Unique Outbreak of Rift Valley Fever in Sudan, 2019

Trends in emerging vector-borne viral infections and their outcome in children over two decades

This review utilizes quatitative methods and bibliometric data to analyse the trends of emerging and re-emerging vector-borne diseases, with a focus on their impact on pediatric population. To conduct this analysis, a systematic search of PubMed articles from the past two decades was performed, specifically looking at 26 different vector-borne viruses listed in WHO and CDC list of vector-borne viruses. The review found that diseases like Dengue, Zika, West Nile, and Chikungunya were frequently discussed in the literature. On the other hand, diseases such as Tick-borne encephalitis, Rift Valley fever, Venezuelan equine encephalitis, Sindbis fever, Venezuelan equine encephalitis, Ross River virus, and Eastern equine encephalitis showed an upward trend in publications, indicating potential resurgence. In addition to discussing trends and patterns, the review delves into the clinical manifestations and long-term effects of the top 10 viruses in children. It highlights various factors including deforestation, urbanization, global travel, and immunosuppression that contribute to disease emergence and resurgence. To effectively combat these vector-borne diseases, continuous surveillance is crucial. The review also emphasizes the importance of increased vaccination efforts and targeted research to address the health challenges they pose. IMPACT: This review employs quantitative analysis of publications to elucidate trends in emerging pediatric vector-borne viral diseases over two decades. Dengue, the most prevalent of these diseases, has spread to new regions. New strains of Japanese Encephalitis have caused outbreaks. Resurgence of Tick-borne Encephalitis, West Nile, and Yellow Fever due to vaccine hesitancy has also transpired. Continuous global surveillance, increased vaccination, and research into novel therapeutics are imperative to combat the substantial morbidity and mortality burden these diseases pose for children worldwide.

Arthropod-Borne Viruses in Mauritania: A Literature Review

During the past four decades, recurrent outbreaks of various arthropod-borne viruses have been reported in Mauritania. This review aims to consolidate the current knowledge on the epidemiology of the major arboviruses circulating in Mauritania. Online databases including PubMed and Web of Science were used to retrieve relevant published studies. The results showed that numerous arboviral outbreaks of variable magnitude occurred in almost all 13 regions of Mauritania, with Rift Valley fever (RVF), Crimean-Congo hemorrhagic fever (CCHF), and dengue (DEN) being the most common infections. Other arboviruses causing yellow fever (YF), chikungunya (CHIK), o'nyong-nyong (ONN), Semliki Forest (SF), West Nile fever (WNF), Bagaza (BAG), Wesselsbron (WSL), and Ngari (NRI) diseases have also been found circulating in humans and/or livestock in Mauritania. The average case fatality rates of CCHF and RVF were 28.7% and 21.1%, respectively. RVF outbreaks have often occurred after unusually heavy rainfalls, while CCHF epidemics have mostly been reported during the dry season. The central and southeastern regions of the country have carried the highest burden of RVF and CCHF. Sheep, cattle, and camels are the main animal reservoirs for the RVF and CCHF viruses. Culex antennatus and Cx. poicilipes mosquitoes and Hyalomma dromedarii, H. rufipes, and Rhipicephalus everesti ticks are the main vectors of these viruses. DEN outbreaks occurred mainly in the urban settings, including in Nouakchott, the capital city, and Aedes aegypti is likely the main mosquito vector. Therefore, there is a need to implement an integrated management strategy for the prevention and control of arboviral diseases based on sensitizing the high-risk occupational groups, such as slaughterhouse workers, shepherds, and butchers for zoonotic diseases, reinforcing vector surveillance and control, introducing rapid point-of-care diagnosis of arboviruses in high-risk areas, and improving the capacities to respond rapidly when the first signs of disease outbreak are identified.

Rift Valley fever and malaria co-infection: A case report

Key Clinical Message

We report a case of febrile illness that was presented with mild symptoms. However, laboratory investigation confirmed a malaria and Rift Valley fever co-infection. Healthcare providers in settings endemic with several infectious diseases should seek rolling out possibilities of other infections prior to starting treatment for achieving effective case management with less resources and better safety of patients.

Abstract

Here we report a case of febrile illness that confirmed to be a co-infection of malaria and Rift Valley fever. The patient was initially diagnosed with malaria and started on treatment immediately. However, due to the lack of response to the treatment further laboratory investigations were pursued.

