121 research outputs found
Malaria parasite detection increases during pregnancy in wild chimpanzees
Background: The diversity of malaria parasites (Plasmodium sp.) infecting chimpanzees (Pan troglodytes) and their close relatedness with those infecting humans is well documented. However, their biology is still largely unexplored and there is a need for baseline epidemiological data. Here, the effect of pregnancy, a well-known risk factor for malaria in humans, on the susceptibility of female chimpanzees to malaria infection was investigated.
Methods: A series of 384 faecal samples collected during 40 pregnancies and 36 post-pregnancies from three habituated groups of wild chimpanzees in the Tai National Park, Cote d'Ivoire, were tested. Samples were tested for malaria parasites by polymerase chain reaction (PCR) and sequencing. Data were analysed using a generalized linear mixed model.
Results: Probability of malaria parasite detection significantly increased towards the end of pregnancy and decreased with the age of the mother.
Conclusions: This study provides evidence that susceptibility to malaria parasite infection increases during pregnancy, and, as shown before, in younger individuals, which points towards similar dynamics of malaria parasite infection in human and chimpanzee populations and raises questions about the effects of such infections on pregnancy outcome and offspring morbidity/mortality
E box motifs as mediators of proviral latency of human retroviruses
The palindromic sequence motifs (CANNTG) known as E boxes are considered as binding sites for the basic helix-loop-helix (bHLH) class of DNA-binding proteins. Their presence has been reported in the long terminal repeats (LTR) of the HIV-1 and HTLV-1 proviruses. Their close proximity with the TATA region of both LTRs indicates that the bHLH proteins may act as important regulators of the function of proviral transcription. Indeed, observations on HIV-1 and recent results on HTLV-1 underline that these E boxes may be critically involved in the regulation of the proviral transcription of these human retroviruses. Indeed, of the two E boxes flanking the TATA sequences of the HIV-1 provirus, the 3' E box has been implicated in the transcriptional inhibition of viral gene expression. Such a role might also be played by the unique 5' E box present in the HTLV-1 LTR. In both cases, the expression of tissue-specfic bHLH proteins, like TAL1 might counteract the inhibitory effect exerted by E box proteins, thereby increasing proviral transcription. Finally, a phylogenetic study encompassing several subtypes of these two human retroviruses underlines that these E box motifs have recently appeared in the proviral LTRs and may be considered as potential mediators in the establishment of proviral latency
Assessing the feasibility of fly based surveillance of wildlife infectious diseases
Monitoring wildlife infectious agents requires acquiring samples suitable for analyses, which is often logistically demanding. A possible alternative to invasive or non-invasive sampling of wild-living vertebrates is the use of vertebrate material contained in invertebrates feeding on them, their feces, or their remains. Carrion flies have been shown to contain vertebrate DNA; here we investigate whether they might also be suitable for wildlife pathogen detection. We collected 498 flies in TaĂŻ National Park, CĂŽte dâIvoire, a tropical rainforest and examined them for adenoviruses (family Adenoviridae), whose DNA is frequently shed in feces of local mammals. Adenoviral DNA was detected in 6/142 mammal-positive flies. Phylogenetic analyses revealed that five of these sequences were closely related to sequences obtained from local non-human primates, while the sixth sequence was closely related to a murine adenovirus. Next-generation sequencing-based DNA-profiling of the meals of the respective flies identified putative hosts that were a good fit to those suggested by adenoviral sequence affinities. We conclude that, while characterizing the genetic diversity of wildlife infectious agents through fly-based monitoring may not be cost-efficient, this method could probably be used to detect the genetic material of wildlife infectious agents causing wildlife mass mortality in pristine areas
Detection of Retroviral Super-Infection from Non-Invasive Samples
While much attention has been focused on the molecular epidemiology of retroviruses in wild primate populations, the correlated question of the frequency and nature of super-infection events, i.e., the simultaneous infection of the same individual host with several strains of the same virus, has remained largely neglected. In particular, methods possibly allowing the investigation of super-infection from samples collected non-invasively (such as faeces) have never been properly compared. Here, we fill in this gap by assessing the costs and benefits of end-point dilution PCR (EPD-PCR) and multiple bulk-PCR cloning, as applied to a case study focusing on simian foamy virus super-infection in wild chimpanzees (Pan troglodytes). We show that, although considered to be the gold standard, EPD-PCR can lead to massive consumption of biological material when only low copy numbers of the target are expected. This constitutes a serious drawback in a field in which rarity of biological material is a fundamental constraint. In addition, we demonstrate that EPD-PCR results (single/multiple infection; founder strains) can be well predicted from multiple bulk-PCR clone experiments, by applying simple statistical and network analyses to sequence alignments. We therefore recommend the implementation of the latter method when the focus is put on retroviral super-infection and only low retroviral loads are encountered
