YIKI is an antimalarial phytomedicine used by a traditional healer to treat malaria in Bobo-Dioulasso. However, there is no scientific evidence to support its use by local populations. The aim of this study was to ide...YIKI is an antimalarial phytomedicine used by a traditional healer to treat malaria in Bobo-Dioulasso. However, there is no scientific evidence to support its use by local populations. The aim of this study was to identify the medicinal practices of the healer holder of YIKI and assess the clinical evidence of its phytomedicine in the uncomplicated malaria treatment. Ethnomedical survey based on a semi-structured and open questionnaire was conducted from October to December 2019 with the healer. Malaria knowledge and diagnosis methods, patient treatment and monitoring, and recipe formulation steps were surveyed. Moreover, thick and thin blood smears were taken, haemoglobin levels and temperature of consenting patients were measured before treatment, mid-treatment and at the end of treatment. The survey revealed that the healer has a good knowledge of malaria symptoms and his diagnosis is based on observation and physical examination of patients. The healer’s malaria diagnosis was rudimentary and had accuracy problems, with only 62.79% of malaria cases confirmed by microscopy. The formulation of YIKI and its use to treat malaria follow a standard process for plant harvesting, powder quantities and posology, but do not use any reproducible parameters for dose adjustment. Forty-three patients diagnosed and treated by the healer participated in the study. Laboratory results revealed 27 Plasmodium falciparum infection cases, including 2 with parasitaemia ≥ 200,000 p/µl blood. 25 patients were selected for therapeutic evidence assessment. There was a 48% elimination of parasites, a 28% parasitaemia decrease without complete cure, with gametocytogenesis in some patients, and a 24% parasitaemia increase. Haemoglobin and temperature results suggested that YIKI was not cytotoxic and reduced fever. Encouraging preliminary results have been obtained, but in view of the low number of patients, further YIKI efficacy and toxicity studies will be necessary for patient safety.展开更多
The objective of this multicentric study was to assess the prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma génitalium and Trichomonas vaginalis infections in Brazzaville, in the Republic of...The objective of this multicentric study was to assess the prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma génitalium and Trichomonas vaginalis infections in Brazzaville, in the Republic of Congo, using molecular methods. From January to December 2021, the sexually transmitted disease risk participants were recruited from six centers: The Association of Young HIV-Positive People of Congo, The Congolese Association for Family Welfare, The Association for Support to Vulnerable Groups, Talangaï hospital, Brazzaville university hospital (outpatient service) and the private clinic COGEMO (outpatient service). The real-time multiplex PCR was carried out to detect these pathogens. Each patient had at least one specimen (urine, urethral, anal and/or vaginal samples). The patients were considered infected when one of their samples was positive. 287 participants made of 227 women and 60 men were tested. The general prevalence of these infections was: Chlamydia trachomatis 2.79%, Neisseria gonorrhoeae 3.14%, Mycoplasma génitalium 3.45% and Trichomonas vaginalis 2.97. The prevalence rates according to sex were: C. trachomatis, M. génitalium, N. gonorrhea and T. vaginalis were 1.32%, 2.05%, 1.32% and 3.42% in women and 8.33%, 7.02%, 10% and 1.75% in men, respectively. Most infected patients were asymptomatic. Prevalence rates were higher in bisexual individuals, with the exception of T. vaginalis which showed higher prevalence in heterosexual patients. The bisexual and homosexual individuals represent a major public health problem in sexually active young adults, particularly among men having sex with men. These sexually transmitted infections are mainly asymptomatic, their diagnosis and management remain difficult in developing countries.展开更多
In this experiment carried out on Caribbean chili pepper plants(Capsicum chinensis),the bio-insecticide azadirachtin in combination with an NPK fertilizer proved to have a greater lethal impact on the larvae of Aedes ...In this experiment carried out on Caribbean chili pepper plants(Capsicum chinensis),the bio-insecticide azadirachtin in combination with an NPK fertilizer proved to have a greater lethal impact on the larvae of Aedes albopictus than each substance on its own.This synergistic effect is noticeably important when both inputs are sprayed directly on the leaves of the plant(foliar application).While the plants treated with azadirachtin or NPK alone cause a 33.6%and 36.4%mortal-ity respectively of the Ae.albopictus larvae,the combination of the two inputs induces a 74.4%mortality on the mosquito larvae.To account for this synergistic effect phenomenon inside the plant,the azadirachtin+NPK combination most likely interacts with the capsaicinoid compounds naturally produced by the plant.Not only does this study carried out on azadirachtin reveal major results but the methodology itself offers a most interesting approach on how to boost the agricultural inputs within the plants.As a matter of fact,this research axis demands developing since the control of pests harmful to men has been dramatically lacking insecticide molecules acting on new targets over the past three decades.展开更多
