Fever In Africa Research Articles

Looking Beyond the Lens of Crimean-Congo Hemorrhagic Fever in Africa.

Crimean-Congo hemorrhagic fever (CCHF) is a lethal viral disease that has severe public health effects throughout Africa and a case fatality rate of 10%-40%. CCHF virus was first discovered in Crimea in 1944 and has since caused a substantial disease burden in Africa. The shortage of diagnostic tools, ineffective tick control efforts, slow adoption of preventive measures, and cultural hurdles to public education are among the problems associated with continued CCHF virus transmission. Progress in preventing virus spread is also hampered by the dearth of effective serodiagnostic testing for animals and absence of precise surveillance protocols. Intergovernmental coordination, creation of regional reference laboratories, multiinstitutional public education partnerships, investments in healthcare infrastructure, vaccine development, and a One Health approach are strategic methods for solving prevention challenges. Coordinated efforts and financial commitments are needed to combat Crimean-Congo hemorrhagic fever and improve all-around readiness for newly developing infectious illnesses in Africa.

Use of in silico approaches, synthesis and profiling of Pan-filovirus GP-1,2 preprotein specific antibodies.

Intermolecular interactions of protein-protein complexes play a principal role in the process of discovering new substances used in the diagnosis and treatment of many diseases. Among such complexes of proteins, we have to mention antibodies; they interact with specific antigens of two genera of single-stranded RNA viruses belonging to the family Filoviridae-Ebolavirus and Marburgvirus; both cause rare but fatal viral hemorrhagic fever in Africa, with pandemic potential. In this research, we conduct studies aimed at the design and evaluation of antibodies targeting the filovirus glycoprotein precursor GP-1,2 to develop potential targets for the pan-filovirus easy-to-use rapid diagnostic tests. The in silico research using the available 3D structure of the natural antibody-antigen complex was carried out to determine the stability of individual protein segments in the process of its formation and maintenance. The computed free binding energy of the complex and its decomposition for all amino acids allowed us to define the residues that play an essential role in the structure and indicated the spots where potential antibodies can be improved. Following that, the study involved targeting six epitopes of the filovirus GP1,2 with two polyclonal antibodies (pABs) and 14 monoclonal antibodies (mABs). The evaluation conducted using Enzyme Immunoassays tested 62 different sandwich combinations of monoclonal antibodies (mAbs), identifying 10 combinations that successfully captured the recombinant GP1,2 (rGP). Among these combinations, the sandwich option (3G2G12* - (rGP) - 2D8F11) exhibited the highest propensity for capturing the rGP antigen.

Mapping the incidence rate of typhoid fever in sub-Saharan Africa.

With more than 1.2 million illnesses and 29,000 deaths in sub-Saharan Africa in 2017, typhoid fever continues to be a major public health problem. Effective control of the disease would benefit from an understanding of the subnational geospatial distribution of the disease incidence. We collated records of the incidence rate of typhoid fever confirmed by culture of blood in Africa from 2000 to 2022. We estimated the typhoid incidence rate for sub-Saharan Africa on 20 km × 20 km grids by exploring the association with geospatial covariates representing access to improved water and sanitation, health conditions of the population, and environmental conditions. We identified six published articles and one pre-print representing incidence rate estimates in 22 sites in 2000-2022. Estimated incidence rates showed geospatial variation at sub-national, national, and regional levels. The incidence rate was high in Western and Eastern African subregions followed by Southern and Middle African subregions. By age, the incidence rate was highest among 5-14 yo followed by 2-4 yo, > 14 yo, and 0-1 yo. When aggregated across all age classes and grids that comprise each country, predicted incidence rates ranged from 43.7 (95% confidence interval: 0.6 to 591.2) in Zimbabwe to 2,957.8 (95% CI: 20.8 to 4,245.2) in South Sudan per 100,000 person-years. Sub-national heterogeneity was evident with the coefficient of variation at the 20 km × 20 km grid-level ranging from 0.7 to 3.3 and was generally lower in high-incidence countries and widely varying in low-incidence countries. Our study provides estimates of 20 km × 20 km incidence rate of typhoid fever across sub-Saharan Africa based on data collected from 2000 through 2020. Increased understanding of the subnational geospatial variation of typhoid fever in Africa may inform more effective intervention programs by better targeting resources to heterogeneously disturbed disease risk.

