RESUMO
Although Plasmodium vivax is responsible for the majority of malaria infections outside Africa, little is known about its evolution and pathway to humans. Its closest genetic relative, P. vivax-like, was discovered in African great apes and is hypothesized to have given rise to P. vivax in humans. To unravel the evolutionary history and adaptation of P. vivax to different host environments, we generated using long- and short-read sequence technologies 2 new P. vivax-like reference genomes and 9 additional P. vivax-like genotypes. Analyses show that the genomes of P. vivax and P. vivax-like are highly similar and colinear within the core regions. Phylogenetic analyses clearly show that P. vivax-like parasites form a genetically distinct clade from P. vivax. Concerning the relative divergence dating, we show that the evolution of P. vivax in humans did not occur at the same time as the other agents of human malaria, thus suggesting that the transfer of Plasmodium parasites to humans happened several times independently over the history of the Homo genus. We further identify several key genes that exhibit signatures of positive selection exclusively in the human P. vivax parasites. Two of these genes have been identified to also be under positive selection in the other main human malaria agent, P. falciparum, thus suggesting their key role in the evolution of the ability of these parasites to infect humans or their anthropophilic vectors. Finally, we demonstrate that some gene families important for red blood cell (RBC) invasion (a key step of the life cycle of these parasites) have undergone lineage-specific evolution in the human parasite (e.g., reticulocyte-binding proteins [RBPs]).
Assuntos
Plasmodium vivax/genética , Plasmodium/genética , Animais , Sequência de Bases/genética , Culicidae , Eritrócitos/parasitologia , Evolução Molecular , Genoma/genética , Humanos , Malária/parasitologia , Malária Falciparum/parasitologia , Malária Vivax/genética , Pan troglodytes/genética , Filogenia , Plasmodium falciparum/genéticaRESUMO
Recent studies have highlighted the large diversity of malaria parasites infecting African great apes (subgenus Laverania) and their strong host specificity. Although the existence of genetic incompatibilities preventing the cross-species transfer may explain host specificity, the existence of vectors with a high preference for a determined host represents another possibility. To test this hypothesis, we undertook a 15-mo-long longitudinal entomological survey in two forest regions of Gabon, where wild apes live, at different heights under the canopy. More than 2,400 anopheline mosquitoes belonging to 18 species were collected. Among them, only three species of Anopheles were found infected with ape Plasmodium: Anopheles vinckei, Anopheles moucheti, and Anopheles marshallii Their role in transmission was confirmed by the detection of the parasites in their salivary glands. Among these species, An. vinckei showed significantly the highest prevalence of infection and was shown to be able to transmit parasites of both chimpanzees and gorillas. Transmission was also shown to be conditioned by seasonal factors and by the heights of capture under the canopy. Moreover, human landing catches of sylvan Anopheles demonstrated the propensity of these three vector species to feed on humans when available. Our results suggest therefore that the strong host specificity observed in the Laveranias is not linked to a specific association between the vertebrate host and the vector species and highlight the potential role of these vectors as bridge between apes and humans.
Assuntos
Anopheles/parasitologia , Vetores de Doenças/classificação , Hominidae/microbiologia , Hominidae/parasitologia , Malária/parasitologia , Plasmodium/isolamento & purificação , Animais , Gabão , Humanos , Floresta Úmida , Especificidade da Espécie , Zoonoses/microbiologia , Zoonoses/parasitologiaRESUMO
Sickle cell disease (SCD) is a genetic disorder that poses a serious health threat in tropical Africa, which the World Health Organization has declared a public health priority. Its persistence in human populations has been attributed to the resistance it provides to Plasmodium falciparum malaria in its heterozygous state, called sickle cell trait (SCT). Because of migration, SCT is becoming common outside tropical countries: It is now the most important genetic disorder in France, affecting one birth for every 2,400, and one of the most common in the United States. We assess the strength of the association between SCT and malaria, using current data for both SCT and malaria infections. A total of 3,959 blood samples from 195 villages distributed over the entire Republic of Gabon were analyzed. Hemoglobin variants were identified by using HPLCy (HPLC). Infections by three species of Plasmodium were detected by PCR followed by sequencing of a 201-bp fragment of cytochrome b. An increase of 10% in P. falciparum malaria prevalence is associated with an increase by 4.3% of SCT carriers. An increase of 10 y of age is associated with an increase by 5.5% of SCT carriers. Sex is not associated with SCT. These strong associations show that malaria remains a selective factor in current human populations, despite the progress of medicine and the actions undertaken to fight this disease. Our results provide evidence that evolution is still present in humans, although this is sometimes questioned by scientific, political, or religious personalities.
