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Search Results: 1 - 3 of 3 matches for " Voahirana Camosseto "
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Induction of GADD34 Is Necessary for dsRNA-Dependent Interferon-β Production and Participates in the Control of Chikungunya Virus Infection
Giovanna Clavarino equal contributor,Nuno Cláudio equal contributor,Thérèse Couderc equal contributor,Alexandre Dalet,Delphine Judith,Voahirana Camosseto,Enrico K. Schmidt,Till Wenger,Marc Lecuit,Evelina Gatti ? ,Philippe Pierre ?
PLOS Pathogens , 2012, DOI: 10.1371/journal.ppat.1002708
Abstract: Nucleic acid sensing by cells is a key feature of antiviral responses, which generally result in type-I Interferon production and tissue protection. However, detection of double-stranded RNAs in virus-infected cells promotes two concomitant and apparently conflicting events. The dsRNA-dependent protein kinase (PKR) phosphorylates translation initiation factor 2-alpha (eIF2α) and inhibits protein synthesis, whereas cytosolic DExD/H box RNA helicases induce expression of type I-IFN and other cytokines. We demonstrate that the phosphatase-1 cofactor, growth arrest and DNA damage-inducible protein 34 (GADD34/Ppp1r15a), an important component of the unfolded protein response (UPR), is absolutely required for type I-IFN and IL-6 production by mouse embryonic fibroblasts (MEFs) in response to dsRNA. GADD34 expression in MEFs is dependent on PKR activation, linking cytosolic microbial sensing with the ATF4 branch of the UPR. The importance of this link for anti-viral immunity is underlined by the extreme susceptibility of GADD34-deficient fibroblasts and neonate mice to Chikungunya virus infection.
Is the Mbita trap a reliable tool for evaluating the density of anopheline vectors in the highlands of Madagascar?
Rémi Laganier, Fara M Randimby, Voahirana Rajaonarivelo, Vincent Robert
Malaria Journal , 2003, DOI: 10.1186/1475-2875-2-42
Abstract: Our study was carried out in the highlands of Madagascar in three traditional villages, for 28 nights distributed over six months, with a final comparison between 448 men-nights for human landing and 84 men-nights for Mbita trap, resulting in 6,881 and 85 collected mosquitoes, respectively.The number of mosquitoes collected was 15.4 per human-night and 1.0 per trap-night, i.e. an efficiency of 0.066 for Mbita trap vs. human landing. The number of anophelines was 10.30 per human-night and 0.55 per trap-night, i.e. an efficiency of 0.053. This efficiency was 0.10 for indoor Anopheles funestus, 0.24 for outdoor An. funestus, and 0.03 for Anopheles arabiensis. Large and unexplained variations in efficiency were observed between villages and months.In the highlands of Madagascar with its unique, highly zoophilic malaria vectors, Mbita trap collection was poor and unreliable compared to human landing collections, which remains the reference method for evaluating mosquito density and malaria transmission. This conclusion, however, should not be extrapolated directly to other areas such as tropical Africa, where malaria vectors are consistently endophilic.Malaria transmission is ordinarily calculated as the product of the density of anopheline vectors per human and the infectivity of this anthropophilic fraction of mosquitoes. Up to now all-night stationary direct bait collections (also called human landing collections) with a human acting both as bait and collector has been the reference method for evaluating mosquito density per human. Most of the time, mosquitoes that land on human skin are collected before they have bitten but, clearly, this method exposes men to mosquito bites. Therefore, alternative methods are needed and there have been many attempts to develop new strategies and traps, with varying degrees of success [1].Mathenge and collaborators [2] have published a complete description of a new trap design. The 'Mbita trap':- is baited by one human protected from
Distribution of the species of the Anopheles gambiae complex and first evidence of Anopheles merus as a malaria vector in Madagascar
Jean-Michel Pock Tsy, Jean-Bernard Duchemin, Laurence Marrama, Patrick Rabarison, Gilbert Le Goff, Voahirana Rajaonarivelo, Vincent Robert
Malaria Journal , 2003, DOI: 10.1186/1475-2875-2-33
Abstract: Sampling took place at 38 sites and 2,067 females were collected. Species assessment was performed using a PCR targeting a sequence in the IGS of the rDNA. Analysis focused on the relative prevalence of the species per site, bioclimatic domain and altitude. Infectivity of Anopheles merus was assessed using an ELISA to detect the presence of malarial circumsporozoite protein in the head-thorax.Three species were identified: An. gambiae, Anopheles arabiensis and An. merus. The distribution of each species is mainly a function of bioclimatic domains and, to a lesser extent, altitude. An. arabiensis is present in all bioclimatic domains with highest prevalence in sub-humid, dry and sub-arid domains. An. gambiae has its highest prevalence in the humid domain, is in the minority in dry areas, rare in sub-humid and absent in sub-arid domains. An. merus is restricted to the coastal fringe in the south and west; it was in the majority in one southern village. The majority of sites were sympatric for at least two of the species (21/38) and two sites harboured all three species.The role of An. merus as malaria vector was confirmed in the case of two human-biting females, which were ELISA-positive for Plasmodium falciparum.Despite the huge environmental (mainly man-made) changes in Madagascar, the distribution of An. gambiae and An. arabiensis appears unchanged for the past 35 years. The distribution of An. merus is wider than was previously known, and its effectiveness as a malaria vector has been shown for the first time; this species is now on the list of Malagasy malaria vectors.The Anopheles gambiae complex plays a central role in malaria transmission. Numbers of studies have been conducted to draw the picture of its distribution in Africa south of the Sahara, Madagascar and small, related islands. Distribution maps have been made based on thousands of observations [1-3].Madagascar is an area of special interest for such studies because it concentrates in a relatively smal
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