Isolation, characterization, and circulation sphere of a filovirus in fruit bats

Bats are associated with the circulation of most mammalian filoviruses (FiVs), with pathogenic ones frequently causing deadly hemorrhagic fevers in Africa. Divergent FiVs have been uncovered in Chinese bats, raising concerns about their threat to public health. Here, we describe a long-term surveillance to track bat FiVs at orchards, eventually resulting in the identification and isolation of a FiV, Dehong virus (DEHV), from Rousettus leschenaultii bats. DEHV has a typical filovirus-like morphology with a wide spectrum of cell tropism. Its entry into cells depends on the engagement of Niemann-Pick C1, and its replication is inhibited by remdesivir. DEHV has the largest genome size of filoviruses, with phylogenetic analysis placing it between the genera Dianlovirus and Orthomarburgvirus, suggesting its classification as the prototype of a new genus within the family Filoviridae. The continuous detection of viral RNA in the serological survey, together with the wide host distribution, has revealed that the region covering southern Yunnan, China, and bordering areas is a natural circulation sphere for bat FiVs. These emphasize the need for a better understanding of the pathogenicity and potential risk of FiVs in the region.

Toxicological Studies and Antibacterial Efficacy of Sorghum bicolor Fermented Liquor Extracts of Bambusa tuldoides cv. ventricosa Leaf against Salmonella typhi

Abstract Background: Bamboo leaf extracted with steep liquor from fermented cereal grains has been used as an ethnomedicine for the treatment of severe typhoid fever in Africa without the proper documentation of its efficacy and side effects. Aim: This study embarks on the evaluation of the toxicity and pharmacological safety profile of fermented Sorghum bicolor liquor extract of Bambusa tuldoides cv. ventricosa leaf as an ethnomedicine against Salmonella typhi infection. Settings and Design: Reconstituted concentrates of various fermented extracts were used for the minimum inhibitory concentration (MIC) assay. Acute toxicity assay comprised two phases. The bioassay constitutes a total of 25 albino mice randomly distributed into 5 test groups. Materials and Methods: Steep liquor from fermented S. bicolor seeds served as the extracting solvent for the leaf of B. tuldoides using Soxhlet apparatus. The determination of both the sensitivity test and MIC assay used different levels. Extracts were orally administered for acute toxicity and dosage determination studies. Extracts were administered at concentrations 25, 50, and 100 mg/mL per day for the bioassays. Application of one-way analysis of variance was used for the determination of the statistical significance of the variations at 0.05 and 0.01 levels. Results and Conclusions: The average zones of inhibition were between 15.00 ± 2.34 and 20.00 ± 4.64 mm, and MIC was 12.5 mg/mL for the growth of S. typhi. The extract administered was found to be safe up to 5000 mg/kg body weight dosage. The agglutination result showed a concentration-dependent effectiveness of fermented liquor extract against S. typhi. Therefore, the bamboo leaf extract is efficient for the treatment of S. typhi infection.

Seasonal Patterns and Genetic Variability of Aedes Mosquitoes in Some Selected Communities of Maiduguri Metropolitan Council, Borno State, Nigeria

Aedes aegypti and Aedes albopictus mosquitoes spread dengue and yellow fever in Africa and worldwide. Rural-urban drift creates Aedes mosquito breeding sites through uncontrolled urbanization, inadequate urban infrastructure, lack of basic public health delivery, indiscriminate waste disposal, varying socioeconomic activities, and climatic changes. The above have happened in Maiduguri Metropolis since Boko Haram insurgencies began. This study will examine Aedes aegypti's seasonal distribution, abundance, composition, and genetic variability in selected Maiduguri Metropolitan Council and Jere Local Government Council communities. From October 2016 to May 2017, CDC traps and vacuum aspirators collected adult mosquitoes from study sites and stored at – 80 C. These were identified morphologically with taxonomy keys and stereomicroscopes, then molecularly with markers. Aedes mosquito population structure and genetic variability were determined using statistical software and molecular methods on samples. Hot-dry season has the highest relative abundance of this mosquito species in these study sites, while cold-dry season has the lowest. The molecular identification found Aedes aegypti in nine of twelve study locations but not Aedes albopictus. Some mosquitoes from the study locations had mutations due to carrying dengue virus or host population genes, but those without mutations showed a good phylogenetic relationship with Aedes aegypti mosquitoes from other countries, suggesting no genetic variability. The relative abundance of Aedes mosquitoes in Maiduguri Metropolitan Council increases the risk of dengue, zika, yellow fever, and chikungunya virus infections, and this mosquito species' seasonal distributions vary within and across seasons, but no genetic variability was found in the mosquitoes from the different locations used in this study.