Long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) are the main indoor malaria vector tools control tools. The study examined housing characteristics and investigated the relationship bet...Long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) are the main indoor malaria vector tools control tools. The study examined housing characteristics and investigated the relationship between the total volume of household possessions, the volume of the sleeping room, and the hanging of LLINs. A total of 831 bedrooms were randomly selected in Benin in 2015. The findings showed that mud walls were predominant in rural areas (more than 75%), while metal roofs were common (77.3% - 97.9%). Battery-powered lighting was prevalent in rural areas in Northern (97%), while open-flame oil lamps were commonly used in rural areas in Southern (86%). The availability of correct bedding was low, ranging from 1% to 10% in all households. 20% of the bedrooms had at least 50% of their volume occupied by household possessions in urban areas. In rural areas, bedrooms without LLINs had a lower mean rate ratio of the volume occupied by possessions per the total volume of the room compared to bedrooms with at least one LLIN installed (p < 0.0001). The characteristics of human habitats are not favourable to the correct use of vector control intervention indoors. It is therefore important to improve people’s living conditions as the next step for malaria elimination.展开更多
<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> The increasing phenome...<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> The increasing phenomenon of bacterial resistance to antibiotics is a real public health problem. The main causes are poor management of hygiene and water quality, but also the use of antibiotics without precaution. The objective of this study was to isolate and determine the antibiotic resistance profile of the different bacteria found in the main hospitals and bacteriology laboratories in Gabon. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> 6034 samples were taken from hospitals in seven main cities of Gabon, and analyzed according to the usual techniques. The pathogenic strains were identified by Matrix-Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometry. Antimicrobial susceptibility testing was performed by the agar disc diffusion method, according to the Antibiogram Committee of the French Society for Microbiology guidelines. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">974 pathogenic bacterial strains were found, including 890/974 (91</span><span style="font-family:Verdana;">.4%) Gram-negative bacilli. The systematic antimicrobial suscepti</span><span style="font-family:Verdana;">bility testings identified 160/974 (16.4%) multi-resistant strains. </span><i><span style="font-family:Verdana;">Escherichia coli</span></i><span style="font-family:Verdana;"> was t</span><span style="font-family:Verdana;">he most represented species. 12.5%</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">-</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">25% of </span><i><span style="font-family:Verdana;">Escherichia coli</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Klebsiel</span></i></span><i><span style="font-family:Verdana;">la pneumoniae</span></i><span style="font-family:""><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Enterobacter cloacae</span></i><span style="font-family:Verdana;">, and </span><i><span style="font-family:Verdana;">Citrobacter sedlakii</span></i><span style="font-family:Verdana;"> strains were resistant to amoxicillin + clavulanic acid, third and fourth generation cephalosporins. Aminoglycoside resistance rates of 8.5%</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">-</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">19% were also noted. 4.5% to 25% of the bacteria found were resistant to quinolones and cotrimoxazole. Resistance rates to carbapenems ranged from 1% to 10.5%. 16% of </span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><span style="font-family:Verdana;"> were methicillin-resistant (MRSA). Rates of extended spectr</span><span style="font-family:Verdana;">um beta-lactamase-producing enterobacteriaceae (ESBL-PE) ran</span><span style="font-family:Verdana;">ged from 2.5% to 25%. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> This study showed an increasing evolution of bacteri</span><span style="font-family:Verdana;">al resistance to antibiotics that </span></span><span style="font-family:Verdana;">are</span><span style="font-family:Verdana;"> spreading throughout Gabon. Th</span><span style="font-family:Verdana;">is constitutes a threat to the health of Gabonese population.展开更多
