Seasonal Flooded Forests and Shifting Bushmeat Dynamics in West Africa: Opportunistic Consumption of Snakes and Other Reptiles in Itu Wetlands, Nigeria

BackgroundAfrican swine fever (ASF) causes severe socio-economic impacts due to high mortality and trade restrictions. Many risk factors of ASF have been identified at farm level. However, understanding the risk factors, especially wild suid hosts, determining ASF transmission at regional level remains limited.MethodsBased on ASF outbreak data in domestic pigs during 2006–2014, we here tested, separately for West and East Africa, which risk factors were linked to ASF presence at a regional level, using generalized linear mixed models.ResultsOur results show that ASF infections in the preceding year was an important predictor for ASF presence in both West and East Africa. Both pig density and human density were positively associated with ASF presence in West Africa. In East Africa, ASF outbreaks in domestic pigs were also correlated with higher percentages of areas occupied by giant forest hogs and by high-tick-risk areas.ConclusionsOur results suggest that regional ASF risk in East Africa and in West Africa were associated with different sets of risk factors. Regional ASF risk in West Africa mainly followed the domestic cycle, whereas the sylvatic cycle may influence regional ASF risk in East Africa. With these findings, we contribute to the better understanding of the risk factors of ASF occurrence at regional scales that may aid the implementation of effective control measures.

BackgroundThe HIV-1 epidemic in sub-Saharan Africa is heterogeneous with diverse unevenly distributed subtypes and regional differences in prevalence. Subtype-specific differences in disease progression rate and transmission efficiency have been reported, but the underlying biological mechanisms have not been fully characterized. Here, we tested the hypothesis that the subtypes prevalent in the East Africa, where adult prevalence rate is higher, have lower viral replication capacity (VRC) than their West African counterparts where adult prevalence rates are lower.ResultsGag-protease sequencing was performed on 213 and 160 antiretroviral-naïve chronically infected participants from West and East Africa respectively and bioinformatic tools were used to infer subtypes and recombination patterns. VRC of patient-derived gag-protease chimeric viruses from West (n = 178) and East (n = 114) Africa were determined using a green fluorescent protein reporter-based cell assay. Subtype and regional differences in VRC and amino acid variants impacting VRC were identified by statistical methods. CRF02_AG (65%, n = 139), other recombinants (14%, n = 30) and pure subtypes (21%, n = 44) were identified in West Africa. Subtypes A1 (64%, n = 103), D (22%, n = 35), or recombinants (14%, n = 22) were identified in East Africa. Viruses from West Africa had significantly higher VRC compared to those from East Africa (p < 0.0001), with subtype-specific differences found among strains within West and East Africa (p < 0.0001). Recombination patterns showed a preference for subtypes D, G or J rather than subtype A in the p6 region of gag, with evidence that subtype-specific differences in this region impact VRC. Furthermore, the Gag A83V polymorphism was associated with reduced VRC in CRF02_AG. HLA-A*23:01 (p = 0.0014) and HLA-C*07:01 (p = 0.002) were associated with lower VRC in subtype A infected individuals from East Africa.ConclusionsAlthough prevalent viruses from West Africa displayed higher VRC than those from East Africa consistent with the hypothesis that lower VRC is associated with higher population prevalence, the predominant CRF02_AG strain in West Africa displayed higher VRC than other prevalent strains suggesting that VRC alone does not explain population prevalence. The study identified viral and host genetic determinants of virus replication capacity for HIV-1 CRF02_AG and subtype A respectively, which may have relevance for vaccine strategies.

