Publications by authors named "Catherine Cêtre-Sossah"

47 Publications

The role of livestock movements in the spread of Rift Valley fever virus in animals and humans in Mayotte, 2018-19.

PLoS Negl Trop Dis 2021 Mar 8;15(3):e0009202. Epub 2021 Mar 8.

Veterinary Epidemiology, Economics and Public Health group, Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hatfield, United Kingdom.

Rift Valley fever (RVF) is a vector-borne viral disease of major animal and public health importance. In 2018-19, it caused an epidemic in both livestock and human populations of the island of Mayotte. Using Bayesian modelling approaches, we assessed the spatio-temporal pattern of RVF virus (RVFV) infection in livestock and human populations across the island, and factors shaping it. First, we assessed if (i) livestock movements, (ii) spatial proximity from communes with infected animals, and (iii) livestock density were associated with the temporal sequence of RVFV introduction into Mayotte communes' livestock populations. Second, we assessed whether the rate of human infection was associated with (a) spatial proximity from and (b) livestock density of communes with infected animals. Our analyses showed that the temporal sequence of RVFV introduction into communes' livestock populations was associated with livestock movements and spatial proximity from communes with infected animals, with livestock movements being associated with the best model fit. Moreover, the pattern of human cases was associated with their spatial proximity from communes with infected animals, with the risk of human infection sharply increasing if livestock in the same or close communes were infected. This study highlights the importance of understanding livestock movement networks in informing the design of risk-based RVF surveillance programs.
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http://dx.doi.org/10.1371/journal.pntd.0009202DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7939299PMC
March 2021

Rift Valley Fever - epidemiological update and risk of introduction into Europe.

EFSA J 2020 Mar 6;18(3):e06041. Epub 2020 Mar 6.

Rift Valley fever (RVF) is a vector-borne disease transmitted by a broad spectrum of mosquito species, especially Aedes and Culex genus, to animals (domestic and wild ruminants and camels) and humans. Rift Valley fever is endemic in sub-Saharan Africa and in the Arabian Peninsula, with periodic epidemics characterised by 5-15 years of inter-epizootic periods. In the last two decades, RVF was notified in new African regions (e.g. Sahel), RVF epidemics occurred more frequently and low-level enzootic virus circulation has been demonstrated in livestock in various areas. Recent outbreaks in a French overseas department and some seropositive cases detected in Turkey, Tunisia and Libya raised the attention of the EU for a possible incursion into neighbouring countries. The movement of live animals is the most important pathway for RVF spread from the African endemic areas to North Africa and the Middle East. The movement of infected animals and infected vectors when shipped by flights, containers or road transport is considered as other plausible pathways of introduction into Europe. The overall risk of introduction of RVF into EU through the movement of infected animals is very low in all the EU regions and in all MSs (less than one epidemic every 500 years), given the strict EU animal import policy. The same level of risk of introduction in all the EU regions was estimated also considering the movement of infected vectors, with the highest level for Belgium, Greece, Malta, the Netherlands (one epidemic every 228-700 years), mainly linked to the number of connections by air and sea transports with African RVF infected countries. Although the EU territory does not seem to be directly exposed to an imminent risk of RVFV introduction, the risk of further spread into countries neighbouring the EU and the risks of possible introduction of infected vectors, suggest that EU authorities need to strengthen their surveillance and response capacities, as well as the collaboration with North African and Middle Eastern countries.
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http://dx.doi.org/10.2903/j.efsa.2020.6041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527653PMC
March 2020

Rift Valley Fever: risk of persistence, spread and impact in Mayotte (France).

EFSA J 2020 Apr 15;18(4):e06093. Epub 2020 Apr 15.

Rift Valley fever (RVF) is a vector-borne disease transmitted by different mosquito species, especially Aedes and Culex genus, to animals and humans. In November 2018, RVF re-emerged in Mayotte (France) after 11 years. Up to the end of October 2019, 126 outbreaks in animals and 143 human cases were reported. RVF mortality was 0.01%, and the number of abortions reported in polymerase chain reaction (PCR)-positive ruminants was fivefold greater than the previous 7 years. Milk loss production in 2019 compared to 2015-2018 was estimated to be 18%, corresponding to an economic loss of around €191,000 in all of Mayotte. The tropical climate in Mayotte provides conditions for the presence of mosquitoes during the whole year, and illegal introductions of animals represent a continuous risk of (re)introduction of RVF. The probability of RVF virus (RVFV) persisting in Mayotte for 5 or more years was estimated to be < 10% but could be much lower if vertical transmission in vectors does not occur. Persistence of RVF by vertical transmission in Mayotte and Réunion appears to be of minor relevance compared to other pathways of re-introduction (i.e. animal movement). However, there is a high uncertainty since there is limited information about the vertical transmission of some of the major species of vectors of RVFV in Mayotte and Réunion. The only identified pathways for the risk of spread of RVF from Mayotte to other countries were by infected vectors transported in airplanes or by wind currents. For the former, the risk of introduction of RVF to continental France was estimated to 4 × 10 epidemic per year (median value; 95% CI: 2 × 10; 0.0007), and 0.001 epidemic per year to Réunion (95% CI: 4 × 10; 0.16). For the latter pathway, mosquitoes dispersing on the wind from Mayotte between January and April 2019 could have reached the Comoros Islands, Madagascar, Mozambique and, possibly, Tanzania. However, these countries are already endemic for RVF, and an incursion of RVFV-infected mosquitoes would have negligible impact.
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http://dx.doi.org/10.2903/j.efsa.2020.6093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7448016PMC
April 2020

In vitro shared transcriptomic responses of Aedes aegypti to arboviral infections: example of dengue and Rift Valley fever viruses.

Parasit Vectors 2020 Aug 5;13(1):395. Epub 2020 Aug 5.

CIRAD, UMR ASTRE, 97490, Sainte Clotilde, La Réunion, France.

Background: Arthropod borne virus infections are the cause of severe emerging diseases. Among the diseases due to arboviruses, dengue (DEN) and Rift Valley fever (RVF) are in the top ten in the list of diseases responsible of severe human cases worldwide. Understanding the effects of viral infection on gene expression in competent vectors is a challenge for the development of early diagnostic tools and may enable researchers and policy makers to better anticipate outbreaks in the next future.