Prevalence of and risk factors for microscopic and submicroscopic malaria infections in pregnancy: a systematic review and meta-analysis

Malaria infections during pregnancy can cause adverse birth outcomes, yet many infections are undetected by microscopy. We aimed to describe the epidemiology of submicroscopic malaria infections in pregnant women in Asia, the Americas, and Africa using aggregated and individual participant data (IPD). For this systematic review and meta-analysis, studies (published Jan 1, 1997 to Nov 10, 2021) with information on both microscopic and submicroscopic infections during pregnancy from Asia, the Americas, or Africa, identified in the Malaria-in-Pregnancy Library, were eligible. Studies (or subgroups or study groups) that selected participants on the basis of the presence of fever or a positive blood smear were excluded to avoid selection bias. We obtained IPD (when available) and aggregated data. Estimates of malaria transmission intensity and sulfadoxine-pyrimethamine resistance, matched by study location and year, were obtained using publicly available data. One-stage multivariable logit and multinomial models with random intercepts for study site were used in meta-analysis to assess prevalence of and risk factors for submicroscopic infections during pregnancy and at delivery. This study is registered with PROSPERO, number CRD42015027342. The search identified 87 eligible studies, 68 (78%) of which contributed to the analyses. Of these 68 studies, 45 (66%) studies contributed IPD (48 869 participants) and 23 (34%) studies contributed aggregated data (11 863 participants). During pregnancy, median prevalence estimates were 13·5% (range 0·0-55·9, 66 substudies) for submicroscopic and 8·0% (0·0-50·6, 66 substudies) for microscopic malaria. Among women with positive Plasmodium nucleic acid amplification tests (NAATs), the median proportion of submicroscopic infections was 58·7% (range 0·0-100); this proportion was highest in the Americas (73·3%, 0·0-100), followed by Asia (67·2%, 36·4-100) and Africa (56·5%, 20·5-97·7). In individual patient data analysis, compared with women with no malaria infections, those with submicroscopic infections were more likely to present with fever in Africa (adjusted odds ratio 1·32, 95% CI 1·02-1·72; p=0·038) but not in other regions. Among women with NAAT-positive infections in Asia and the Americas, Plasmodium vivax infections were more likely to be submicroscopic than Plasmodium falciparum infections (3·69, 2·45-5·54; p<0·0001). Risk factors for submicroscopic infections among women with NAAT-positive infections in Africa included older age (age ≥30 years), multigravidity, and no HIV infection. During pregnancy, submicroscopic infections are more common than microscopic infections and are associated with fever in Africa. Malaria control in pregnancy should target both microscopic and submicroscopic infections. Bill & Melinda Gates Foundation through the Worldwide Antimalarial Resistance Network.

Antiviral Activity of Quercetin Hydrate against Zika Virus.

Zika virus (ZIKV) has re-emerged in recent decades, leading to outbreaks of Zika fever in Africa, Asia, and Central and South America. Despite its drastic re-emergence and clinical impact, no vaccines or antiviral compounds are available to prevent or control ZIKV infection. This study evaluated the potential antiviral activity of quercetin hydrate against ZIKV infection and demonstrated that this substance inhibits virus particle production in A549 and Vero cells under different treatment conditions. In vitro antiviral activity was long-lasting (still observed 72 h post-infection), suggesting that quercetin hydrate affects multiple rounds of ZIKV replication. Molecular docking indicates that quercetin hydrate can efficiently interact with the specific allosteric binding site cavity of the NS2B-NS3 proteases and NS1-dimer. These results identify quercetin as a potential compound to combat ZIKV infection in vitro.

Recent advances in the diagnosis and management of typhoid fever in Africa: A review.