A highly potent human neutralizing antibody prevents vertical transmission of Rift Valley fever virus in a rat model

Rift Valley fever virus (RVFV) is an emerging mosquito-transmitted virus that circulates in livestock and humans in Africa and the Middle East. Outbreaks lead to high rates of miscarriages in domesticated livestock. Women are also at risk of vertical virus transmission and late-term miscarriages. MAb RVFV-268 is a highly potent recombinant neutralizing human monoclonal antibody that targets RVFV. Here we show that mAb RVFV-268 reduces viral replication in rat placenta explant cultures and prevents vertical transmission in a rat model of congenital RVF. Passive transfer of mAb RVFV-268 from mother to fetus occurs as early as 6 h after administration and persists through 24 h. Administering mAb RVFV-268 2 h prior to RVFV challenge or 24 h post-challenge protects the dams and offspring from RVFV infection. These findings support mAb RVFV-268 as a pre- and post-infection treatment to subvert RVFV infection and vertical transmission, thus protecting the mother and offspring.

Rift valley fever (RVF) viral zoonotic disease steadily circulates in the Mauritanian animals and humans: A narrative review

Background and Aim

Rift valley fever (RVF) virus (RVFV) is reportedly steadily circulating in Mauritania being repeated in 1987, 2010, 2012, 2015, and 2020. Mauritania seems a preferred niche for RVF virus due to its persistent outbreak there. Lately, nine Mauritanian wilayas confirmed 47 (23 fatalities with 49% CFR) human cases between August 30 and October 17, 2022. Most of the cases were largely among livestock breeders associated with animal husbandry activities. The review aimed at understanding the origin, cause, and measures to counter the virus.

Methods

The facts and figures from the various published articles sourced from databases including Pubmed, Web of Science, and the Scopus as also some primary data from health agencies like WHO, CDC, and so forth were evaluated and the efficacy of countermeasures reviewed.

Results

Among the reported confirmed cases, it was found that 3-70 year age-group males outnumbered the females. Deaths after fever occurred primarily due to acute hemorrhagic thrombocytopenia. Human infections often occurred through zoonotic transmission mainly through mosquitoes in the population contiguous to cattle outbreak, a conducive site for local RVFV transmission. Many transmission cases were through direct or indirect contact with blood or organs of the infected animal.

Conclusion

RVFV infection was predominant in the Mauritanian regions bordering Mali, Senegal, and Algeria. High human and domesticated animal density as also the existing zoonotic vectors further contributed to RVF virus circulation. Mauritanian RVF infection data confirmed that RVFV was zoonotic that included small ruminants, cattle, and camel. This observation hints at the role of transborder animal mobility in RVFV transmission. In light of this, preventive approaches with effective surveillance and monitoring system following the One Health model is extremely beneficial for a free and fair healthy world for all.

Mosquito gene targeted RNAi studies for vector control

Vector-borne diseases are serious public health concern. Mosquito is one of the major vectors responsible for the transmission of a number of diseases like malaria, Zika, chikungunya, dengue, West Nile fever, Japanese encephalitis, St. Louis encephalitis, and yellow fever. Various strategies have been used for mosquito control, but the breeding potential of mosquitoes is such tremendous that most of the strategies failed to control the mosquito population. In 2020, outbreaks of dengue, yellow fever, and Japanese encephalitis have occurred worldwide. Continuous insecticide use resulted in strong resistance and disturbed the ecosystem. RNA interference is one of the strategies opted for mosquito control. There are a number of mosquito genes whose inhibition affected mosquito survival and reproduction. Such kind of genes could be used as bioinsecticides for vector control without disturbing the natural ecosystem. Several studies have targeted mosquito genes at different developmental stages by the RNAi mechanism and result in vector control. In the present review, we included RNAi studies conducted for vector control by targeting mosquito genes at different developmental stages using different delivery methods. The review could help the researcher to find out novel genes of mosquitoes for vector control.

Mosquito-Borne Diseases and Their Control Strategies: An Overview Focused on Green Synthesized Plant-Based Metallic Nanoparticles

Mosquitoes act as vectors of pathogens that cause most life-threatening diseases, such as malaria, Dengue, Chikungunya, Yellow fever, Zika, West Nile, Lymphatic filariasis, etc. To reduce the transmission of these mosquito-borne diseases in humans, several chemical, biological, mechanical, and pharmaceutical methods of control are used. However, these different strategies are facing important and timely challenges that include the rapid spread of highly invasive mosquitoes worldwide, the development of resistance in several mosquito species, and the recent outbreaks of novel arthropod-borne viruses (e.g., Dengue, Rift Valley fever, tick-borne encephalitis, West Nile, yellow fever, etc.). Therefore, the development of novel and effective methods of control is urgently needed to manage mosquito vectors. Adapting the principles of nanobiotechnology to mosquito vector control is one of the current approaches. As a single-step, eco-friendly, and biodegradable method that does not require the use of toxic chemicals, the green synthesis of nanoparticles using active toxic agents from plant extracts available since ancient times exhibits antagonistic responses and broad-spectrum target-specific activities against different species of vector mosquitoes. In this article, the current state of knowledge on the different mosquito control strategies in general, and on repellent and mosquitocidal plant-mediated synthesis of nanoparticles in particular, has been reviewed. By doing so, this review may open new doors for research on mosquito-borne diseases.