Assuntos
Anemia Falciforme/epidemiologia , Anemia Falciforme/genética , Evolução Biológica , Malária Falciparum/epidemiologia , Malária Falciparum/genética , Plasmodium/genética , Seleção Genética , Fatores Etários , Sequência de Bases , Cromatografia Líquida de Alta Pressão , Estudos de Coortes , Gabão/epidemiologia , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
Q fever is a highly infectious disease with a worldwide distribution. Its causative agent, the intracellular bacterium Coxiella burnetii, infects a variety of vertebrate species, including humans. Its evolutionary origin remains almost entirely unknown and uncertainty persists regarding the identity and lifestyle of its ancestors. A few tick species were recently found to harbor maternally-inherited Coxiella-like organisms engaged in symbiotic interactions, but their relationships to the Q fever pathogen remain unclear. Here, we extensively sampled ticks, identifying new and atypical Coxiella strains from 40 of 58 examined species, and used this data to infer the evolutionary processes leading to the emergence of C. burnetii. Phylogenetic analyses of multi-locus typing and whole-genome sequencing data revealed that Coxiella-like organisms represent an ancient and monophyletic group allied to ticks. Remarkably, all known C. burnetii strains originate within this group and are the descendants of a Coxiella-like progenitor hosted by ticks. Using both colony-reared and field-collected gravid females, we further establish the presence of highly efficient maternal transmission of these Coxiella-like organisms in four examined tick species, a pattern coherent with an endosymbiotic lifestyle. Our laboratory culture assays also showed that these Coxiella-like organisms were not amenable to culture in the vertebrate cell environment, suggesting different metabolic requirements compared to C. burnetii. Altogether, this corpus of data demonstrates that C. burnetii recently evolved from an inherited symbiont of ticks which succeeded in infecting vertebrate cells, likely by the acquisition of novel virulence factors.
Assuntos
Evolução Biológica , Doenças Transmissíveis Emergentes/transmissão , Coxiella burnetii/fisiologia , Saúde Global , Febre Q/transmissão , Simbiose , Carrapatos/microbiologia , Animais , Sequência de Bases , Comportamento Animal , Linhagem Celular , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/microbiologia , Doenças Transmissíveis Emergentes/veterinária , Coxiella burnetii/classificação , Coxiella burnetii/crescimento & desenvolvimento , Coxiella burnetii/isolamento & purificação , Coxiellaceae/classificação , Coxiellaceae/crescimento & desenvolvimento , Coxiellaceae/isolamento & purificação , Coxiellaceae/fisiologia , Feminino , Genoma Bacteriano , Humanos , Masculino , Troca Materno-Fetal , Viabilidade Microbiana , Dados de Sequência Molecular , Filogenia , Gravidez , Prevalência , Febre Q/epidemiologia , Febre Q/microbiologia , Febre Q/veterinária , Carrapatos/fisiologiaRESUMO
Lymphocytic choriomeningitis virus (LCMV) can cause acute fatal disease on all continents but was never detected in Africa. We report the first detection of LCMV RNA in a common European house mouse (Mus musculus domesticus) in Africa. Phylogenetic analyses show a close relationship with North American strains. These findings suggest that there is a risk of the appearance of LCMV acute encephalitis cases. This is a perfect example of virus dissemination by its natural host that may have dramatic public health consequences.