Typhoid fever, a classical disease of enteric origin caused by Salmonella species of bacteria, is among the most important diseases threatening public health in Africa. The African continent is a marker for both low resources within the healthcare system and poor disease control policy formulations in managing endemic infectious diseases. Since the colonial era, the Widal serological test has been used to confirm typhoid fever in Africa, however recent studies recommend blood culture, and when blood culture cannot be obtained, clinical findings, laboratory Widal test confirmation, and ruling out other febrile illnesses as confirmatory pathway to diagnose typhoid fever in Africa. Managing typhoid fever relies on antimicrobials. In 1980s chloramphenicol was the medication of choice. Years later, amoxicillin and co-trimoxazole were adopted. However, the instantaneous rise of resistant strains of Salmonella enterica confers an important challenge to treat the burdensome enteric fever. The current treatment algorithm of typhoid fever in Africa relies significantly on the use of fluoroquinolones, macrolides, and cephalosporins. Developed nations have successfully addressed and controlled typhoid fever via improvement in accessing safe water and food, better sanitary and hygienic behaviours, and vaccines development. Nevertheless, there is significant evidence to infer improvement in the diagnosis management of typhoid fever over the last few decades, and efforts are underway to control the disease spread in Africa. This review aims to provide an overview of the latest developments in typhoid fever diagnosis and management in Africa and provide key recommendations for a coordinated approach to mitigate typhoid in the continent.

Emerging Arboviruses of Public Health Concern in Africa: Priorities for Future Research and Control Strategies

Arboviruses are most prevalent in tropical and subtropical regions, where arthropods are widespread. The World Health Organization (WHO) estimated that the mortality burden of arbovirus diseases, such as yellow fever in Africa, was 84,000–170,000 severe cases and 29,000–60,000 deaths in 2013. These epidemics emphasize the urgent need for integrated control and prevention of arboviral diseases. Challenges in managing and controlling arboviral diseases in Africa are mainly attributed to poor insect vector control, insecticide resistance, and poor sanitation and solid waste management. The removal or reduction of mosquito populations amongst susceptible individuals is identified as the most effective measure to control many vector-borne diseases. Current public health needs call for efficient vector control programs and maintenance of adequate surveillance systems through the availability of trained personnel and rapid diagnostic facilities, providing an interdisciplinary response to control and mitigate the threats of emerging and re-emerging arboviruses. Furthermore, research priorities should focus on understanding the factors responsible for adaptation to other vectors, determinants of infection and transmission, and the development of high efficiency antiviral molecules or candidate vaccines. Here, we explore and review our current understanding of arboviruses of public health importance in Africa, with a focus on emerging arboviruses, their arthropod vectors, and the epidemiology of major arboviruses. Finally, we appraise the role of planetary health in addressing the threat of arboviruses and identify other priority areas of research for effective control.

A Comprehensive Review on Lassa Fever in Africa: Epidemiology, Diagnosis, Prevention and Control

Lassa fever is a highly prevalent viral zoonosis that affects two to three million people in West Africa. This is a rodent-borne disease, which has serious consequences on the population and hospital staff in endemic areas. Lassa fever is a public health concern inflicting severe morbidity and important mortality (Case rate (CFR) ≥ 50%), particularly in epidemic cases. The disease has emerged as one of the most prevalent and debilitating viral hemorrhagic fevers and is endemic in the West Africa region. The control and prevention of the regular outbreak of the disease have become a herculean task in the affected; there is inadequate healthcare facility (including laboratory/diagnostic and care centers), poor socioeconomic environment, lack of awareness among the populace, and presence of favorable ecologic niche for the survival and propagation of the natural host and reservoir mouse (Mastomys natalensis) of Lassa virus. It is mainly transmitted by contact with excretions and secretions of infected rats via foods and water as well as exposure to other contaminated items. It is an enveloped, single-stranded (SS) segmented RNA virus with the ability to replicate very rapidly. The virus infects almost every tissue in the human body resulting in multisystem dysfunction. The incubation period is generally between 6 to 21 days resulting in 3 stages of clinical manifestation viz: Acute phase characterized by flu-like, non-specific illness; hemorrhagic phase accompanied with gastrointestinal symptoms and cardiovascular/neurologic complications. Laboratory help is required in order to make an unequivocal diagnosis of the disease. Early diagnosis and prompt therapy are crucial to saving the life of the patient. Currently, there is no clinically certified Lassa fever vaccine thus complicating preventive, and control measures.

