Trastuzumab was added to the South African Essential Medicines List (EML) in 2017 for the adjuvant management of human epidermal growth factor receptor 2 (HER2)-positive early breast cancer. However, ...access has remained inconsistent, as some provinces continue to regard trastuzumab as unaffordable within the contexts of their respective oncology budgets. The intention of providing access to trastuzumab through its inclusion on the EML, therefore, has not been met. The National EML Committee (NEMLC) recently reviewed newly published peer-reviewed information investigating the impact of a shorter trastuzumab treatment period on both clinical efficacy and safety. On account of this review, and with a view to improving access while reducing cost and toxicity, the NEMLC has revised the duration of trastuzumab therapy, i.e. from 12 months to 6 months in the adjuvant management of early HER2-positive breast cancer. This article explores and reports on the data used to make this policy amendment.
Blue carbon ecosystems (mangroves, salt marshes, and seagrasses) contribute towards climate change mitigation because they are efficient at sequestering atmospheric CO2 into long-term total ecosystem ...carbon stocks. Destruction or disturbance therefore reduces sink capacity and leads to significant CO2 emissions. This study reports the first national estimates of: 1) total carbon storage, 2) CO2 emissions from anthropogenic activities, 3) the potential for restoration to enhance carbon sequestration for blue carbon ecosystems in South Africa. Mangrove ecosystems have the greatest carbon storage per unit area (253–534 Mg C ha−1), followed by salt marshes (100–199 Mg C ha−1) and seagrasses (45–144 Mg C ha−1). Salt marshes are the most extensive and contribute 67 % to the national carbon stock of 4000 Gg C. Since 1930, 6500 ha has been lost across all blue carbon ecosystems (26 % of the natural extent), equivalent to losing 1086 Gg C from the national carbon stock. Historic CO2 emissions were estimated at an average rate of 30,266 t CO2e yr−1. Despite losses, a total of 3998 ha could be restored to increase carbon sequestration and CO2 removals of 14,845 tCO2e.yr−1. Extractive activities have declined rapidly in recent decades, but abiotic pressures on estuarine ecosystems (flow modification, reduced water quality, and artificial breaching) have been increasing. There is an urgent need to quantify the potential impact of these pressures and include them in estuarine management and restoration plans. Blue carbon ecosystems cover a relatively small area in South Africa, but they are valued for their multiple ecosystem services that contribute towards climate change adaptation and biodiversity co-benefits. These ecosystems need to be included in national policies driving climate change response in the Agriculture, Forestry and Other Land-Use (AFOLU) sector, such as incorporating them into the wetland subcategory of the national GHG inventory.
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•Blue carbon ecosystems are not widely incorporated into national GHG inventories.•A national assessment estimated total ecosystem carbon sink capacity.•The IPCC Wetlands Supplement was applied to quantify CO2 emissions and removals.•26 % of natural area has been lost, but restoration can enhance carbon sink potential.•Blue carbon ecosystems should be included in AFOLU climate change response plans.
Salt marshes protect estuary banks from erosion by acting as buffers between marine and terrestrial environments. Residents living near the Breede River estuary, Western Cape Province, South Africa, ...raised concerns about ongoing erosion evident at Groenpunt, the main salt marsh. This study aimed to determine how long erosion has been taking place, the rate and possible causes thereof. Aerial images and environmental data were assessed for the years 2002–2020. Erosion was first evident in 2003. By 2020, the marsh edge had been eroded into a series of micro-bays, incised horizontally up to 7 m, with a scarp height of 0.7 m, corresponding to a loss of 1 313 m2 of salt marsh and a bank retreat rate of 0.66 (SE 0.44) m year−1. Over the study period, there was a regular pattern of high-frequency gale-force winds (>8 on the Beaufort scale), with significantly more winds of this magnitude occurring in 2002 than in other years. The wind wave fetch adjacent to the marsh is up to 1 km in the direction of the predominant wind, and it is likely that the cumulative effects of constant wind-generated waves drove the erosion process. Estuary water and tidal levels over the period reflected normal seasonal fluctuation patterns. The bank supporting Groenpunt salt marsh is eroding at a rate that could possibly see it disappear within the next 60 years, reducing biodiversity and ecosystem services in the estuary. In the face of increasing climatic variability predicted in the future, similar salt marsh erosion is likely to become more prevalent.