Assuntos
Infecções por Arenaviridae/veterinária , Vírus da Coriomeningite Linfocítica/isolamento & purificação , Doenças dos Roedores/virologia , Animais , Infecções por Arenaviridae/virologia , Análise por Conglomerados , Gabão , Vírus da Coriomeningite Linfocítica/classificação , Vírus da Coriomeningite Linfocítica/genética , Camundongos , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , RNA Viral/isolamento & purificação , Análise de Sequência de DNARESUMO
Plasmodium vivax is considered to be absent from Central and West Africa because of the protective effect of Duffy negativity. However, there are reports of persons returning from these areas infected with this parasite and observations suggesting the existence of transmission. Among the possible explanations for this apparent paradox, the existence of a zoonotic reservoir has been proposed. May great apes be this reservoir? We analyze the mitochondrial and nuclear genetic diversity of P. vivax parasites isolated from great apes in Africa and compare it to parasites isolated from travelers returning from these regions of Africa, as well as to human isolates distributed all over the world. We show that the P. vivax sequences from parasites of great apes form a clade genetically distinct from the parasites circulating in humans. We show that this clade's parasites can be infectious to humans by describing the case of a traveler returning from the Central African Republic infected with one of them. The relationship between this P. vivax clade in great apes and the human isolates is discussed.
Assuntos
Evolução Molecular , Especificidade de Hospedeiro , Malária/parasitologia , Plasmodium vivax/genética , Adulto , Animais , República Centro-Africana , Culicidae/parasitologia , DNA Mitocondrial/genética , Variação Genética , Genoma , Haplótipos , Hominidae/parasitologia , Humanos , Masculino , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Fatores de TempoRESUMO
Although Plasmodium infections have never been clearly associated with symptoms in non-human primates, the question of the pathogenicity of Plasmodium parasites in non-human primates still remains unanswered. A young chimpanzee, followed before and after release to a sanctuary, in a semi-free ranging enclosure located in an equatorial forest, showed fever and strong anaemia associated with a high Plasmodium reichenowi infection, shortly after release. The animal recovered from anaemia after several months despite recurrent infection with other Plasmodium species. This may be the first description of malaria-like symptoms in a chimpanzee infected with Plasmodium.
Assuntos
Malária , Pan troglodytes/parasitologia , Plasmodium , Anemia/parasitologia , Anemia/veterinária , Animais , Peso Corporal , Feminino , Malária/parasitologia , Malária/fisiopatologia , Malária/veterináriaRESUMO
BACKGROUND: There have been many reports on the population genetic structure of Plasmodium falciparum from different endemic regions especially sub-Saharan Africa. However, few studies have been performed on neglected populations, such as the Pygmy populations. In this study, the population genetic structure of P. falciparum was investigated in the Baka Pygmies of Gabon and compared to that observed in neighboring villages composed mostly of Bantu farmers. METHODS: A total of 342 blood samples were collected from 170 Baka Pygmies and 172 Bantus in the north of Gabon (Woleu Ntem Province). Plasmodium infections were characterized by sequencing a portion of the parasite cytochrome b gene. Population genetic structure of P. falciparum in the different villages was analysed using microsatellite markers and genes coding for antigenic proteins (MSP1, MSP2, GLURP, and EBA-175). RESULTS: Overall, prevalence of P. falciparum was around 57 % and no significant difference of prevalence was observed between Pygmies and Bantus. No significant differences of population genetic structure of P. falciparum was found between Pygmy and Bantu people except for one antigen-coding gene, glurp, for which genetic data suggested the existence of a potentially disruptive selection acting on this gene in the two types of populations. The genetic structure of P. falciparum followed a pattern of isolation by distance at the scale of the study. CONCLUSION: The prevalence and genetic diversity of P. falciparum observed in Baka demonstrates a significant transmission of the parasite in this population, and some exchanges of parasites with Bantu neighbours. Despite that, some antigen-coding genes seem to have had a particular evolutionary trajectory in certain Pygmy populations due to specific local human and/or mosquito characteristics.