Methods: In this study, alterations in gene expression across the entire Aedes aegypti genome during infection with DENV and RVFV were investigated in vitro at two time points of infection, the early phase (24 h) and the late phase (6 days) of infection using the RNA sequencing approach RESULTS: A total of 10 upregulated genes that share a similar expression profile during infection with both viruses at early and late phases of infection were identified. Family B and D clip-domain serine proteases (CLIP) were clearly overrepresented as well as C-type lectins and transferrin.

Conclusions: Our data highlight the presence of 10 viral genes upregulated in Ae. aegypti during infection. They may also be targeted in the case of the development of broad-spectrum anti-viral diagnostic tools focusing the mosquito vectors rather than the mammalian hosts as they may predict the emergence of outbreaks.
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http://dx.doi.org/10.1186/s13071-020-04253-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7404916PMC
August 2020

A phylogenetic analysis of the biting midges belonging to Culicoides Latreille (Diptera: Ceratopogonidae) subgenus Avaritia using molecular data.

Parasit Vectors 2020 May 12;13(1):243. Epub 2020 May 12.

ASTRE, Univ Montpellier, Cirad, INRA, Montpellier, France.

Background: Within the genus Culicoides (Diptera: Ceratopogonidae), the subgenus Avaritia is of particular interest as it contains a significant number of economically important vector species. Disagreements about the systematic classification of species within this subgenus have resulted in a taxonomic imbroglio.

Methods: A molecular phylogeny of the subgenus Avaritia was conducted to test the existing systematic classification, which is based on phenetic assessment of morphological characters. Three nuclear ribosomal markers, internal transcribed spacer 1 and 2 (ITS1, ITS2), 5.8S, and three mitochondrial markers, cytochrome c oxidase subunit 1 and 2, and cytochrome b (cox1, cox2 and cytb), were obtained for 37 species of the subgenus Avaritia from all six biogeographical regions. Phylogenetic reconstructions using these genes independently and in combination were implemented using Bayesian inference analysis and maximum likelihood methods.

Results: Phylogenetic reconstructions gave strong support to several monophyletic groups within the subgenus Avaritia. Both C. actoni and C. pusillus formed a single clade with C. grahamii so their respective groups, the Actoni and Pusillus groups, have been merged with the Grahamii group. Some support was provided for the Boophagus and Jacobsoni groups. A group of species currently placed into the Orientalis group clustered in a clade with poor support. The Obsoletus group was defined as a sister clade to all other Avaritia groups. The clade including the Imicola group was well supported based on phylogenetic criteria.

Conclusions: This phylogenetic study combining five distinct molecular markers has provided meaningful insights into the systematic relationships of Culicoides (Avaritia) and highlighted future directions to continue the study of this subgenus. While the cox2 marker appeared to be useful to investigate closely related species, the 5.8S marker was highly conserved and uninformative. Further investigations including species absent from this work are needed to confirm the proposed systematic scheme. However, this systematic scheme can now serve as a foundation to investigate cryptic species affiliation within the subgenus. We advocate that future studies employ a combination of morphological and molecular analyses.
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http://dx.doi.org/10.1186/s13071-020-04111-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7216621PMC
May 2020

Seroprevalence and associated risk factors of Rift Valley fever in cattle and selected wildlife species at the livestock/wildlife interface areas of Gonarezhou National Park, Zimbabwe.

Onderstepoort J Vet Res 2020 Apr 8;87(1):e1-e7. Epub 2020 Apr 8.

Department of Clinical Veterinary Studies, Faculty of Veterinary Science, University of Zimbabwe, Harare.

A study was conducted to investigate the seroprevalence and associated risk factors of Rift Valley fever (RVF) infection in cattle and some selected wildlife species at selected interface areas at the periphery of the Great Limpopo Transfrontier Conservation Area in Zimbabwe. Three study sites were selected based on the type of livestock-wildlife interface: porous livestock-wildlife interface (unrestricted); non-porous livestock-wildlife interface (restricted by fencing) and livestock-wildlife non-interface (totally absent contact or control). Sera were collected from cattle aged ≥ 2 years representing both female and intact male. Sera were also collected from selected wild ungulates from Mabalauta (porous interface) and Chipinda Pools (non-interface) areas of the Gonarezhou National Park. Sera were tested for antibodies to Rift Valley fever virus (RVFV) using a competitive enzyme-linked immunosorbent assay (ELISA) test. AX2 test was used to assess differences between categories, and p 0.05 was considered as significant. In cattle, the overall seroprevalence was 1.7% (17/1011) (95% confidence interval [CI]: 1.01-2.7). The porous interface recorded a seroprevalence of 2.3% (95% CI: 1.2-4.3), the non-porous interface recorded a prevalence of 1.8% (95% CI: 0.7-4.3) and the non-interface area recorded a seroprevalence of 0.4% (955 CI: 0.02-2.5), but the difference in seroprevalence according to site was not significant (p 0.05). All impala and kudu samples tested negative. The overall seroprevalence in buffaloes was 11.7% (95% CI: 6.6-19.5), and there was no significant (p = 0.38) difference between the sites (Mabalauta, 4.4% [95% CI: 0.2-24] vs. Chipinda, 13.6% [95% CI: 7.6-23]). The overall seroprevalence in buffaloes (11.7%, 13/111) was significantly (p 0.0001) higher than in cattle (1.7%, 17/1011). The results established the presence of RVFV in cattle and selected wildlife and that sylvatic infections may be present in buffalo populations. Further studies are required to investigate if the virus is circulating between cattle and wildlife.
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http://dx.doi.org/10.4102/ojvr.v87i1.1731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7203192PMC
April 2020

Enabling animal rabies diagnostic in low-access areas: Sensitivity and specificity of a molecular diagnostic test from cerebral tissue dried on filter paper.

PLoS Negl Trop Dis 2020 03 6;14(3):e0008116. Epub 2020 Mar 6.

Rabies National Reference Laboratory, Virology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar.