An upsurge in African horse sickness (AHS) in the Eastern Cape, South Africa, from 2006 led to an epidemiological reassessment of the disease there. Light trapping surveys carried out near horses, ...donkeys and zebras in 2014–2016 collected 39 species of Culicoides midge (Diptera: Ceratopogonidae) that are potential vectors of AHS. To establish if these midges fed on equids, DNA sequences were obtained from the gut contents of 52 female midges (35 freshly blood‐fed, 13 gravid and four parous), representing 11 species collected across 11 sites. Culicoides leucostictus fed on all three equids. Culicoides bolitinos, Culicoides imicola and Culicoides magnus fed on both horses and donkeys. Culicoides onderstepoortensis fed on donkeys, and Culicoides similis and Culicoides pycnostictus fed on zebras. Bloodmeals from cows, pigs, warthogs, impalas and a domestic dog were also identified in various species, but none of the midges tested had fed on birds. These results contribute to knowledge of the vectorial capacity of several species of Culicoides with regard to AHS in the Eastern Cape and point to potential reservoir hosts, of which donkeys, zebras and domestic dogs have previously been found to harbour AHS. Blood‐fed midges were also obtained throughout winter, indicating the potential for endemic AHS in the province.
New data represent the first records of Culicoides species feeding on donkeys, horses and zebras, and reveal an equine overlap in host preferences and the associated vector potentials of these midge species.
Findings in Culicoides imicola and Culicoides bolitinos supported their status as vectors of African horse sickness (AHS) virus and as feeding on equid hosts, both horses and donkeys, in addition to other domestic animals at sites of confirmed AHS cases.
These findings support the vectorial capacity of multiple additional Culicoides species and the roles of other mammalian hosts, including domestic dogs, based on the study of host preferences.
African horse sickness (AHS), a disease of equids caused by the AHS virus, is of major concern in South Africa. With mortality reaching up to 95% in susceptible horses and the apparent reoccurrence ...of cases in regions deemed non‐endemic, most particularly the Eastern Cape, epidemiological research into factors contributing to the increase in the range of this economically important virus became imperative. The vectors, Culicoides (Diptera: Ceratopogonidae), are considered unable to proliferate during the unfavourable climatic conditions experienced in winter in the province, although the annual occurrence of AHS suggests that the virus has become established and that vector activity continues throughout the year. Surveillance of Culicoides within the province is sparse and little was known of the diversity of vector species or the abundance of known vectors, Culicoides imicola and Culicoides bolitinos. Surveillance was performed using light trapping methods at selected sites with varying equid species over two winter and two outbreak seasons, aiming to determine diversity, abundance and vector epidemiology of Culicoides within the province. The research provided an updated checklist of Culicoides species within the Eastern Cape, contributing to an increase in the knowledge of AHS vector epidemiology, as well as prevention and control in southern Africa.
The diversity and distribution of Culicoides in the Eastern Cape has changed, suggesting a previous underestimation and an epidemiological mechanism for endemic African horse sickness (AHS).
Under‐representation of proven vectors Culicoides bolitinos and Culicoides imicola compared with northern provinces, as well as the continuous presence of other orally‐susceptible species, is supportive of additional vectors contributing to local AHS virus persistence.
Based on abundance, C. bolitinos contributes most to vector epidemiology, with an apparent persistence of vectors throughout winter in the absence of an annual reintroduction from northern provinces, enabling endemic AHS.
Sea-level rise is a significant threat to salt marshes. However, these habitats can respond by increasing their relative elevation, or by migrating into adjacent areas. Here we provide the first ...report on surface elevation change for salt marsh at the Knysna Estuary, South Africa, and predict the responses of these habitats to sea-level rise using the Sea-Level Affecting Marshes Model (SLAMM). Recent (2018) surface elevation measurements at lower intertidal salt marsh sites were compared with those from 2009-2011. The long-term (1960-2017) relative sea-level rise (RSLR) was estimated as 2.19 mm y−1 and only two of the seven sites assessed are keeping pace with this RSLR. The SLAMM, which was applied to a focus area near Thesen's Island, predicted up to 40% loss of upper intertidal salt marsh by 2100, because development in the adjacent area prevents habitat migration. Currently, salt marsh habitats cover a total of 667 ha, and artificial structures are present along 20.7 km of the perimeter. Protecting areas for salt marsh migration should be a conservation priority, because this estuary supports the third largest area of intertidal salt marsh in the country. Monitoring the responses of coastal wetlands should be prioritised so that natural capital contributes towards future resilience.