Assuntos
Variação Genética , Malária Falciparum/parasitologia , Plasmodium falciparum/classificação , Plasmodium falciparum/genética , Sangue/parasitologia , Citocromos b/genética , Transmissão de Doença Infecciosa , Etnicidade , Gabão/epidemiologia , Humanos , Malária Falciparum/epidemiologia , Malária Falciparum/transmissão , Repetições de Microssatélites , Epidemiologia Molecular , Plasmodium falciparum/isolamento & purificação , Prevalência , Proteínas de Protozoários/genética , Análise de Sequência de DNARESUMO
BACKGROUND: Until 2009, the Laverania subgenus counted only two representatives: Plasmodium falciparum and Plasmodium reichenowi. The recent development of non-invasive methods allowed re-exploration of plasmodial diversity in African apes. Although a large number of great ape populations have now been studied regarding Plasmodium infections in Africa, there are still vast areas of their distribution that remained unexplored. Gabon constitutes an important part of the range of western central African great ape subspecies (Pan troglodytes troglodytes and Gorilla gorilla gorilla), but has not been studied so far. In the present study, the diversity of Plasmodium species circulating in great apes in Gabon was analysed. METHODS: The analysis of 1,261 faecal samples from 791 chimpanzees and 470 gorillas collected from 24 sites all over Gabon was performed. Plasmodium infections were characterized by amplification and sequencing of a portion of the Plasmodium cytochrome b gene. RESULTS: The analysis of the 1,261 samples revealed that at least six Plasmodium species circulate in great apes in Gabon (Plasmodium praefalciparum, Plasmodium gorA (syn Plasmodium adleri), Plasmodium gorB (syn Plasmodium blacklocki) in gorillas and Plasmodium gaboni, P. reichenowi and Plasmodium billcollinsi in chimpanzees). No new phylogenetic lineages were discovered. The average infection rate was 21.3% for gorillas and 15.4% for chimpanzees. A logistic regression showed that the probability of infection was significantly dependent on the freshness of the droppings but not of the host species or of the average pluviometry of the months of collection.
Assuntos
Doenças dos Símios Antropoides/epidemiologia , Gorilla gorilla , Malária/veterinária , Pan troglodytes , Plasmodium/genética , Proteínas de Protozoários/genética , Animais , Doenças dos Símios Antropoides/parasitologia , Gabão/epidemiologia , Malária/epidemiologia , Malária/parasitologia , Dados de Sequência Molecular , Filogenia , Plasmodium/classificação , Plasmodium/isolamento & purificação , Proteínas de Protozoários/metabolismo , Análise de Sequência de DNA/veterináriaRESUMO
The origin of Plasmodium falciparum in South America is controversial. Some studies suggest a recent introduction during the European colonizations and the transatlantic slave trade. Other evidence--archeological and genetic--suggests a much older origin. We collected and analyzed P. falciparum isolates from different regions of the world, encompassing the distribution range of the parasite, including populations from sub-Saharan Africa, the Middle East, Southeast Asia, and South America. Analyses of microsatellite and SNP polymorphisms show that the populations of P. falciparum in South America are subdivided in two main genetic clusters (northern and southern). Phylogenetic analyses, as well as Approximate Bayesian Computation methods suggest independent introductions of the two clusters from African sources. Our estimates of divergence time between the South American populations and their likely sources favor a likely introduction from Africa during the transatlantic slave trade.
Assuntos
Demografia , Emigração e Imigração , Variação Genética , Filogenia , Plasmodium falciparum/genética , Teorema de Bayes , Análise por Conglomerados , Genética Populacional , Humanos , Modelos Logísticos , Repetições de Microssatélites/genética , Modelos Genéticos , Filogeografia , Plasmodium falciparum/classificação , Polimorfismo de Nucleotídeo Único/genética , Análise de Componente Principal , América do SulRESUMO
Pathogens, which have recently colonized a new host species or new populations of the same host, are interesting models for understanding how populations may evolve in response to novel environments. During its colonization of South America from Africa, Plasmodium falciparum, the main agent of malaria, has been exposed to new conditions in distinctive new human populations (Amerindian and populations of mixed origins) that likely exerted new selective pressures on the parasite's genome. Among the genes that might have experienced strong selective pressures in response to these environmental changes, the eba genes (erythrocyte-binding antigens genes), which are involved in the invasion of the human red blood cells, constitute good candidates. In this study, we analysed, in South America, the polymorphism of three eba genes (eba-140, eba-175, eba-181) and compared it to the polymorphism observed in African populations. The aim was to determine whether these genes faced selective pressures in South America distinct from what they experienced in Africa. Patterns of genetic variability of these genes were compared to the patterns observed at two housekeeping genes (adsl and serca) and 272 SNPs to separate adaptive effects from demographic effects. We show that, conversely to Africa, eba-140 seemed to be under stronger diversifying selection in South America than eba-175. In contrast, eba-181 did not show any sign of departure from neutrality. These changes in the patterns of selection on the eba genes could be the consequence of changes in the host immune response, the host receptor polymorphisms and/or the ability of the parasite to silence or express differentially its invasion proteins.
