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International audience; The role of antibodies directed against the hyper variable envelope region V1 of human immunode-ficiency virus type 1 (HIV-1), has not been thoroughly studied. We show that a vaccine able to elicit strain-specific non-neutralizing antibodies to this region of gp120 is associated with control of highly pathogenic chimeric SHIV 89.6P replication in rhesus macaques. The vaccinated animal that had the highest titers of antibodies to the amino terminus portion of V1, prior to challenge, had secondary antibody responses that mediated cell killing by antibody-dependent cellular cytotoxicity (ADCC), as early as 2 weeks after infection and inhibited viral replication by antibody-dependent cell-mediated virus inhibition (ADCVI), by 4 weeks after infection. There was a significant inverse correlation between virus level and binding antibody titers to the envelope protein, (R = −0.83, p = 0.015), and ADCVI (R = −0.84 p = 0.044). Genotyping of plasma virus demonstrated in vivo selection of three SHIV 89.6P variants with changes in potential N-linked glycosylation sites in V1. We found a significant inverse correlation between virus levels and titers of antibodies that mediated ADCVI against all the identified V1 virus variants. A significant inverse correlation was also found between neutralizing antibody titers to SHIV 89.6 and virus levels (R = −0.72 p = 0.0050). However, passive inoculation of purified immunoglobulin from animal M316, the macaque that best controlled virus, to a naïve macaque, resulted in a low serum neutralizing antibodies and low ADCVI activity that failed to protect from SHIV 89.6P challenge. Collectively, while our data suggest that anti-envelope antibodies with neutralizing and non-neutralizing Fc(R-dependent activities may be important in the control of SHIV replication, they also demonstrate that low levels of these antibodies alone are not sufficient to protect from infection.

Introduction Le role des variables demographiques et geographiques telles que la densite de population et la subdivision bioclimatique dans la transmission de la grippe est controverse et reste meconnu pour la situation de Madagascar. L’objectif de cette analyse est d’evaluer la qualite des donnees des syndromes grippaux (ILI) recueillies a travers les sites du reseau sentinelle de l’Institut Pasteur de Madagascar (IPM, 34 sites) de 2012 a 2016. Methodes La densite annuelle de population et son evolution au cours de la periode etudiee ont ete estimees en rapport avec l’aire d’attraction de chaque site. Les cinq regions bioclimatiques de Madagascar ont ete prises en compte pour classer et categoriser les sites. La promptitude d’envoi de donnees (≤ 2 jours) et l’appartenance entre les bornes des intervalles de confiance a 95 % de la moyenne des nombres de cas par region bioclimatique constituent les deux premieres metriques. Les donnees d’ILI ont ete evaluees en faible ou fort niveau de taux de risque relatif (densite × cas d’ILI) pour identifier « les vrais zeros » par le calcul de completude pendant les mois de forte transmission utilisant la technique de « mixture gaussienne ». Ensuite, pour classer les sites, des scores composites de performance ont ete calcules a partir de ces metriques : l’intervalle de confiance et la « mixture gaussienne » pour la periode de 2012 a 2016 et l’ensemble des trois metriques pour la periode de 2015 a 2016. Resultats Les scores calcules (variant de 2 a 49) via les deux premieres metriques de 2012 a 2016 mettent en avant dix sites : Mahajanga, Maroantsetra, Ambositra, Fianarantsoa, Ambatondrazaka, Morombe, Tsaralalana, Ihosy, Manjakaray, et Sambava. Les scores qui couvrent sur 18 mois de 2015 a 2016 (variant de 01 a 40) prevalent cinq sites : Mahajanga (Nord-Ouest), Ambositra (Hautes Terres), Maintirano (Ouest), Morondava (Sud-Ouest) et Fianarantsoa (Hautes Terres). Ce classement reflete bien la diversite geographique du pays. Conclusion Cette analyse, d’une part, a partir de l’identification des sites a faible score permet d’ameliorer le processus de collecte de donnees. D’autre part, avec les sites mieux scores, elle facilite aussi leur selection dans le cadre d’une future analyse de donnees en serie-temporelle. Ces resultats renforcent ainsi la capacite du reseau de surveillance des syndromes grippaux et leur contribution comme appui au systeme de sante publique.

The development of a subunit vaccine for smallpox represents a potential strategy to avoid the safety concerns associated with replication-competent vaccinia virus. Preclinical studies to date with subunit smallpox vaccine candidates, however, have been limited by incomplete information regarding protective antigens and the requirement for multiple boost immunizations to afford protective immunity. Here we explore the protective efficacy of replication-incompetent, recombinant adenovirus serotype 35 (rAd35) vectors expressing the vaccinia virus intracellular mature virion (IMV) antigens A27L and L1R and extracellular enveloped virion (EEV) antigens A33R and B5R in a murine vaccinia virus challenge model. A single immunization with the rAd35-L1R vector effectively protected mice against a lethal systemic vaccinia virus challenge. The rAd35-L1R vector also proved more efficacious than the combination of four rAd35 vectors expressing A27L, L1R, A33R, and B5R. Moreover, serum containing L1R-specific neutralizing antibodies afforded postexposure prophylaxis after systemic vaccinia virus infection. In contrast, the combination of rAd35-L1R and rAd35-B5R vectors was required to protect mice against a lethal intranasal vaccinia virus challenge, suggesting that both IMV- and EEV-specific immune responses are important following intranasal infection. Taken together, these data demonstrate that different protective antigens are required based on the route of vaccinia virus challenge. These studies also suggest that rAd vectors warrant further assessment as candidate subunit smallpox vaccines.

International audience; BACKGROUND:The seasonal drivers of influenza activity remain debated in tropical settings where epidemics are not clearly phased. Antananarivo is a particularly interesting case study because it is in Madagascar, an island situated in the tropics and with quantifiable connectivity levels to other countries.OBJECTIVES:We aimed at disentangling the role of environmental forcing and population fluxes on influenza seasonality in Madagascar.METHODS:We compiled weekly counts of laboratory-confirmed influenza-positive specimens for the period 2002 to 2012 collected in Antananarivo, with data available from sub-Saharan countries and countries contributing most foreign travelers to Madagascar. Daily climate indicators were compiled for the study period.RESULTS:Overall, influenza activity detected in Antananarivo predated that identified in temperate Northern Hemisphere locations. This activity presented poor temporal matching with viral activity in other countries from the African continent or countries highly connected to Madagascar excepted for A(H1N1)pdm09. Influenza detection in Antananarivo was not associated with travel activity and, although it was positively correlated with all climatic variables studied, such association was weak.CONCLUSIONS:The timing of influenza activity in Antananarivo is irregular, is not driven by climate, and does not align with that of countries in geographic proximity or highly connected to Madagascar. This work opens fresh questions regarding the drivers of influenza seasonality globally particularly in mid-latitude and less-connected regions to tailor vaccine strategies locally.

