Disease In Africa Research Articles

Ending the burden of sickle cell disease in Africa

Ending the burden of sickle cell disease in Africa

Access to essential therapy for sickle cell disease in Africa: Experience from a national program in Ghana

Novartis, a global medicines company, and the Sickle Cell Foundation of Ghana (SCFG), an advocacy organization, have endeavored to support the implementation of global best practices in the care of people living with sickle cell disease (SCD) in Africa, and to address unmet needs relating to this condition on the continent. Beginning in 2019, a multifaceted SCD program was implemented in Ghana through a public-private partnership involving the government of Ghana, the SCFG, Novartis, and other partners. A key component of the program involved expanding the reach of hydroxyurea (HU), the only approved disease-modifying generic treatment for SCD, in ways that would promote sustainable access. The program helped to raise the profile of SCD in Ghana and, in 2022, the government adopted HU into its National Health Insurance Scheme. Features of the effort in Ghana are now being expanded to other countries in Africa through cocreated programs with in-country partners. This article reviews the program's history, progress, challenges, and lessons learned.

The mystery of an unprecedented plant disease in Africa: The appearance of an Asian strain of bacterial blight in Tanzania threatens rice production in Africa.

A severe outbreak of bacterial blight in East Africa has scientists puzzled about the origin of the pathogen and how to deal with it.

Contribution of cardiovascular disease to the burden of non-communicable diseases in Africa: an analysis of data from Global Burden of Disease database, 1990–2019

Background and purpose: Disease burden of non-communicable diseases (NCDs) has been increasing in low- and middle-income countries, especially in African countries. Cardiovascular disease (CVD) is a common NCDs and the leading cause of death in Africa. Yet, evidence on the contribution of CVD to the total NCDs burden is scarce. This study aimed to investigate the contribution of CVD to the total disease burden caused by NCDs in Africa between 1990 and 2019. Methods: Data on NCDs, including CVD, were extracted from the Global Burden of Disease (GBD) database. Disease burden was measured by disability-adjusted life years (DALYs) and deaths. Results: From 1990 to 2019, the share of CVD in the total NCDs burden increased and remained as the first contributor. In 2019, NCDs caused 204 million DALYs and over 2.18 million deaths in the Africa Union, among which 49.1% of the total DALYs and 66.0% of deaths were caused by the traditional five NCDs, including CVD that accounted for the largest burden of NCDs (20.5% of DALYs and 35.2% of deaths). The proportion of CVD to the total NCDs burden was most considerable, reaching up to 32.4% and 52.4% in Northern Africa for DALYs and deaths, respectively. CVD were important contributors to NCDs burden in Africa, including ischemic heart disease (1334 DALYs per 100,000 and 27.79 deaths per 100,000) and intracerebral hemorrhage (632 DALYs per 100,000 and 13.53 deaths per 100,000) that were the top two causes of NCDs in 2019. Conclusions: CVD has been the biggest contributor to NCDs burden in the Africa Union over the thirty years. Given the increase in the share of NCDs burden attributable to CVD, it demands a close attention to implementing cost-effective policies and interventions for CVD to achieve an improvement in population health and reduction of health loss from NCDs.

Second Soguipit Congress "emerging and re-emerging infectious diseases in Africa: governance, challenges and prospects". 13 - 14 October 2022, Conakry, Guinea

Second Soguipit Congress "emerging and re-emerging infectious diseases in Africa: governance, challenges and prospects". 13 - 14 October 2022, Conakry, Guinea

Pandemic potential of poxviruses: From an ancient killer causing smallpox to the surge of monkeypox.

Smallpox caused by the variola virus (VARV) was one of the greatest infectious killers of mankind. Historical records trace back smallpox for at least a millennium while phylogenetic analysis dated the ancestor of VARV circulating in the 20th century into the 19th century. The discrepancy was solved by the detection of distinct VARV sequences first in 17th-century mummies and then in human skeletons dated to the 7th century. The historical records noted marked variability in VARV virulence which scientists tentatively associated with gene losses occurring when broad-host poxviruses narrow their host range to a single host. VARV split from camel and gerbil poxviruses and had no animal reservoir, a prerequisite for its eradication led by WHO. The search for residual pockets of VARV led to the discovery of the monkeypox virus (MPXV); followed by the detection of endemic smallpox-like monkeypox (mpox) disease in Africa. Mpox is caused by less virulent clade 2 MPXV in West Africa and more virulent clade 1 MPXV in Central Africa. Exported clade 2 mpox cases associated with the pet animal trade were observed in 2003 in the USA. In 2022 a world-wide mpox epidemic infecting more than 80,000 people was noted, peaking in August 2022 although waning rapidly. The cases displayed particular epidemiological characteristics affecting nearly exclusively young men having sex with men (MSM). In contrast, mpox in Africa mostly affects children by non-sexual transmission routes possibly from uncharacterized animal reservoirs. While African children show a classical smallpox picture, MSM mpox cases show few mostly anogenital lesions, low-hospitalization rates and 140 fatal cases worldwide. MPXV strains from North America and Europe are closely related, derived from clade 2 African MPXV. Distinct transmission mechanisms are more likely causes for the epidemiological and clinical differences between endemic African cases and the 2022 epidemic cases than viral traits.