Sudden emergence and spread of cutaneous larva migrans in Sudan: A case series calls for urgent actions

Cutaneous larva migrans (CLM) is a self-limiting dermatosis parasitic disease that is caused by zoonotic hookworm mainly infects cats, dogs, and accidentally humans. The disease affects hosts through the invasion and the migration of the hookworm larva into top layers of the skin. The disease occurs in tropical and subtropical regions; where people commonly are infected when sitting or barefoot walking on places contaminated with feces of infected cats or dogs. Due to self-limiting nature of the disease, the exact burden and prevalence are commonly underestimated. In this communication, we investigated all cases presented to the skin-diseases outpatient clinic' at the reference hospital of Tropical Diseases Medicine in Khartoum state between January 2019 and January 2021. This is the first-ever a case series report of cutaneous larva migrans in Sudan. We identified 15 cases of CLM presented with rash (100 %), redness of skin (67 %), and only adults were presented with larva crawling under their skins (27 %). Infection sites were (53 %) leg, (40 %) foot, only 7 % showed abdominal infection. The majority of patients were children or young adults, 47 % of them are ≤5 year-old, male to female ratio is 2.75:1. Duration of infection was one to three weeks and all patients fully recovered after treatment with albendazole. This urges for One Health interventions including deworming cats and dogs, improving water, sanitation, and hygiene, community-engagement and raising awareness in area with risk of infection.

Strengthening a One Health approach to emerging zoonoses

Given the enormous global impact of the COVID-19 pandemic, outbreaks of highly pathogenic avian influenza in Canada, and manifold other zoonotic pathogen activity, there is a pressing need for a deeper understanding of the human-animal-environment interface and the intersecting biological, ecological, and societal factors contributing to the emergence, spread, and impact of zoonotic diseases. We aim to apply a One Health approach to pressing issues related to emerging zoonoses, and propose a functional framework of interconnected but distinct groups of recommendations around strategy and governance, technical leadership (operations), equity, education and research for a One Health approach and Action Plan for Canada. Change is desperately needed, beginning by reorienting our approach to health and recalibrating our perspectives to restore balance with the natural world in a rapid and sustainable fashion. In Canada, a major paradigm shift in how we think about health is required. All of society must recognize the intrinsic value of all living species and the importance of the health of humans, other animals, and ecosystems to health for all.

Bilateral macular retinitis in patients with presumed rift valley fever from Sudan: A case series

BACKGROUND

Epidemic retinitis occurs seasonally following febrile infections in endemic regions. Rift valley fever (RVF) is endemic to Sudan, with a recent outbreak starting in 2019.

METHODS

Retrospective case series of 3 patients travelling from Sudan with post-febrile retinitis, and with a history and clinical picture suggestive of RVF retinitis.

RESULTS

The three patients were adult males with underlying medical conditions and underwent fundus fluorescein angiography that confirmed bilateral retinitis and occlusive vasculitis involving the posterior pole. Optical coherence tomography showed distortion of the macular layers. Case 2 presented 1 month following febrile illness and had retinal thinning, with optical coherence tomography angiography showing marked reduction in vessel density.

CONCLUSION

We present multimodal imaging data of three cases with presumed RVF retinitis from a recent outbreak in Sudan. The unavailability of standardized methods of testing for RVF, as is the case for most epidemic retinitis-causing pathogens, makes the diagnosis challenging.