International audience; BACKGROUND:Bats are amongst the natural reservoirs of many coronaviruses (CoVs) of which some can lead to severe infection in human. African bats are known to harbor a range of pathogens (e.g., Ebola and Marburg viruses) that can infect humans and cause disease outbreaks. A recent study in South Africa isolated a genetic variant closely related to MERS-CoV from an insectivorous bat. Though Madagascar is home to 44 bat species (41 insectivorous and 3 frugivorous) of which 34 are endemic, no data exists concerning the circulation of CoVs in the island's chiropteran fauna. Certain Malagasy bats can be frequently found in close contact with humans and frugivorous bats feed in the same trees where people collect and consume fruits and are hunted and consumed as bush meat. The purpose of our study is to detect and identify CoVs from frugivorous bats in Madagascar to evaluate the risk of human infection from infected bats.METHODS:Frugivorous bats belonging to three species were captured in four different regions of Madagascar. We analyzed fecal and throat swabs to detect the presence of virus through amplification of the RNA-dependent RNA polymerase (RdRp) gene, which is highly conserved in all known coronaviruses. Phylogenetic analyses were performed from positive specimens.RESULTS:From 351 frugivorous bats, we detected 14 coronaviruses from two endemic bats species, of which 13 viruses were identified from Pteropus rufus and one from Eidolon dupreanum, giving an overall prevalence of 4.5%. Phylogenetic analysis revealed that the Malagasy strains belong to the genus Betacoronavirus but form three distinct clusters, which seem to represent previously undescribed genetic lineages.CONCLUSIONS:Our findings suggest that CoVs circulate in frugivorous bats of Madagascar, demonstrating the needs to evaluate spillover risk to human populations especially for individuals that hunt and consume infected bats. Possible dispersal mechanisms as to how coronaviruses arrived on Madagascar are discussed.

Item does not contain fulltext BACKGROUND: Data on causes of death due to respiratory illness in Africa are limited. METHODS: From January to April 2013, 28 African countries were invited to participate in a review of severe acute respiratory illness (SARI)-associated deaths identified from influenza surveillance during 2009-2012. RESULTS: Twenty-three countries (82%) responded, 11 (48%) collect mortality data, and 8 provided data. Data were collected from 37 714 SARI cases, and 3091 (8.2%; range by country, 5.1%-25.9%) tested positive for influenza virus. There were 1073 deaths (2.8%; range by country, 0.1%-5.3%) reported, among which influenza virus was detected in 57 (5.3%). Case-fatality proportion (CFP) was higher among countries with systematic death reporting than among those with sporadic reporting. The influenza-associated CFP was 1.8% (57 of 3091), compared with 2.9% (1016 of 34 623) for influenza virus-negative cases (P < .001). Among 834 deaths (77.7%) tested for other respiratory pathogens, rhinovirus (107 [12.8%]), adenovirus (64 [6.0%]), respiratory syncytial virus (60 [5.6%]), and Streptococcus pneumoniae (57 [5.3%]) were most commonly identified. Among 1073 deaths, 402 (37.5%) involved people aged 0-4 years, 462 (43.1%) involved people aged 5-49 years, and 209 (19.5%) involved people aged >/=50 years. CONCLUSIONS: Few African countries systematically collect data on outcomes of people hospitalized with respiratory illness. Stronger surveillance for deaths due to respiratory illness may identify risk groups for targeted vaccine use and other prevention strategies.

International audience; So far, no published data was available concerning the circulation of Bluetongue virus (BTV) in Madagascar. During a survey on Rift Valley Fever, we were able to detect a virus belonging to BTV. Therefore, we conducted a study aiming at characterizing molecularly the BTV isolated and assess the importance of circulation of BTV in Madagascar. A total of 4393 sera from ruminants selected randomly by stratification and sampled in 30 districts of Madagascar were tested for BTV. Moreover, 175 cattle were followed during 11 months.Phylogenetic analyses were performed from virus isolated from unfed pools of mosquitoes.Overall, the estimated mean seroprevalence of infection at the national level was 95.9% (95% CI: [95.2–96.5]) in cattle and 83.7% (95% CI: [81.4–85.9]) in small ruminants. Estimation of incidence rate was 54 per 100 cattle-years assuming that the incidence rate is constant allyear along. Phylogenetic analyses revealed that BTV detected belong to serotype 2.In conclusion, our results showed that BTV is endemic in Madagascar and highly prevalent among cattle. In our study we did not work on the vector involved in transmission of BTV in cattle. Thus, research should be conducted to better describe epidemiology of BTV in Madagascar including vectors and assess economic impact of the disease associated to BTV infections.

International audience; BACKGROUND:Epidemics pose major threats in resource-poor countries, and surveillance tools for their early detection and response are often inadequate. In 2007, a sentinel surveillance system was established in Madagascar, with the aim of rapidly identifying potential epidemics of febrile or diarrhoeal syndromes and issuing alerts. We present the health and process indicators for the five years during which this system was constructed, showing the spatiotemporal trends, early-warning sign detection capability and process evaluation through timely analyses of high-quality data.METHODS:The Malagasy sentinel surveillance network is currently based on data for fever and diarrhoeal syndromes collected from 34 primary health centres and reported daily via the transmission of short messages from mobile telephones. Data are analysed daily at the Institut Pasteur de Madagascar to make it possible to issue alerts more rapidly, and integrated process indicators (timeliness, data quality) are used to monitor the system.RESULTS:From 2007 to 2011, 917,798 visits were reported. Febrile syndromes accounted for about 11% of visits annually, but the trends observed differed between years and sentinel sites. From 2007 to 2011, 21 epidemic alerts were confirmed. However, delays in data transmission were observed (88% transmitted within 24 hours in 2008; 67% in 2011) and the percentage of forms transmitted each week for validity control decreased from 99.9% in 2007 to 63.5% in 2011.CONCLUSION:A sentinel surveillance scheme should take into account both epidemiological and process indicators. It must also be governed by the main purpose of the surveillance and by local factors, such as the motivation of healthcare workers and telecommunication infrastructure. Permanent evaluation indicators are required for regular improvement of the system.

Understanding cell dynamics in animal models have implications for therapeutic strategies elaborated against leukemia in human. Quantification of the cell turnover in closely related primate systems is particularly important for rare and aggressive forms of human cancers, such as adult T-cell leukemia. For this purpose, we have measured the death and proliferation rates of the CD4+ T lymphocyte population in squirrel monkeys (Saimiri sciureus) infected by human T-lymphotropic virus type 1 (HTLV-1). The kinetics of in vivo bromodeoxyuridine labeling revealed no modulation of the cell turnover in HTLV-1-infected monkeys with normal CD4 cell counts. In contrast, a substantial decrease in the proliferation rate of the CD4+ T population was observed in lymphocytic monkeys (e.g. characterized by excessive proportions of CD4+ T lymphocytes and by the presence of abnormal flower-like cells). Unexpectedly, onset of HTLV-associated leukemia thus occurs in the absence of increased CD4+ T-cell proliferation. This dynamics significantly differs from the generalized activation of the T-cell turnover induced by other primate lymphotropic viruses like HIV and SIV.