Banana bunchy top disease in Africa—Predicting continent‐wide disease risks by combining survey data and expert knowledge

AbstractAcross Africa, banana bunchy top disease (BBTD) severely impacts banana production and livelihoods of millions of smallholder farmers. Mapping vulnerability of landscapes to monitor BBTD establishment and spread is crucial for proactive measures of disease exclusion. To highlight current and future risks of BBTD in Africa, the relationship between 1160 field observations from 14 BBTD surveys and environmental covariate maps was determined using logistic regression. From these relationships, we inferred the environmental suitability of the African landscape for the possible wider spread of BBTD. Using this information and expert knowledge, we generated a map highlighting the main banana production areas at risk of BBTD entry and establishment. We combined these maps to create a priority map that highlights the areas that need most attention in combating BBTD through surveillance and measures to prevent its spread. Our analysis shows that BBTD is widespread across tropical Africa, with dispersal over several hotspots. Central and Western Africa are most favourable for the development of BBTD. Central, West and South‐East Africa are most at risk of BBTD entry and initial establishment. Areas in West and Central Africa, in the Great Lakes Region in Eastern Africa and in South‐East Africa, particularly in Malawi and Mozambique, score high on the prioritization index for surveillance and mitigation efforts. Recent reports of BBTD presence in north‐western Uganda and western Tanzania support these risk predictions. For these and other not‐yet‐infected areas, measures for close surveillance and proactive management of the disease are needed.

Antischistosomal effects of green and chemically synthesized silver nanoparticles: In vitro and in vivo murine model

Schistosomiasis is one of the most important neglected tropical diseases in Africa, caused by blood fluke, Schistosoma sp. The use of nanotechnology in the treatment of this type of disease is urgently important to avoid the unwanted side effects of chemotherapy. The present study aimed to evaluate the efficacy of green silver nanoparticles (G-AgNPs), fabricated by (Calotropis procera), comparing with both chemically prepared silver ones (C-AgNPs) and Praziquantel (PZQ) treatments. The study included in vitro and in vivo evaluations. In in vitro study, 4 groups of schistosome worms were exposed to treatments as follows: the first one with a dose of PZQ (0.2 µg/ml), the 2nd and 3rd groups with different concentrations of G-AgNPs and C-AgNPs, respectively and the last one act as a negative control group. In in vivo study, six groups of mice were infected and then treated as follows: the first one with a dose of PZQ, the second with G-AgNPs, the third with C-AgNPs, the fourth with G-AgNPs plus a half dose of PZQ, the fifth with C-AgNPs accompanied by a half dose of PZQ, and the last group acted as a positive control group. The parasitological (worm burden, egg count & oogram) and histopathological parameters (hepatic granuloma profile) were used to evaluate antischistosomal activities in experimental groups. Additionally, the subsequent ultrastructural alterations were observed in adult worms using scanning electron microscopy (SEM). Transmission electron microscopy analysis showed that G-AgNPs and C-AgNPs have 8–25 and 8–11 nm in diameter, respectively, besides, fourier transform infrared analysis (FTIR) revealed the presence of organic compounds (aromatic ring groups) which act as capping agents around the surfaces of biogenic silver nanoparticles. In in vitro experiment, adult worms incubated either with G-AgNPs or C-AgNPs at concentrations higher than 100 µg/ml or 80 µg/ml, respectively, showed full mortality of parasites after 24 h. In the infected treated groups (with G-AgNPs plus PZQ & C-AgNPs plus PZQ) showed the most significant reduction in the total worm burdens (92.17% & 90.52%, respectively). Combined treatment with C-AgNPs and PZQ showed the highest value of dead eggs (93,6%), followed by G-AgNPs plus PZQ-treated one (91%). This study showed that mice treated with G-AgNPs plus PZQ significantly has the highest percentage of reduction in granuloma size and count (64.59%, 70.14%, respectively). Both G-AgNPs plus PZQ-treated & C-AgNPs plus PZQ treated groups showed the highest similar values of reduction percentage of total ova count in tissues (98.90% & 98.62%, respectively). Concerning SEM, G-AgNPs-treated worms showed more variability in ultrastructural alterations than G-AgNPs plus PZQ-treated one, besides, worms treated with C-AgNPs plus PZQ exhibited the maximum level of contractions or (shrinkage) as a major impact.