Assuntos
Antígenos de Protozoários/genética , Malária Falciparum/parasitologia , Plasmodium falciparum/genética , Polimorfismo Genético , Proteínas de Protozoários/genética , Seleção Genética , África , Proteínas de Transporte/genética , DNA de Protozoário/genética , Eritrócitos/parasitologia , Genética Populacional , Humanos , Proteínas de Membrana , Dados de Sequência Molecular , Análise de Sequência de DNA , América do SulRESUMO
Recent molecular exploration of the Plasmodium species circulating in great apes in Africa has revealed the existence of a large and previously unknown diversity of Plasmodium. For instance, gorillas were found to be infected by parasites closely related to Plasmodium falciparum, suggesting that the human malignant malaria agent may have arisen after a transfer from gorillas. Although this scenario is likely in light of the data collected in great apes, it remained to be ascertained whether P. falciparum-related parasites may infect other nonhuman primates in Africa. Using molecular tools, we here explore the diversity of Plasmodium species infecting monkeys in Central Africa. In addition to previously described Hepatocystis and Plasmodium species (Plasmodium gonderi and Plasmodium sp DAJ-2004), we have found one African monkey to be infected by a P. falciparum-related parasite. Examination of the nuclear and mitochondrial genomes of this parasite reveals that it is specific of nonhuman primates, indicating that P. falciparum-related pathogens can naturally circulate in some monkey populations in Africa. We also show that at least two distinct genetic entities of P. falciparum infect nonhuman primates and humans, respectively. Our discoveries bring into question the proposed gorilla origin of human P. falciparum.
Assuntos
Cercopithecidae , Malária Falciparum/veterinária , Doenças dos Macacos/epidemiologia , Doenças dos Macacos/parasitologia , Filogenia , Plasmodium falciparum/genética , Animais , Sequência de Bases , Primers do DNA/genética , Transferência Ressonante de Energia de Fluorescência , Gabão/epidemiologia , Funções Verossimilhança , Malária Falciparum/epidemiologia , Repetições de Microssatélites/genética , Modelos Genéticos , Dados de Sequência Molecular , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Mutação/genética , Polimorfismo de Nucleotídeo Único/genética , Análise de Componente Principal , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
From which host did the most malignant human malaria come: birds, primates, or rodents? When did the transfer occur? Over the last half century, these have been some of the questions up for debate about the origin of Plasmodium falciparum, the most common and deadliest human malaria parasite, which is responsible for at least one million deaths every year. Recent findings bring elements in favor of a transfer from great apes, but are these evidences really solid? What are the grey areas that remain to be clarified? Here, we examine in depth these new elements and discuss how they modify our perception of the origin and evolution of P. falciparum. We also discuss the perspectives these new discoveries open.