International audience; Little is known about the major histocompatibility complex (MHC) class 1 in squirrel monkeys ( Saimiri sciureus). We cloned, sequenced and characterized two alleles and the cDNA of the coding region of MHC class 1 in these New World monkeys. Phylogenetic analyses showed that these sequences are related to HLA class 1 genes ( HLA-A and HLA-G). The structure and organization of one of the two identified clones was similar to that of a class 1 MHC gene ( HLA-A2). All the exon/intron splice acceptor/donor sites are conserved and their locations correspond to the HLA-A2 gene. The sequences of the newly described cDNAs reveal that they code for the characteristic class 1 MHC proteins, with all the features thought necessary for cell surface expression. Typical sequences for the leader peptide, alpha(1), alpha(2), alpha(3), transmembrane and cytoplasmic domains were found.

International audience; Primates have long been used as models to study the basic mechanisms of human disease. The squirrel monkey, Saimiri sciureus,is a New World monkey that can be satisfactorily bred in captivity and infected with various human pathogens. The basic immunological parameters of squirrel monkeys, including immunoglobulin subclasses and markers for lymphocyte subsets, have already been characterized. However, immunological reagents and assays specific for the detection and quantification of squirrel monkey cytokines are required to elucidate the immunological and physiopathological changes that occur during experimental infection of these animals with pathogens. We therefore cloned, sequenced, and characterized the cDNAs encoding various squirrel monkey Th1 and Th2 cytokines, including interleukin (IL)-1 beta, IL-2, IL-5, IL-6, IL-10, tumor necrosis factor alpha, and gamma interferon. We found 91.4%-98.1% homology between the nucleotide sequence of the squirrel monkey cytokine genes and published sequences of equivalent human and non-human primate genes. The aligned sequences of cytokines for Saimiriand several New and Old World primates and human are shown, and a phylogenetic analysis of published sequences of selected cytokines in other species and those of non-human primates is given. In addition, we adapted a previously described quantitative, reverse transcriptase, competitive polymerase chain reaction technique to measure the mRNA expression of those cytokines in squirrel monkeys. The primer and competitor plasmids that allowed quantification are described. We showed that the assay is sensitive and reproducible.

Background Measles containing vaccine was introduced to Madagascar in 1985. Since 2007, intensification of efforts has bought Madagascar closer to the goal of elimination. Nevertheless, recent data also indicate that population immunity might be eroding in the face of high birth rates and barriers to vaccine delivery. Despite evidence that many factors likely to shape vaccination programme effectiveness are seasonal (including transmission, which responds to seasonal human behaviour, and birth rates), how seasonal fluctuations in vaccination shape outbreak risk and timeliness of vaccination is rarely considered. We aimed to evaluate this here. Methods We obtained data from the national passive surveillance system for fever and rash in Madagascar from 2004 to 2015 and combined them cross-sectional data for children's vaccination status from the 2008 Demographic Health Survey to characterise seasonality in childhood-infection transmission, access to vaccination, and births, and the signature of extreme climatic events (eg, cyclones). Measles incidence is too low for direct inference into seasonality in transmission, but we leveraged data for rubella, which is likely to have similar drivers. We integrated these data with mathematical models to assess the effect of seasonality in vaccination on outbreak risk and but also timeliness of vaccination—eg, the degree to which children obtain vaccination at the appropriate age. We additionally assessed barriers to vaccination that shape seasonal uptake by pairing this analysis with a detailed case study on vaccination access in a focal region of Madagascar. Findings Seasonal fluctuations in vaccination coverage can affect measles outbreak risk and interact with seasonality in births to affect the timeliness. While the theoretical optimal seasonal timing of vaccination can be identified, understanding barriers to access to health centers, their staffing, and vaccine supply is essential to strengthening health system functioning, and developing robust responses to extreme climatic events. Interpretation Small changes in the timing of vaccination are relatively straightforward to implement and have the potential to strengthen vaccination programmes. Funding Wellcome Trust.

International audience; Background: Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic arboviral infection with hemorrhagic manifestation and often a fatal ending. Human become infected mainly through tick bite or by crushing infected tick, by contact with blood or tissues from viraemic livestock or patient. CCHF virus (CCHFV) has been isolated once in Madagascar but data on the epidemiology of the disease in the country are very scarce. Objectives: To investigate the circulation and the geographic distribution of CCHFV infection among at risk population in Madagascar. Study design: A national cross-sectional serologic survey was performed in 2008–2009 among slaughterhouse workers. Results: A total of 1995 workers were included. A recent CCHFV infection was detected in 1 of the 1995 participants (0.5‰; 95% confidence interval [CI]: 0–0.15%), and a past CCHFV infection was detected in 15 participants (0.75%; 95% CI: 0.37–1.13%). Conclusion: Overall, the percentage of CCHFV infection seen in Madagascar among at-risk professionals is very low compared to endemic countries. An assessment of the prevalence in livestock as a sensitive indicator of CCHFV activity must be considered in order to confirm the lack or the weak endemicity of CCHF in Madagascar.

The Paramyxoviridae form an increasingly diverse viral family, infecting a wide variety of different hosts. In recent years, they have been linked to disease emergence in many different animal populations and in humans. Bats and rodents have been identified as major animal populations capable of harboring paramyxoviruses, and host shifting between these animals is likely to be an important driving factor in the underlying evolutionary processes that eventually lead to disease emergence. Here, we have studied paramyxovirus circulation within populations of endemic and introduced wild small mammals of the southwestern Indian Ocean region and belonging to four taxonomic orders: Rodentia, Afrosoricida, Soricomorpha, and Chiroptera. We report elevated infection levels as well as widespread paramyxovirus dispersal and frequent host exchange of a newly emerging genus of the Paramyxoviridae , currently referred to as the unclassified morbillivirus-related viruses (UMRVs). In contrast to other genera of the Paramyxoviridae , where bats have been shown to be a key host species, we show that rodents (and, in particular, Rattus rattus ) are significant spreaders of UMRVs. We predict that the ecological particularities of the southwestern Indian Ocean, where small mammal species often live in densely packed, multispecies communities, in combination with the increasing invasion of R. rattus and perturbations of endemic animal communities by active anthropological development, will have a major influence on the dynamics of UMRV infection. IMPORTANCE Identification of the infectious agents that circulate within wild animal reservoirs is essential for several reasons: (i) infectious disease outbreaks often originate from wild fauna; (ii) anthropological expansion increases the risk of contact between human and animal populations and, as a result, the risk of disease emergence; (iii) evaluation of pathogen reservoirs helps in elaborating preventive measures to limit the risk of disease emergence. Many paramyxoviruses for which bats and rodents serve as major reservoirs have demonstrated their potential to cause disease in humans and animals. In the context of the biodiversity hot spot of southwestern Indian Ocean islands and their rich endemic fauna, we show that highly diverse UMRVs exchange between various endemic animal species, and their dissemination likely is facilitated by the introduced Rattus rattus . Hence, many members of the Paramyxoviridae appear well adapted for the study of the viral phylodynamics that may be associated with disease emergence.

