Convergence of row sequences of simultaneous Pad\'{e}-Faber approximants

We consider row sequences of vector valued Pad\'{e}-Faber approximants (simultaneous Pad\'{e}-Faber approximants) and prove a Montessus de Ballore type theorem.Comment: This paper is accepted and will be published in Journal "Mathematical Notes" V. 103, 201

Culex pipiens, an Experimental Efficient Vector of West Nile and Rift Valley Fever Viruses in the Maghreb Region

West Nile fever (WNF) and Rift Valley fever (RVF) are emerging diseases causing epidemics outside their natural range of distribution. West Nile virus (WNV) circulates widely and harmlessly in the old world among birds as amplifying hosts, and horses and humans as accidental dead-end hosts. Rift Valley fever virus (RVFV) re-emerges periodically in Africa causing massive outbreaks. In the Maghreb, eco-climatic and entomologic conditions are favourable for WNV and RVFV emergence. Both viruses are transmitted by mosquitoes belonging to the Culex pipiens complex. We evaluated the ability of different populations of Cx. pipiens from North Africa to transmit WNV and the avirulent RVFV Clone 13 strain. Mosquitoes collected in Algeria, Morocco, and Tunisia during the summer 2010 were experimentally infected with WNV and RVFV Clone 13 strain at titers of 107.8 and 108.5 plaque forming units/mL, respectively. Disseminated infection and transmission rates were estimated 14–21 days following the exposure to the infectious blood-meal. We show that 14 days after exposure to WNV, all mosquito st developed a high disseminated infection and were able to excrete infectious saliva. However, only 69.2% of mosquito strains developed a disseminated infection with RVFV Clone 13 strain, and among them, 77.8% were able to deliver virus through saliva. Thus, Cx. pipiens from the Maghreb are efficient experimental vectors to transmit WNV and to a lesser extent, RVFV Clone 13 strain. The epidemiologic importance of our findings should be considered in the light of other parameters related to mosquito ecology and biology

Ecophysiological characterization and molecular differentiation of Culex pipiens forms (Diptera: Culicidae) in Tunisia

Abstract Background The Culex pipiens complex (Diptera: Culicidae) includes the most widespread mosquito species in the world. Members of this complex are the primary enzootic and epidemic vectors of the West Nile virus (genus Flavivirus) in several countries. The two recognized forms of Cx. pipiens (Linnaeus, 1758) - pipiens and molestus - exhibit behavioral and physiological differences. Natural populations of Cx. pipiens were investigated in several sites in Tunisia to evaluate the ecophysiological and molecular characteristics of their forms. Results The analysis showed the sympatric presence of Cx. pipiens forms and hybrids in all studied sites. Of all the tested larvae of Cx. pipiens, 33.5% were identified as pipiens, 30.8% were identified as molestus, and 35.6% were identified as hybrids. The molestus and hybrid forms were positively correlated with urban habitats and belowground sites while the pipiens form was positively correlated with rural habitats and aboveground sites. Autogeny was expressed in all types of habitats and breeding sites. By contrast with the microsatellite CQ11, the two molecular markers, ace-2 and cytb, did not allow differentiation between the Cx. pipiens forms. Conclusions Our study shows the ubiquitous distribution and the plasticity of the different forms of Cx. pipiens in a wide range of ecological conditions. It suggests that the behavioral traits assigned to the forms of Cx. pipiens seem to be more flexible than previously assumed. Our analysis also proves that the microsatellite CQ11 remains an efficient tool for distinguishing between Cx. pipiens forms

Additional file 5: Table S5. of Ecophysiological characterization and molecular differentiation of Culex pipiens forms (Diptera: Culicidae) in Tunisia

Results of the relationship between habitat type and breeding site type and the percentage of autogeny of Cx. pipiens mosquitoes, based on a Generalized Linear Model with Poisson distribution. (PDF 88 kb

