Climate changes could jeopardize a main source of livelihood in Africa’s drylands

Climate change in Africa poses a serious threat to many ecosystems and livelihoods, making them vulnerable to climate-related risks. Gum and resin bearing tree species as the genus Boswellia are the main economic and livelihood sources in most dryland areas of Africa. We use species distribution models to find critical sites where Boswellia species may no longer occur in the future. Our models identify potential regions that could benefit from their cultivation and promote conservation efforts for the species to thrive. We projected models to new CMIP6 scenarios and different dispersal profiles. Despite the prevailing aridity already imposed on the species, Boswellia distribution shows a dramatic reduction. Future investments in Boswellia restoration and strategies to promote sustainable extraction of resources may be key to sustain populations and Boswellia dominated forests in many parts of the African continent.     

The ghost of a recent invasion in the reduced feeding rates of spitting cobras during the dry season in a rainforest region of tropical Africa?

Two species of cobras (Naja melanoleuca and Naja nigricollis) are known to occur in south eastern Nigeria, where much of the pristine rainforest surface has been felled in the last thirty years, and where the actual landscape is generally constituted by a mosaic of farmlands, plantations, suburban areas, with a few remnant forest fragments. In this region, Naja nigricollis is currently extending its range, especially by exploiting recently deforested areas. Based on the known general distribution range of this species and on the available literature data, it appears that Naja nigricollis has been colonizing the forested region of south eastern Nigeria, starting from the relatively arid savannas of central Nigeria, where this species aestivates during the driest months. In the forest region, however, snakes do not need to aestivate during the dry season. Nevertheless, whereas Naja melanoleuca has a foraging activity extended all-the-year round, Naja nigricollis reduces feeding rates during the dry months, although it does not suspend above-ground activity in these months. I suggest that rainforest spitting cobras suspend feeding during the dry months because their behaviour is just a ‘ghost’ of their recent past, when they were ‘normal’ spitting cobras of dry savana regions, which were thus constrained to aestivate during the dry season as it is the rule in this species in central and northern Nigeria. The ‘gost-of-the-past hypothesis’ seems to fit well with the ‘invading’ presence of Naja nigricollis in Nigerian areas where they were reported as rare or, even, absent, up to a few decades ago. Other hypotheses are discussed, and rejected.     

Application of traditional ecological knowledge in the management and sustainability of fisheries in East Africa: a long-neglected strategy?

Management and sustainability of fisheries has been guided by theories and models derived from modern ecological science. Traditional ecological knowledge (TEK) has been ignored in all spheres of decision-making for management and sustainability of fisheries in East Africa. TEK guided African communities in the way they associated and interacted with the natural environment around them. Spiritual rituals, religious practices, social taboos and sacred animal totems guided the peoples on how and when to utilize the available natural resources. In the advent of modern scientific knowledge, the African traditional knowledge quickly faded away and is generally seen as irrelevant. Today the potential of TEK in the management and sustainability of fisheries in East Africa has not been realized and its status and future is unknown. TEK should be complementary to modern scientific knowledge in the management and sustainability of fisheries. This paper therefore focuses on the potential application of TEK in the management and sustainability of fisheries in East Africa and the issues that impede its application.     

In Situ Enrichment of a Diverse Community of Bacteria from a 4–5 km Deep Fault Zone in South Africa