Trypanosomiasis,transmitted by tsetse flies(Glossina spp.),poses a significant health threat in 36 sub-Saharan African countries.Current control methods targeting tsetse flies,while effective,allow reinfestation.This ...Trypanosomiasis,transmitted by tsetse flies(Glossina spp.),poses a significant health threat in 36 sub-Saharan African countries.Current control methods targeting tsetse flies,while effective,allow reinfestation.This study investigates paratransgenesis,a novel strategy to engineer symbiotic bacteria in tsetse flies,Sodalis glossinidius,to deliver anti-trypanosome compounds.Disrupting the trypanosome life cycle within the fly and reducing parasite transmission could offer a sustainable solution for trypanosomiasis control.In this context,we tested the effect of cecropin,reported to be lethal for Trypanosoma cruzi(Chagas disease)and TbgTCTP(Translationally Controlled Tumor Protein from Trypanosoma brucei gambiense),previously reported to modulate the growth of bacteria isolated from the fly microbiome,to delay the first peak of parasitemia and the death of trypanosome-infected mice.We have successfully cloned and transfected the genes encoding the two proteins into Sodalis strains.These Sodalis recombinant strains(recSodalisTbgTCTP and recSodaliscecropin)have been then microinjected into the L3 larval stage of Glossina palpalis gambiensis flies.The stability of the cloned genes was checked up to the 20th day after microinjection of recSodalis.The rate of fly emergence from untreated pupae was 95%;it was reduced by nearly 50%due to the mechanical injury caused by microinjection.It decreased to nearly 7%when larvae were injected with recSodalisTbgTCTP,which suggests TCTP could have a lethal impact to larvae development.When challenged with T.brucei gambiense,a slightly lower,but statistically non-significant,infection rate was recorded in flies harboring recSodaliscecropin compared to control flies.The effect of recSodalisTbgTCTP could not be measured due to the very low rate of fly emergence after corresponding treatment of the larvae.The results do not allow to conclude on the effect of cecropin or TCTP,delivered by para-transgenesis into the fly's gut,on the fly infection by the trypanosome.Nevertheless,the results are encouraging insofar as the technical approach works on the couple G.p.gambiensis/T.brucei gambiense.The next step will be to optimize the system and test other targets chosen among the ESPs(Excreted-Secreted Proteins)of the trypanosome secretum,or the differentially expressed genes associated with the sensitivity/resistance of the fly to trypanosome infection.展开更多
Background Leprosy remains a persistent public health challenge,where human-to-human transmission of Mycobacterium leprae via respiratory droplets is well established.In the tropical Americas,growing evidence implicat...Background Leprosy remains a persistent public health challenge,where human-to-human transmission of Mycobacterium leprae via respiratory droplets is well established.In the tropical Americas,growing evidence implicates armadillos as important zoonotic reservoirs,particularly through direct contact during hunting and handling.However,such transmission has so far been considered rare and highly localised.This study provides a comprehensive spatial analysis of the role of armadillo hunting in human leprosy transmission,quantifying its contribution to disease prevalence and identifying geographic hotspots where interventions could be most effective.Methods Using Brazil’s 326,001 reported leprosy cases from 2013 to 2022,we applied a pathogeographical approach to explore transmission dynamics.We compiled data on 554 hunted armadillos across 175 municipalities and M.leprae prevalence in 376 armadillo individuals from 97 municipalities(mean prevalence=38.5%).These were used to build spatial models assessing hunting-related infection risk and integrated as a variable into a generalised linear model alongside socioeconomic,climatic,and environmental predictors to evaluate their effects on human leprosy prevalence.Results Key predictors of armadillo hunting included higher population density(P<0.001)and firearm availability(P<0.01).Infection in armadillos was negatively correlated with native habitat coverage(coefficient:−2.28;P<0.001),suggesting that environmental degradation can amplify infection risk.The armadillo-hunting infection risk variable—generated by combining armadillo hunting and infection favourability models—emerged as the second strongest predictor of human leprosy prevalence(coefficient:1.69;P<0.001),accounting for~25%of cases nationally and around 40%in deforestation hotspots.Additional positive predictors included greater precipitation seasonality(coefficient:0.82;P<0.001)and malnutrition(coefficient:0.01;P<0.001),while higher population density(coefficient:−0.64;P<0.001),natural habitat coverage(coefficient:−0.50;P<0.001)and socioeconomic status(coefficient:−0.47;P=0.013)were linked to reduced disease prevalence.Conclusions Armadillo hunting seems to play a more significant role in human leprosy transmission than previously recognised.To address this overlooked pathway,targeted interventions should focus on reducing unsafe and illegal hunting,improving communication around zoonotic risks,strengthening disease surveillance in high-risk areas,and conducting genetic studies to confirm wildlife-to-human transmission.Our findings highlight the importance of incorporating wildlife-associated transmission pathways into strategies to reduce disease prevalence and mitigate future outbreaks in tropical regions facing rapid environmental change and persistent poverty.展开更多