There is considerable regional variation in the incidences of ovarian cancer (OC); Europe and North America have the highest rate of 10.1 and 8.7 per 100,000 respectively whereas Japan and developing countries present with lowest incidences. Recent studies showed that West and East Africa women have high proportion of non-epithelial ovarian cancer, 30% and 39.5% from West and East Africa women respectively compared to 14%, 12%, 3% and 4.12% from US Born Black, Caribbean Born Black, US Born white and Alberta women, respectively. Africa women with epithelial ovarian cancer (EOC) presented at a lower age group; median age of 52.5 years compared with 59 years and above for the other group of women. The objective of the study was to evaluate a large cohort of OC tumors from West Africa, Nigeria to determine the patients’ demographics, the diagnostic accuracy and the tumor histotypes with the aim at identifying opportunities to improve the OC diagnosis in Africa and long-term goal of reduction in mortality and morbidity associated with the disease condition. This is a multi-centered retrospective study of OC involving 19 tertiary health institutions in West Africa, Nigeria over a period of 3 years (2017-2019). The histological records were accessed with the retrieval of patients’ demographics, original diagnosis and formalin fixed paraffin embedded (FFPE) tissue blocks of the corresponding patients. The FFPEs were sent to the collaborating institution, Division of Gynecological Oncology, Miller School of Medicine, University of Miami, Florida for further diagnostic appraisal. All FFPEs were sectioned, stained with hematoxylin and eosin (H&amp;E) and reviewed by two pathologists. Immunohistochemistry (IHC) was performed on cases in which the morphology features were not diagnostic. A total of 422 FFPE ovarian tissue blocks were reviewed, corresponding to 377 patients. 238 (63.1%) of the cases fulfilled criteria for inclusion such as documentation of original diagnosis, presence of tumor on the slides, and interpretable morphologic features. 95 (39.9%) cases had some changes in their diagnosis. 5 cases (2.1%) had a complete change from malignant tumor to benign or borderline. IHC was required to perform differential diagnosis in 42 (44.2%) while the remaining 55 (56.8%) cases were made after histological secondary review. Epithelial ovarian cancer was 48.3% (115) of cases while non-epithelial ovarian cancer cases were 41 (36.4%) and other malignancies such as sarcoma, metastasis and hematological neoplasm accounted for the remaining 60 (25.2%) with 35 (58.3%) of the cases being metastatic tumors to the ovary. Our findings confirmed that West African women have a lower percentage of EOC compared to East Africa and North America women. We further demonstrated that secondary review of surgical pathology cases in a sub-specialized academic center and the use of ancillary techniques such as IHC may improve the diagnosis accuracy of OC in a low resource country. There would be need to incorporate this into the management of OC in low resource countries. Citation Format: Ayodele Joshua Omotoso. Higher incidence of rare ovarian tumors in West Africa [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr A083.

UC Berkeley Phonology Lab Annual Report (2013) Nicholas Rolle UC Berkeley “Nasal vowel patterns in West Africa” 1 n.rolle@berkeley.edu 1. I NTRODUCTION Nasal vowels are a common feature of West African phonologies, and have received a significant amount of attention concerning their (suprasegmental) representation, their interaction with nasal consonants, and their phonetic realization. Numerous authors have presented surveys of varying degrees of (targeted) depth which address the distribution of contrastive nasal vowels in (West) Africa, including Hyman (1972), Williamson (1973), Ruhlen (1978), Maddieson (1984, 2007), Clements (2000), Clements & Rialland (2006), and Hajek (2011). Building on this literature, this present study provides a more extensive survey on contrastive nasal vowels in West Africa, and specifically studies the types of systematic gaps found. For example, the language Togo-Remnant language Bowili has a 7 oral vowel inventory canonical of West Africa /i e ɛ a ɔ o u/, as well as a full set of nasal counterparts /ĩ ẽ ɛ a ɔ o ũ/ (Williamson 1973). In contrast, the Gur language Bariba has the same 7 oral vowel inventory, though a more limited nasal set /ĩ ɛ a ɔ ũ/, missing mid-high vowels */ẽ o/ (Hyman 1972:201). Using this as a starting point, this paper addresses the following questions: What are the recurring patterns one finds in West African nasal vowel systems and inventories? o What restrictions are there on mid vowels in the nasal inventory? In which families/areal zones do we find these patterns? To which factors can we attribute these patterns? o Genetic – Vertical inheritance o Areal – Horizontal spread o Universal Phonetic – Parallel Developments How do these patterns manifest in the phonologies of these languages o E.g. Restrictions of (co-)occurrences Are these patterns anomalous or expected when viewed in a cross-linguistic perspective? This paper presents a survey of 168 languages and language clusters, incorporating previous studies on nasal vowels cross-linguistically, and nasal vowels in (West) Africa. This study finds that nasality is pervasive across the region, and does not align well with genetic classification. Both the presence and absence of contrastive nasal vowels is shown in Atlantic groups, Gur groups, Mande, Kru, Kwa/Gbe groups, and Benue-Congo groups, including Igboid, Defoid, Edoid, Plateau/Kainji, Nupoid, Cross River, etc. This strongly suggests [1] areal spread introducing/initiating contrastive nasal vowels or nasal loss, [2] independent innovation/loss of contrastive nasal vowels, or [3] both. In addition, this present survey is unique in coding for the presence/absence of high-mid nasal vowels /ẽ o/, which have been described by many authors as rare in West Africa. This This paper is a working draft stemming from a large-scale project on nasal vowels cross-linguistically. Initial thanks to Larry Hyman, Matt Faytak, Florian Lionnet, Lev Michael, Zachary O'Hagan, Roger Blench, Stuart McGill, and Otelemate Harry. All comments very much welcome!