Rabies is a lethal zoonotic encephalomyelitis that causes an estimated 59,000 human deaths yearly worldwide. Although developing countries of Asia and Africa bear the heaviest burden, surveillance and disease detection in these countries is often hampered by the absence of local laboratories able to diagnose rabies and/or the difficulties of sample shipment from low-access areas to national reference laboratories. Filter papers offer a convenient cost-effective alternative for the sampling, shipment, and storage of biological materials for the diagnosis of many pathogens including rabies virus, yet the properties of diagnostic tests using this support have not been evaluated thoroughly. Sensitivity and specificity of molecular diagnosis of rabies infection using a reverse transcription followed by a hemi-nested polymerase chain reaction (RT-hn-PCR) either directly on brain tissue or using brain tissue dried on filter paper were assessed on 113 suspected field animal samples in comparison to the direct fluorescent antibody test (FAT) recommended by the World Health Organization as one of the reference tests for rabies diagnosis. Impact of the duration of the storage was also evaluated. The sensitivity and the specificity of RT-hn-PCR i) on brain tissue were 96.6% (95% CI: [88.1-99.6]) and 92.7% (95% CI: [82.4-98.0]) respectively and ii) on brain tissue dried on filter paper 100% (95% CI: [93.8-100.0]) and 90.9% (95% CI: [80.0-97.0]) respectively. No loss of sensitivity of RT-hn-PCR on samples of brain tissue dried on filter paper left 7 days at ambient temperature was detected indicating that this method would enable analyzing impregnated filter papers sent to the national reference laboratory at ambient temperature within a 1-week shipment time. It could therefore be an effective alternative to facilitate storage and shipment of samples from low-access areas to enhance and expand rabies surveillance.
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http://dx.doi.org/10.1371/journal.pntd.0008116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7135319PMC
March 2020

Spatial Multicriteria Evaluation for Mapping the Risk of Occurrence of Peste des Petits Ruminants in Eastern Africa and the Union of the Comoros.

Front Vet Sci 2019 12;6:455. Epub 2019 Dec 12.

UMR ASTRE, CIRAD, Ste-Clotilde, France.

Peste des petits ruminants virus (PPRV), responsible for peste des petits ruminants (PPR), is widely circulating in Africa and Asia. The disease is a huge burden for the economy and development of the affected countries. In Eastern Africa, the disease is considered endemic. Because of the geographic proximity and existing trade between eastern African countries and the Comoros archipelago, the latter is at risk of introduction and spread, and the first PPR outbreaks occurred in the Union of the Comoros in 2012. The objective of this study was to map the areas suitable for PPR occurrence and spread in the Union of the Comoros and four eastern African countries, namely Ethiopia, Uganda, Kenya, and Tanzania. A Geographic Information System (GIS)-based Multicriteria Evaluation (MCE) was developed. Risk factors for PPR occurrence and spread, and their relative importance, were identified using literature review and expert-based knowledge. Corresponding geographic data were collected, standardized, and combined based on a weighted linear combination to obtain PPR suitability maps. The accuracy of the maps was assessed using outbreak data from the EMPRES database and a ROC curve analysis. Our model showed an excellent ability to distinguish between absence and presence of outbreaks in Eastern Africa (AUC = 0.907; 95% CI [0.820-0.994]), and a very good performance in the Union of the Comoros (AUC = 0.889, 95% CI: [0.694-1]). These results highlight the efficiency of the GIS-MCE method, which can be applied at different geographic scales: continental, national and local. The resulting maps provide decision support tools for implementation of disease surveillance and control measures, thus contributing to the PPR eradication goal of OIE and FAO by 2030.
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http://dx.doi.org/10.3389/fvets.2019.00455DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6922030PMC
December 2019

Modelling temporal dynamics of Culicoides Latreille (Diptera: Ceratopogonidae) populations on Reunion Island (Indian Ocean), vectors of viruses of veterinary importance.

Parasit Vectors 2019 Nov 27;12(1):562. Epub 2019 Nov 27.

CIRAD, UMR ASTRE, 97490, Sainte-Clotilde, La Réunion, France.

Background: Reunion Island regularly faces outbreaks of epizootic haemorrhagic disease (EHD) and bluetongue (BT), two viral diseases transmitted by haematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae) to ruminants. To date, five species of Culicoides are recorded in Reunion Island in which the first two are proven vector species: Culicoides bolitinos, C. imicola, C. enderleini, C. grahamii and C. kibatiensis. Meteorological and environmental factors can severely constrain Culicoides populations and activities and thereby affect dispersion and intensity of transmission of Culicoides-borne viruses. The aim of this study was to describe and predict the temporal dynamics of all Culicoides species present in Reunion Island.

Methods: Between 2016 and 2018, 55 biweekly Culicoides catches using Onderstepoort Veterinary Institute traps were set up in 11 sites. A hurdle model (i.e. a presence/absence model combined with an abundance model) was developed for each species in order to determine meteorological and environmental drivers of presence and abundance of Culicoides.

Results: Abundance displayed very strong heterogeneity between sites. Average Culicoides catch per site per night ranged from 4 to 45,875 individuals. Culicoides imicola was dominant at low altitude and C. kibatiensis at high altitude. A marked seasonality was observed for the three other species with annual variations. Twelve groups of variables were tested. It was found that presence and/or abundance of all five Culicoides species were driven by common parameters: rain, temperature, vegetation index, forested environment and host density. Other parameters such as wind speed and farm building opening size governed abundance level of some species. In addition, Culicoides populations were also affected by meteorological parameters and/or vegetation index with different lags of time, suggesting an impact on immature stages. Taking into account all the parameters for the final hurdle model, the error rate by Normalized Root mean Square Error ranged from 4.4 to 8.5%.

Conclusions: To our knowledge, this is the first study to model Culicoides population dynamics in Reunion Island. In the absence of vaccination and vector control strategies, determining periods of high abundance of Culicoides is a crucial first step towards identifying periods at high risk of transmission for the two economically important viruses they transmit.
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http://dx.doi.org/10.1186/s13071-019-3812-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6880491PMC
November 2019

Development and validation of a pen side test for Rift Valley fever.

PLoS Negl Trop Dis 2019 09 11;13(9):e0007700. Epub 2019 Sep 11.

ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France.

Background: Rift Valley fever (RVF) is one of the main vector borne zoonotic diseases that affects a wide range of ruminants and human beings in Africa and the Arabian Peninsula. A rapid and specific test for RVF diagnosis at the site of a suspected outbreak is crucial for the implementation of control measures.