We look at the link between climate change and vector-borne diseases in low-and middle-income countries in Africa.The large endemicity and escalating threat of diseases such as malaria and arboviral diseases,intensifi...We look at the link between climate change and vector-borne diseases in low-and middle-income countries in Africa.The large endemicity and escalating threat of diseases such as malaria and arboviral diseases,intensified by climate change,disproportionately affects vulnerable communities globally.We highlight the urgency of prioritizing research and development,advocating for robust scientific inquiry to promote adaptation strategies,and the vital role that the next generation of African research leaders will play in addressing these challenges.Despite significant challenges such as funding shortages within countries,various pan-African-oriented funding bodies such as the African Academy of Sciences,the Africa Research Excellence Fund,the Wellcome Trust,the U.S.National Institutes of Health,and the Bill and Melinda Gates Foundation as well as initiatives such as the African Research Initiative for Scientific Excellence and the Pan-African Mosquito Control Association,have empowered(or are empowering)these researchers by supporting capacity building activities,including continental and global networking,skill development,mentoring,and African-led research.This article underscores the urgency of increased national investment in research,proposing the establishment of research government agencies to drive evidence-based interventions.Collaboration between governments and scientific communities,sustained by pan-African funding bodies,is crucial.Through these efforts,African nations are likely to enhance the resilience and adaptive capacity of their systems and communities by navigating these challenges effectively,fostering scientific excellence and implementing transformative solutions against climate-sensitive vector-borne diseases.展开更多
Background:More than half of the world’s population currently lives in urban settlements that grow both in size and number.By 2050,approximately 70%of the global population will be living in urban conglomerations,mai...Background:More than half of the world’s population currently lives in urban settlements that grow both in size and number.By 2050,approximately 70%of the global population will be living in urban conglomerations,mainly in low-and middle-income countries.Mobility,poverty,different layers of inequalities as well as climate variability and change are some of the social and environmental factors that influence the exposure of human populations in urban settings to vector-borne diseases,which pose eminent public health threats.Accurate,consistent,and evidencebased interventions for prevention and control of vector-borne and other infectious diseases of poverty in urban settings are needed to implement innovative and cost-effective public policy and to promote inclusive and equitable urban health services.Main body:While there is growing awareness of vector-borne diseases epidemiology at the urban level,there is still a paucity of research and action being undertaken in this area,hindering evidence-based public health policy decisions and practice and strategies for active community engagement.This paper describes the collaboration and partnership of the Special Programme for Research and Training in Tropical Diseases(TDR)hosted by the World Health Organization(WHO)and the“VEctor boRne DiseAses Scoping reviews”(VERDAS)Research Consortium as they joined efforts in response to filling this gap in knowledge and evidence by supporting the development of a series of scoping reviews that highlight priority research gaps and policy implications to address vector-borne and other infectious diseases at the urban level.Conclusions:The set of scoping reviews proposed in this special issue presents a critical analysis of the state-of-the-art of research on urban health interventions for the prevention and control of vector-borne and other infectious diseases of poverty.The authors of the 6 reviews highlighted severe gaps in knowledge and identified organizational and theoretical limitations that need to be urgently tackled to improve cities preparedness and vector control response.The more pressing need at present is to ensure that more implementation research on vector-borne diseases in urban settings is conducted,addressing policy and practice implications and calling for more political commitment and social mobilization through adequate citizen engagement strategies.展开更多
Background:The significant malaria burden in Africa has often eclipsed other febrile illnesses.Burkina Faso’s first dengue epidemic occurred in 1925 and the most recent in 2013.Yet there is still very little known ab...Background:The significant malaria burden in Africa has often eclipsed other febrile illnesses.Burkina Faso’s first dengue epidemic occurred in 1925 and the most recent in 2013.Yet there is still very little known about dengue prevalence,its vector proliferation,and its poverty and equity impacts.Methods:An exploratory cross-sectional survey was performed from December 2013 to January 2014.Six primary healthcare centers in Ouagadougou were selected based on previously reported presence of Flavivirus.All patients consulting with fever or having had fever within the previous week and with a negative rapid diagnostic test(RDT)for malaria were invited to participate.Sociodemographic data,healthcare use and expenses,mobility,health-related status,and vector control practices were captured using a questionnaire.Blood samples of every eligible subject were obtained through