Mass Media Exposure and Lassa Fever Risk Perception in Rural Communities of South-south Nigeria

Nigeria bears the highest burden of Lassa fever in Africa, accounting for about 60% of the 5,000 annual mortalities attributable to the haemorrhagic disease. In the absence of preventive vaccines, the mass media have been deployed as independent and complementary interventions against the spread of the infection. This study examines the influence of mass media exposure on Lassa fever risk perception and risk behaviours among residents of eight rural communities in South-south Nigeria. Anchored on the Health Belief Model and Social Influence Theory, the study used survey questionnaires to collect data from 384 respondents selected through multistage sampling. Findings show that media exposure is positively related to Lassa fever risk perception (β = .519, 95% CI: .432, .607), but negatively associated with risk behaviours towards the zoonotic disease (β = -.797, 95% CI: -.922, -.671). Nevertheless, media influence on respondents’ risk perception and risk behaviours tends to vary significantly along sex, geographical region and employment status. Given the endemic nature of Lassa fever in Nigeria, the study recommends the sustenance of public sensitisation efforts aimed at preventing the spread of the disease, especially in rural areas. It also advocates the need for relevant health authorities to enforce healthier public environmental practices and initiate mastomys eradication programmes to reduce the presence of rats in residential areas. Keywords: Haemorrhagic fever, infectious disease, media sensitisation, public health, risk communication.

First Data on Ornithodoros moubata Aquaporins: Structural, Phylogenetic and Immunogenic Characterisation as Vaccine Targets.

Ornithodoros moubata transmits African swine fever and human relapsing fever in Africa. The elimination of O. moubata populations from anthropic environments is expected to improve the prevention and control of these diseases. Tick vaccines have emerged as a sustainable method for tick control, and tick aquaporins (AQPs) are promising targets for tick vaccines due to their vital functions, immunogenicity and ease of access by neutralising host antibodies. This study aimed at the systematic identification of the AQPs expressed by O. moubata (OmAQPs) and their characterisation as vaccine targets. Therefore, AQP coding sequences were recovered from available transcriptomic datasets, followed by PCR amplification, cloning, sequence verification and the analysis of the AQP protein structure and epitope exposure. Seven OmAQPs were identified and characterised: six were aquaglyceroporins, and one was a water-specific aquaporin. All of these were expressed in the salivary glands and midgut and only three in the coxal glands. Epitope exposure analysis identified three extracellular domains in each AQP, which concentrate overlapping B and T cell epitopes, making them interesting vaccine targets. Based on these domain sequences, a set of ten antigenic peptides was designed, which showed adequate properties to be produced and tested in pilot vaccine trials.

Evaluation of Whatman FTA cards for the preservation of yellow fever virus RNA for use in molecular diagnostics.

Yellow fever virus (YFV) is a flavivirus that frequently causes outbreaks of hemorrhagic fever in Africa and South America and is considered a reemerging public health threat. Accurate diagnosis of yellow fever (YF) disease is critical as one confirmed case constitutes an outbreak and may trigger a mass vaccination campaign. Highly sensitive and specific molecular diagnostics have been developed; however, these assays require maintenance of cold-chain during transport of specimens to prevent the degradation of viral RNA prior to testing. Such cold-chain requirements are difficult to meet in some regions. In this study, we investigated Whatman FTA cards as an alternative stabilization method of YFV RNA for use in molecular diagnosis. Using contrived specimens, linear regression analysis showed that RNA detection from a single 6mm FTA card punch was significantly less sensitive than traditional RNA extraction; however, pooling RNA extracted from two FTA punches significantly lowered the limit of detection to be equal to that of the traditional RNA extraction gold standard. In experiments addressing the ability of FTA card methodology to stabilize YFV RNA at variable temperature, RNA could be detected for more than two weeks following storage at 25°C. Even more promising, YFV RNA was detectable on cards held at 37°C from two days to over two weeks depending on viral input. FTA cards were also shown to stabilize YFV RNA at high humidity if cards were desiccated prior to inoculation. These results support that FTA cards could be cost effective and easy to use in molecular diagnosis of YF, preserving viral RNA to allow for positive diagnoses in situations where maintaining cold-chain is not feasible.