Methodology/principal Findings: A first-line lateral flow immunochromatographic strip test (LFT) was developed for the detection of the nucleoprotein (N) of the RVF virus (RVFV). Its diagnostic performance characteristics were evaluated using reference stocks isolates recovered from different hosts and in geographic regions mimicking clinical specimens and from known RVF negative serum samples. A high level of diagnostic accuracy (DSe (35/35), DSp (167/169)) was observed, including the absence of cross-reactivity with viruses belonging to different genera.

Conclusion/significance: The fact no specialized reagents and laboratory equipment are needed, make this assay a valuable, first-line diagnostic tool in resource-poor diagnostic territories for on-site RVFV detection, however the staff require training.
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http://dx.doi.org/10.1371/journal.pntd.0007700DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6738586PMC
September 2019

Co-circulation and characterization of novel African arboviruses (genus Ephemerovirus) in cattle, Mayotte island, Indian Ocean, 2017.

Transbound Emerg Dis 2019 Nov 27;66(6):2601-2604. Epub 2019 Aug 27.

ASTRE, Univ Montpellier (I-MUSE), CIRAD, INRA, Montpellier, France.

Mayotte is an island located in the Mozambique Channel, between Mozambique and Madagascar, in the South Western Indian Ocean region. A severe syndrome of unknown aetiology has been observed seasonally since 2009 in cattle (locally named "cattle flu"), associated with anorexia, nasal discharge, hyperthermia and lameness. We sampled blood from a panel of those severely affected animals at the onset of disease signs and analysed these samples by next-generation sequencing. We first identified the presence of ephemeral bovine fever viruses (BEFV), an arbovirus belonging to the genus Ephemerovirus within the family Rhabdoviridae, thus representing the first published sequences of BEFV viruses of African origin. In addition, we also discovered and genetically characterized a potential new species within the genus Ephemerovirus, called Mavingoni virus (MVGV) from one diseased animal. Finally, both MVGV and BEFV have been identified in cattle from the same herd, evidencing a co-circulation of different ephemeroviruses on the island. The clinical, epidemiological and virological information strongly suggests that these viruses represent the etiological agents of the observed "cattle flu" within this region. This study highlights the importance of the strengthening and harmonizing arboviral surveillance in Mayotte and its neighbouring areas, including Africa mainland, given the importance of the diffusion of infectious diseases (such as BEFV) mediated by animal and human movements in the South Western Indian Ocean area.
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http://dx.doi.org/10.1111/tbed.13323DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6899740PMC
November 2019

Evidence of bluetongue and Epizootic Haemorrhagic disease circulation on the island of Mayotte.

Acta Trop 2019 Mar 24;191:24-28. Epub 2018 Dec 24.

ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France; CIRAD, UMR ASTRE, Sainte Clotilde, La Réunion, France.

A cross-sectional study was conducted to explore the epidemiological situation in Mayotte regarding two orbiviruses: Bluetongue virus (BTV) and Epizootic Haemorrhagic Disease virus (EHDV). In all, 385 individual asymptomatic cattle were blood-sampled (one EDTA and one serum tube per animal) between February and June 2016. Antibody (ELISA) and genome prevalence (PCR) was assessed. Almost all the selected cattle showed antibodies against both BTV and EHDV, at 99.5% (CI95% [98.00, 100]) and 96.9% (CI95% [94.5, 98.3]), respectively. Most of the cattle acquired antibodies in their first years of age. EHDV and BTV genomes were detected in 25.2% (CI95% [21.1, 29.8]) and 18.2% (CI95% [14.6, 22.4]) of samples, respectively. Coinfection with BTV and EHDV was observed in 9.4% of samples (CI95% [6.8, 12.7]). Cattle under three years old were more frequently reported as positive for genome detection by PCR than older cattle. Five serotypes of BTV and one serotype of EHDV were identified from eight samples: BTV-4, BTV-9, BTV-11, BTV-15, BTV-19 and EHDV-6, of which some were reported in neighbouring areas. BTV and EHDV both circulate in Mayotte and in its surrounding territories.
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http://dx.doi.org/10.1016/j.actatropica.2018.12.037DOI Listing
March 2019

Expression of cytokines following vaccination of goats with a recombinant capripoxvirus vaccine expressing Rift Valley fever virus proteins.

Vet Immunol Immunopathol 2018 Mar 8;197:15-20. Epub 2018 Jan 8.

ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France; CIRAD, UMR ASTRE, F-34398 Sainte-Clotilde, La Réunion, France. Electronic address:

The mosquito-borne Rift Valley fever virus (RVFV) causes severe diseases in domesticated animals including cattle, sheep, camels and goats. Capripoxviruses (CPV) are suitable vectors for multivalent vaccine development. A recombinant rKS1-based CPV expressing the gene encoding the viral glycoprotein Gn of RVFV has been shown to induce protection in mice and sheep. The aim of this study was to evaluate the immunogenicity induced by this candidate vaccine in goats, and the level of cytokines produced by RVFV-specific Th1 and Th2 lymphocytes. The results of this study suggest that Th2 mediates immunity mainly through the significant production of IL4, which, coupled with a decrease in IFN-γ, may be involved in the replication of the capripoxvirus expressing the G of RVFV. CD4+ cells may play the role of helper cells in B cell responses and neutralizing antibody production in the anti-CPV humoral response, leading to strong immunity against RVFV.
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http://dx.doi.org/10.1016/j.vetimm.2018.01.001DOI Listing
March 2018

Drivers for Rift Valley fever emergence in Mayotte: A Bayesian modelling approach.

PLoS Negl Trop Dis 2017 Jul 21;11(7):e0005767. Epub 2017 Jul 21.

Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom.

Rift Valley fever (RVF) is a major zoonotic and arboviral hemorrhagic fever. The conditions leading to RVF epidemics are still unclear, and the relative role of climatic and anthropogenic factors may vary between ecosystems. Here, we estimate the most likely scenario that led to RVF emergence on the island of Mayotte, following the 2006-2007 African epidemic. We developed the first mathematical model for RVF that accounts for climate, animal imports and livestock susceptibility, which is fitted to a 12-years dataset. RVF emergence was found to be triggered by the import of infectious animals, whilst transmissibility was approximated as a linear or exponential function of vegetation density. Model forecasts indicated a very low probability of virus endemicity in 2017, and therefore of re-emergence in a closed system (i.e. without import of infected animals). However, the very high proportion of naive animals reached in 2016 implies that the island remains vulnerable to the import of infectious animals. We recommend reinforcing surveillance in livestock, should RVF be reported is neighbouring territories. Our model should be tested elsewhere, with ecosystem-specific data.
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http://dx.doi.org/10.1371/journal.pntd.0005767DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5540619PMC
July 2017

A G-protein-coupled chemokine receptor: A putative insertion site for a multi-pathogen recombinant capripoxvirus vaccine strategy.