finger pricks during the survey for dengue RDT using SD BIOLINE Dengue Duo(NS1Ag and IgG/IgM)®and to obtain blood spots for reverse transcription polymerase chain reaction(RT-PCR)analysis.In a sample of randomly selected yards and those of patients,potential Aedes breeding sites were found and described.Larvae were collected and brought to the laboratory to monitor the emergence of adults and identify the species.Results:Of the 379 subjects,8.7%(33/379)had positive RDTs for dengue.Following the 2009 WHO classification,38.3%(145/379)had presumptive,probable,or confirmed dengue,based on either clinical symptoms or laboratory testing.Of 60 samples tested by RT-PCR(33 from the positive tests and 27 from the subsample of negatives),15 were positive.The serotypes observed were DENV2,DENV3,and DENV4.Odds of dengue infection in 15-to-20-year-olds and persons over 50 years were 4.0(CI 95%:1.0–15.6)and 7.7(CI 95%:1.6–37.1)times higher,respectively,than in children under five.Average total spending for a dengue episode was 13771 FCFA[1300–67300 FCFA](1$US=478 FCFA).On average,2.6 breeding sites were found per yard.Potential Aedes breeding sites were found near 71.4%(21/28)of patients,but no adult Aedes were found.The most frequently identified potential breeding sites were water storage containers(45.2%).Most specimens collected in yards were Culex(97.9%).Conclusions:The scientific community,public health authorities,and health workers should consider dengue as a possible cause of febrile illness in Burkina Faso.展开更多
Background:Vector-borne diseases(VBDs)continue to represent a global threat,with“old”diseases like malaria,and“emergent”or“re-emergent”ones like Zika,because of an increase in international trade,demographic gro...Background:Vector-borne diseases(VBDs)continue to represent a global threat,with“old”diseases like malaria,and“emergent”or“re-emergent”ones like Zika,because of an increase in international trade,demographic growth,and rapid urbanization.In this era of globalization,surveillance is a key element in controlling VBDs in urban settings,but surveillance alone cannot solve the problem.A review of experiences is of interest to examine other solution elements.The objectives were to assess the different means of VBD surveillance in urban environments,to evaluate their potential for supporting public health actions,and to describe the tools used for public health actions,the constraints they face,and the research and health action gaps to be filled.Main body:For this scoping review we searched peer-reviewed articles and grey literature published between 2000 and 2016.Various tools were used for data coding and extraction.A quality assessment was done for each study reviewed,and descriptive characteristics and data on implementation process and transferability were analyzed in all studies.After screening 414 full-text articles,we retained a total of 79 articles for review.The main targets of the articles were arboviral diseases(65.8%)and malaria(16.5%).The positive aspects of many studies fit within the framework of integrated vector management.Public awareness is considered a key to successful vector control programs.Advocacy and legislation can reinforce both empowerment and capacity building.These can be achieved by collaboration within the health sector and with other sectors.Research is needed to develop well designed studies and new tools for surveillance and control.Conclusions:The need for surveillance systems in urban settings in both developing and developed countries was highlighted.Countries face the same challenges relating to human,financial,and structural resources.These findings also constitute a wake-up call for governments,academia,funders,and World Health Organization to strengthen control programs and enhance VBD research in urban environments.展开更多
This paper highlights the critical importance of evidence on vector-borne diseases(VBD)prevention and control interventions in urban settings when assessing current and future needs,with a view to setting policy prior...This paper highlights the critical importance of evidence on vector-borne diseases(VBD)prevention and control interventions in urban settings when assessing current and future needs,with a view to setting policy priorities that promote inclusive and equitable urban health services.Research should produce knowledge about policies and interventions that are intended to control and prevent VBDs at the population level and to reduce inequities.Such interventions include policy,program,and resource distribution approaches that address the social determinants of health and exert influence at organizational and system levels.展开更多