Seasonal assessment of pupal habitat productivity of malaria vector: Anopheles gambiae s.l as influence by physico-chemical conditions at selected breeding habitats in Niger, Nigeria

Malaria is the most significant protozoan disease in Africa and the principal vector-borne disease (VBD) in Nigeria, which is influenced by the quality of breeding habitats that are reflected through the stage preceding adult. Control of Anopheles gambiae s.l. populations through source reduction is still considered the most effective way of prevention and control, although it has proven unsustainable in Niger State. Physico-chemical cues were investigated. Samples were taken inside and outside 1m2 cages weekly by dipping and emptying the cages from May 2019 to March 2020. The data subjected to analysis of variance (one and two-way Anova). The findings revealed the mean pupae abundance (MPA), were significantly higher in Large Water bodies (624.50±217.81), and followed by Gutters (436.00±184.2) and Swamps (285.50±125.06). The mean pupae productivity (MPP), followed the order of descending rate >GT (717.50±219.38) >LW (677.21±145.10) >SW (530.40±136.97). The result also showed that emptying technique (ET) was more sufficient and reliable than dipping technique (DT). The peak abundance and productivity of the pupal stage was June to August then declined in March,2020 both habitats. However, MPP differed significantly (p<0.05) from one another across the months in all the habitat types. The physical and chemical cues of the breeding sites, varied significantly, except in temperature, total hardness, biochemical oxygen demands, conductivity, and pH in all the habitats. This study revealed high utilization of physico-chemical properties and poses increased risk of malaria. Thus, emphasis on the vector management strategies should be given specially on gutters and large water bodies as breeding habitats of malaria vectors (MV), in Niger State

Susceptibility of Ugandan Plasmodium falciparum Isolates to the Antimalarial Drug Pipeline.

Malaria, especially Plasmodium falciparum infection, remains an enormous problem, and its treatment and control are seriously challenged by drug resistance. New antimalarial drugs are needed. To characterize the Medicines for Malaria Venture pipeline of antimalarials under development, we assessed the ex vivo drug susceptibilities to 19 compounds targeting or potentially impacted by mutations in P. falciparum ABC transporter I family member 1, acetyl-CoA synthetase, cytochrome b, dihydroorotate dehydrogenase, elongation factor 2, lysyl-tRNA synthetase, phenylalanyl-tRNA synthetase, plasmepsin X, prodrug activation and resistance esterase, and V-type H+ ATPase of 998 fresh P. falciparum clinical isolates collected in eastern Uganda from 2015 to 2022. Drug susceptibilities were assessed by 72-h growth inhibition (half-maximum inhibitory concentration [IC50]) assays using SYBR green. Field isolates were highly susceptible to lead antimalarials, with low- to midnanomolar median IC50s, near values previously reported for laboratory strains, for all tested compounds. However, outliers with decreased susceptibilities were identified. Positive correlations between IC50 results were seen for compounds with shared targets. We sequenced genes encoding presumed targets to characterize sequence diversity, search for polymorphisms previously selected with in vitro drug pressure, and determine genotype-phenotype associations. We identified many polymorphisms in target genes, generally in <10% of isolates, but none were those previously selected in vitro with drug pressure, and none were associated with significantly decreased ex vivo drug susceptibility. Overall, Ugandan P. falciparum isolates were highly susceptible to 19 compounds under development as next-generation antimalarials, consistent with a lack of preexisting or novel resistance-conferring mutations in circulating Ugandan parasites. IMPORTANCE Drug resistance necessitates the development of new antimalarial drugs. It is important to assess the activities of compounds under development against parasites now causing disease in Africa, where most malaria cases occur, and to determine if mutations in these parasites may limit the efficacies of new agents. We found that African isolates were generally highly susceptible to the 19 studied lead antimalarials. Sequencing of the presumed drug targets identified multiple mutations in these genes, but these mutations were generally not associated with decreased antimalarial activity. These results offer confidence that the activities of the tested antimalarial compounds now under development will not be limited by preexisting resistance-mediating mutations in African malaria parasites.