Malaria transmission in Africa: Its relationship with yellow fever and measles.

Malaria has been strongly linked to the transmission and pathophysiology of some viral diseases. Malaria and vaccine-preventable diseases often co-exist in endemic countries but the implication of their co-existence on their transmission dynamics and control is poorly understood. The study aims to evaluate the relationships between the incidence of malaria and cases of measles and yellow fever in Africa. The malaria incidence, death due to malaria, measles and yellow fever data were sourced from the WHO database. Poisson and zero-inflated time-trend regression were used to model the relationships between malaria and the two vaccine-preventable diseases. P-values <0.05 were considered statistically significant. A significant negative relationship existed between malaria incidence and measles cases (P<0.05), however, malaria showed a positive relationship with yellow fever (P<0.05). The relationships between death due to malaria and measles/yellow fever cases followed similar trends but with a higher level of statistical significance (P<0.001). Malaria varied negatively with measles cases but positively with yellow fever. The relationships observed in this study could be important for the management of malaria and the studied vaccine-preventable diseases. Increase vaccination coverage and/or malaria treatment could modulate the direction of these relationships.

One hundred years of African swine fever in Africa: Where have we been, where are we now, where are we going?

One hundred years have passed since the first paper on African swine fever (ASF) was published by Montgomery in 1921. With no vaccine, ineffectiveness of prevention and control measures and lack of common interest in eradicating the disease, ASF has proven to be one of the most devastating diseases because of its significant sanitary and socioeconomic consequences. The rapid spread of the disease on the European and Asian continents and its recent appearance in the Caribbean puts all countries at great risk because of global trade. The incidence of ASF has also increased on the African continent over the last few decades, extending its distribution far beyond the area in which the ancient sylvatic cycle is present with its complex epidemiological transmission pathways involving virus reservoirs in ticks and wild African Suidae. Both in that area and elsewhere, efficient transmission by infected domestic pigs and virus resistance in infected animal products and fomites mean that human driven factors along the pig value chain are the dominant impediments for its prevention, control and eradication. Control efforts in Africa are furthermore hampered by the lack of information about the size and location of the fast-growing pig population, particularly in the dynamic smallholder sector that constitutes up to 90% of pig production in the region. A vaccine that will be both affordable and effective against multiple genotypes of the virus is not a short-term reality. Therefore, a strategy for management of ASF in sub-Saharan Africa is needed to provide a roadmap for the way forward for the continent. This review explores the progression of ASF and our knowledge of it through research over a century in Africa, our current understanding of ASF and what must be done going forward to improve the African situation and contribute to global prevention and control.

Rift valley fever in Africa with the emerging interest in Libya

Rift valley fever (RVF) is an acute vector-borne viral zoonotic disease of domestic and wild ruminants. The RVF virus (RVFV) belonging to the Phlebovirus genus of the Bunyaviridae family causes this disease. Studies have shown that mosquitoes are the vectors that transmit RVFV. Specifically, Aedes and Culex mosquito species are among the many vectors of this virus, which affects not only sheep, goats, buffalo, cattle, and camels but also human beings. Since the 30s of the last century, RVF struck Africa, and to a lesser extent, Asian continents, with subsequent episodes of epizootic, epidemic, and sporadic outbreaks. These outbreaks, therefore, resulted in the cumulative loss of thousands of human lives, thereby disrupting the livestock market or only those with seropositive cases. After that outbreak episode, RVF was not reported in Libya until January 13, 2020, where it was reported for the 1st time in a flock of sheep and goats in the southern region of the country. Although insufficient evidence to support RVF clinical cases among the confirmed seropositive animals exists, neither human cases nor death were reported in Libya. Yet, the overtime expansion of RVF kinetics in the Libyan neighborhoods, in addition to the instability and security vacuum experienced in the country, lack of outbreak preparedness, and the availability of suitable climatic and disease vector factors, makes this country a possible future scene candidate for RVF expansion. Urgently, strengthening veterinary services (VS) and laboratory diagnostic capacities, including improvement of monitoring and surveillance activity programs, should be implemented in areas at risk (where imported animals crossing borders from Libyan neighborhoods and competent vectors are found) at national, sub-national, and regional levels. The Libyan government should also implement a tripartite framework (one health approach) among the veterinary public health, public health authority, and environmental sanitation sectors to implement RVF surveillance protocols, along with an active partnership with competent international bodies (OIE, FAO, and WHO). Therefore, this review comprises the most updated data regarding the epidemiological situation of RVF infections and its socioeconomic impacts on African and Asian continents, and also emphasize the emerging interest of RVF in Libya.

