21 research outputs found
Urgent need for a non-discriminatory and non-stigmatizing nomenclature for monkeypox virus
Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9451062/We propose a novel, non-discriminatory classification of monkeypox virus diversity. Together with the World Health Organization, we named three clades (I, IIa and IIb) in order of detection. Within IIb, the cause of the current global outbreak, we identified multiple lineages (A.1, A.2, A.1.1 and B.1) to support real-time genomic surveillance.info:eu-repo/semantics/publishedVersio
The Chikungunya Epidemic on La Réunion Island in 2005–2006: A Cost-of-Illness Study
For a long time, studies of chikungunya virus infection have been neglected, but since its resurgence in the south-western Indian Ocean and on La Réunion Island, this disease has been paid greater amounts of attention. The economic and social impacts of chikungunya epidemics are poorly documented, including in developed countries. This study estimated the cost-of-illness associated with the 2005–2006 chikungunya epidemics on La Réunion Island, a French overseas department with an economy and health care system of a developed country. “Cost-of-illness” studies measure the amount that would have been saved in the absence of a disease. We found that the epidemic incurred substantial medical expenses estimated at €43.9 million, of which 60% were attributable to direct medical costs related, in particular, to expenditure on medical consultations (47%), hospitalization (32%) and drugs (19%). The costs related to care in ambulatory and hospitalized cases were €90 and €2000 per case, respectively. This study provides the basic inputs for conducting cost-effectiveness and cost-benefit evaluations of chikungunya prevention strategies
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century
Invasion of Aedes albopictus (Diptera: Culicidae) into central Africa : what consequences for emerging diseases ?
Aedes albopictus, a mosquito native to Asia, has invaded all five continents during the past three decades. It was reported in central Africa in the 2000s, first in Cameroon, and, since then, has colonised almost all countries of the region. The species, originally considered a secondary vector of dengue viruses, has been showed to play a major role in transmission of chikungunya virus in numerous countries, including in the central African region. We review the current spread of Ae. albopictus in central Africa, its larval ecology and its impact on indigenous species such as Ae. aegypti. We explore the potential of Ae. albopictus to affect the epidemiology of emerging or re-emerging arboviruses and discuss the conventional means for its control, while emphasizing the importance of data on its susceptibility to insecticides to cope with potential outbreaks
Entomological profile of yellow fever epidemics in the Central African Republic, 2006-2010
BACKGROUND: The causative agent of yellow fever is an arbovirus of the Flaviviridae family transmitted by infected Aedes mosquitoes, particularly in Africa. In the Central African Republic since 2006, cases have been notified in the provinces of Ombella-Mpoko, Ouham-Pende, Basse-Kotto, Haute-Kotto and in Bangui the capital. As the presence of a vector of yellow fever virus (YFV) represents a risk for spread of the disease, we undertook entomological investigations at these sites to identify potential vectors of YFV and their abundance. FINDINGS: Between 2006 and 2010, 5066 mosquitoes belonging to six genera and 43 species were identified. The 20 species of the Aedes genus identified included Ae. aegypti, the main vector of YFV in urban settings, and species found in tropical forests, such as Ae. africanus, Ae. simpsoni, Ae. luteocephalus, Ae. vittatus and Ae. opok. These species were not distributed uniformly in the various sites studied. Thus, the predominant Aedes species was Ae. aegypti in Bangui (90.7 %) and Basse-Kotto (42.2 %), Ae. africanus in Ombella-Mpoko (67.4 %) and Haute-Kotto (77.8 %) and Ae. vittatus in Ouham-Pende (62.2 %). Ae. albopictus was also found in Bangui. The distribution of these dominant species differed significantly according to study site (P < 0.0001). None of the pooled homogenates of Aedes mosquitoes analysed by polymerase chain reaction contained the YFV genome. CONCLUSION: The results indicate a wide diversity of vector species for YFV in the Central African Republic. The establishment of surveillance and vector control programs should take into account the ecological specificity of each species
Phylogeny of African fruit bats (Chiroptera, Pteropodidae) based on complete mitochondrial genomes