International audience; Most circulating strains of Human enterovirus 71 (EV-A71) have been classified primarily into three genogroups (A to C) on the basis of genetic divergence between the 1D gene, which encodes the VP1 capsid protein. The aim of the present study was to provide further insights into the diversity of the EV-A71 genogroups following the recent description of highly divergent isolates, in particular those from African countries, including Madagascar. We classified recent EV-A71 isolates by a large comparison of 3,346 VP1 nucleotidic sequences collected from GenBank. Analysis of genetic distances and phylogenetic investigations indicated that some recently-reported isolates did not fall into the genogroups A-C and clustered into three additional genogroups, including one Indian genogroup (genogroup D) and 2 African ones (E and F). Our Bayesian phylogenetic analysis provided consistent data showing that the genogroup D isolates share a recent common ancestor with the members of genogroup E, while the isolates of genogroup F evolved from a recent common ancestor shared with the members of the genogroup B. Our results reveal the wide diversity that exists among EV-A71 isolates and suggest that the number of circulating genogroups is probably underestimated, particularly in developing countries where EV-A71 epidemiology has been poorly studied.

International audience; Until now, there was only serological evidence that hantaviruses were circulating in rodents and infecting humans from Madagascar. To assess the presence of a hantavirus on the island, between October, 2008, and March, 2010, we sampled 585 rodents belonging to seven species in the Anjozorobe-Angavo forest corridor, 70 km north from the capital city Antananarivo. A hantavirus was detected from organs of the ubiquist roof rat (Rattus rattus) and of the endemic Major's tufted-tailed rat (Eliurus majori). Amazingly, sequence analysis of the S (small), M (medium), and L (large) coding DNA sequence of this virus showed that the Anjozorobe strain (proposed name) was a new genetic variant of Thailand virus (THAIV) that comprises other variants found in Southeast Asia. Because THAIV is suspected of causing hemorrhagic fever with renal syndrome in humans, ongoing studies are addressing the risk of infection by this new variant in the Malagasy population.

International audience; 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.

International audience; We report the first complete genome sequence of an enterovirus isolate belonging to the human enterovirus A species of the Pi-cornaviridae family and to type A120 (EV-A120). The EV-A120 isolate MAD-2741-11 was obtained from the stool of a healthy child living on Madagascar Island. The isolate genome was amplified by a reverse transcription-PCR method, and the consensus sequence was determined. Citation Razafindratsimandresy R, Joffret M-L, Delpeyroux F, Heraud J-M. 2014. First full genome sequence of a human enterovirus A120, isolated in Madagascar. Genome Announc. 2(3):e00568-14.

The annual incidence of Q fever in French Guiana was found to have increased in 1996 and was 37/100,000 population over the last 4 years. Subsequent investigations in Cayenne and its suburbs indicated that a wild reservoir of the bacteria was responsible for the epidemiologic pattern. A case-control study showed that residence near a forest and occupations and activities that result in exposure to aerosols of dusts from the soil are risk factors for Q fever. By means of time-series analysis, a strong positive correlation between rainfall and the incidence of Q fever with a time lag of 1-3 months was found. The spatial distribution of the cases showed that transmission occurs widely throughout greater Cayenne, which is incompatible with a pinpoint source of contamination. Transmission from livestock and dissemination of the bacteria by the wind appeared to be unlikely, which strengthens the hypothesis that a wild reservoir is responsible for transmission.

Background Acute respiratory infections are a leading cause of infectious disease-related morbidity, hospitalisation and mortality among children worldwide, and particularly in developing countries. In these low-income countries, most patients with acute respiratory infection (ARI), whether it is mild or severe, are still treated empirically. The aim of the study was to evaluate the risk factors associated with the evolution and outcome of respiratory illnesses in patients aged under 5 years old. Materials and Methods We conducted a prospective study in a paediatric ward in Antananarivo from November 2010 to July 2012 including patients under 5 years old suffering from respiratory infections. We collected demographic, socio-economic, clinical and epidemiological data, and samples for laboratory analysis. Deaths, rapid progression to respiratory distress during hospitalisation, and hospitalisation for more than 10 days were considered as severe outcomes. We used multivariate analysis to study the effects of co-infections. Results From November 2010 to July 2012, a total of 290 patients were enrolled. Co-infection was found in 192 patients (70%). Co-infections were more frequent in children under 36 months, with a significant difference for the 19–24 month-old group (OR: 8.0). Sixty-nine percent (230/290) of the patients recovered fully and without any severe outcome during hospitalisation; the outcome was scored as severe for 60 children and nine patients (3%) died. Risk factors significantly associated with worsening evolution during hospitalisation (severe outcome) were admission at age under 6 months (OR = 5.3), comorbidity (OR = 4.6) and low household income (OR = 4.1). Conclusion Co-mordidity, low-income and age under 6 months increase the risk of severe outcome for children infected by numerous respiratory pathogens. These results highlight the need for implementation of targeted public health policy to reduce the contribution of respiratory diseases to childhood morbidity and mortality in low income countries.

International audience; Hepatitis E virus (HEV) causes an orofecal disease transmitted through poor hygiene environments, contaminated food (mainly pork products), or by contacts with infected animals. Very little data are currently available regarding the disease in the Southwestern Indian Ocean Islands. We report the first sero- and viro-survey for HEV in human and swine in Madagascar. A seroprevalence rate of 14.1% (60 of 427) was measured in slaughterhouse workers. Seroprevalence to HEV in pigs was estimated to 71.2% (178 of 250), strongly suggesting the existence of a zoonotic cycle. Three out of 250 pig livers (1.2%) tested HEV RNA-positive by quantitative polymerase chain reaction. Phylogenetic analyses based on 1-kb sequences of the ORF 2-3 identified these viruses as HEV genotype 3. Sequences clustered in a distinct Malagasy sub-clade, possibly representative of a new sub-genotype, for which the date of emergence was estimated around 1989. Further studies are needed to confirm other transmission routes of HEV to humans, especially through non-zoonotic cycles.

Influenza is a well-documented cause of morbidity and mortality in high- and middle-income countries. In the past few decades and particularly during the recent influenza pandemic, numerous studies and surveillance reports in the United States, Europe, Australia, and parts of Asia have improved our understanding of the epidemiology and burden of influenza in those regions. In Africa, however, the picture is quite different. Until the latter half of the last decade minimal effort had been made to understand the epidemiology, burden, and seasonality of influenza in Africa, a continent where some of the poorest populations in the world reside; where human immunodeficiency virus (HIV) infection and AIDS, tuberculosis, and malaria have long ravaged residents; and where resources for health are scarce and often directed at securing basic healthcare and prevention measures. As a result, the impact of the disease in this region has been considered negligible [1].