The First Molecular Detection of Aedes albopictus in Sudan Associates with Increased Outbreaks of Chikungunya and Dengue

As part of our surveys of the invasive malaria vector Anopheles stephensi in four Sudanese states, including North and South Kordofan, Sennar, and White Nile, we collected 166 larvae. Our morphological identification confirmed that 30% of the collected mosquito samples were Anopheles species, namely An. gambiae s.l. and An. stephensi, while the 117 Aedes specimens were Ae. luteocephalus (39%), Ae. aegypti (32%), Ae. vexans (9%), Ae. vittatus (9%), Ae. africanus (6%), Ae. metalicus (3%), and Ae. albopictus (3%). Considering the serious threat of Ae. albopictus emergence for the public health in the area and our limited resources, we prioritized Ae. albopictus samples for further genomic analysis. We extracted the DNA from the three specimens and subsequently sequenced the cytochrome oxidase 1 (CO1) gene and confirmed their identity as Aedes albopictus and their potential origin by phylogenetic and haplotype analyses. Aedes albopictus, originating from Southeast Asia, is an invasive key vector of chikungunya and dengue. This is the first report and molecular characterization of Ae. albopictus from Sudan. Our sequences cluster with populations from the Central African Republic and La Réunion. Worryingly, this finding associates with a major increase in chikungunya and dengue outbreaks in rural areas of the study region and might be linked to the mosquito’s spread across the region. The emergence of Ae. albopictus in Sudan is of serious public health concern and urges for the improvement of the vector surveillance and control system through the implementation of an integrated molecular xenosurveillance. The threat of major arboviral diseases in the region underlines the need for the institutionalization of the One Health strategy for the prevention and control of future pandemics.

Seroprevalence of Rift Valley fever virus in domestic ruminants of various origins in two markets of Yaoundé, Cameroon

Background

Rift Valley fever (RVF) is a mosquito-borne zoonosis endemic in Africa. With little known of the burden or epidemiology of RVF virus (RVFV) in Cameroon, this study aimed to determine the seroprevalence of RVFV in domestic ruminants of various origins in two markets of Yaoundé, Cameroon.

Methodology/Principal findings

The origin of animals randomly sampled at two livestock markets in Yaoundé were recorded and plasma samples collected for competitive and capture Enzyme-linked Immunosorbent Assay (ELISA) to determine the prevalence of Immunoglobulins G (IgG) and Immunoglobulins M (IgM) antibodies. Following ELISA IgM results, a real-time reverse transcription-polymerase chain reaction (qRT-PCR) was performed to detect RVFV RNA. In June-August 2019, February-March 2020, and March-April 2021, 756 plasma samples were collected from 441 cattle, 168 goats, and 147 sheep. RVFV IgG seroprevalence was 25.7% for all animals, 42.2% in cattle, 2.7% in sheep, and 2.4% in goats. However, IgM seroprevalence was low, at 0.9% in all animals, 1.1% in cattle, 1.4% in sheep, and 0% in goats. The seroprevalence rates varied according to the animal’s origin with the highest rate (52.6%) in cattle from Sudan. In Cameroon, IgG and IgM rates respectively were 45.1% and 2.8% in the North, 44.8% and 0% in the Adamawa, 38.6% and 1.7% in the Far-North. All IgM positive samples were from Cameroon. In cattle, 2/5 IgM positive samples were also IgG positive, but both IgM positive samples in sheep were IgG negative. Three (42.9%) IgM positive samples were positive for viral RVFV RNA using qRT-PCR but given the high ct values, no amplicon was obtained.

Conclusion/Significance

These findings confirm the circulation of RVFV in livestock in Cameroon with prevalence rates varying by location. Despite low IgM seroprevalence rates, RVF outbreaks can occur without being noticed. Further epidemiological studies are needed to have a broad understanding of RVFV transmission in Cameroon.

Assessment of Knowledge, Attitudes, and Practices towards Rift Valley Fever among Livestock Farmers in Selected Districts of Malawi

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis whose cases go unreported in endemic areas without active surveillance. Information on the knowledge, attitude, and practice of RVF among livestock farmers remains speculative in Malawi. A cross-section survey using a semi-structured questionnaire (n = 400) was conducted in eight districts of Malawi to capture information on knowledge, attitude, and management practices (KAP) regarding RVF. The average KAP score was calculated from total scores for knowledge, attitude, and practices and then assessed. The association between the level of knowledge and factors of knowledge, factors of attitude, and factors of practices was determined using Pearson chi-square. Multivariate analysis was used to determine the predictors of knowledge. Participants had an overall poor knowledge (score = 17.94%), negative attitude (score = 9.40%), and poor management practices (score = 41.23%) towards RVF. Only 8.25% (33/400) of participants had sufficient knowledge of RVF. The study found that the cause of abortion (OR: 3.86 (95% CI: 1.14–13.05)) (p = 0.030) and knowledge on transmission of RVFV (OR: 5.65 (95% CI: 1.76–18.12)) (p = 0.004) were predictors of insufficient knowledge of RVF. The current study reported that participants had insufficient knowledge and a negative attitude despite displaying limited management practices towards RVF. Therefore, this study recommends community sensitization to RVF and advocates for the importance of reporting suspected cases to relevant authorities for proper management.