Management of advanced HIV disease in Africa

Management of advanced HIV disease in Africa

Unmet Needs for Cardiac Rehabilitation in Africa: A Perennial Gap in the Management of Individuals with Cardiac Diseases.

Cardiac rehabilitation (CR) is a standard model of care, and an established component of comprehensive care that has been proven to reduce mortality and morbidity in patients with cardiac diseases. International clinical practice guidelines routinely recommend that cardiac patients participate in CR programs for comprehensive secondary prevention. However, there is scant guidance on how to deliver these programs in low-resourced settings. This dearth of clinical practice guidelines may be an indication of low emphasis placed on CR as a component of cardiac health services in low-income countries, especially in Africa. Indeed, CR programs are almost non-existent in Africa despite the unmet need for CR in patients with ischemic heart disease in Africa reported to be about one million. This figure represents the highest unmet need of any World Health Organization region, and is colossal given the projected accelerated increases in incidence of cardiovascular diseases (CVD) in the region. This narrative review explored the availability of CR programs, potential barriers to CR and strategies that can mitigate such barriers in Africa.

Advances in Chronic Kidney Disease in Africa

Africa, particularly sub-Sharan Africa (SSA), faces major challenges in respect to chronic kidney disease (CKD). There is a rising prevalence due to the combined effects of hypertension, diabetes, and human immunodeficiency virus (HIV) (and the interaction between them) and the effect of apolipoprotein L1 (APOL1) variants on the susceptibility to CKD. Epidemiological data on the prevalence of CKD are of low-to-medium quality, and reliable data are urgently needed for health planning. Furthermore, there are important deficiencies in creatinine-based equations in underestimating the prevalence of CKD in Africa, and evidence suggests that cystatin C based equations are more reliable. There is a changing spectrum of HIV related CKD with the greater availability of antiretroviral treatment. Major clinical trials using SGLT2 inhibitors have signalled a major advance in the treatment of CKD, especially in relation to type 2 diabetes, but the affordability, availability, and relevance to the African population is not established. The importance of the effects of hypertension in pregnancy and pregnancy related acute kidney injury on CKD and the newer concept of CKD of unknown cause (CKDu) are highlighted. Hypertension remains a dominant cause of CKD in Africa, and newer information suggests that the most appropriate treatment to control blood pressure and thus prevent CKD is the combination of either amlodipine plus a thiazide diuretic or angiotensin converting enzyme (ACE) inhibitor.

Development of a dual vaccine against East Coast fever and lumpy skin disease.

East Coast fever is an acute bovine disease caused by the apicomplexan parasite Theileria parva and is regarded as one of the most important tick-vectored diseases in Africa. The current vaccination procedure has many drawbacks, as it involves the use of live T. parva sporozoites. As a novel vaccination strategy, we have constructed the recombinant lumpy skin disease virus (LSDV) named LSDV-SODis-p67HA-BLV-Gag, encoding a modified form of the T. parva p67 surface antigen (p67HA), as well as the bovine leukemia virus (BLV) gag gene for the formation of virus-like particles (VLPs) to potentially enhance p67 immunogenicity. In place of the native sequence, the chimeric p67HA antigen has the human tissue plasminogen activator signal sequence and the influenza hemagglutinin A2 transmembrane domain and cytoplasmic tail. p67HA was detected on the surface of infected cells, and VLPs comprising BLV Gag and p67HA were produced. We also show that higher multiple bands observed in western blot analysis are due to glycosylation of p67. The two vaccines, pMExT-p67HA (DNA) and LSDV-SODis-p67HA-BLV-Gag, were tested for immunogenicity in mice. p67-binding antibodies were produced by vaccinated animals, with higher titers detected in mice vaccinated with the recombinant LSDV. This candidate dual vaccine warrants further testing in cattle.

Prevalence of neuroinfectious diseases and outcomes in Africa

Prevalence of neuroinfectious diseases and outcomes in Africa

The unmet need of organ transplantation in Africa.

The unmet need of organ transplantation in Africa.

Diagnostic options for pulmonary fungal diseases in Africa.