International audience; BACKGROUND: In response to the potential threat of an influenza pandemic, several international institutions and governments, in partnership with African countries, invested in the development of epidemiologic and laboratory influenza surveillance capacity in Africa and the African Network of Influenza Surveillance and Epidemiology (ANISE) was formed. METHODS: We used a standardized form to collect information on influenza surveillance system characteristics, the number and percent of influenza-positive patients with influenza-like illness (ILI), or severe acute respiratory infection (SARI) and virologic data from countries participating in ANISE. RESULTS: Between 2006 and 2010, the number of ILI and SARI sites in 15 African countries increased from 21 to 127 and from 2 to 98, respectively. Children 0-4 years accounted for 48% of all ILI and SARI cases of which 22% and 10%, respectively, were positive for influenza. Influenza peaks were generally discernible in North and South Africa. Substantial cocirculation of influenza A and B occurred most years. CONCLUSIONS: Influenza is a major cause of respiratory illness in Africa, especially in children. Further strengthening influenza surveillance, along with conducting special studies on influenza burden, cost of illness, and role of other respiratory pathogens will help detect novel influenza viruses and inform and develop targeted influenza prevention policy decisions in the region.

International audience; BACKGROUND: Madagascar was one of the first African countries to be affected by the 2009 pandemic of influenza A virus subtype H1N1 [A(H1N1)pdm2009] infection. The outbreak started in the capital city, Antananarivo, and then spread throughout the country from October 2009 through February 2010. METHODS: Specimens from patients presenting with influenza-like illness were collected and shipped to the National Influenza Center in Madagascar for analyses, together with forms containing patient demographic and clinical information. RESULTS: Of the 2303 specimens tested, 1016 (44.1%) and 131 (5.7%) yielded A(H1N1)pdm09 and seasonal influenza virus, respectively. Most specimens (42.0%) received were collected from patients 50 years old to be infected with A(H1N1)pdm09 (odds ratio, 2.1; 95% confidence interval, 1.7-2.6; P < .01). Although phylogenetic analyses of A(H1N1)pdm09 suggested multiple introductions of the virus into Madagascar, no antigenic differences between A(H1N1)pdm09 viruses recovered in Madagascar and those that circulated worldwide were observed. CONCLUSIONS: The high proportion of respiratory specimens positive for A(H1N1)pdm09 is consistent with a widespread transmission of the pandemic in Madagascar. The age distribution of cases of A(H1N1)pdm09 infection suggests that children and young adults could be targeted for interventions that aim to reduce transmission during an influenza pandemic.

International audience; BACKGROUND: Although recent work has described the spatiotemporal diffusion of influenza viruses worldwide, comprehensive data on spatiotemporal patterns of influenza from the African continent and Madagascar are still lacking. METHODS: National Influenza Centers from 5 countries-Cameroon, Côte d'Ivoire, Madagascar, Niger, and Senegal--collected specimens from patients presenting with influenza-like illness who visited sentinel surveillance clinics during a 2-year period (2008-2009). Isolates were genetically and antigenically characterized. RESULTS: Overall, 8312 specimens were tested. Seasonal influenza A virus subtypes H1N1 and H3N2 and influenza B viruses were detected in 329, 689, and 148 specimens, respectively. In 2009, pandemic influenza A virus subtype H1N1 was detected in Madagascar most commonly (98.5% of cases). Influenza activity was either significant year-round or occurred during a specific period of the year in the African countries we evaluated. CONCLUSIONS: Our results demonstrate that, from Madagascar to Senegal, the epidemiologic and virologic characteristics of influenza viruses are diverse in terms of spatiotemporal circulation of the different virus types, subtypes, and strains. Our data highlight the importance of country-specific surveillance and of data and virus sharing, and they provide a rational basis to aid policy makers to develop strategies, such as vaccination at the right moment and with the right formulation, aimed at reducing the disease burden in Africa and Madagascar.

International audience; Bats are reservoirs for many emerging zoonotic viruses. In this study, we screened 197 animals from 15 different bat species of the Southwest Indian Ocean for paramyxovirus infection and identified paramyxoviruses in five insectivorous bat-species from the Union of the Comoros (3/66), Mauritius (1/55) and Madagascar (4/76). Viral isolation was possible via cell culture and phylogenetic analysis revealed these viruses clustered in a Morbillivirus-related lineage, with relatively high nucleotide sequence similarity to other recently discovered insectivorous-bat paramyxoviruses but distinct from those known to circulate in frugivorous bats.

Introduction Malgre la persistance d’un schema vaccinal contre la rougeole d’une seule dose a Madagascar, aucune epidemie n’a ete rapportee depuis 10 ans sur l’ile, qui est en periode de « lune de miel ». L’objectif principal de cette etude etait de decrire l’immunite contre la rougeole a partir de donnees serologiques recueillies a l’institut Pasteur de Madagascar. L’objectif secondaire etait de tester la concordance entre taux d’immunisation et taux de couverture vaccinale. Methodes Une etude retrospective a partir des donnees serologiques (IgG et IgM) recueillies entre 2010 et 2014 a eu lieu. Elle comprenait tous les sujets consultants dans une structure de soin et consideres comme cas suspects pour la rougeole. Les analyses ont ete realisees par region, par densite de population regionale et par annee de diagnostic. Resultats Au total, 2696 patients ont ete preleves. 77,4 % sont immunises contre la rougeole. La population immunisee est significativement plus âgee que la population non immunisee (10 ans versus 6,6 ans, p Discussion La population immunisee est majoritairement jeune et feminine. Des biais de selection et d’information ont pu sous-estimer la part de population immunisee. La sous-declaration est certaine. L’immunite ne reflete que partiellement la couverture vaccinale. Une amelioration des campagnes de vaccination, de la qualite des donnees recueillies et la modelisation du risque de survenue d’epidemie semblent primordiales.

Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008-2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i) to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii) to identify human behaviors favoring human infections in Malagasy contexts.First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA). Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human) as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior) as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (p0.001). Areas with high cattle density were at risk (p0.01; OR = 2.6). Furthermore, our analysis showed that frequent contact with raw milk contributed to explain human infection (OR = 1.6). Finally, our study highlighted the eastern-coast, western and north-western parts as high-risk areas for RVF transmission in cattle.Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission probably occurs in both cattle and human. The relative contribution of vectorial or direct transmissions could be further assessed by mathematic modelling.