Background:Several studies highlighted the impact of community-based interventions whose purpose was to reduce the vectors’breeding sites.These strategies are particularly interesting in low-and-middle-income countri...Background:Several studies highlighted the impact of community-based interventions whose purpose was to reduce the vectors’breeding sites.These strategies are particularly interesting in low-and-middle-income countries which may find it difficult to sustainably assume the cost of insecticide-based interventions.In this case study we determine the spatial distribution of a community-based intervention for dengue vector control using different entomological indices.The objective was to evaluate locally where the intervention was most effective,using spatial analysis methods that are too often neglected in impact assessments.Methods:Two neighbourhoods,Tampouy and Juvenat in Ouagadougou,Burkina Faso,were chosen among five after a survey was conducted,as part of an assessment related to the burden of dengue.As part of the communitybased intervention conducted in Tampouy between August and early October 2016,an entomological survey was implemented in two phases.The first phase consisted of a baseline entomological characterization of potential breeding sites in the neighbourhood of Tampouy as well as in Juvenat,the control area.This phase was conducted in October 2015 at the end of the rainy season.The mosquito breeding sites were screened in randomly selected houses:206 in Tampouy and 203 in Juvenat.A second phase took place after the intervention,in October 2016.The mosquito breeding sites were investigated in the same yards as during the baseline phase.We performed several entomological analyses to measure site productivity as well as before and after analysis using multilevel linear regression.We used Local Indicators of Spatial Association(LISAs)to analyse spatial concentrations of larvae.Results:After the intervention,it is noted that LISAs at Tampouy reveal few aggregates of all types and the suppression of those existing before the intervention.The analysis therefore reveals that the intervention made it possible to reduce the number of concentration areas of high and low values of pupae.Conclusions:The contribution of spatial methods for assessing community-based intervention are relevant for monitoring at local levels as a complement to epidemiological analyses conducted within neighbourhoods.They are useful,therefore,not only for assessment but also for establishing interventions.This study shows that spatial analyses also have their place in population health intervention research.展开更多
Introduction:The persistence of generalists and specialists is a topical question in community ecology and results from both ecological and evolutionary processes.At fine taxonomical scales,ecological specialisation,i...Introduction:The persistence of generalists and specialists is a topical question in community ecology and results from both ecological and evolutionary processes.At fine taxonomical scales,ecological specialisation,i.e.organisms preferentially exploiting a subset of available habitats,is thought to be a driver promoting niche diversity.It is not clear,however,how different mechanisms interact to shape specialist-generalist coexistence.Methods:We reconstruct the structure of five bacteria-phage networks from soil isolates,and perform an analysis of the relationships between host phylogenetic diversity,parasite specialism,and parasite performance.Results:We show that the co-occurrence of species on a continuum of specialism/generalism is influenced by niche overlap,phage impact on bacterial hosts,and host phylogenetic structure.In addition,using a null-model analysis we show that infection strategies of the phages have more explanatory power than bacterial defenses on key structural features of these antagonistic communities.Conclusions:We report that generalists have more impact on their hosts than specialists,even when the phylogenetic heterogeneity of hosts is controlled for.We discuss our results in the light of their implications for the evolution of biotic interactions.展开更多
文摘YIKI is an antimalarial phytomedicine used by a traditional healer to treat malaria in Bobo-Dioulasso. However, there is no scientific evidence to support its use by local populations. The aim of this study was to identify the medicinal practices of the healer holder of YIKI and assess the clinical evidence of its phytomedicine in the uncomplicated malaria treatment. Ethnomedical survey based on a semi-structured and open questionnaire was conducted from October to December 2019 with the healer. Malaria knowledge and diagnosis methods, patient treatment and monitoring, and recipe formulation steps were surveyed. Moreover, thick and thin blood smears were taken, haemoglobin levels and temperature of consenting patients were measured before treatment, mid-treatment and at the end of treatment. The survey revealed that the healer has a good knowledge of malaria symptoms and his diagnosis is based on observation and physical examination of patients. The healer’s malaria diagnosis was rudimentary and had accuracy problems, with only 62.79% of malaria cases confirmed by microscopy. The formulation of YIKI and its use to treat malaria follow a standard process for plant harvesting, powder quantities and posology, but do not use any reproducible parameters for dose adjustment. Forty-three patients diagnosed and treated by the healer participated in the study. Laboratory results revealed 27 Plasmodium falciparum infection cases, including 2 with parasitaemia ≥ 200,000 p/µl blood. 25 patients were selected for therapeutic evidence assessment. There was a 48% elimination of parasites, a 28% parasitaemia decrease without complete cure, with gametocytogenesis in some patients, and a 24% parasitaemia increase. Haemoglobin and temperature results suggested that YIKI was not cytotoxic and reduced fever. Encouraging preliminary results have been obtained, but in view of the low number of patients, further YIKI efficacy and toxicity studies will be necessary for patient safety.