Hepatitis E Virus Outbreak among Tigray War Refugees from Ethiopia, Sudan

We report hepatitis E virus (HEV) outbreaks among refugees from Ethiopia in Sudan during June 2021-February 2022. We identified 1,589 cases of acute jaundice syndrome and used PCR to confirm HEV infection in 64% of cases. Implementing vaccination, water, sanitation, and hygiene programs might reduce HEV outbreak risk.

Epidemiology of Mosquito-Borne Viruses in Egypt: A Systematic Review

There are at least five common mosquito-borne viruses (MBVs) recorded in Egypt, including dengue virus (DENV), Rift Valley fever virus (RVFV), West Nile virus (WNV), Chikungunya virus, and Sindbis virus. Unexpected outbreaks caused by MBVs reflect the deficiencies of the MBV surveillance system in Egypt. This systematic review characterized the epidemiology of MBV prevalence in Egypt. Human, animal, and vector prevalence studies on MBVs in Egypt were retrieved from Web of Science, PubMed, and Bing Scholar, and 33 eligible studies were included for further analyses. The monophyletic characterization of the RVFV and WNV strains found in Egypt, which spans about half a century, suggests that both RVFV and WNV are widely transmitted in this nation. Moreover, the seropositive rates of DENV and WNV in hosts were on the rise in recent years, and spillover events of DENV and WNV to other countries from Egypt have been recorded. The common drawback for surveillance of MBVs in Egypt is the lack of seroprevalence studies on MBVs, especially in this century. It is necessary to evaluate endemic transmission risk, establish an early warning system for MBVs, and develop a sound joint system for medical care and public health for managing MBVs in Egypt.

Epidemics of Crimean-Congo Hemorrhagic Fever (CCHF) in Sudan between 2010 and 2020

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic arboviral disease that poses a great threat to global health in the Old World, and it is endemic in Europe, Asia, and Africa, including Sudan. In this retrospective study, we reviewed previous epidemiological reports about the major epidemics of CCHF throughout Sudan between 2010 and 2020. During these epidemics, the infection of humans with Crimean-Congo hemorrhagic fever virus (CCHFV), the causative agent of CCHF, was diagnosed using qRT-PCR. We have identified 88 cases of CCHF, including 13 fatalities reported during five epidemics that occurred in 2010, 2011, 2015, 2019, and 2020. The two epidemics in 2010 and 2011 were by far the largest, with 51 and 27 cases reported, respectively. The majority of cases (78%) were reported in the endemic region of Kordofan. Here, we document that the first emergence of CCHFV in the Darfur region, West Sudan, occurred in 2010. We were not able to investigate outbreak dynamics through phylogenetic analysis due to the limited diagnostic capacity and the lack of sequencing services in the country. These findings call for establishing a genomic-based integrated One Health surveillance and response system for the early preparedness, prevention, and control of CCHF in the country.

Blood meal profile and positivity rate with malaria parasites among different malaria vectors in Sudan

Background

Malaria is a life-threatening public health problem globally with particularly heavy burden in the sub-Saharan Africa including Sudan. The understanding of feeding preference of malaria vectors on different hosts is a major challenge for hindering the transmission cycle of malaria. In this study, blood meals taken by blood-fed Anopheles mosquitoes collected from the field in malaria endemic areas of Sudan were analysed for source of blood meal and malaria parasite presence.

Methods

Anopheles mosquitoes were collected from different regions in Sudan: Khartoum state, Sennar state, Northern state, and El Gedarif state between September 2020 and February 2021. Anopheles mosquitoes were collected using the standard pyrethrum spray catch and back-pack aspirator. Mosquito samples were sorted and morphologically identified to species level using international identification keys. Morphologically identified mosquito species were also confirmed using PCR. Genomic DNA was extracted from mosquitoes for molecular identification of blood meal source and parasite detection. The presence of Plasmodium species DNA in each mosquito sample was investigated using semi-nested PCR. Frequency of each blood meal source, Anopheles mosquito vector, and malaria parasite detected was calculated. Positivity rate of each fed female Anopheles mosquito was calculated for each species.