International audience; Few countries in Africa currently include rubella-containing vaccination (RCV) in their immunization schedule. The Global Alliance for Vaccines Initiative (GAVI) recently opened a funding window that has motivated more widespread roll-out of RCV. As countries plan RCV introductions, an understanding of the existing burden, spatial patterns of vaccine coverage, and the impact of patterns of local extinction and reintroduction for rubella will be critical to developing effective programmes. As one of the first countries proposing RCV introduction in part with GAVI funding, Madagas-car provides a powerful and timely case study. We analyse serological data from measles surveillance systems to characterize the epidemiology of rubella in Madagascar. Combining these results with data on measles vaccination delivery, we develop an age-structured model to simulate rubella vaccination scenarios and evaluate the dynamics of rubella and the burden of congenital rubella syndrome (CRS) across Madagascar. We additionally evaluate the drivers of spatial heterogeneity in age of infection to identify focal locations where vaccine surveillance should be strengthened and where challenges to successful vaccination introduction are expected. Our analyses indicate that characteristics of rubella in Madagascar are in line with global observations, with an average age of infection near 7 years, and an impact of frequent local extinction with reintroductions causing localized epidemics. Modelling results indicate that introduction of RCV into the routine programme alone may initially decrease rubella incidence but then result in cumulative increases in the burden of CRS in some regions (and transient increases in this burden in many regions). Deployment of RCV with regular supplementary campaigns will mitigate these outcomes. Results suggest that introduction of RCV offers a potential for elimination of rubella in Madagascar, but also emphasize both that targeted vaccination is likely to be a lynchpin of this success, and the public health vigilance that this introduction will require.

SUMMARYIt is difficult to assess the mortality burden of influenza epidemics in tropical countries. Until recently, the burden of influenza was believed to be negligible in Africa. We assessed the impact of the 2009 influenza epidemic on mortality in Madagascar by conducting Poisson regression analysis on mortality data from the deaths registry, after the first wave of the 2009 A(H1N1) virus pandemic. There were 20% more human deaths than expected in Antananarivo, Madagascar in November 2009, with excess mortality in the ⩾50 years age group (relative risk 1·41). Furthermore, the number of deaths from pulmonary disease was significantly higher than the number of deaths from other causes during this pandemic period. These results suggest that the A(H1N1) 2009 virus pandemic may have been accompanied by an increase in mortality.

Human immunodeficiency virus (HIV) infection is associated with immune activation, CD4 + -T-cell loss, and a progressive decline of immune functions. Antiretroviral therapy (ART) only partially reverses HIV-associated immune dysfunction, suggesting that approaches that target immune activation and improve virus-specific immune responses may be needed. We performed a preclinical study in rhesus macaques infected with the pathogenic simian immunodeficiency virus SIV mac251 and treated with ART. We tested whether vaccination administered together with cytotoxic-T-lymphocyte-associated antigen 4 (CTLA-4) blockade and treatment with the indoleamine 2,3-dioxygenase (IDO) inhibitor 1-methyl- d -tryptophan ( d -1mT), decreased immune activation and improved vaccine efficacy. The treatment did not augment vaccine immunogenicity; rather, it dramatically increased ART-related toxicity, causing all treated animals to succumb to acute pancreatitis and hyperglycemic coma. The onset of fulminant diabetes was associated with severe lymphocyte infiltration of the pancreas and complete loss of the islets of Langerhans. Thus, caution should be used when considering approaches aimed at targeting immune activation during ART.

International audience; PROBLEM:The revision of the International Health Regulations (IHR) and the threat of influenza pandemics and other disease outbreaks with a major impact on developing countries have prompted bolstered surveillance capacity, particularly in low-resource settings.APPROACH:Surveillance tools with well-timed, validated data are necessary to strengthen disease surveillance. In 2007 Madagascar implemented a sentinel surveillance system for influenza-like illness (ILI) based on data collected from sentinel general practitioners.SETTING:Before 2007, Madagascar's disease surveillance was based on the passive collection and reporting of data aggregated weekly or monthly. The system did not allow for the early identification of outbreaks or unexpected increases in disease incidence.RELEVANT CHANGES:An innovative case reporting system based on the use of cell phones was launched in March 2007. Encrypted short message service, which costs less than 2 United States dollars per month per health centre, is now being used by sentinel general practitioners for the daily reporting of cases of fever and ILI seen in their practices. To validate the daily data, practitioners also report epidemiological and clinical data (e.g. new febrile patient's sex, age, visit date, symptoms) weekly to the epidemiologists on the research team using special patient forms.LESSONS LEARNT:Madagascar's sentinel ILI surveillance system represents the country's first nationwide "real-time" surveillance system. It has proved the feasibility of improving disease surveillance capacity through innovative systems despite resource constraints. This type of syndromic surveillance can detect unexpected increases in the incidence of ILI and other syndromic illnesses.

The Animal Risk regional network: surveillance and research in the Indian Ocean. To meet the challenges of emerging diseases in the Indian Ocean region, in 2009 animal health stakeholders set up the Animal Risk-OI network, designed to provide technicaland scientific support to surveillance systems and to suggest ways of improving health risk control in the area. The network is supported by OIE referring bodies for the Indian Ocean—veterinary services and animal health research organizations. Animal Risk-OI is not intended to replace current monitoring systems but to help consider arising issues through bimonthly webconferences, annual meetings and quarterly newsletters, and to provide information for research aiming to clarify theepidemiology of certain diseases and recommend suitable control measures. This paper presents the preliminary findings following the monitoring and investigation of diseases considered by network partners to be of top priority. Apart from pursuing synergy between surveillance and research activities, the network aims to bridge the gap between animal and human health to instigate ajoint, standardized approach to the assessment and control of health risks in the Indian Ocean region., Pour répondre aux défis lancés par les maladies émergentes dans l’Océan Indien, les acteurs de la santé animale ont mis en place depuis début 2009 le réseau AnimalRisk-OI. Ce réseau a pour objectif d’apporter un soutien technique et scientifique aux systèmes de surveillance et de proposer des réponses pour une meilleure gestion des risques sanitaires dans la zone. Les partenaires sont les référents de l’OIE dans l’Océan Indien, à savoir les services vétérinaires ainsi que les structures de recherché impliquées en santé animale. Le réseau AnimalRisk-OI n’a pas pour vocation de se substituer aux systèmes de surveillance existants, mais il est chargé d’animer une réflexion autour des problématiques observées par des téléweb conférences bimensuelles, des réunions annuelles et des bulletins d’information trimestriels et de nourrir des actions de recherche qui visent à mieux comprendre l’épidémiologie de certaines maladies et donc de proposer des mesures de gestion adéquates pour mieux les maîtriser. Les premiers résultats de la surveillance et des investigations sur certaines maladies considérées prioritaires par les partenaires sont présentés ici. Les orientations envisagées, outre la poursuite de la synergie entre les actions de surveillance et de recherche, sont un rapprochement avec la santé humaine pour permettre une approche commune et harmonisée de l’appréciation et de la gestion des risques sanitaires dans l’Océan Indien.