DNA from extinct giant lemurs links archaeolemurids to extant indriids
<p>Abstract</p> <p>Background</p> <p>Although today 15% of living primates are endemic to Madagascar, their diversity was even greater in the recent past since dozens of extinct species have been recovered from Holocene excavation sites. Among them were the so-called "giant lemurs" some of which weighed up to 160 kg. Although extensively studied, the phylogenetic relationships between extinct and extant lemurs are still difficult to decipher, mainly due to morphological specializations that reflect ecology more than phylogeny, resulting in rampant homoplasy.</p> <p>Results</p> <p>Ancient DNA recovered from subfossils recently supported a sister relationship between giant "sloth" lemurs and extant indriids and helped to revise the phylogenetic position of <it>Megaladapis edwardsi </it>among lemuriformes, but several taxa â such as the Archaeolemuridae â still await analysis. We therefore used ancient DNA technology to address the phylogenetic status of the two archaeolemurid genera (<it>Archaeolemur </it>and <it>Hadropithecus</it>). Despite poor DNA preservation conditions in subtropical environments, we managed to recover 94- to 539-bp sequences for two mitochondrial genes among 5 subfossil samples.</p> <p>Conclusion</p> <p>This new sequence information provides evidence for the proximity of <it>Archaeolemur </it>and <it>Hadropithecus </it>to extant indriids, in agreement with earlier assessments of their taxonomic status (Primates, Indrioidea) and in contrast to recent suggestions of a closer relationship to the Lemuridae made on the basis of analyses of dental developmental and postcranial characters. These data provide new insights into the evolution of the locomotor apparatus among lemurids and indriids.</p
Non-invasive genomics of respiratory pathogens infecting wild great apes using hybridisation capture
Human respiratory pathogens have repeatedly caused lethal outbreaks in wild great apes across Africa, leading to population declines. Nonetheless, our knowledge of potential genomic changes associated with pathogen introduction and spread at the human-great ape interface remains sparse. Here, we made use of target enrichment coupled with next generation sequencing to non-invasively investigate five outbreaks of human-introduced respiratory disease in wild chimpanzees living in TaĂŻ National Park, Ivory Coast. By retrieving 34 complete viral genomes and three distinct constellations of pneumococcal virulence factors, we provide genomic insights into these spillover events and describe a framework for non-invasive genomic surveillance in wildlife.Peer Reviewe
Ebola virus disease: an orphan zoonosis ?
The gigantic Ebola virus disease
outbreak that recently swept several West African countries has revealed how little we know
about this infectious disease. The question of the animal reservoir of this zoonosis remains
particularly mysterious. Bats seem to be involved in the ecology of the virus but it remains
unclear whether or not they may be at the origin of spill-over events towards humans. Almost
40 years after the discovery of the Ebola virus, this short communication offers a summary
of the progresses made and an outlook on upcoming efforts to solve this outstanding
question.La terrible épidémie de
maladie Ă virus Ebola qui a balayĂ© lâAfrique de lâOuest a mis en Ă©vidence combien nos
connaissances sur cette maladie infectieuse sont limitées. Une question particuliÚrement
mystĂ©rieuse reste celle du rĂ©servoir animal de cette zoonose. Lâimplication des
chauves-souris dans lâĂ©cologie du virus semble probable mais il nâest pas encore Ă©tabli
quâelles jouent un rĂŽle dans sa transmission Ă lâhomme. PrĂšs de 40 ans aprĂšs la dĂ©couverte
du virus, cette communication se propose de faire le point sur les savoirs accumulés et de
dégager des pistes de réflexion utiles
Comparison of mosquito and fly derived DNA as a tool for sampling vertebrate biodiversity in suburban forests in Berlin, Germany
The use of invertebrateâderived DNA (iDNA) is a promising nonâinvasive tool to monitor wildlife. While most studies have been carried out in dense tropical and subâtropical forests and have focused on the use of a single category of invertebrates, this study compares the use of flies and mosquitoesâderived DNA to assess vertebrate diversity in semiâurban environments. We conducted our sampling in four different forest plots in Berlin, Germany. Pools of flies and nonâbloodfed mosquitoes were metabarcoded using 108âbp vertebrateâspecific 12âS rRNA (12âSâV5) and 94âbp mammalâspecific 16âS rRNA (16Smam) mitochondrial markers, and individual bloodfed mosquitoes were sequenced using the 340âbp vertebrateâspecific 12âS rRNA fragment (Mamâ12âSâ340). Most sequencing was only successful for mammal species. From the fly pools, we detected 10 mammal species using 16Smam, and six species using 12âSâV5. From the nonâbloodfed mosquito pools, we only amplified putative contaminant DNA, indicating that mosquito females without visual signs of a blood meal carry no traces of vertebrate DNA. Finally, in the bloodfed mosquitoes, we identified four mammal species. We did not find significant differences in the proportion of mammal species detected regarding the total available number of species between sampling localities. Fly samples were easier to obtain and more abundant over the sampled localities compared to mosquito samples. We conclude that, while there are a few advantages in using mosquito blood meals, the use of flies in the detection of wildlife in a suburban environment is more effective in terms of collection of samples and detection of vertebrates, although this technique is limited to few mammal species in the urban environment
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