Results

A total of 2132 Anopheles mosquitoes were collected. 571 (26.8%) were males and 1561 (73.2%) were females classified based on their abdominal status into 1048 (67.1%) gravid, 274 (17.6%) fed, and 239 (15.3%) unfed females. Among the blood fed Anopheles mosquitoes, 263 (96.0%) were morphologically identified and confirmed using PCR to Anopheles arabiensis, 9 (3.3%) to Anopheles stephensi, and 2 (0.7%) to Anopheles rufipes. Of 274 blood-fed An. arabiensis, 68 (25.9%) fed on mixed blood meals from human and cattle, 8 (3.0%) fed on cattle and goat, and 13 (4.8%) fed on human, cattle and goat. For single blood meal sources, 70 (26.6%) fed on human, 95 (36.1%) fed on cattle, 8 (3.0%) fed on goat, and 1 (0.4%) fed on dog. While An. rufipes and An. stephensi fed on dog (2; 0.75%) and cattle (9; 3.3%), respectively. Plasmodium parasite detection in the blood meals showed that 25/274 (9.1%) An. arabiensis meals were positive for Plasmodium vivax and 19/274 (6.9%) An. arabiensis meals were positive for Plasmodium falciparum. The rate of positivity of An. arabiensis with any Plasmodium species was 16.7%. However, the positivity rate with P. falciparum only was 7.2%, while P. vivax was 9.5%. Both An. rufipes and An. stephensi were having positivity rates of 0.0% each.

Conclusions

This study which was mainly on blood-fed Anopheles mosquitoes showed a diversity in the type of diet from human, cattle, and goat. Anopheles mosquitoes especially An. arabiensis in Sudan, are opportunistic blood feeders and can feed broadly on both human and cattle. The application of blood meal identification is not only important in malaria vector epidemiological surveillance but also is very useful in areas where arthropods exhibit zoophilic feeding behaviour for mammals.

Utilization of Viral Vector Vaccines in Preparing for Future Pandemics

As the global response to COVID-19 continues, government stakeholders and private partners must keep an eye on the future for the next emerging viral threat with pandemic potential. Many of the virus families considered to be among these threats currently cause sporadic outbreaks of unpredictable size and timing. This represents a major challenge in terms of both obtaining sufficient funding to develop vaccines, and the ability to evaluate clinical efficacy in the field. However, this also presents an opportunity in which vaccines, along with robust diagnostics and contact tracing, can be utilized to respond to outbreaks as they occur, and limit the potential for further spread of the disease in question. While mRNA-based vaccines have proven, during the COVID-19 response, to be an effective and safe solution in terms of providing a rapid response to vaccine development, virus vector-based vaccines represent a class of vaccines that can offer key advantages in certain performance characteristics with regard to viruses of pandemic potential. Here, we will discuss some of the key pros and cons of viral vector vaccines in the context of preparing for future pandemics.

The Phylodynamic and Spread of the Invasive Asian Malaria Vectors, Anopheles stephensi, in Sudan

Simple Summary

Climate change increases the suitability of some environments for the establishment of newly introduced insects and is a major driver for the spread of mosquitoes that transmit diseases. Anopheles stephensi is a disease vector mosquito that transmits malaria and is naturally endemic in Asia. This vector newly emerged in Africa (first report from Djibouti in 2012), where annual malaria infections and deaths are the highest worldwide. This mosquito has different ecology and behavior from previously known malaria vectors in Africa, which makes control difficult for local under-resourced health systems. Considering the capacity of this vector to transmit at least two malaria-causing parasites (Plasmodium falciparum and Plasmodium vivax), we investigated its distribution and population structure in Sudan and assessed the potential risk of its further spread into neighboring countries. Using morphological and genomic sequencing techniques, we confirmed the presence of Anopheles stephensi along the borders of six countries previously assumed as free, including Chad, Egypt, Eritrea, Libya, Republic of Central Africa, and South Sudan. African countries need to enhance vector surveillance and control services and utilize genomics tools for tracking the dynamics of invasive disease vectors.

Abstract

Anopheles stephensi is an invasive Asian malaria vector that initially emerged in Africa in 2012 and was reported in Sudan in 2019. We investigated the distribution and population structure of An. stephensi throughout Sudan by using sequencing and molecular tools. We confirmed the presence of An. stephensi in eight border-states, identifying both natural and human-made breeding sites. Our analysis revealed the presence of 20 haplotypes with different distributions per state. This study revealed a countrywide spread of An. stephensi in Sudan, with confirmed presence in borders states with Chad, Egypt, Eritrea, Ethiopia, Libya, Republic of Central Africa, and South Sudan. Detection of An. stephensi at points of entry with these countries, particularly Chad, Libya, and South Sudan, indicates the rapid previously undetected spread of this invasive vector. Our phylogenetic and haplotype analysis suggested local establishment and evolutionary adaptation of the vector to different ecological and environmental conditions in Sudan. Urgent engagement of the global community is essential to control and prevent further spread into Africa.