International audience; (See the editorial commentary by Bray, on pages 1037-9.) The licensed smallpox vaccine, ACAM2000, is a cell culture derivative of Dryvax. Both ACAM2000 and Dryvax are administered by skin scarification and can cause progressive vaccinia, with skin lesions that disseminate to distal sites. We have investigated the immunologic basis of the containment of vaccinia in the skin with the goal to identify safer vaccines for smallpox. Macaques were depleted systemically of T or B cells and vaccinated with either Dryvax or an attenuated vaccinia vaccine, LC16m8. B cell depletion did not affect the size of skin lesions induced by either vaccine. However, while depletion of both CD4(+) and CD8(+) T cells had no adverse effects on LC16m8-vaccinated animals, it caused progressive vaccinia in macaques immunized with Dryvax. As both Dryvax and LC16m8 vaccines protect healthy macaques from a lethal monkeypox intravenous challenge, our data identify LC16m8 as a safer and effective alternative to ACAM2000 and Dryvax vaccines for immunocompromised individuals.

Background. Rabies virus (RABV) has circulated in Madagascar at least since the 19th century.Objectives. To assess the circulation of lyssavirus in the island from 2005 to 2010.Materials and Methods. Animal (including bats) and human samples were tested for RABV and other lyssavirus using antigen, ribonucleic acid (RNA), and antibodies detection and virus isolation.Results. Half of the 437 domestic or tame wild terrestrial mammal brains tested were found RABV antigen positive, including 54% of the 341 dogs tested. This percentage ranged from 26% to 75% across the period. Nine of the 10 suspected human cases tested were laboratory confirmed. RABV circulation was confirmed in 34 of the 38 districts sampled. No lyssavirus RNA was detected in 1983 bats specimens. Nevertheless, antibodies against Lagos bat virus were detected in the sera of 12 among 50Eidolon dupreanumspecimens sampled.Conclusion. More than a century after the introduction of the vaccine, rabies still remains endemic in Madagascar.

Coinfection with human T-cell lymphotropic virus type 2 (HTLV-2) and human immunodeficiency virus type 1 (HIV-1) has been reported to have either a slowed disease course or to have no effect on progression to AIDS. In this study, we generated a coinfection animal model and investigated whether HTLV-2 could persistently infect macaques, induce a T-cell response, and impact simian immunodeficiency virus SIV mac251 -induced disease. We found that inoculation of irradiated HTLV-2-infected T cells into Indian rhesus macaques elicited humoral and T-cell responses to HTLV-2 antigens at both systemic and mucosal sites. Low levels of HTLV-2 provirus DNA were detected in the blood, lymphoid tissues, and gastrointestinal tracts of infected animals. Exposure of HTLV-2-infected or naïve macaques to SIV mac251 demonstrated comparable levels of SIV mac251 viral replication, similar rates of mucosal and peripheral CD4 + T-cell loss, and increased T-cell proliferation. Additionally, neither the magnitude nor the functional capacity of the SIV-specific T-cell-mediated immune response was different in HTLV-2/SIV mac251 coinfected animals versus SIV mac251 singly infected controls. Thus, HTLV-2 targets mucosal sites, persists, and importantly does not exacerbate SIV mac251 infection. These data provide the impetus for the development of an attenuated HTLV-2-based vectored vaccine for HIV-1; this approach could elicit persistent mucosal immunity that may prevent HIV-1/SIV mac251 infection.

Background Following the outbreak of chikungunya in the Indian Ocean, the Ministry of Health directed the necessary development of an early outbreak detection system. A disease surveillance team including the Institut Pasteur in Madagascar (IPM) was organized to establish a sentinel syndromic-based surveillance system. The system, which was set up in March 2007, transmits patient data on a daily basis from the various voluntary general practitioners throughout the six provinces of the country to the IPM. We describe the challenges and steps involved in developing a sentinel surveillance system and the well-timed information it provides for improving public health decision-making. Methods Surveillance was based on data collected from sentinel general practitioners (SGP). The SGPs report the sex, age, visit date and time, and symptoms of each new patient weekly, using forms addressed to the management team. However, the system is original in that SGPs also report data at least once a day, from Monday to Friday (number of fever cases, rapid test confirmed malaria, influenza, arboviral syndromes or diarrhoeal disease), by cellular telephone (encrypted message SMS). Information can also be validated by the management team, by mobile phone. This data transmission costs 120 ariary per day, less than US$1 per month. Results In 2008, the sentinel surveillance system included 13 health centers, and identified 5 outbreaks. Of the 218,849 visits to SGPs, 12.2% were related to fever syndromes. Of these 26,669 fever cases, 12.3% were related to Dengue-like fever, 11.1% to Influenza-like illness and 9.7% to malaria cases confirmed by a specific rapid diagnostic test. Conclusion The sentinel surveillance system represents the first nationwide real-time-like surveillance system ever established in Madagascar. Our findings should encourage other African countries to develop their own syndromic surveillance systems. Prompt detection of an outbreak of infectious disease may lead to control measures that limit its impact and help prevent future outbreaks.

International audience; Loss of CD4(+) T cells in the gut is necessary but not sufficient to cause AIDS in animal models, raising the possibility that a differential loss of CD4(+) T-cell subtypes may be important. We found that CD4(+) T cells that produce interleukin (IL)-17, a recently identified lineage of effector CD4(+) T-helper cells, are infected by SIV(mac251)in vitro and in vivo, and are found at lower frequency at mucosal and systemic sites within a few weeks from infection. In highly viremic animals, Th1 cells predominates over Th17 T cells and the frequency of Th17 cells at mucosal sites is negatively correlated with plasma virus level. Because Th17 cells play a central role in innate and adaptive immune response to extracellular bacteria, our finding may explain the chronic enteropathy in human immunodeficiency virus (HIV) infection. Thus, therapeutic approaches that reconstitute an adequate balance between Th1 and Th17 may be beneficial in the treatment of HIV infection.

The importance of chronic immune activation in progression to AIDS has been inferred by correlative studies in HIV-infected individuals and in nonhuman primate models of SIV infection. Using the SIVmac251 macaque model, we directly address the impact of immune activation by inhibiting CTLA-4, an immunoregulatory molecule expressed on activated T cells and a subset of regulatory T cells. We found that CTLA-4 blockade significantly increased T cell activation and viral replication in primary SIVmac251 infection, particularly at mucosal sites, and increased IDO expression and activity. Accordingly, protracted treatment with anti-CTLA-4 Ab of macaques chronically infected with SIVmac251 decreased responsiveness to antiretroviral therapy and abrogated the ability of therapeutic T cell vaccines to decrease viral set point. These data provide the first direct evidence that immune activation drives viral replication, and suggest caution in the use of therapeutic approaches for HIV infection in vivo that increase CD4+ T cell proliferation.

We have developed an animal model of experimental HTLV-1 infection in Saimiri sciureus monkeys in order to study both the immunological and the virological aspects of the infection. As cytokines expressed by immune cells play an essential role during viral infection, we have studied the correlation between the expression of some Th1/Th2 cytokines, including IL-2, IL-5, IL-6, IL-10, and IFN-gamma, and immunological dynamics during primary and chronic HTLV-1 infection in this model. We first demonstrated that, during primary infection, IFN-gamma, IL-2 and IL-10 are expressed at different times and levels. The expression of these cytokines is concomitant with the increase in the numbers of CD4(+), CD8(+) and CD16(+) cells and with the presence of tax/rex viral mRNA. These data indicate the involvement of various cell types in the antiviral immune response. Subsequently, we showed that peripheral blood mononuclear cells freshly isolated from chronically infected monkeys express IFN-gamma and IL-6 at higher levels than those from uninfected animals. IFN-gamma expression is quantitatively correlated to the proviral load and to the presence of circulating effector T-cells against Tax peptide, as detected by Elispot. Further studies will be needed to determine the effective role of these cytokines and other immune system modulators in the control of viral replication during primary HTLV-1 infection or latency.