Members of the family Pteropodidae, also known as Old World fruit bats, are represented in Africa by 14 genera and 44 species. Here, we sequenced 67 complete mitochondrial genomes from African and Asian pteropodids to better understand the evolutionary history of the subfamily Rousettinae, which includes most of the African species. An increased frequency of guanine to adenine transitions is detected in the mtDNA genomes of Macroglossus sobrinus and all species of Casinycteris and Scotonycteris. Our phylogenetic and molecular dating analyses based on 126 taxa and 15,448 characters indicate a low signal for deep relationships within the family, suggesting a rapid diversification during the Late Oligocene period of "warming." Within the subfamily Rousettinae, most nodes are highly supported by our different analyses (all nucleotide sites, SuperTRI analyses of a sliding window, transversions only, coding genes only, and amino acid sequences). The results indicate the existence of four tribes: Rousettini-distributed from Africa through Mediterranean region and South Asia to South-East Asia; Eonycterini-found in Asia; and Epomophorini and Scotonycterini-restricted to sub-Saharan Africa. Although most interspecies relationships are highly supported, three parts of the Rousettinae mitochondrial tree are still unresolved, suggesting rapid diversification: (a) among the three subtribes Epomophorina (Epomophorus sensu lato, i.e., including Micropteropus, Epomops, Hypsignathus, Nanonycteris), Plerotina (Plerotes), and Myonycterina (Myonycteris, Megaloglossus) in the Late Miocene; (b) among Epomops, Hypsignathus, and other species of Epomophorina at the Pliocene-Pleistocene boundary; and (c) among Myonycteris species in the Early Pleistocene. Within the Epomophorini, Stenonycteris lanosus emerged first, suggesting that lingual echolocation may have appeared in the common ancestor of Epomophorini and Rousettini. Our analyses suggest that multiple events of mtDNA introgression occurred within the Epomophorus species complex during the Pleistocene
Viral exploration of negative acute febrile cases observed during chikungunya outbreaks in Gabon
Non-malarial febrile illness outbreaks were documented in 2007 and 2010 in Gabon. After investigation, these outbreaks were attributed to the chikungunya and dengue viruses (CHIKV and DENV). However, for more than half of the samples analyzed, the causative agent was not identified. Given the geographical and ecological position of Gabon, where there is a great animal and microbial diversity, the circulation of other emerging viruses was suspected in these samples lacking aetiology. A total of 436 undiagnosed samples, collected between 2007 and 2013, and originating from 14 urban, suburban, and rural Gabonese locations were selected. These samples were used for viral isolation on newborn mice and VERO cells. In samples with signs of viral replication, cell supernatants and brain suspensions were used to extract nucleic acids and perform real-time RT-PCR targeting specific arboviruses, i.e., CHIKV, DENV, yellow fever, Rift Valley fever, and West Nile and Zika viruses. Virus isolation was conclusive for 43 samples either on newborn mice or by cell culture. Virus identification by RT-PCR led to the identification of CHIKV in 37 isolates. A total of 18 complete genomes and 19 partial sequences containing the E2 and E1 genes of CHIKV were sequenced using next-generation sequencing technology or the Sanger method. Phylogenetic analysis of the complete genomes showed that all the sequences belong to the East Central South Africa lineage. Furthermore, we identified 2 distinct clusters. The first cluster was made up of sequences from the western part of Gabon, whereas the second cluster was made up of sequences from the southern regions, reflecting the way CHIKV spread across the country following its initial introduction in 2007. Similar results were obtained when analyzing the CHIKV genes of the E2 and E1 structural proteins. Moreover, study of the mutations found in the E2 and E1 structural proteins revealed the presence of several mutations that facilitate the adaptation to the Aedes albopictus mosquito, such as E2 I211T and E1 A226V, in all the Gabonese CHIKV strains. Finally, sequencing of 6 additional viral isolates failed to lead to any conclusive identification
Identification of Ebola virus sequences present as RNA or DNA in organs of terrestrial small mammals of the Central African Republic
WOS:000084213200007International audienceThe life cycle of the Ebola (EBO) virus remains enigmatic. We tested for EBO virus in the organs of 242 small mammals captured during ecological studies in the Central African Republic. EBO virus glycoprotein or polymerase gene sequences were detected by reverse transcription PCR in RNA extracts of the organs of seven animals and by PCR in DNA extract of one animal. Neither live virus nor virus antigen was detected in any organ sample. Direct sequencing of amplicons identified the virus as being of the Zaire/Gabon subtype. Virus-like nucleocapsids were observed by electron microscopy in the cytoplasm of the spleen cells of one animal. The animals belonged to two genera of rodents (Muridae; Mus setulosus, Praomys sp1 and P. sp2) and one species of shrew (Soricidae; Sylvisorex ollula). These preliminary results provide evidence that common terrestrial small mammals living in peripheral forest areas have been in contact with the EBO virus and demonstrate the persistence of EBO virus RNA and DNA in the organs of the animals. Our findings should lead to better targeting of research into the life cycle of the EBO virus. (C) 1999 Editions scientifiques et medicales Elsevier SAS