Population Genetic Analysis of Aedes aegypti Mosquitoes From Sudan Revealed Recent Independent Colonization Events by the Two Subspecies

Increases in arbovirus outbreaks in Sudan are vectored by Aedes aegypti, raising the medical importance of this mosquito. We genotyped 12 microsatellite loci in four populations of Ae. aegypti from Sudan, two from the East and two from the West, and analyzed them together with a previously published database of 31 worldwide populations to infer population structure and investigate the demographic history of this species in Sudan. Our results revealed the presence of two genetically distinct subspecies of Ae. aegypti in Sudan. These are Ae. aegypti aegypti in Eastern Sudan and Ae. aegypti formosus in Western Sudan. Clustering analysis showed that mosquitoes from East Sudan are genetically homogeneous, while we found population substructure in West Sudan. In the global context our results indicate that Eastern Sudan populations are genetically closer to Asian and American populations, while Western Sudan populations are related to East and West African populations. Approximate Bayesian Computation Analysis supports a scenario in which Ae. aegypti entered Sudan in at least two independent occasions nearly 70–80 years ago. This study provides a baseline database that can be used to determine the likely origin of new introductions for this invasive species into Sudan. The presence of the two subspecies in the country should be consider when designing interventions, since they display different behaviors regarding epidemiologically relevant parameters, such as blood feeding preferences and ability to transmit disease.

Detection of Rift Valley Fever Virus Lineage H from South Africa through Syndromic Sentinel Surveillance Network in Senegal

Background

Rift Valley fever virus (RVFV) is an arbovirus that causes epizootics and epidemics among livestock population and humans. Our surveillance system has revealed multiple emergences and re-emergences of RVFV in West Africa over the last decade.

Methods

The Sentinel Syndromic Surveillance Network in Senegal (4S) has been implemented since 2011. Samples from human suspected arbovirus infection in 4S sentinel sites were sent to Institut Pasteur de Dakar (IPD), where arbovirus diagnosis by enzyme-linked immunosorbent assay (ELISA), real-time reverse transcription polymerase chain reaction (RT-PCR), and virus isolation was performed. Overall, IPD has received a total of 1149 samples from arboviral suspected patients through the 4S network from January to December 2020. These samples were screened for 7 arboviruses including RVFV. Whole-genome sequencing of positive RVFV samples by RT-PCR was performed using the Illumina Miseq platform followed by genome assembly. Phylogenetic analyses were performed using MEGA X.

Results

Out of the 1149 arbovirus suspected cases, 4 RVFV-positive samples were detected with RT-PCR while 5 RVFV-positive samples were detected by ELISA. Complete genome sequences were obtained for 3 strains among the 4 positive samples by RT-PCR. Phylogenetic analyses indicated an emergence of a virus first described in South Africa during a major outbreak.

Conclusions

This strong surveillance system allowed the detection of an RVFV outbreak in Senegal in 2020. The obtained genomes clustered with strains from South Africa belonging to lineage H. This calls for implementation of a strong surveillance system for wild animals, humans, and livestock simultaneously in all African countries.

The Emergence of Rift Valley Fever in Gedaref State Urges the Need for a Cross-Border One Health Strategy and Enforcement of the International Health Regulations

This study investigated the causative agent of a haemorrhagic fever epidemic in Gedaref state, south-east Sudan. Six cases of febrile illness with haemorrhagic manifestations presented at outpatient health-clinics. Blood samples were collected from the patients and shipped to Khartoum where they were tested for dengue virus (DENV), chikungunya virus (CHIKV), and Rift Valley fever virus (RVFV) using real-time qPCR. Fifty percent (3/6) of them tested positive for RVFV and neither DENV or CHIKV was detected. All patients were males between 20 and 48 years old who had no history of recent travel. This finding describes the first emergence of RVFV in Gedaref state. Considering that the state hosts a major market of livestock, and it has one of the largest-seasonal open pastures in the country that is usually flooded with herds from the neighbouring states and countries during the rainy season, this emergence could represent a major threat to public health in the region and countries importing animals and/or animal products from east Africa. Therefore, we urge the policymakers of the health and animal resources sectors to implement a one health strategy with a well-established early warning surveillance and response system to prevent the establishment of the disease in the area.