J Immunol Methods 2017 09 31;448:112-115. Epub 2017 May 31.

INRA, UMR1309 CMAEE, F-34398 Montpellier, France; CIRAD UMR ASTRE, F-97170 Petit-Bourg, France.

Capripoxviruses (CaPVs) have been shown to be ideal viral vectors for the development of recombinant multivalent vaccines to enable delivery of immunogenic genes from ruminant pathogens. So far, the viral thymidine kinase (TK) gene is the only gene used to generate recombinants. A putative non-essential gene encoding a G-protein-coupled chemokine receptor subfamily homologue (GPCR) was targeted as an additional insertion site. Peste des petits ruminants (PPR) was chosen as a disease model. A new recombinant CaPV expressing the viral attachment hemagglutinin (H) of the PPR virus (PPRV) in the GPCR insertion site (rKS1-HPPR-GPCR) was generated in the backbone North African isolate KS1 strain of lumpy skin disease virus (LSDV). Comparison with the recombinant CaPV expressing the H of PPRV in the TK gene (rKS1-HPPR-TK) shown to induce protection against both PPR and LSD in both sheep and goats was assessed. The suitability of the GPCR gene to be a putative additional insertion site in the CaPV genome is evaluated and discussed.
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http://dx.doi.org/10.1016/j.jim.2017.05.007DOI Listing
September 2017

Absence of Evidence of Rift Valley Fever Infection in Eulemur fulvus (Brown Lemur) in Mayotte During an Interepidemic Period.

Vector Borne Zoonotic Dis 2017 05 21;17(5):358-360. Epub 2017 Feb 21.

6 UMR CMAEE, CIRAD, Sainte-Clotilde, La Réunion, France .

The potential role of Eulemur fulvus (brown lemur) in the epidemiology of Rift Valley fever (RVF) in Mayotte, during an interepidemic period, was explored. In February and March 2016, 72 animals were blood sampled and tested for RVF. No evidence of RVF genome or antibodies was found in the samples. The role of other wild mammals on the island should, however, be further investigated.
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http://dx.doi.org/10.1089/vbz.2016.2079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5421605PMC
May 2017

Population dynamics of mosquito species in a West Nile virus endemic area in Madagascar.

Parasite 2017 30;24. Epub 2017 Jan 30.

Laboratoire d'Entomologie Médicale, Institut Pasteur de Madagascar, Ambatofotsikely, Antananarivo 101, Madagascar.

Human and animal serological surveys suggest that West Nile virus (WNV) circulation is widely distributed in Madagascar. However, there are no reported West Nile fever outbreaks or epizootics in the country and only one fatal human case has been reported to date. Currently there is very limited information on the maintenance and the transmission of WNV in Madagascar and particularly on the mosquito species involved in transmission cycles. In 2014, we initiated a study to investigate mosquito species composition, relative abundance, and trophic behavior in Mitsinjo District close to Lake Kinkony, a WNV endemic area in north-western Madagascar. We collected a total of 2519 adult mosquitoes belonging to 21 different species. The most abundant species was Aedeomyia (Aedeomyia) madagascarica Brunhes, Boussès & da Cunha Ramos, which made up 83% of all the mosquitoes collected. Mosquito abundance was associated with proximity to the lake (Morafeno and Ankelimitondrotra). Additionally, a correlation was observed between the lake-side biotope and the abundance of mosquito vectors in Morafeno. WNV RNA was detected in one pool of Ae. madagascarica and one pool of Anopheles (Cellia) pauliani Grjebine, suggesting that these two species may be involved in the maintenance and/or transmission of WNV in Madagascar.
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http://dx.doi.org/10.1051/parasite/2017005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5780677PMC
August 2017

The Epidemiology of Rift Valley Fever in Mayotte: Insights and Perspectives from 11 Years of Data.

PLoS Negl Trop Dis 2016 06 22;10(6):e0004783. Epub 2016 Jun 22.

UMR CMAEE, CIRAD, Sainte-Clotilde, La Réunion, France.

Rift Valley fever (RVF) is a zoonotic arboviral disease that is a threat to human health, animal health and production, mainly in Sub-Saharan Africa. RVF virus dynamics have been poorly studied due to data scarcity. On the island of Mayotte in the Indian Ocean, off the Southeastern African coast, RVF has been present since at least 2004. Several retrospective and prospective serological surveys in livestock have been conducted over eleven years (2004-15). These data are collated and presented here. Temporal patterns of seroprevalence were plotted against time, as well as age-stratified seroprevalence. Results suggest that RVF was already present in 2004-07. An epidemic occurred between 2008 and 2010, with IgG and IgM peak annual prevalences of 36% in 2008-09 (N = 142, n = 51, 95% CI [17-55]) and 41% (N = 96, n = 39, 95% CI [25-56]), respectively. The virus seems to be circulating at a low level since 2011, causing few new infections. In 2015, about 95% of the livestock population was susceptible (IgG annual prevalence was 6% (N = 584, n = 29, 95% CI [3-10])). Monthly rainfall varied a lot (2-540mm), whilst average temperature remained high with little variation (about 25-30°C). This large dataset collected on an insular territory for more than 10 years, suggesting a past epidemic and a current inter-epidemic period, represents a unique opportunity to study RVF dynamics. Further data collection and modelling work may be used to test different scenarios of animal imports and rainfall pattern that could explain the observed epidemiological pattern and estimate the likelihood of a potential re-emergence.
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http://dx.doi.org/10.1371/journal.pntd.0004783DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4917248PMC
June 2016

First External Quality Assessment of Molecular and Serological Detection of Rift Valley Fever in the Western Mediterranean Region.

PLoS One 2015 13;10(11):e0142129. Epub 2015 Nov 13.

Ministère des Affaires étrangères et du Développement international, Paris, France.

