus infection was negatively related to body condition in juvenile ducks; relationships between Leucocytozoon infection and body condition varied among host species. Conclusions We present prevalence estimates for Haemoproteus, Leucocytozoon, and Plasmodium infections in waterfowl at the interface of the sub-Arctic and Arctic and provide evidence for local transmission of all three parasite genera. Variation in prevalence and molecular detection of hematozoa parasites in wild ducks is influenced by seasonal timing and a number of host traits. A positive correlation in co-infection of Leucocytozoon and Haemoproteus suggests that infection probability by parasites in one or both genera is enhanced by infection with the other, or that encounter rates of hosts and genus-specific vectors are correlated. Using size-adjusted mass as an index of host condition, we did not find evidence for strong deleterious consequences of hematozoa infection in wild ducks.Geological Survey (U.S.) (Wildlife Program of the Ecosystem Mission Area)U.S. Fish and Wildlife ServiceDelta Waterfowl FoundationInstitute for Wetland and Waterfowl ResearchIcahn School of Medicine at Mount Sinai (Center for Research on Influenza Pathogenesis)Center of Excellence for Influenza Research and Surveillance (contracts HHSN272201400008C and HHSN266200700010C

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

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Detection of GFP-expressing BCG by innate cells and association between absolute numbers of innate cells and mycobacterial growth inhibition.

<p>(<b>A</b>) Representative flow cytometry plot of IL-6, IL-12 and TNF-α cytokine expression by myeloid dentritic cells (mDCs), monocytes and neutrophils, measured in whole blood stimulated for 6 hours with BCG, BCG-GFP (shown) or LPS, relative to an unstimulated control sample. (<b>B</b>) Representative histograms indicating proportions of innate cells that phagocytosed BCG-GFP (green). (<b>C</b>) Absolute numbers of innate cell subsets per milliliter of unstimulated whole blood plotted against <i>M</i>.<i>tb</i> H37Rv growth. R and p values were calculated using Spearman’s correlation. (<b>D</b>) Absolute numbers of BCG-GFP-positive mDCs, monocytes or neutrophils per mL of whole blood in adult individuals, stratified by QFT status. The inclusion of TruCount beads during the cell staining steps of the innate whole blood assay allowed determination of the absolute number of each subset of cells per mL of whole blood. The red and blue circles represent QFT+ and QFT- adults, respectively. Horizontal lines represent medians and whiskers, the interquartile range. Differences in absolute counts of BCG-GFP-positive innate cells between the groups were evaluated with the Mann-Whitney test (shown <i>P</i> values). The pie charts show relative proportions of BCG-GFP-positive cells among each innate cell subset.</p

Mycobacteria-specific T cells in whole blood from adults and mycobacterial growth inhibition.

<p>(<b>A</b>) Absolute numbers of BCG-specific CD4, CD8 and γδ T cell subsets co-expressing IL-2, IFN-γ, TNF-α and/or IL-17, in whole bood from QFT+ (red) and QFT- (blue) adults. Medians are represented by the horizontal lines, interquartile ranges by the boxes, and ranges by the whiskers. The Mann-Whitney test was used to assess differences between QFT+ and QFT- adults and none were found to be different. (<b>B</b>) <i>M</i>.<i>tb</i> H37Rv growth plotted against frequencies of BCG-specific CD4, CD8 or γδ T cells expressing IFN-γ, or CD4 T cells expressing IL-17 in adults. R and p values were calculated using Spearman’s correlation analysis.</p

Mycobacteria-specific cytokine expression by innate cells in whole blood from adults and mycobacterial growth inhibition.

<p>(<b>A</b>) Absolute numbers of total cytokine expressing innate cells per mL of whole blood plotted against <i>M</i>.<i>tb</i> H37Rv growth. R and p values were calculated using Spearman’s correlation analysis. (<b>B</b>) Numbers of BCG-specific mDCs, monocytes and neutrophils co-expressing IL-6, IL-12 and/or TNF-α in whole blood from QFT+ (red) and QFT- (blue) adults. Medians are represented by the horizontal line, interquartile ranges by the boxes, and ranges by the whiskers. The Mann-Whitney test was used to assess differences between QFT+ and QFT- adults and none were found to be different.</p

<i>In vitro</i> mycobacterial growth inhibition in <i>M</i>.<i>tb</i>-infected (QFT+) and uninfected (QFT-) individuals.

<p>Inhibition of <i>M</i>.<i>tb</i> H37Rv growth by whole blood from QFT+ and QFT- adults (<b>A</b>), young adults (<b>B</b>) and children (<b>C</b>) assessed using a mycobacterial growth inhibition assay (MGIA). The growths of <i>M</i>. <i>bovis</i> BCG, <i>M</i>.<i>tb</i> H37Rv, <i>M</i>.<i>tb</i> isolate CDC1551 and <i>M</i>.<i>tb</i> isolate HN878 in the whole blood of adults (<b>D</b>) and young adults (<b>E</b>), respectively were compared. Spearman’s correlation analyses of the growth of different mycobacterial strains (<b>F</b> and <b>G</b>). The growth of BCG (<b>H</b>), HN878 and CDC1551 (<b>I</b> and <b>J</b>), was measured in the whole blood of adults and young adults, respectively. The red and blue circles represent QFT+ and QFT- individuals, respectively while the green and orange circles represent children and young adults respectively. The horizontal line represents the median, the boxes represent the interquartile range, and the whiskers represent the range. Differences in mycobacterial growth inhibition between both groups of individuals were evaluated with the Mann-Whitney test (shown <i>P</i> values).</p

Application of a whole blood mycobacterial growth inhibition assay to study immunity against <i>Mycobacterium tuberculosis</i> in a high tuberculosis burden population

<div><p>The determinants of immunological protection against <i>Mycobacterium tuberculosis (M</i>.<i>tb)</i> infection in humans are not known. Mycobacterial growth inhibition assays have potential utility as <i>in vitro</i> surrogates of <i>in vivo</i> immunological control of <i>M</i>.<i>tb</i>. We evaluated a whole blood growth inhibition assay in a setting with high burden of TB and aimed to identify immune responses that correlate with control of mycobacterial growth. We hypothesized that individuals with underlying <i>M</i>.<i>tb</i> infection will exhibit greater <i>M</i>.<i>tb</i> growth inhibition than uninfected individuals and that children aged 4 to 12 years, an age during which TB incidence is curiously low, will also exhibit greater <i>M</i>.<i>tb</i> growth inhibition than adolescents or adults. Neither <i>M</i>.<i>tb</i> infection status, age of the study participants, nor <i>M</i>.<i>tb</i> strain was associated with differential control of mycobacterial growth. Abundance and function of innate or T cell responses were also not associated with mycobacterial growth. Our data suggest that this assay does not provide a useful measure of age-associated differential host control of <i>M</i>.<i>tb</i> infection in a high TB burden setting. We propose that universally high levels of mycobacterial sensitization (through environmental non-tuberculous mycobacteria and/or universal BCG vaccination) in persons from high TB burden settings may impart broad inhibition of mycobacterial growth, irrespective of <i>M</i>.<i>tb</i> infection status. This sensitization may mask the augmentative effects of mycobacterial sensitization on <i>M</i>.<i>tb</i> growth inhibition that is typical in low burden settings.</p></div