Canine leishmaniosis in Tunisia: Growing prevalence, larger zones of infection

International audienceBackgroundDiscovered by Nicolle and Comte in 1908 in Tunisia, Leishmania infantum is an intracellular protozoan responsible for zoonotic canine leishmaniosis (CanL) and zoonotic human visceral leishmaniasis (HVL). It is endemic in several regions of the world, including Tunisia, with dogs considered as the main domestic reservoir. The geographic expansion of canine leishmaniosis (CanL) has been linked to global environmental changes that have affected the density and the distribution of its sand fly vectors.Methodology/Principal findingsIn this study, a cross-sectional epidemiological survey on CanL was carried out in 8 localities in 8 bioclimatic areas of Tunisia. Blood samples were taken from 317 dogs after clinical examination. Collected sera were tested by indirect fluorescent antibody test (IFAT; 1:80) for the presence of anti-Leishmania infantum antibodies. The overall seroprevalence was 58.3% (185/317). Among positive dogs, only 16.7% showed clinical signs suggestive of leishmaniosis. Seroprevalence rates varied from 6.8% to 84.6% and from 28% to 66% by bioclimatic zone and age group, respectively. Serological positivity was not statistically associated with gender. The presence of Leishmania DNA in blood, using PCR, revealed 21.2% (64/302) prevalence in dogs, which varied by bioclimatic zone (7.3% to 31%) and age group (7% to 25%). The entomological survey carried out in the studied localities showed 16 species of the two genera (Phlebotomus and Sergentomyia). P. perniciosus, P. papatasi, and P. perfiliewi were the most dominant species with relative abundances of 34.7%, 25% and 20.4%, respectively.Conclusions/SignificanceThe present report suggests a significant increase of CanL in all bioclimatic areas in Tunisia and confirms the ongoing spread of the infection of dogs to the country’s arid zone. Such an expansion of infection in dog population could be attributed to ecological, agronomic, social and climatic factors that affect the presence and density of the phlebotomine vectors

The recently introduced Aedes albopictus in Tunisia has the potential to transmit chikungunya, dengue and Zika viruses

International audienceThe mosquito Aedes albopictus was detected for the first time in Tunisia in 2018. With its establishment in the capital city of Tunis, local health authorities fear the introduction of new human arboviral diseases, like what happened in Europe with unexpected local cases of chikungunya, dengue and Zika. Even though this mosquito is competent to transmit the arboviruses mentioned above, the transmission level will vary depending on the couple, mosquito population and virus genotype. Here, we assessed the vector competence of Ae. albopictus Tunisia by experimental infections with chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viruses. We found that Ae. albopictus Tunisia was highly competent for CHIKV (transmission efficiency of 25% at 21 post-infection) and to a lesser extent, for ZIKV (8.7%) and DENV (8.3%). Virus was detected in mosquito saliva at day 3 (CHIKV), day 10 (ZIKV) and day 21 (DENV) post-infection. These results suggest that the risk of emergence of chikungunya is the highest imposing a more sustained surveillance to limit Ae. albopictus populations in densely populated urban dwellings and at the entry points of travelers returning from CHIKV-endemic regions

Relation entre facteurs environnementaux et densités larvaires d’ Ochlerotatus caspius Pallas 1771 et Ochlerotatus detritus Haliday 1833 (Diptera: Culicidae) en Tunisie

International audienceOchlerotatus caspius and Oc. detritus, two major mosquito species considered as pests in Tunisia, are subjected to intensive insecticide treatments. Considering the large areas colonized by immature stages and high adult densities generated at each egg hatching period, the efficiency of insecticide control is limited. In order to define more suitable control strategies, we aim in this study to characterize the ecological niche of each mosquito species using multivariate analyses (CA, HAC). Our results show that larval densities of both mosquito species are mainly related to plant composition and salinity of breeding sites. Indeed, Oc. detritus is more adapted to salty biotopes mainly colonized by Sarcocornia fruticosa when Oc. caspius is mostly associated to biotopes with more diversified vegetation bearing a low salinity and predominantly occupied by Juncus maritimus.Ochlerotatus caspius et Oc. detritus , deux espèces de moustiques fréquemment rencontrées en Tunisie, font l’objet de traitements insecticides en vue de limiter leur nuisance. Cependant, la portée de ces traitements demeure limitée compte tenu des grandes étendues de leurs biotopes larvaires et du caractère synchrone de leurs éclosions. Le but de cette étude vise à caractériser, à travers des analyses multivariées (AFC, CHA), la niche écologique de chaque espèce afin de définir des plans d’intervention plus adaptés. Nos résultats montrent que les abondances larvaires d’ Oc. caspius et Oc. detritus sont principalement corrélées au couvert végétal et à la salinité des gîtes larvaires. En effet, Oc. detritus se développe abondamment dans les milieux fortement salés dominés par Sarcocornia fruticosa, alors qu’ Oc. caspius est associé à une végétation plus diversifiée supportant une salinité moindre dominée par Juncus maritimus , et développant une litière végétale plus abondante

<i>Leishmania</i> identification by kDNA real time PCR.

<p>A: Standard curve obtained from serial dilutions of <i>Leishmania</i> DNA expressed as the number of parasites per reaction tube. The standard curve was established from <i>Leishmania</i> DNA extracted from 10⁶ <i>L</i>. <i>infantum</i> promastigotes. One μl of serial dilutions, ranging from 1000 (P1) to 0.01 parasites (P6) was introduced into reaction tubes. P5 (0.01 parasites per μl) showed a Ct = 32.8. B: Real time PCR amplification curves showing qPCR positive sandfly female specimen (F) as well as negative sandfly male specimen (M). Amplification plots obtained from the serial dilution of <i>Leishmania</i> DNA (P1 to P6) are also shown.</p