Rift Valley fever (RVF) is a mosquito-borne viral zoonosis which affects humans and a wide range of domestic and wild ruminants. The large spread of RVF in Africa and its potential to emerge beyond its geographic range requires the development of surveillance strategies to promptly detect the disease outbreaks in order to implement efficient control measures, which could prevent the widespread of the virus to humans. The Animal Health Mediterranean Network (REMESA) linking some Northern African countries as Algeria, Egypt, Libya, Mauritania, Morocco, Tunisia with Southern European ones as France, Italy, Portugal and Spain aims at improving the animal health in the Western Mediterranean Region since 2009. In this context, a first assessment of the diagnostic capacities of the laboratories involved in the RVF surveillance was performed. The first proficiency testing (external quality assessment--EQA) for the detection of the viral genome and antibodies of RVF virus (RVFV) was carried out from October 2013 to February 2014. Ten laboratories participated from 6 different countries (4 from North Africa and 2 from Europe). Six laboratories participated in the ring trial for both viral RNA and antibodies detection methods, while four laboratories participated exclusively in the antibodies detection ring trial. For the EQA targeting the viral RNA detection methods 5 out of 6 laboratories reported 100% of correct results. One laboratory misidentified 2 positive samples as negative and 3 positive samples as doubtful indicating a need for corrective actions. For the EQA targeting IgG and IgM antibodies methods 9 out of the 10 laboratories reported 100% of correct results, whilst one laboratory reported all correct results except one false-positive. These two ring trials provide evidence that most of the participating laboratories are capable to detect RVF antibodies and viral RNA thus recognizing RVF infection in affected ruminants with the diagnostic methods currently available.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0142129PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4643972PMC
June 2016

Hyaluronidase Activity in Saliva of European Culicoides (Diptera: Ceratopogonidae).

J Med Entomol 2016 Jan 19;53(1):212-6. Epub 2015 Oct 19.

Department of Parasitology, Charles University in Prague, Faculty of Science, Czech Republic

Biting midges of the genus Culicoides transmit pathogens of veterinary importance such as bluetongue virus (Reoviridae: Orbivirus). The saliva of Culicoides is known to contain bioactive molecules including peptides and proteins with vasodilatory and immunomodulative properties. In this study, we detected activity of enzyme hyaluronidase in six Culicoides species that commonly occur in Europe and that are putative vectors of arboviruses. Hyaluronidase was present in all species studied, although its molecular size, sensitivity to SDS, and substrate specificity differed between species. Further studies on the potential effect of hyaluronidase activity on the vector competence of Culicoides species for arboviruses would be beneficial.
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http://dx.doi.org/10.1093/jme/tjv147DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4710844PMC
January 2016

How do species, population and active ingredient influence insecticide susceptibility in Culicoides biting midges (Diptera: Ceratopogonidae) of veterinary importance?

Parasit Vectors 2015 Aug 28;8:439. Epub 2015 Aug 28.

Cirad, UMR15 CMAEE; INRA, UMR1309 CMAEE, 34398, Montpellier, France.

Background: Culicoides biting midges are biological vectors of internationally important arboviruses of livestock and equines. Insecticides are often employed against Culicoides as a part of vector control measures, but systematic assessments of their efficacy have rarely been attempted. The objective of the present study is to determine baseline susceptibility of multiple Culicoides vector species and populations in Europe and Africa to the most commonly used insecticide active ingredients. Six active ingredients are tested: three that are based on synthetic pyrethroids (alpha-cypermethrin, deltamethrin and permethrin) and three on organophosphates (phoxim, diazinon and chlorpyrifos-methyl).

Methods: Susceptibility tests were conducted on 29,064 field-collected individuals of Culicoides obsoletus Meigen, Culicoides imicola Kieffer and a laboratory-reared Culicoides nubeculosus Meigen strain using a modified World Health Organization assay. Populations of Culicoides were tested from seven locations in four different countries (France, Spain, Senegal and South Africa) and at least four concentrations of laboratory grade active ingredients were assessed for each population.

Results: The study revealed that insecticide susceptibility varied at both a species and population level, but that broad conclusions could be drawn regarding the efficacy of active ingredients. Synthetic pyrethroid insecticides were found to inflict greater mortality than organophosphate active ingredients and the colony strain of C. nubeculosus was significantly more susceptible than field populations. Among the synthetic pyrethroids, deltamethrin was found to be the most toxic active ingredient for all species and populations.

Conclusions: The data presented represent the first parallel and systematic assessment of Culicoides insecticide susceptibility across several countries. As such, they are an important baseline reference to monitor the susceptibility status of Culicoides to current insecticides and also to assess the toxicity of new active ingredients with practical implications for vector control strategies.
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http://dx.doi.org/10.1186/s13071-015-1042-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4551713PMC
August 2015

Comprehensive phylogenetic reconstructions of Rift Valley fever virus: the 2010 northern Mauritania outbreak in the Camelus dromedarius species.

Vector Borne Zoonotic Dis 2014 Dec;14(12):856-61

1 Centre National d'Elevage et de Recherche Vétérinaire (CNERV) , Nouakchott, Mauritania .

Rift valley fever (RVF) is a mosquito-borne disease of domestic and wild ruminants caused by RVF virus (RVFV), a phlebovirus (Bunyaviridae). RVF is widespread in Sub-Saharan Africa. In September of 2010, an RVF outbreak occurred in northern Mauritania involving mass abortions in small ruminants and camels (Camelus dromedarius) and at least 63 human clinical cases, including 13 deaths. In camels, serological prevalence was 27.5-38.5% (95% confidence interval, n=279). For the first time, clinical signs other than abortions were reported in this species, including hemorrhagic septicemia and severe respiratory distress in animals. We assessed the presence of RVFV in camel sera sampled during this outbreak and generated whole-genome sequences of RVFV to determine the possible origin of this RVFV strain. Phylogenetic analyses suggested a shared ancestor between the Mauritania 2010 strain and strains from Zimbabwe (2269, 763, and 2373), Kenya (155_57 and 56IB8), South Africa (Kakamas, SA75 and SA51VanWyck), Uganda (Entebbe), and other strains linked to the 1987 outbreak of RVF in Mauritania (OS1, OS3, OS8, and OS9).
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http://dx.doi.org/10.1089/vbz.2014.1605DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270112PMC
December 2014

Evidence for circulation of the rift valley fever virus among livestock in the union of Comoros.

PLoS Negl Trop Dis 2014 31;8(7):e3045. Epub 2014 Jul 31.

Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), UMR 15 CMAEE, Sainte Clotilde, La Réunion, France; Institut National de la Recherche Agronomique (INRA), UMR 1309 CMAEE, Sainte Clotilde, La Réunion, France; Centre de Recherche et de Veille sur les Maladies Émergentes dans l'Océan Indien (CRVOI), Plateforme de Recherche CYROI, Sainte Clotilde, La Réunion, France.

Rift Valley fever virus (RVFV) is an arthropod-borne phlebovirus reported to be circulating in most parts of Africa. Since 2009, RVFV has been suspected of continuously circulating in the Union of Comoros. To estimate the incidence of RVFV antibody acquisition in the Comorian ruminant population, 191 young goats and cattle were selected in six distinct zones and sampled periodically from April 2010 to August 2011. We found an estimated incidence of RVFV antibody acquisition of 17.5% (95% confidence interval (CI): [8.9-26.1]) with a significant difference between islands (8.2% in Grande Comore, 72.3% in Moheli and 5.8% in Anjouan). Simultaneously, a longitudinal entomological survey was conducted and ruminant trade-related information was collected. No RVFV RNA was detected out of the 1,568 blood-sucking caught insects, including three potential vectors of RVFV mosquito species. Our trade survey suggests that there is a continuous flow of live animals from eastern Africa to the Union of Comoros and movements of ruminants between the three Comoro islands. Finally, a cross-sectional study was performed in August 2011 at the end of the follow-up. We found an estimated RVFV antibody prevalence of 19.3% (95% CI: [15.6%-23.0%]). Our findings suggest a complex RVFV epidemiological cycle in the Union of Comoros with probable inter-islands differences in RVFV circulation patterns. Moheli, and potentially Anjouan, appear to be acting as endemic reservoir of infection whereas RVFV persistence in Grande Comore could be correlated with trade in live animals with the eastern coast of Africa. More data are needed to estimate the real impact of the disease on human health and on the national economy.
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http://dx.doi.org/10.1371/journal.pntd.0003045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4117442PMC
March 2015

Towards the PCR-based identification of Palaearctic Culicoides biting midges (Diptera: Ceratopogonidae): results from an international ring trial targeting four species of the subgenus Avaritia.

Parasit Vectors 2014 May 14;7:223. Epub 2014 May 14.

Cirad, UMR15 CMAEE, 34398 Montpellier, France.

Background: Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are biological vectors of internationally important arboviruses. To understand the role of Culicoides in the transmission of these viruses, it is essential to correctly identify the species involved. Within the western Palaearctic region, the main suspected vector species, C. obsoletus, C. scoticus, C. dewulfi and C. chiopterus, have similar wing patterns, which makes it difficult to separate and identify them correctly.

Methods: In this study, designed as an inter-laboratory ring trial with twelve partners from Europe and North Africa, we assess four PCR-based assays which are used routinely to differentiate the four species of Culicoides listed above. The assays based on mitochondrial or ribosomal DNA or microarray hybridisation were tested using aliquots of Culicoides DNA (extracted using commercial kits), crude lysates of ground specimens and whole Culicoides (265 individuals), and non-Culicoides Ceratopogonidae (13 individuals) collected from across Europe.

Results: A total of 800 molecular assays were implemented. The in-house assays functioned effectively, although specificity and sensitivity varied according to the molecular marker and DNA extraction method used. The Obsoletus group specificity was overall high (95-99%) while the sensitivity varied greatly (59.6-100%). DNA extraction methods impacted the sensitivity of the assays as well as the type of sample used as template for the DNA extraction.

Conclusions: The results are discussed in terms of current use of species diagnostic assays and the future development of molecular tools for the rapid differentiation of cryptic Culicoides species.
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http://dx.doi.org/10.1186/1756-3305-7-223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4024274PMC
May 2014

The emergence of Schmallenberg virus across Culicoides communities and ecosystems in Europe.

Prev Vet Med 2014 Oct 18;116(4):360-9. Epub 2014 Mar 18.

Cirad, UMR15 CMAEE, F-34398 Montpellier, France; INRA, UMR1309 CMAEE, F-34398 Montpellier, France.

Schmallenberg virus (SBV), a novel arboviral pathogen, has emerged and spread across Europe since 2011 inflicting congenital deformities in the offspring of infected adult ruminants. Several species of Culicoides biting midges (Diptera: Ceratopogonidae) have been implicated in the transmission of SBV through studies conducted in northern Europe. In this study Culicoides from SBV outbreak areas of mainland France and Italy (Sardinia) were screened for viral RNA. The role of both C. obsoletus and the Obsoletus complex (C. obsoletus and C. scoticus) in transmission of SBV were confirmed in France and SBV was also discovered in a pool of C. nubeculosus for the first time, implicating this species as a potential vector. While collections in Sardinia were dominated by C. imicola, only relatively small quantities of SBV RNA were detected in pools of this species and conclusive evidence of its potential role in transmission is required. In addition to these field-based studies, infection rates in colony-derived individuals of C. nubeculosus and field-collected C. scoticus are also examined in the laboratory. Rates of infection in C. nubeculosus were low, confirming previous studies, while preliminary examination of C. scoticus demonstrated that while this species can replicate SBV to a potentially transmissible level, further work is required to fully define comparative competence between species in the region. Finally, the oral competence for SBV of two abundant and widespread mosquito vector species in the laboratory is assessed. Neither Aedes albopictus nor Culex pipiens were demonstrated to replicate SBV to transmissible levels and appear unlikely to play a major role in transmission. Other vector competence data produced from studies across Europe to date is then comprehensively reviewed and compared with that generated previously for bluetongue virus.
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http://dx.doi.org/10.1016/j.prevetmed.2014.03.007DOI Listing
October 2014

Epizootic haemorrhagic disease virus in Reunion Island: evidence for the circulation of a new serotype and associated risk factors.

Vet Microbiol 2014 Jun 16;170(3-4):383-90. Epub 2014 Feb 16.

CIRAD, UMR CMAEE, F-97490 Sainte Clotilde, La Réunion, France; INRA, UMR 1309 CMAEE, F-34398 Montpellier, France; Centre de Recherche et de Veille sur les maladies émergentes dans l'Océan Indien (CRVOI), plateforme de recherche CYROI, F-97490 Sainte Clotilde, La Réunion, France.