Fungal lung diseases are global in distribution and require specific tests for diagnosis. We report a survey of diagnostic service provision in Africa. A written questionnaire was followed by a video conference call with each respondent(s) and external validation. To disseminate the questionnaire, a snowball sample was used. Data were successfully collected from 50 of 51 African countries with populations >1 million. The questionnaire was completed by respondents affiliated with 72 health facilities. Of these 72 respondents, 33 (45.8%) reported data for the whole country while others reported data for a specific region/province within their country. In the public sector, chest X-ray and computed tomography are performed often in 49 countries (98%) and occasionally in 37 countries (74%), and less often in the private sector. Bronchoscopy and spirometry were done often in 28 countries (56%) and occasionally in 18 countries (36%) in the tertiary health facilities of public sector. The most conducted laboratory diagnostic assay was fungal culture (often or occasionally) in 29 countries (58%). In collaboration with the Africa Centre for Disease Control and Prevention, regional webinars and individual country profiles provided further data validation. This survey has found a huge disparity of diagnostic test capability across the African continent. Some good examples of good diagnostic provision and very high-quality care were seen, but this was unusual. The unavailability of essential testing such as spirometry was noted, which has a high impact in the diagnosis of lung diseases. It is important for countries to implement tests based on the World Health Organization Essential Diagnostics List.

The emerging epidemics in recent: mpox

In 2022, while the world has yet to be free from the aftermath of the long-term pandemic caused by COVID-19, the unusual epidemic of endemic diseases in Africa called mpox (monkeypox) was designated as the Public Health Emergency of International Concert by the World Health Organization, drawing world’s attention to whether new pandemic will occur. Fatal epidemics such as the Middle East respiratory syndrome coronavirus, Ebola, Novel swine-origin influenza, severe acute respiratory syndrome, Zika virus infection, and Nipa virus infection, including mpox and severe acute respiratory syndrome coronavirus 2, which were relatively recently prevalent worldwide, and the mentioned diseases were infected to humans due to contact with host animals. Thus, this study aims to investigate the overall characteristics and mechanisms of mpox, including transmission of the virus, symptoms, diagnosis, treatment, and prevention, and analyze the global trend status to understand the progress of epidemic. To prevent the recurrence of existing diseases such as mpox and the spread of new diseases, future studies to understand the causes and mechanisms of spillover and to preserve biodiversity on a global level is essential.

The COVID-19 pandemic in sub-Saharan Africa: The significance of presumed immune sufficiency.

A novel coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in China in 2019 and later ignited a global pandemic. Contrary to expectations, the effect of the pandemic was not as devastating to Africa and its young population compared to the rest of the world. To provide insight into the possible reasons for the presumed immune sufficiency to coronavirus disease 2019 (COVID-19) in Africa, this review critically examines literature published from 2020 onwards on the dynamics of COVID-19 infection and immunity and how other prevalent infectious diseases in Africa might have influenced the outcome of COVID-19. Studies characterising the immune response in patients with COVID-19 show that the correlates of protection in infected individuals are T-cell responses against the SARS-CoV-2 spike protein and neutralising titres of immunoglobin G and immunoglobin A antibodies. In some other studies, substantial pre-existing T-cell reactivity to SARS-CoV-2 was detected in many people from diverse geographical locations without a history of exposure. Certain studies also suggest that innate immune memory, which offers protection against reinfection with the same or another pathogen, might influence the severity of COVID-19. In addition, an initial analysis of epidemiological data showed that COVID‑19 cases were not severe in some countries that implemented universal Bacillus Calmette-Guerin (BCG) vaccination policies, thus supporting the potential of BCG vaccination to boost innate immunity. The high burden of infectious diseases and the extensive vaccination campaigns previously conducted in Africa could have induced specific and non-specific protective immunity to infectious pathogens in Africans.

Tackling noncommunicable diseases in Africa through football: The case of Malawi

AbstractThere is evidence that physical inactivity and dietary factors are more common among modifiable risk factors for noncommunicable diseases (NCDs) which are on the rise in Malawi. Football has been shown to have a wide range of health‐related benefits in health education programs, including the promotion of physical activity as a potential intervention in addressing NCDs. In Malawi, few football‐based health promotion programs have been implemented to address NCDs. Among the programs implemented were the Federation Internationale de Football Association 11 for Health initiative which was a school‐based health education program for the youth and the Malawi Ministry of Health's SPORTS FOR HEALTH initiative targeting civil servants. These programs produced significant improvement in physical activity in the participants and also increased their knowledge of both communicable and NCDs. However, these initiatives were not rolled out to many sites across Malawi. As Malawi is tackling rising cases of NCDs, football can be used as a powerful tool in promoting physical activity and it also provides an important platform for the delivery of NCDs’ health promotion messages to a wider audience. Such football‐based initiatives must be designed to directly address modifiable risk factors of NCDs. For successful implementation, there must be a good collaboration among the Ministries of Health and Sports, local football leagues, and other stakeholders.