Assuntos
Evolução Biológica , Malária Falciparum/parasitologia , Plasmodium falciparum/genética , Infecções Protozoárias em Animais/parasitologia , Animais , Animais Selvagens/parasitologia , Humanos , Malária Falciparum/genética , Malária Falciparum/transmissão , Pan troglodytes/parasitologia , Filogenia , Infecções Protozoárias em Animais/genética , Infecções Protozoárias em Animais/transmissão , Zoonoses/parasitologia , Zoonoses/transmissãoRESUMO
Plasmodium reichenowi, a chimpanzee parasite, was until very recently the only known close relative of Plasmodium falciparum, the most virulent agent of human malaria. Recently, Plasmodium gaboni, another closely related chimpanzee parasite, was discovered, suggesting that the diversity of Plasmodium circulating in great apes in Africa might have been underestimated. It was also recently shown that P. reichenowi is a geographically widespread and genetically diverse chimpanzee parasite and that the world diversity of P. falciparum is fully included within the much broader genetic diversity of P. reichenowi. The evidence indicates that all extant populations of P. falciparum originated from P. reichenowi, likely by a single transfer from chimpanzees. In this work, we have studied the diversity of Plasmodium species infecting chimpanzees and gorillas in Central Africa (Cameroon and Gabon) from both wild-living and captive animals. The studies in wild apes used noninvasive sampling methods. We confirm the presence of P. reichenowi and P. gaboni in wild chimpanzees. Moreover, our results reveal the existence of an unexpected genetic diversity of Plasmodium lineages circulating in gorillas. We show that gorillas are naturally infected by two related lineages of parasites that have not been described previously, herein referred to as Plasmodium GorA and P. GorB, but also by P. falciparum, a species previously considered as strictly human specific. The continuously increasing contacts between humans and primate populations raise concerns about further reciprocal host transfers of these pathogens.
Assuntos
Gorilla gorilla/genética , Interações Hospedeiro-Parasita , Pan troglodytes/genética , Filogenia , Plasmodium falciparum/genética , Plasmodium/genética , Animais , Camarões , Fezes/parasitologia , Gabão , Gorilla gorilla/sangue , Gorilla gorilla/parasitologia , Humanos , Pan troglodytes/sangue , Pan troglodytes/parasitologia , Plasmodium/fisiologia , Plasmodium falciparum/fisiologiaRESUMO
It is increasingly suggested that the dynamics of antimicrobial-resistant bacteria in the wild are mostly anthropogenically driven, but the spatial and temporal scales at which these phenomena occur in landscapes are only partially understood. Here, we explore this topic by studying antimicrobial resistance in the commensal bacteria from micromammals sampled at 12 sites from a large heterogenous landscape (the Carmargue area, Rhone Delta) along a gradient of anthropization: natural reserves, rural areas, towns, and sewage-water treatment plants. There was a positive relationship between the frequency of antimicrobial-resistant bacteria and the level of habitat anthropization. Although low, antimicrobial resistance was also present in natural reserves, even in the oldest one, founded in 1954. This study is one of the first to support the idea that rodents in human-altered habitats are important components of the environmental pool of resistance to clinically relevant antimicrobials and also that a "One Health" approach is required to assess issues related to antimicrobial resistance dynamics in anthropized landscapes.
Assuntos
Ecossistema , Roedores , Animais , Humanos , Bactérias , AntibacterianosRESUMO
BACKGROUND: Flow cytometry and cell sorting are powerful tools enabling the selection of particular cell types within heterogeneous cell mixtures. These techniques, combined with whole genome amplification that non-specifically amplify small amounts of starting DNA, offer exciting new opportunities for the study of malaria genetics. Among them, two are tested in this paper: (1) single cell genotyping and (2) parasite DNA purification for subsequent whole genome sequencing using shotgun technologies. METHODS: The method described allows isolation of Plasmodium falciparum trophozoites, genotyping and whole genome sequencing from the blood of infected patients. For trophozoite isolation, parasite and host nuclei are stained using propidium iodide (PI) followed by flow cytometry and cell sorting to separate trophozoites from host cells. Before genotyping or sequencing, whole genome amplification is used to increase the amount of DNA within sorted samples. The method has been specifically designed to deal with frozen blood samples. RESULTS AND CONCLUSION: The results demonstrate that single trophozoite genotyping is possible and that cell sorting can be successfully applied to reduce the contaminating host DNA for subsequent whole genome sequencing of parasites extracted from infected blood samples.