Bluetongue virus (BTV) and epizootic haemorrhagic disease virus (EHDV) are members of the Orbivirus genus of the Reoviridae family transmitted between ruminants by the bites of Culicoides midges. BTV went undetected in Reunion Island between its first documented emergence in 1979 and two other serious outbreaks with both BTV-3 and EHDV-6 in 2003, and both EHDV-6 and BTV-2 in 2009. In these outbreaks, infected animals developed symptoms including hyperthermia, anorexia, congestion, prostration and nasal discharge. Samples were collected in 2011 to assess the prevalence of BT and EHD in ruminants native to Reunion Island by serological analysis. A cross-sectional study was undertaken on 67 farms, including a total of 276 cattle, 142 sheep and 71 goats. The prevalence rates of BT and EHD were 58% (95% CI [54.03-62.94]) and 38% (95% CI [33.85-42.63], respectively. Two further suspected outbreaks were confirmed to involve EHDV and BTV/EHDV. A new circulating EHDV serotype 1 of unknown origin was isolated. Our results confirm that the prevalence of both BT and EHD is high and that both are likely currently circulating. A high risk of BTV and EHDV infections was associated with the introduction of ruminants from neighbouring farms without quarantine, the presence of organic and other waste on the farm, and treatment against ectoparasites and insects.
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http://dx.doi.org/10.1016/j.vetmic.2014.02.007DOI Listing
June 2014

Development of real-time RT-PCR for the detection of low concentrations of Rift Valley fever virus.

J Virol Methods 2014 Jan 11;195:92-9. Epub 2013 Oct 11.

CIRAD, UMR CMAEE, F-97490 Sainte-Clotilde, La Réunion, France; INRA, UMR 1309 CMAEE, F-34398 Montpellier, France; CRVOI, F-97490 Sainte Clotilde, La Réunion, France. Electronic address:

In recent years, Madagascar and the Comoros archipelago have been affected by epidemics of Rift Valley fever (RVF), however detection of Rift Valley fever virus (RVFV) in zebu, sheep and goats during the post epidemic periods was frequently unsuccessful. Thus, a highly sensitive real-time RT-PCR assay was developed for the detection of RVFV at low viral loads. A new RVF SYBR Green RT-PCR targeting the M segment was tested on serum from different RVF seronegative ruminant species collected from May 2010 to August 2011 in Madagascar and the Comoros archipelago and compared with a RVF specific quantitative real time RT-PCR technique, which is considered as the reference technique. The specificity was tested on a wide range of arboviruses or other viruses giving RVF similar clinical signs. A total of 38 out of 2756 serum samples tested positive with the new RT-PCR, whereas the reference technique only detected 5 out of the 2756. The described RT-PCR is an efficient diagnostic tool for the investigation of enzootic circulation of the RVF virus. It allows the detection of low viral RNA loads adapted for the investigations of reservoirs or specific epidemiological situations such as inter-epizootic periods.
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http://dx.doi.org/10.1016/j.jviromet.2013.10.001DOI Listing
January 2014

European ring trial to evaluate ELISAs for the diagnosis of infection with Rift Valley fever virus.

J Virol Methods 2013 Jan 26;187(1):177-81. Epub 2012 Sep 26.

Department of Virology, Central Veterinary Institute of Wageningen University and Research Centre, Lelystad, The Netherlands.

A ring trial was organized to evaluate Rift Valley fever virus (RVFV) ELISAs by European laboratories. A total of five ELISAs, two of which specific for IgM antibodies, were evaluated by six participants. Sera were derived from cattle or sheep and originated from either a RVFV endemic area, a RVFV-free area or from experimental infection studies. Cohen's kappa analysis showed higher than 90% agreement of two commercially available ELISAs with the virus neutralization test, suggesting that primary screening as well as serological confirmation using these ELISAs is feasible. More extensive validations with sera of known IgM status are, however, required to determine agreement between IgM ELISAs.
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http://dx.doi.org/10.1016/j.jviromet.2012.09.016DOI Listing
January 2013

Development and validation of IIKC: an interactive identification key for Culicoides (Diptera: Ceratopogonidae) females from the Western Palaearctic region.

Parasit Vectors 2012 Jul 9;5:137. Epub 2012 Jul 9.

IPPTS, Université de Strasbourg, EA 4438, 67000, Strasbourg, France.

Background And Methods: The appearance of bluetongue virus (BTV) in 2006 within northern Europe exposed a lack of expertise and resources available across this region to enable the accurate morphological identification of species of Culicoides Latreille biting midges, some of which are the major vectors of this pathogen. This work aims to organise extant Culicoides taxonomic knowledge into a database and to produce an interactive identification key for females of Culicoides in the Western Palaearctic (IIKC: Interactive identification key for Culicoides). We then validated IIKC using a trial carried out by six entomologists based in this region with variable degrees of experience in identifying Culicoides.

Results: The current version of the key includes 98 Culicoides species with 10 morphological variants, 61 descriptors and 837 pictures and schemes. Validation was carried out by six entomologists as a blind trial with two users allocated to three classes of expertise (beginner, intermediate and advanced). Slides were identified using a median of seven steps and seven minutes and user confidence in the identification varied from 60% for failed identifications to a maximum of 80% for successful ones. By user class, the beginner group successfully identified 44.6% of slides, the intermediate 56.8% and the advanced 74.3%.

Conclusions: Structured as a multi-entry key, IIKC is a powerful database for the morphological identification of female Culicoides from the Western Palaearctic region. First developed for use as an interactive identification key, it was revealed to be a powerful back-up tool for training new taxonomists and to maintain expertise level. The development of tools for arthropod involvement in pathogen transmission will allow clearer insights into the ecology and dynamics of Culicoides and in turn assist in understanding arbovirus epidemiology.
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http://dx.doi.org/10.1186/1756-3305-5-137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3483010PMC
July 2012

Genome analysis of Rift Valley fever virus, Mayotte.

Emerg Infect Dis 2012 Jun;18(6):969-71

Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Montpellier, France.

As further confirmation of a first human case of Rift Valley fever in 2007 in Comoros, we isolated Rift Valley fever virus in suspected human cases. These viruses are genetically closely linked to the 2006-2007 isolates from Kenya.
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http://dx.doi.org/10.3201/eid1806.110994DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3358145PMC
June 2012