The extreme environment of South Africa's ultra-deep gold mines offers an opportunity to discover novel microorganisms (e.g., Alkaliphilus transvaalensis), including extremophiles that may provide insight into the origins of life on earth and offer industrial applications because of their thermophilic enzymatic properties. This study employed culture-independent methods to examine the bacterial diversity in water (T = 55° C, pH = 9, Cl^? = 1000 ppm and age = 4–53 Ma) emanating from an exploration borehole in a South African Au mine that intersected a quartzite-hosted fault at 3.3 km below land surface. The more adhesive strains of sulfate reducing bacteria were effectively selected and enriched from the planktonic community by forcing water from a flowing borehole through a sand/agar cartridge that was installed within the borehole. The cartridge's agar contained sulfate and lactate that diffused from the agar into the cartridge. DNA was extracted from the sand, after which a bacterial 16S rDNA gene clone library was generated. Analysis of clone sequences indicated that the groundwater bacterial community was quite diverse, including members of the α-, β-, and γ-Proteobacteria (20%), Actinobacteria (6%), Firmicutes (57%), Chloroflexi (3%), and Deinococcus-Thermus (14%) phyla. One of the most frequently detected clone types was associated with Desulfotomaculum (a known SRB). Another predominant clone type was closely related to Meiothermus cerbereus. A proportion of Proteobacteria clones were closely related to Ralstonia, Alishewanella, Hydrogenophaga, or Methylobacterium species. Some of the Firmicutes clones were closely related to Alkaliphilus transvaalensis, which was isolated from a nearby South African Au mine, or to Clostridium thermocellum. Of the total 21 OTUs identified from the cartridge sand, 6 most likely represent novel species of Firmicutes given their dissimilarity to other 16S rDNA sequences in the GenBank database.     

Epidemiology of Kaposi’s sarcoma in sub-Saharan Africa

Kaposi’s sarcoma (KS) has become a common AIDS-defining cancer in sub-Saharan Africa. Kaposi’s sarcoma-associated human herpesvirus strongly modulated by HIV-related immune suppression are the principal causes of this cancer. No other risk factors have been identified as playing a strong role. HIV prevention programs and good coverage of antiretroviral therapy (ART) in developed countries resulted in a remarkable decline in HIV-KS incidence and better KS prognosis. By contrast, in sub-Saharan Africa, population ART rollout has lagged, but clinical studies have shown positive results in reduction of KS incidence and better KS prognosis. However, the effect of ART rollout in relation to population KS incidence is unclear. We describe the incidence of KS in sub-Saharan Africa, in four time-periods, (1) before 1980 (before HIV/AIDS era); (2) 1981–2000 (early HIV/AIDS era, limited or no ART coverage); (3) 2001–2010 (early ART coverage period); and (4) 2011–2016 (fair to good ART coverage period). We used KS incidence data available from WHO-International Agency for Research on Cancer (IARC) publications and the Africa Cancer Registry Network. National HIV prevalence and ART coverage data were derived from UNAIDS/WHO. A rapid increase in KS incidence was observed throughout sub-Saharan Africa as the HIV epidemic progressed, reaching peak incidences in Period 2 (pre-ART rollout) of 50.8 in males and 20.3 per 100 000 in females (Zimbabwe, Harare). The overall unweighted average decline in KS incidence between 2000 and 2010 and 2011–2016 was 27%, but this decline was not statistically significant across the region. ART rollout coincides with a decline in KS incidence across several regions in sub-Saharan Africa. The importance of other risk factors such as reductions in HIV incidence could not be ascertained.     

Towards diversity in genomics: The emergence of neurogenomics in Africa?

There is a high burden of mental and neurological disorders in Africa. Nevertheless, there appears to be an under-representation of African ancestry populations in large-scale genomic studies. Here, we evaluated the extent of under-representation of Africans in neurogenomic studies in the GWAS Catalog. We found 569 neurogenomic studies, of which 88.9% were exclusively focused on people with European ancestry and the remaining 11.1% having African ancestry cases included. In terms of population, only 1.2% of the total populations involved in these 569 GWAS studies were of African descent. Further, most of the individuals in the African ancestry category were identified to be African-Americans/Afro-Caribbeans, highlighting the huge under-representation of homogenous African populations in large-scale neurogenomic studies. Efforts geared at establishing strong collaborative ties with European/American researchers, maintaining freely accessible biobanks and establishing comprehensive African genome data repositories to track African genome variations are critical for propelling neurogenomics/precision medicine in Africa.     

Different wintering strategies of two Palearctic migrants in West Africa – a consequence of foraging strategies?