A series of studies established that HIV infection in humans originated from multiple episodes of zoonotic transmission of CD4 T cell-tropic lentiviruses infecting African monkey species—Simian Immunodeficiency Viruses (SIV). HIV-1...

Ebola: worldwide dissemination risk and response priorities

To identify which British residents travelling abroad are at greatest risk of malaria infection, and to determine the efficacy of malaria chemoprophylaxis for preventing P falciparum infections in tropical Africa. Prospective cohort study (case-base linkage) with routine national surveillance systems. Denominators (base population) were obtained from monitoring a random sample of returning British travellers with the international passenger survey. Numerators (cases) were obtained from reports of malaria infections in British residents, through the Malaria Reference Laboratory network. International passenger survey conducted at passport control of international airports in Britain. Malaria reports received nationally were collated centrally in London. 2948 British residents (0.2%) returning to Britain in 1987 randomly selected and questioned and 1052 British residents with microscopically confirmed malaria infections in 1987, whose case reports were reviewed and on whom additional data were collected by postal survey. Annual incidence subdivided by categories of risk. Chemoprophylactic efficacy for east and west Africa by principal regimens and compliance. Annual rates of reported infection per 100,000 travellers to Oceania were 4100; to west and east Africa were 375 and 172 respectively; to Latin America, the Far East, and the Middle East were 12, 2, and 1 respectively. Immigrants visiting friends and relatives in Ghana and Nigeria were at greatest risk (1303 and 952 per 100,000 respectively) in west Africa. Business travellers to Kenya experienced the highest attack rates in east Africa (465 per 100,000). Age-sex specific attack rates varied by region. No prophylaxis was reported to have been used by 23% of British visitors to west Africa, 17% to east Africa, 46% to central or southern Africa, and 58% visiting south Asia. The efficacy of chloroquine plus proguanil against P falciparum infection was 73% and 54% in west and east Africa respectively. Lower values were obtained for chloroquine alone and proguanil alone. The efficacy of Maloprim (pyrimethamine-dapsone) was 61% in west Africa, but only 9% in east Africa. Visitors to west Africa who did not comply with their chemoprophylactic regimen were at a 2.5-fold higher risk of infection than fully compliant users. Non-compliant visitors to east Africa had similar rates of infection as non-drug users. In 1987 chloroquine plus proguanil was the preferred chemoprophylactic regimen for P falciparum infection in Africa; antimalarial drugs must be taken regularly to be effective.

This review provides a comparative historical analysis of malaria incidence across West and East Africa, focusing on the unique trends, environmental influences, and socio-political conditions that shape malaria transmission dynamics in these regions. While malaria poses a pervasive public health burden across Africa, West and East Africa differ significantly in terms of climate, healthcare infrastructure, socio-economic status, and malaria control strategies, each influencing regional patterns of malaria incidence. West Africa’s tropical climate fosters year-round transmission, while East Africa, with its diverse topography, experiences seasonal and altitudinal variations in transmission patterns. Historical approaches to malaria control in both regions reveal numerous challenges, including limited healthcare access, economic constraints, and socio-political instability, all of which have impacted the effectiveness of interventions. Through comparative analysis, this review examines the successes and limitations of past and current malaria control efforts, emphasizing the need for region-specific approaches that address climate-adapted interventions, insecticide and drug resistance management, community engagement, and sustainable funding. By analyzing historical and contemporary malaria control strategies, this review highlights best practices and challenges, offering insights for future policies aimed at reducing malaria incidence sustainably and advancing regional public health. Keywords: Malaria incidence, West Africa, East Africa, malaria transmission, public health.