Yellow Fever in Nigeria: A Review of Past, Current, and Future Strides

Since 1985, there has been resurgence of yellow fever in Africa with outbreaks occurring in more than 33 countries. From that time, thousands of cases have occurred in Nigeria which is the most populous country in Africa. Semi-urban and urban centres across the country are densely populated, with numerous sparsely populated rural settings in every State, some of which contain heavy forests. A wide-range of vegetation zones exists which lead to smooth transition of several tropical climates. As a result, there is preponderance of Aedes species in many parts of the country especially during the rainy season when relative humidity is high. Vector control is not applicable to jungle yellow fever, but infection in human population can be prevented by vaccination. Yellow fever deaths were recently reported in Nigeria, causing panic and public outcry. This review highlights the epidemiological trajectory of yellow fever, the past, and the present and future efforts in the country with a view to providing in-depth knowledge of yellow fever activities in order to enhance public health.

The incidence and mortality of yellow fever in Africa: a systematic review and meta-analysis

BackgroundUnderstanding the occurrence of yellow fever epidemics is critical for targeted interventions and control efforts to reduce the burden of disease. We assessed data on the yellow fever incidence and mortality rates in Africa.MethodsWe searched the Cochrane Library, SCOPUS, MEDLINE, CINAHL, PubMed, Embase, Africa-wide and Web of science databases from 1 January 1975 to 30th October 2020. Two authors extracted data from included studies independently and conducted a meta-analysis.ResultsOf 840 studies identified, 12 studies were deemed eligible for inclusion. The incidence of yellow fever per 100,000 population ranged from < 1 case in Nigeria, < 3 cases in Uganda, 13 cases in Democratic Republic of the Congo, 27 cases in Kenya, 40 cases in Ethiopia, 46 cases in Gambia, 1267 cases in Senegal, and 10,350 cases in Ghana. Case fatality rate associated with yellow fever outbreaks ranged from 10% in Ghana to 86% in Nigeria. The mortality rate ranged from 0.1/100,000 in Nigeria to 2200/100,000 in Ghana.ConclusionThe yellow fever incidence rate is quite constant; in contrast, the fatality rates vary widely across African countries over the study period. Standardized demographic health surveys and surveillance as well as accurate diagnostic measures are essential for early recognition, treatment and control.

A novel approach to modeling epidemic vulnerability, applied to Aedes aegypti-vectored diseases in Per\xfa

BackgroundA proactive approach to preventing and responding to emerging infectious diseases is critical to global health security. We present a three-stage approach to modeling the spatial distribution of outbreak vulnerability to Aedes aegypti-vectored diseases in Perú.MethodsExtending a framework developed for modeling hemorrhagic fever vulnerability in Africa, we modeled outbreak vulnerability in three stages: index case potential (stage 1), outbreak receptivity (stage 2), and epidemic potential (stage 3), stratifying scores on season and El Niño events. Subsequently, we evaluated the validity of these scores using dengue surveillance data and spatial models.ResultsWe found high validity for stage 1 and 2 scores, but not stage 3 scores. Vulnerability was highest in Selva Baja and Costa, and in summer and during El Niño events, with index case potential (stage 1) being high in both regions but outbreak receptivity (stage 2) being generally high in Selva Baja only.ConclusionsStage 1 and 2 scores are well-suited to predicting outbreaks of Ae. aegypti-vectored diseases in this setting, however stage 3 scores appear better suited to diseases with direct human-to-human transmission. To prevent outbreaks, measures to detect index cases should be targeted to both Selva Baja and Costa, while Selva Baja should be prioritized for healthcare system strengthening. Successful extension of this framework from hemorrhagic fevers in Africa to an arbovirus in Latin America indicates its broad utility for outbreak and pandemic preparedness and response activities.