First report of epidemic dengue fever and malaria co-infections among internally displaced persons in humanitarian camps of North Darfur, Sudan

Objectives:

This study aimed to investigate an outbreak of a non-malaria, undifferentiated febrile illness, among internally displaced persons (IDPs) living in humanitarian camps in North Darfur, Sudan, in 2019.

Methods:

An investigation team was deployed to North Darfur to identify suspected cases and collect blood samples, and clinical and demographical data. Blood samples were examined microscopically for Plasmodium spp and tested for dengue (DENV) and yellow fever viruses by reverse transcriptase-quantitative polymerase chain reaction.

Results:

Between September 7 and December 18, 2019, we clinically identified 18 (24%), 41 (54%), and 17 (22%) cases of dengue fever, dengue with warning signs, and severe dengue, respectively. Blood samples were collected from 22% of patients, and 47% of these tested positive for DENV-1 RNA. We confirmed 32 malaria cases with 5 co-infections with DENV. This outbreak of dengue was the first among IDPs in the humanitarian camps.

Conclusions:

Our findings indicate that dengue has become endemic or that there has been a new introduction. Further epidemiological, entomological, and phylogenetic studies are needed to understand disease transmission in the area. An early warning and response system and an effective health policy are crucial for preventing and controlling arboviruses in Sudan.

External quality assessment of Rift Valley fever diagnosis in countries at risk of the disease: African, Indian Ocean and Middle-East regions

Rift Valley fever virus (RVFV), an arbovirus belonging to the Phlebovirus genus of the Phenuiviridae family, causes the zoonotic and mosquito-borne RVF. The virus, which primarily affects livestock (ruminants and camels) and humans, is at the origin of recent major outbreaks across the African continent (Mauritania, Libya, Sudan), and in the South-Western Indian Ocean (SWIO) islands (Mayotte). In order to be better prepared for upcoming outbreaks, to predict its introduction in RVFV unscathed countries, and to run efficient surveillance programmes, the priority is harmonising and improving the diagnostic capacity of endemic countries and/or countries considered to be at risk of RVF. A serological inter-laboratory proficiency test (PT) was implemented to assess the capacity of veterinary laboratories to detect antibodies against RVFV. A total of 18 laboratories in 13 countries in the Middle East, North Africa, South Africa, and the Indian Ocean participated in the initiative. Two commercial kits and two in-house serological assays for the detection of RVFV specific IgG antibodies were tested. Sixteen of the 18 participating laboratories (88.9%) used commercial kits, the analytical performance of test sensitivity and specificity based on the seroneutralisation test considered as the reference was 100%. The results obtained by the laboratories which used the in-house assay were correct in only one of the two criteria (either sensitivity or specificity). In conclusion, most of the laboratories performed well in detecting RVFV specific IgG antibodies and can therefore be considered to be prepared. Three laboratories in three countries need to improve their detection capacities. Our study demonstrates the importance of conducting regular proficiency tests to evaluate the level of preparedness of countries and of building a network of competent laboratories in terms of laboratory diagnosis to better face future emerging diseases in emergency conditions.

The first laboratory-confirmed imported infections of SARS-CoV-2 in Sudan

BACKGROUND

The rapidly growing pandemic of coronavirus disease 2019 (COVID-19) has challenged health systems globally. Here we report the first identified infections of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; aetiology of COVID-19) among recent international arrivals to Sudan and their contacts.

METHODS

Suspected cases were identified clinically and/or epidemiologically. Samples from suspected cases and their contacts were tested in the National Influenza Centre following World Health Organization protocols. Two real-time reverse transcription quantitative polymerase chain reaction assays were used to detect and confirm SARS-CoV-2 infection.

RESULTS

Seven cases of COVID-19, including two deaths, were confirmed in Sudan between 27 February and 30 March 2020. Suspected cases were identified and tested. As of 30 March, no local transmission was yet reported in the country. Fifty-nine percent of the suspected cases were international travellers coming from areas with current COVID-19 epidemics. Cough and fever were the major symptoms, presented by 65% and 60% of the suspected cases, respectively. By early April, an additional seven cases were confirmed through limited contact tracing that identified the first locally acquired infections in recent contact with imported cases.

CONCLUSIONS

The high mortality rate of COVID-19 cases in Sudan might be due to limitations in test and trace and case management services. Unfortunately, infections have spread further into other states and the country has no capacity for mass community screening to better estimate disease prevalence. Therefore external support is urgently needed to improve the healthcare and surveillance systems.