The measles campaign in West and Central Africa: Remembering the future

The underlying motivation of this study is to account for the spatial variation of factors affecting women’s access to land, which has been largely ignored by the traditional regression-based model studies, much to the detriment of spatially varying relationships. Using household and individual-level data from the Demographic and Health Surveys (DHS), this study used Geographically Weighted Regression to explore and analyze the spatial relationships between women’s access to own or family land and determinants that influence women’s access to land in Africa. The results demonstrated that HIV-positive women in West Africa and Ethiopia were more likely to have access to own land than family land. Educated women in North, West and Southern Africa were less likely to have access to own land than their non-educated counterparts. Population density exhibited predominantly negative influence over women’s access to both own and family land. The relationship between rural areas and women’s access to their own land was mostly not significant across the continent. However, both rural and urban women in West Africa and Ethiopia were negatively associated with access to family land. Women within the 15–24 age group in West, Central and East Africa were more likely to have access to own land than family land, while those within the 25–34 and 35–49 age groups had a better chance of gaining access to family than own land, with the results being significant in Southern, West and North Africa. While some of the reasons for these variations have been discussed in this paper there is still need for further investigation particularly focusing on smaller regions since this study shows that women’s access to land changes as one crosses geographical boundaries even within the same country.

Ebola virus disease (EVD) is a complex zoonosis that is highly virulent in humans. The largest recorded outbreak of EVD is ongoing in West Africa, outside of its previously reported and predicted niche. We assembled location data on all recorded zoonotic transmission to humans and Ebola virus infection in bats and primates (1976–2014). Using species distribution models, these occurrence data were paired with environmental covariates to predict a zoonotic transmission niche covering 22 countries across Central and West Africa. Vegetation, elevation, temperature, evapotranspiration, and suspected reservoir bat distributions define this relationship. At-risk areas are inhabited by 22 million people; however, the rarity of human outbreaks emphasises the very low probability of transmission to humans. Increasing population sizes and international connectivity by air since the first detection of EVD in 1976 suggest that the dynamics of human-to-human secondary transmission in contemporary outbreaks will be very different to those of the past.DOI: http://dx.doi.org/10.7554/eLife.04395.001

The Neotropical invasive plant Chromolaena odorata R.M. King and H. Robinson (Asteraceae) is a serious weed in West and Central Africa and two biological control agents that have been introduced into West Africa to help reduce its impacts on agriculture and biodiversity, have established. The stem-galling fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae), has spread widely across West Africa since its release in only Côte d’Ivoire, occurring in six countries. This study aimed to investigate whether the gall fly had spread further across West Africa and into Central Africa. Here, we surveyed C. odorata for C. connexa galls in Cameroon between October 2018 and October 2020, along roadsides, on farms, residential areas, and abandoned plots, encompassing various vegetation types. Additional surveys were conducted across four countries (Ghana, Togo, Benin Republic and Nigeria) in West Africa that we considered the probable pathway for the spread of the gall fly into Central Africa. Cecidochares connexa was present at five of the six locations surveyed in Cameroon, albeit in varying abundance. In Africa, these findings represent the first-ever report of C. connexa outside of West Africa. In West Africa, we recorded significant expansion in the geographic range of C. connexa, as reflected in the absent-present record of C. connexa in two locations in Nigeria and one in Ghana, as well as its occurrence in all locations surveyed in Benin Republic and Togo. Clearly, Ghana, Togo, Benin Republic and Nigeria served as the dispersal pathway of C. connexa from the release sites in Côte d’Ivoire into Cameroon, covering over 2,300 km. Following the spread and establishment of C. connexa into Cameroon, we anticipate that it will continue to spread further into other parts of Central Africa which are climatically suitable. Cecidochares connexa is currently the only biological control agent for C. odorata in Central Africa. Given that it has significantly reduced populations of C. odorata in other countries where it has established, it is expected to have a similar impact in Central Africa.