International audience; Regulatory T (T reg) cells are a subset of CD25 ؉ CD4 ؉ T cells that constitutively express high levels of cytotoxic T lymphocyte antigen-4 (CTLA-4) and suppress T-cell activation and effector functions. T reg cells are increased in tissues of individuals infected with HIV-1 and macaques infected with simian immunodeficiency virus (SIV mac251). In HIV-1 infection, T reg cells could exert contrasting effects: they may limit viral replication by decreasing immune activation, or they may increase viral replication by suppressing virusspecific immune response. Thus, the outcome of blocking T reg function in HIV/SIV should be empirically tested. Here, we demonstrate that CD25 ؉ T cells inhibit virus-specific T-cell responses in cultured T cells from blood and lymph nodes of SIV-infected macaques. We investigated the impact of CTLA-4 blockade using the anti-CTLA-4 human antibody MDX-010 in SIV-infected macaques treated with antiretroviral therapy (ART). CTLA-4 blockade decreased expression of the tryptophan-depleting enzyme IDO and the level of the suppressive cytokine transforming growth factor-␤ (TGF-␤) in tissues. CTLA-4 blockade was associated with decreased viral RNA levels in lymph nodes and an increase in the effector function of both SIV-specific CD4 ؉ and CD8 ؉ T cells. Therefore, blunting T reg function in macaques infected with SIV did not have detrimental virologic effects and may provide a valuable approach to complement ART and therapeutic vaccination in the treatment of HIV-1 infection.

The smallpox vaccine Dryvax, a live vaccinia virus (VACV), protects against smallpox and monkeypox, but is contraindicated in immunocompromised individuals. Because Abs to VACV mediate protection, a live virus vaccine could be substituted by a safe subunit protein-based vaccine able to induce a protective Ab response. We immunized rhesus macaques with plasmid DNA encoding the monkeypox orthologs of the VACV L1R, A27L, A33R, and B5R proteins by the intradermal and i.m. routes, either alone or in combination with the equivalent recombinant proteins produced in Escherichia coli. Animals that received only DNA failed to produce high titer Abs, developed innumerable skin lesions after challenge, and died in a manner similar to placebo controls. By contrast, the animals vaccinated with proteins developed moderate to severe disease (20–155 skin lesions) but survived. Importantly, those immunized with DNA and boosted with proteins had mild disease with 15 or fewer lesions that resolved within days. DNA/protein immunization elicited Th responses and binding Ab titers to all four proteins that correlated negatively with the total lesion number. The sera of the immunized macaques recognized a limited number of linear B cell epitopes that are highly conserved among orthopoxviruses. Their identification may guide future efforts to develop simpler, safer, and more effective vaccines for monkeypox and smallpox.

International audience; The aim of this study was to assess the awareness of human T-cell lymphotropic virus (HTLV) transmission, especially through breastfeeding, in a small group of 40 HTLV-seropositive women in French Guiana and to examine the public health policies in place to reduce transmission. The results show that the majority of HTLV-positive women were aware of having a blood virus, diagnosed antenatally, and were advised to avoid breastfeeding. This advice was followed in the majority of cases despite financial difficulty. Participants were largely unaware of other modes of transmission. Public awareness was low, leading to increased stigmatising of people with HTLV, more so than HIV. Health policies in place to reduce transmission of HTLV are focused on vertical transmission, with women being routinely tested antenatally and advised to avoid breastfeeding. There was no further advice routinely given on other modes of transmission. There was no routine follow-up of HTLV-positive women. Suggestions include public education programmes such as those that are in place for HIV, education of healthcare workers, and setting up a network for systematic follow-up and support of HTLV patients.

International audience; Human T-cell lymphotropic virus type 1 (HTLV-1)-associated adult T-cell leukemia/lymphoma (ATLL) has a poor prognosis owing to its intrinsic resistance to chemotherapy. Although zidovudine (AZT) and alpha interferon (IFN-alpha) give rise to some response and improve the prognosis of ATLL, alternative therapies are needed. Arsenic trioxide (As(2)O(3)) has been shown to synergize with IFN-alpha in arresting cell growth and inducing apoptosis of ATLL cells in vitro. In this study, we evaluated the toxicity and the efficacy of this combined treatment in HTLV-1-infected squirrel monkeys (Saimiri sciureus) and HTLV-1 infected cell lines derived therefrom. We first show that treatment with As(2)O(3) and IFN-alpha can induce growth arrest in HTLV-1-transformed monkey T-cell lines in vitro. We then show that treatment of squirrel monkeys with As(2)O(3) in vivo is highly toxic at 0.9 or 0.3mg/day but not at 0.14mg/day for up to 2 weeks. Although the combination of As(2)O(3) and IFN-alpha did not affect significantly the HTLV-1 proviral load in infected monkeys, it reduced the absolute numbers of CD3(+), CD4(+) and CD8(+) cells during treatment, with a significant reduction in the total number of circulating HTLV-1 flower cells in the infected monkeys with chronic ATLL-like disease.

A squirrel monkey model of human T-cell leukemia virus type 1 (HTLV-1) infection was used to evaluate the immunogenicity and protective efficacy of a chimeric peptide vaccine composed of a B-cell epitope from the envelope region (aa 175–218) and three HLA-A*0201-restricted cytotoxic T-lymphocyte epitopes derived from Tax protein (Tri-Tax). These selected Tax peptides induced secretion of gamma interferon (IFN-γ) in peripheral blood mononuclear cells obtained from monkeys chronically infected with HTLV-1. After immunization, a high titre of antibodies and a high frequency of IFN-γ-producing cells were detected against the Env and the Tri-Tax immunogens, but not against the individual Tax peptides. This might indicate that epitope(s) distinct from those recognized by humans are recognized by responder monkeys. After challenge, it was shown by competitive PCR that partial protection against HTLV-1 infection could be raised in immunized animals. Further studies should be developed to determine the duration of this protection.

A laboratory worker developed clinical signs of infection with Mayaro virus (Togaviridae), an arbovirus of South and Central America, 6 days after preparation of Mayaro viral antigen and 10 days after a trip to a rain forest. There was no evidence of skin lesions during the antigen preparation, and level 3 containment safety measures were followed. Therefore, molecular characterization of the virus was undertaken to identify the source of infection. RT–PCR and DNA sequence comparisons proved the infection was with the laboratory strain. Airborne Mayaro virus contamination is thus a hazard to laboratory personnel.