Assuntos
Citometria de Fluxo/métodos , Parasitologia/métodos , Plasmodium falciparum/isolamento & purificação , DNA de Protozoário/genética , DNA de Protozoário/isolamento & purificação , Genótipo , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Malária Falciparum/parasitologia , Plasmodium falciparum/genética , Propídio/metabolismo , Coloração e Rotulagem/métodos , TrofozoítosRESUMO
ASPICov was developed to provide a rapid, reliable and complete analysis of NGS SARS-Cov2 samples to the biologist. This broad application tool allows to process samples from either capture or amplicon strategy and Illumina or Ion Torrent technology. To ensure FAIR data analysis, this Nextflow pipeline follows nf-core guidelines and use Singularity containers. Pipeline is implemented and available at https://gitlab.com/vtilloy/aspicov.
Assuntos
COVID-19/genética , Biologia Computacional , Sequenciamento de Nucleotídeos em Larga Escala , RNA Viral/genética , SARS-CoV-2/genética , Sequenciamento Completo do Genoma , HumanosRESUMO
Malaria is considered one of the most important scourges that humanity has faced during its history, being responsible every year for numerous deaths worldwide. The disease is caused by protozoan parasites, among which two species are responsible of the majority of the burden, Plasmodium falciparum and Plasmodium vivax. For these two parasite species, the questions of their origin (how and when they appeared in humans), of their spread throughout the world, as well as how they have adapted to humans have long been of interest to the scientific community. In this paper we review the existing body of knowledge, including current research dealing with these questions, focusing particularly on genetic and genomic analyses of these parasites and comparison with related Plasmodium species infecting other species of host (such as non-human primates).
Assuntos
Malária Falciparum , Malária , Plasmodium , Animais , Genética Populacional , Humanos , Malária/parasitologia , Plasmodium/genética , Plasmodium falciparum/genética , Plasmodium vivax/genéticaRESUMO
Wild animal species living in anthropogenic areas are commonly carriers of antimicrobial-resistant bacteria (AMRB), but their role in the epidemiology of these bacteria is unclear. Several studies on AMRB in wildlife have been cross-sectional in design and sampled individual animals at only one point in time. To further understand the role of wildlife in maintaining and potentially transmitting these bacteria to humans and livestock, longitudinal studies are needed in which samples are collected from individual animals over multiple time periods. In Europe, free-ranging yellow-legged gulls (Larus michahellis) commonly live in industrialized areas, forage in landfills, and have been found to carry AMRB in their feces. Using bacterial metagenomics and antimicrobial resistance characterization, we investigated the spatial and temporal patterns of AMRB in a nesting colony of yellow-legged gulls from an industrialized area in southern France. We collected 54 cloacal swabs from 31 yellow-legged gull chicks in 20 nests on three dates in 2016. We found that AMRB in chicks increased over time and was not spatially structured within the gull colony. This study highlights the complex occurrence of AMRB in a free-ranging wildlife species and contributes to our understanding of the public health risks and implications associated with ARMB-carrying gulls living in anthropogenic areas.
RESUMO
Many emerging infectious diseases originate from wild animals, so there is a profound need for surveillance and monitoring of their pathogens. However, the practical difficulty of sample acquisition from wild animals tends to limit the feasibility and effectiveness of such surveys. Xenosurveillance, using blood-feeding invertebrates to obtain tissue samples from wild animals and then detect their pathogens, is a promising method to do so. Here, we describe the use of tsetse fly blood meals to determine (directly through molecular diagnostic and indirectly through serology), the diversity of circulating blood-borne pathogens (including bacteria, viruses and protozoa) in a natural mammalian community of Tanzania. Molecular analyses of captured tsetse flies (182 pools of flies totalizing 1728 flies) revealed that the blood meals obtained came from 18 different vertebrate species including 16 non-human mammals, representing approximately 25% of the large mammal species present in the study area. Molecular diagnostic demonstrated the presence of different protozoa parasites and bacteria of medical and/or veterinary interest. None of the six virus species searched for by molecular methods were detected but an ELISA test detected antibodies against African swine fever virus among warthogs, indicating that the virus had been circulating in the area. Sampling of blood-feeding insects represents an efficient and practical approach to tracking a diversity of pathogens from multiple mammalian species, directly through molecular diagnostic or indirectly through serology, which could readily expand and enhance our understanding of the ecology and evolution of infectious agents and their interactions with their hosts in wild animal communities.