Effectiveness of screening for Ebola at airports

In West and Central Africa, countries with high rates of emigration and immigration tend to have higher rates of HIV infection. However, there is one exception, Senegal, an exception demonstrating that high levels of mobility and migration do not necessarily lead to rapid and extensive spread of HIV infection.Five different population groups are considered in this article, either because their numbers are substantial or because their role in the spread of HIV and STDs is known to be important. They are migrant labourers, truck drivers, itinerant traders, commercial sex workers (CSWs), and refugees.It is difficult to estimate numbers of migrant labourers but they are common in West Africa. Principal migration routes flow towards the coast, with three coastal countries constituting the main centres of immigration: Senegal, Nigeria and Côte d’Ivoire. In Central Africa, the most prominent are between Cameroon, Congo, Gabon and the Democratic Republic of Congo (formerly Zaire). The role of truck drivers in the spread of HIV/STDs is well documented in East Africa, but less so in West and Central Africa. Itinerant trading is often a major economic activity for women. Itinerant women traders may be especially vulnerable to infection with HIV and other STDs since their trading activities often involve travelling long distances without their families and selling sexual services to supplement their other trading activities. In West and Central Africa, prostitutes constitute a particular type of migrant, many of whom travel on an international scale. Prostitutes from Senegal and Guinea Bissau work in Gambia, those from Togo work in Côte d’Ivoire, and those from Ghana work in Benin, Senegal and Côte d’Ivoire. Finally, the continent has seen large‐scale refugee movements in recent years.The research indicates a complex relationship between migration and HIV infection. Clearly not all migrants have the same risk of infection and thus do not contribute equally to the spread of HIV. However, there is little analysis to date on the influences of different types of migration (which might be characterized by duration, frequency of return visits, living conditions, etc.) on the spread of HIV infection. Strong associations between migration and HIV seropositivity have suggested to various authors that migrant workers may be more involved in sexual activities with multiple partners, particularly while away from their home environment. However, few studies verify this hypothesis directly.Practical strategies for preventing the spread of HIV/AIDS among migrant populations in West and Central Africa must aim at providing information before departure, along the communication routes, at the final destination and at the time of their return journey. The degree of concentration at each stage will depend on the characteristics of the population. For example, male migrants should be informed before departure of the risk they take by having non‐protected sexual contacts during their absence. This is perhaps the most effective strategy for truck drivers and seasonal migrant labourers. Whatever strategy is used, however, solid collaboration will be required between countries, particularly with respect to information and prevention campaigns, and to the avoidance of stigmatization of any group of individuals.

Avian influenza viruses (AIVs) of the H9N2 subtype have become widespread in Western Africa since their first detection in 2017 in Burkina Faso. However, the genetic characteristics and diffusion patterns of the H9N2 virus remain poorly understood in Western Africa, mainly due to limited surveillance activities. In addition, Mali, a country considered to play an important role in the epidemiology of AIVs in the region, lacks more comprehensive data on the genetic characteristics of these viruses, especially the H9N2 subtype. To better understand the genetic characteristics and spatio-temporal dynamics of H9N2 virus within this region, we carried out a comprehensive genetic characterization of H9N2 viruses collected through active surveillance in live bird markets in Mali between 2021 and 2022. We also performed a continuous phylogeographic analysis to unravel the dispersal history of H9N2 lineages between Northern and Western Africa. The identified Malian H9N2 virus belonged to the G1 lineage, similar to viruses circulating in both Western and Northern Africa, and possessed multiple molecular markers associated with an increased potential for zoonotic transmission and virulence. Notably, some Malian strains carried the R-S-N-R motif at their cleavage site, mainly observed in H9N2 strains in Asia. Our continuous phylogeographic analysis revealed a single and significant long-distance lineage dispersal event of the H9N2 virus to Western Africa, likely to have originated from Morocco in 2015, shaping the westward diffusion of the H9N2 virus. Our study highlights the need for long-term surveillance of H9N2 viruses in poultry populations in Western Africa, which is crucial for a better understanding of virus evolution and effective management against potential zoonotic AIV strain emergence.