文摘The objective of this multicentric study was to assess the prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma génitalium and Trichomonas vaginalis infections in Brazzaville, in the Republic of Congo, using molecular methods. From January to December 2021, the sexually transmitted disease risk participants were recruited from six centers: The Association of Young HIV-Positive People of Congo, The Congolese Association for Family Welfare, The Association for Support to Vulnerable Groups, Talangaï hospital, Brazzaville university hospital (outpatient service) and the private clinic COGEMO (outpatient service). The real-time multiplex PCR was carried out to detect these pathogens. Each patient had at least one specimen (urine, urethral, anal and/or vaginal samples). The patients were considered infected when one of their samples was positive. 287 participants made of 227 women and 60 men were tested. The general prevalence of these infections was: Chlamydia trachomatis 2.79%, Neisseria gonorrhoeae 3.14%, Mycoplasma génitalium 3.45% and Trichomonas vaginalis 2.97. The prevalence rates according to sex were: C. trachomatis, M. génitalium, N. gonorrhea and T. vaginalis were 1.32%, 2.05%, 1.32% and 3.42% in women and 8.33%, 7.02%, 10% and 1.75% in men, respectively. Most infected patients were asymptomatic. Prevalence rates were higher in bisexual individuals, with the exception of T. vaginalis which showed higher prevalence in heterosexual patients. The bisexual and homosexual individuals represent a major public health problem in sexually active young adults, particularly among men having sex with men. These sexually transmitted infections are mainly asymptomatic, their diagnosis and management remain difficult in developing countries.
文摘In this experiment carried out on Caribbean chili pepper plants(Capsicum chinensis),the bio-insecticide azadirachtin in combination with an NPK fertilizer proved to have a greater lethal impact on the larvae of Aedes albopictus than each substance on its own.This synergistic effect is noticeably important when both inputs are sprayed directly on the leaves of the plant(foliar application).While the plants treated with azadirachtin or NPK alone cause a 33.6%and 36.4%mortal-ity respectively of the Ae.albopictus larvae,the combination of the two inputs induces a 74.4%mortality on the mosquito larvae.To account for this synergistic effect phenomenon inside the plant,the azadirachtin+NPK combination most likely interacts with the capsaicinoid compounds naturally produced by the plant.Not only does this study carried out on azadirachtin reveal major results but the methodology itself offers a most interesting approach on how to boost the agricultural inputs within the plants.As a matter of fact,this research axis demands developing since the control of pests harmful to men has been dramatically lacking insecticide molecules acting on new targets over the past three decades.
文摘Long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) are the main indoor malaria vector tools control tools. The study examined housing characteristics and investigated the relationship between the total volume of household possessions, the volume of the sleeping room, and the hanging of LLINs. A total of 831 bedrooms were randomly selected in Benin in 2015. The findings showed that mud walls were predominant in rural areas (more than 75%), while metal roofs were common (77.3% - 97.9%). Battery-powered lighting was prevalent in rural areas in Northern (97%), while open-flame oil lamps were commonly used in rural areas in Southern (86%). The availability of correct bedding was low, ranging from 1% to 10% in all households. 20% of the bedrooms had at least 50% of their volume occupied by household possessions in urban areas. In rural areas, bedrooms without LLINs had a lower mean rate ratio of the volume occupied by possessions per the total volume of the room compared to bedrooms with at least one LLIN installed (p < 0.0001). The characteristics of human habitats are not favourable to the correct use of vector control intervention indoors. It is therefore important to improve people’s living conditions as the next step for malaria elimination.