The wintering strategies of Pied Flycatchers Ficedula hypoleuca and Willow Warblers Phylloscopus trochilus in their West African winter quarters were compared. Pied Flycatchers arrived early in the season (September) and stayed in the study area throughout the winter. They were territorial and showed a high return rate. Intraspecific relationships were mostly expressed by territorial behaviour. Interspecific relations seemed to be unimportant. Willow Warblers arrived relatively late (November) and were absent from the area for some weeks in January and February, a behaviour which was interpreted as itinerancy. Willow Warblers were non-territorial and never returned to a site. Willow Warblers usually moved through the area in monospecific or mixed-species flocks. Habitat and microhabitat choice of these species were similar but in feeding ecology they differed by the higher diversity of feeding substrates and feeding techniques of Pied Flycatchers. The differences in the winter strategies are explained by the ability of Pied Flycatchers to defend a territory because of their diversity in foraging behaviour, whereas Willow Warblers are more specialized and are therefore forced to be more mobile to find their patchily distributed food.     

Origin of pre‐islamic architecture in West‐Africa

’Cultural theory’, launched by social anthropologist Mary Douglas, has been highly influential in the inter‐disciplinary field concerned with the study of risk perception and risk communication. The theory derives from the grid‐group analyses that Douglas developed in the 1970s. Cultural theory aims to explain universal ‘cultural bias’ by way of a general typology of group formation and a concomitant cosmology or world view. This article critically examines cultural theory and the study of hazards as culturally construed phenomena.     

Highly conserved tooth morphology in allopatric elasmobranch populations despite contrasting diets—a case of Triakis megalopterus in southern Africa

Environmental Biology of Fishes - The role dentition plays in shaping feeding patterns has significant consequences for understanding the evolution of shark feeding. Despite this, research has...     

The Meaning of ‘Self-Starvation’ in Impoverished Black Adolescents in South Africa

Recent surveys in South Africa have demonstrated that disordered eating is equally common among black and white female students. Self-report measures have been used in these surveys to establish levels of disordered eating. One study in Tanzania, where a two-stage design was implemented, showed that upon interview the majority of participants did not present with disordered eating. The absence of two-stage studies in South Africa brings into question some of the findings from these surveys. In the present study, we surveyed a sample of black and white high school students in South Africa to establish the prevalence of disordered eating. In the second phase of this study, we attempted to interview those black students from one particular school who scored high on the eating disorder measures. This process proved both challenging and elucidating. While a significant number of young black females endorsed eating disorder symptoms on self-report, interviews with some participants showed that self-starvation and related symptoms had a different meaning from what we would typically expect from someone with an eating disorder. Consequently, this study highlights the need to revisit the methods typically employed in cross-cultural research in eating disorders. Careful consideration of a variety of cultural factors that may alter the meaning of standard measures is called for.     

‘Testing Together Challenges the Relationship’: Consequences of HIV Testing as a Couple in a High HIV Prevalence Setting in Rural South Africa

Objective

We conducted qualitative individual and combined interviews with couples to explore their experiences since the time of taking an HIV test and receiving the test result together, as part of a home-based HIV counselling and testing intervention.

Methods

This study was conducted in October 2011 in rural KwaZulu-Natal, South Africa, about 2 years after couples tested and received results together. Fourteen couples were purposively sampled: discordant, concordant negative and concordant positive couples.

Findings

Learning about each other’s status together challenged relationships of the couples in different ways depending on HIV status and gender. The mutual information confirmed suspected infidelity that had not been discussed before. Negative women in discordant partnerships remained with their positive partner due to social pressure and struggled to maintain their HIV negative status. Most of the couple relationships were characterized by silence and mistrust. Knowledge of sero-status also led to loss of sexual intimacy in some couples especially the discordant. For most men in concordant negative couples, knowledge of status was an awakening of the importance of fidelity and an opportunity for behaviour change, while for concordant positive and discordant couples, it was seen as proof of infidelity. Although positive HIV status was perceived as confirmation of infidelity, couples continued their relationship and offered some support for each other, living and managing life together. Sexual life in these couples was characterized by conflict and sometimes violence. In the concordant negative couples, trust was enhanced and behaviour change was promised.

