Ostrich eggshell beads reveal 50,000-year-old social network in Africa

Humans evolved in a patchwork of semi-connected populations across Africa1,2; understanding when and how these groups connected is critical to interpreting our present-day biological and cultural diversity. Genetic analyses reveal that eastern and southern African lineages diverged sometime in the Pleistocene epoch, approximately 350–70 thousand years ago (ka)3,4; however, little is known about the exact timing of these interactions, the cultural context of these exchanges or the mechanisms that drove their separation. Here we compare ostrich eggshell bead variations between eastern and southern Africa to explore population dynamics over the past 50,000 years. We found that ostrich eggshell bead technology probably originated in eastern Africa and spread southward approximately 50–33 ka via a regional network. This connection breaks down approximately 33 ka, with populations remaining isolated until herders entered southern Africa after 2 ka. The timing of this disconnection broadly corresponds with the southward shift of the Intertropical Convergence Zone, which caused periodic flooding of the Zambezi River catchment (an area that connects eastern and southern Africa). This suggests that climate exerted some influence in shaping human social contact. Our study implies a later regional divergence than predicted by genetic analyses, identifies an approximately 3,000-kilometre stylistic connection and offers important new insights into the social dimension of ancient interactions.

Record Longevity and Reproduction of an African Tick, Argas brumpti (Ixodida: Argasidae)

Argas brumpti Neumann is a large argasid (soft) tick that inhabits the drier areas of eastern and southern Africa. This species typically feeds on a wide variety of small to large mammals (including humans) and lizards, and resides in shallow caves, rocky areas, or dust-bath areas used by large mammals. Individuals of this species, collected as nymphs and adults from a semidesert area of Kenya and subsequently maintained under constant conditions in the laboratory, survived for 27 yr. Furthermore, after 8 yr of starvation and at least 4 yr after the last male died, at least one female laid eggs. The progeny developed into considerable numbers of both males and females, some of which are still living after 26 yr. The longevity of these ticks is apparently a record for any species of tick. The delay in reproduction likely represents long-term storage of viable sperm, also apparently a record for any species of tick.

Beyond bacterial vaginosis: vaginal lactobacilli and HIV risk

HIV incidence continues to be unacceptably high in Eastern and Southern Africa, with women disproportionately affected. An increased per-contact risk of HIV acquisition among African, Caribbean, and other Black (ACB) women has been associated with the higher prevalence of bacterial vaginosis (BV) in these communities, wherein the vaginal microbiota is predominated by diverse pro-inflammatory anaerobic bacteria. However, while the vaginal microbiota in BV-free women is typically predominated by one of several different Lactobacillus spp., the degree of HIV protection afforded by a Lactobacillus-predominant vaginal microbiota also varies considerably. Specifically, L. crispatus is associated with an immunoregulatory genital immune environment, exclusion of BV-associated bacteria, and reduced HIV risk. In contrast, less HIV protection or exclusion of BV-associated bacteria and fewer immune benefits have been associated with L. iners—which is unfortunately the most common Lactobacillus species among ACB women. These species-specific clinical differences are underpinned by substantial genomic differences between Lactobacillus species: for instance, the much smaller genome of L. iners lacks the coding sequence for D-lactic acid dehydrogenase and cannot produce the D-lactate isomer that enhances HIV trapping in mucus but encodes for epithelial cell toxins and stress resistance proteins that may enhance bacterial survival in the context of microbiota and environmental fluctuations. While more studies are needed to elucidate whether differences in HIV protection between Lactobacillus species are due to direct genital immune effects or the exclusion of proinflammatory BV-associated bacteria, the current body of work suggests that for BV treatment to succeed as an HIV prevention strategy, it may be necessary to induce a vaginal microbiota that is predominated by specific (non-iners) Lactobacillus species.

Food and medicinal relevance of Cucurbitaceae species in Eastern and Southern Africa

Background The traditional use of medicinal plants is an integral part of African culture and plays a major role in African societies. For centuries, plants have been used to cure diseases and till date, a vast majority of the African people especially in rural communities depend on the use of medicinal plants for the treatment of various ailments. Main body The Cucurbitaceae family has a diversity of medicinally relevant species which also play significant roles in food security in Africa. While some are underutilised and are sourced from the wild, others are domesticated and cultivated for food. This review therefore highlights the significance of Cucurbitaceae species in Eastern and Southern African countries. The use of various species in the traditional food and medicine systems of these countries is documented. The review further discusses some poisonous species with close resemblance to edible plants. The fatal effect of consuming any part of such plant species like young or old leaves and unripe fruit is highlighted. Conclusion This review is thus a documentation of the crucial role of Cucurbitaceae species in food security, treatment of a variety of diseases and its negative effect on humanity and livestock.

The Portable Coup: The Jurisprudence of ‘Revolution’ in Uganda and Nigeria

In the years after independence, former British colonies in eastern and southern Africa struggled to fill the ranks of their judiciaries with African judges. Beginning in the mid-1960s, states including Uganda, Tanzania, and Botswana solved this problem by retaining judges from the Caribbean and West Africa, especially Nigeria. In this same period, a wave of coups brought many independent states under the rule of their militaries (or authoritarian civilian regimes). Foreign judges who had been appointed in the name of pan-African cooperation were tasked with interpreting the laws that soldiers imposed, and assessing the legitimacy of regimes born of coups. The decisions they rendered usually accommodated authoritarianism, but they could also be turned against it. To understand how colonial law and postcolonial solidarities shaped Africa's military dictatorships, this article focuses on one judge, Sir Egbert Udo Udoma of Nigeria, who served as Uganda's first African chief justice and was an influential member of the Nigerian Supreme Court. Udoma and other judges like him traversed the continent in the name of African cooperation, making a new body of jurisprudence as they did so. Their rulings were portable, and they came to underpin military rule in many states, both in Africa and in the wider Commonwealth.