Bat distribution size or shape as determinant of viral richness in African bats
The rising incidence of emerging infectious diseases (EID) is mostly linked to biodiversity loss, changes in habitat use and increasing habitat fragmentation. Bats are linked to a growing number of EID but few studies have explored the factors of viral richness in bats. These may have implications for role of bats as potential reservoirs. We investigated the determinants of viral richness in 15 species of African bats (8 Pteropodidae and 7 microchiroptera) in Central and West Africa for which we provide new information on virus infection and bat phylogeny. We performed the first comparative analysis testing the correlation of the fragmented geographical distribution (defined as the perimeter to area ratio) with viral richness in bats. Because of their potential effect, sampling effort, host body weight, ecological and behavioural traits such as roosting behaviour, migration and geographical range, were included into the analysis as variables. The results showed that the geographical distribution size, shape and host body weight have significant effects on viral richness in bats. Viral richness was higher in large-bodied bats which had larger and more fragmented distribution areas. Accumulation of viruses may be related to the historical expansion and contraction of bat species distribution range, with potentially strong effects of distribution edges on virus transmission. Two potential explanations may explain these results. A positive distribution edge effect on the abundance or distribution of some bat species could have facilitated host switches. Alternatively, parasitism could play a direct role in shaping the distribution range of hosts through host local extinction by virulent parasites. This study highlights the importance of considering the fragmentation of bat species geographical distribution in order to understand their role in the circulation of viruses in Africa
Lutte contre la rage en Afrique: du constat à l’action
International audienceAs a follow-up to the first AfroREB (Africa Rabies Expert Bureau) meeting, held in Grand-Bassam (Côte-d'Ivoire) in March 2008, African rabies experts of the Afro-REB network met a second time to complete the evaluation of the rabies situation in Africa and define specific action plans. About forty French speaking rabies specialists from Northern, Western and Central Africa and Madagascar met in Dakar (Senegal), from March 16th to 19th, 2009. With the participation of delegates from Tunisia, who joined the AfroREB network this year, 15 French speaking African countries were represented. Experts from the Institut Pasteur in Paris, the Alliance for Rabies Control, and the Southern and Eastern African Rabies Group (SEARG, a network of rabies experts from 19 English speaking Southern and Eastern African countries) were in attendance, to participate in the discussion and share their experiences. AfroREB members documented 146 known human rabies cases in all represented countries combined for 2008, for a total population of 209.3 million, or an incidence of 0.07 cases per 100,000 people. Even admitting that the experts do not have access to all reported cases, this is far from the WHO estimation of 2 rabies deaths per 100,000 people in urban areas and 3.6 per 100,000 in rural Africa. It was unanimously agreed that the priority is to break the vicious cycle of indifference and lack of information which is the main barrier to human rabies prevention.Le Bureau des experts de la rage du continent africain (AfroREB) s’est réuni pour la seconde fois, en mars 2009, pour poursuivre leur évaluation de la situation de la rage en Afrique et définir des plans d’action. Une quarantaine d’éminents spécialistes de la rage venant de 15 pays d’Afrique francophone se sont retrouvés à Dakar avec des représentants de l’Institut Pasteur de Paris, du réseau anglophone SEARG (groupe de spécialistes de la rage d’Afrique australe et orientale) et de l’Alliance mondiale contre la rage. En Afrique, de nombreux cas de rage ne sont ni identifiés ni rapportés. Alors que l’OMS estime à 25 000 le nombre de décès annuels dus à la rage sur ce continent (2 à 3,6 décès pour 100 000 habitants), les membres d’AfroREB ont comptabilisé, en tout et pour tout, en 2008, 146 cas pour leurs 15 pays, soit 0,07 cas pour 100 000 habitants. La priorité est de briser le cercle vicieux de l’indifférence et du manque d’information, afin de pouvoir lutter contre la rage humaine