Conclusions

Findings suggest that testing together as couples challenged relationships in both negative and positive ways. Further, knowledge of HIV status indicated potential to influence behaviour change especially among concordant negatives. In the discordant and concordant positive couples, traditional gender roles exposed women’s vulnerability and their lack of decision-making power.     

Yields and accumulations of N and P in farmer-managed intercrops of maize–pigeonpea in semi-arid Africa

Maize (Zea mays L.) is a major staple food in Sub-Saharan Africa but low soil fertility, limited resources and droughts keep yields low. Cultivation of maize intercropped with pigeonpea (Cajanus cajan L. Millsp.) is common in some areas of eastern and southern Africa. The objectives of this study were (1) to investigate dry matter, nitrogen (N) and phosphorus (P) accumulation in different plant components of maize–pigeonpea intercropping systems and (2) to report the effects of the intercrops on soil fertility. Maize–pigeonpea intercrops were compared to sole maize grown using farmersȁ9 practices. Intercropping maize and pigeonpea increased (P < 0.05) total system yield compared to sole maize in terms of biomass, N and P accumulation. Pigeonpea planted in maize did not reduce (P < 0.05) the accumulation of dry matter, N nor P in the maize grain. The harvest indices of maize, calculated on basis dry matter, N or P did not differ either (P < 0.05). Total soil C and N contents and inorganic N content, nitrate and ammonium, were not affected by two seasons of maize–pigeonpea intercropping compared to sole maize (P > 0.11). Nitrate and ammonium levels in soil were still not affected by the treatments after the soils were incubated in anaerobic conditions for 8 days at 37°C (P > 0.11). However, pigeonpea added up to 60 kg of N ha⁻¹ to the system and accumulated up to 6 kg of P ha⁻¹ and only 25% of this N and P were exported in the grain. In conclusion, beside the added grain yield of pigeonpea in the intercropped systems, pigeonpea increased the recirculation of dry matter, N and P, which may have a long-term effect on soil fertility. Furthermore, the stems from pigeonpea contributed to household fuel wood consumption. The intercropped system thus had multiple benefits that gave significant increase in combined yield per unit area without additional labour requirements. The main requirement in order to up-scale the maize–pigeonpea intercropping approach is sufficient supply of high-quality pigeonpea seeds.     

Epidemiology of Staphylococcus aureus Bacteraemia at a Tertiary Children’s Hospital in Cape Town,South Africa

Background

Staphylococcus aureus is an important pathogen in paediatric patients with bloodstream infections. The epidemiology of S. aureus bacteraemia, however, has not been well documented in children in South Africa.

Methods

A retrospective study was conducted at a children’s hospital in Cape Town, South Africa, to investigate the epidemiology of S. aureus bacteraemia from 2007-2011. The incidence, clinical presentation, risk factors, management and outcomes of methicillin sensitive S. aureus (MSSA) and methicillin resistant S. aureus (MRSA) bacteraemia were compared.

Results

Over the five year study period, 365 episodes of S. aureus bacteraemia were identified. The annual incidence was 3.28 cases per 1000 hospital admissions. MRSA was responsible for 26% of S. aureus bacteraemia and 72% of nosocomial infections. Only six possible cases of community-acquired MRSA infections were described. MSSA bacteraemia was more likely to present as pulmonary and bone or joint infections, while bacteraemia without a source was the most common presentation with MRSA.  Infants, children with malnutrition, and residents of long-term care facilities were at highest risk for MRSA bacteraemia. The overall case fatality rate for S. aureus bacteraemia was 8.8% over five years, with MRSA being the only significant risk factor for mortality.