Spartina alterniflora Loisel. is the only known halophyte that is invasive in intertidal salt marsh habitats in South Africa and it poses a considerable threat to the biodiversity of nearby ...estuaries. First detected in 2004, regular chemical treatment during the growing period from 2013 and adjustments to the recommended herbicide mix has almost completely removed the plant from the Great Brak Estuary. Part of the success of this treatment was due to the small area of infestation (~1ha), which was not difficult to access. In 2009 there were 429 stems per m2 but following herbicide treatment between 2013 and 2015, by November 2015 there were only 149 stems in the entire estuary (mean=8 stems per m2). Above-ground biomass had been reduced by 74% and below-ground biomass by 90%. Native salt marsh vegetation began to grow between the dead S. alterniflora shoots by October 2014 and increased to 95% cover by November 2015. The maximum total invaded area of 10,221m2 in 2011 was reduced to 10m2 by November 2015. Average annual costs for the control of S. alterniflora were ~ZAR 34, 349), or $ 2414. This study is important as it is one of a few examples of a national prospect of eradication of an invasive alien plant. However continuous monitoring is necessary, as this plant has been shown in other countries to regrow after chemical treatment.
•The research reports on the almost complete eradication of Spartina alterniflora in the Great Brak Estuary.•Successful control was through the application of a herbicide.•An efficacy of almost 99 % was achieved measured as a significant decrease in stem density and plant biomass.•There has been a recovery of indigenous salt marsh.
Coastal wetlands are vulnerable to sea-level rise (SLR) but are also valued for their potential to provide effective nature-based solutions to climate change mitigation and adaptation. Ecological ...benefits from these ecosystems can be constrained under urban settings by anthropogenic disturbances and pressures, so restoration activities are promoted as a management approach. Here we report on the potential for restoration of disused commercial salt extraction pans to enhance carbon (C) sequestration in the urban Swartkops Estuary, South Africa. We also considered the impact of SLR to 2100 on the distribution of estuarine habitats, the vulnerability of built infrastructure to tidal flooding, and how C sequestration is projected to change over time using the Sea-Level Affecting Marshes Model (SLAMM). Potential restoration of all salt pans (320 ha) to estuarine habitat was estimated to result in a gain of 67 850 Mg C. Establishing tidal connectivity was investigated as a potential restoration action, but most of the salt pan area was above the elevation of the current tidal range and would require excavation. Although conversion of the salt pans to estuarine habitat was predicted to occur without intervention under SLR, 44% of the original area would remain unchanged. Restoring hydrological connectivity to the estuary for these salt pans would significantly increase the extent of transitional/floodplain marsh, even under SLR to 2100. C sequestration was predicted to be 15% higher (54 614.8 Mg C) by 2100 if the salt pans could be restored, compared to if no action is taken. Overall, restoration of the salt pans has the potential to enhance C sequestration, but SLR will still cause large losses of supratidal marsh due to ‘coastal squeeze’ and extensive tidal flooding of developed areas by 2100 in the lower reaches of the estuary. A full-scale restoration approach for the Swartkops Estuary could use C sequestration potential to fund the project through carbon offsetting if the revenue exceeds the cost of the restoration activities, but additional social and ecological goals also need to be incorporated if the outcome is to be holistic and beneficial.
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•Restoration of disused commercial salt extraction pans can enhance carbon storage.•With sea-level rise, up to 66% of desiccated areas will revert to natural habitat.•With restoration, an additional 54 614.8 Mg C can be gained by 2100.•Sea-Level Affecting Marshes Model used to assess sea-level rise vulnerability.•Residential areas in lower reaches will experience tidal flooding by 2100.
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