Conclusion

The incidence of S. aureus bacteraemia and MRSA bacteraemia in children has remained stable over the past five years. MRSA is a predominantly nosocomial pathogen in children with S. aureus bacteraemia in Cape Town, South Africa.     

Nucleotide sequence evidence of the unicentric origin of the βC mutation in Africa

Summary The origin of the ^C mutation was studied by characterizing nucleotide sequence polymorphisms on ^C chromosomes of patients from various African countries. In the majority of cases, the ^C mutation was found in linkage disequilibrium with a single chromosomal structure as defined by classical RFLP haplotypes, intergenic nucleotide sequence polymorphisms immediately upstream of the -globin gene, and intragenic -globin gene polymorphisms (frameworks). In addition, three atypical variant chromosomes carrying the ^C mutation were observed, and are most probably explained either by a meiotic recombination (two cases) or by one nucleotide substitution occurring in an unstable array of tandemly repeated sequences (one case). These data demonstrate the unicentric origin of the ^C mutation in central West Africa, with subsequent mutational modification in a small number of instances. The data also supports gene flow of the ^C chromosome from subsaharan Africa to North Africa.     

What limits fire? An examination of drivers of burnt area in Southern Africa

The factors controlling the extent of fire in Africa south of the equator were investigated using moderate resolution (500 m) satellite-derived burned area maps and spatial data on the environmental factors thought to affect burnt area. A random forest regression tree procedure was used to determine the relative importance of each factor in explaining the burned area fraction and to address hypotheses concerned with human and climatic influences on the drivers of burnt area. The model explained 68% of the variance in burnt area. Tree cover, rainfall in the previous 2 years, and rainfall seasonality were the most important predictors. Human activities – represented by grazing, roads per unit area, population density, and cultivation fraction – were also shown to affect burnt area, but only in parts of the continent with specific climatic conditions, and often in ways counter to the prevailing wisdom that more human activity leads to more fire. The analysis found no indication that ignitions were limiting total burnt area on the continent, and most of the spatial variation was due to variation in fuel load and moisture. Split conditions from the regression tree identified (i) low rainfall regions, where fire is rare; (ii) regions where fire is under human control; and (iii) higher rainfall regions where burnt area is determined by rainfall seasonality. This study provides insights into the physical, climatic, and human drivers of fire and their relative importance across southern Africa, and represents the beginnings of a predictive framework for burnt area.     

Behavioral diversity in populations of free-ranging chimpanzees in Africa: is it culture?

Behavioral differences exist among populations of wild chimpanzees (Pan troglodytes, Hominoidea) across Africa. Deciding if these are cross-cultural differences demands careful interpretation and rigorous scrutiny. Even standard patterns like social grooming may show variation in detail between neighboring populations. Some patterns of tool use, such as using hammers to crack nuts, also vary across far western Africa. At least 37 populations of free-ranging chimpanzees show tool use, and 14 show at least one habitual pattern of tool use. Regional differences exist among the three subspecies or geographical races of chimpanzees. Convincing empirical demonstration of social customs and traditions in non-human species is problematical, and even something so simple in principle as innovation is hard to show in practice. However, culture need not depend on imitation, teaching, or language, either in humans or in other species.     

Effects of tree clumps on soil characteristics in a humid savanna of West Africa (Lamto,Côte d'Ivoire)

The effect of tree clumps on soil characteristics was investigated in a humid savanna (Lamto, Côte d'Ivoire). Soil texture and field capacity were not significantly different under tree clumps compared to open grassland. On the other hand, bulk density was lower under tree clumps, likely due to a greater soil fauna activity under the trees. The pH, available phosphorus, cation exchange capacity, total carbon and total nitrogen contents were higher under tree clumps due to greater organic matter input beneath canopies. Potential soil respiration and mineral nitrogen accumulation were also enhanced, indicating a higher potential microbial activity under tree clumps. Soil water content was slightly lower beneath canopies (from July to November only between 0 and 10 cm depth) when soil moisture was above field capacity. During the other months, no significant difference was measured.