文摘<b><span style="font-family:Verdana;">Background:</span></b><span style="font-family:""><span style="font-family:Verdana;"> The increasing phenomenon of bacterial resistance to antibiotics is a real public health problem. The main causes are poor management of hygiene and water quality, but also the use of antibiotics without precaution. The objective of this study was to isolate and determine the antibiotic resistance profile of the different bacteria found in the main hospitals and bacteriology laboratories in Gabon. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> 6034 samples were taken from hospitals in seven main cities of Gabon, and analyzed according to the usual techniques. The pathogenic strains were identified by Matrix-Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometry. Antimicrobial susceptibility testing was performed by the agar disc diffusion method, according to the Antibiogram Committee of the French Society for Microbiology guidelines. </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">974 pathogenic bacterial strains were found, including 890/974 (91</span><span style="font-family:Verdana;">.4%) Gram-negative bacilli. The systematic antimicrobial suscepti</span><span style="font-family:Verdana;">bility testings identified 160/974 (16.4%) multi-resistant strains. </span><i><span style="font-family:Verdana;">Escherichia coli</span></i><span style="font-family:Verdana;"> was t</span><span style="font-family:Verdana;">he most represented species. 12.5%</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">-</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">25% of </span><i><span style="font-family:Verdana;">Escherichia coli</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Klebsiel</span></i></span><i><span style="font-family:Verdana;">la pneumoniae</span></i><span style="font-family:""><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Enterobacter cloacae</span></i><span style="font-family:Verdana;">, and </span><i><span style="font-family:Verdana;">Citrobacter sedlakii</span></i><span style="font-family:Verdana;"> strains were resistant to amoxicillin + clavulanic acid, third and fourth generation cephalosporins. Aminoglycoside resistance rates of 8.5%</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">-</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">19% were also noted. 4.5% to 25% of the bacteria found were resistant to quinolones and cotrimoxazole. Resistance rates to carbapenems ranged from 1% to 10.5%. 16% of </span><i><span style="font-family:Verdana;">Staphylococcus aureus</span></i><span style="font-family:Verdana;"> were methicillin-resistant (MRSA). Rates of extended spectr</span><span style="font-family:Verdana;">um beta-lactamase-producing enterobacteriaceae (ESBL-PE) ran</span><span style="font-family:Verdana;">ged from 2.5% to 25%. </span><b><span style="font-family:Verdana;">Conclusion:</span></b><span style="font-family:Verdana;"> This study showed an increasing evolution of bacteri</span><span style="font-family:Verdana;">al resistance to antibiotics that </span></span><span style="font-family:Verdana;">are</span><span style="font-family:Verdana;"> spreading throughout Gabon. Th</span><span style="font-family:Verdana;">is constitutes a threat to the health of Gabonese population.
文摘Trypanosomiasis,transmitted by tsetse flies(Glossina spp.),poses a significant health threat in 36 sub-Saharan African countries.Current control methods targeting tsetse flies,while effective,allow reinfestation.This study investigates paratransgenesis,a novel strategy to engineer symbiotic bacteria in tsetse flies,Sodalis glossinidius,to deliver anti-trypanosome compounds.Disrupting the trypanosome life cycle within the fly and reducing parasite transmission could offer a sustainable solution for trypanosomiasis control.In this context,we tested the effect of cecropin,reported to be lethal for Trypanosoma cruzi(Chagas disease)and TbgTCTP(Translationally Controlled Tumor Protein from Trypanosoma brucei gambiense),previously reported to modulate the growth of bacteria isolated from the fly microbiome,to delay the first peak of parasitemia and the death of trypanosome-infected mice.We have successfully cloned and transfected the genes encoding the two proteins into Sodalis strains.These Sodalis recombinant strains(recSodalisTbgTCTP and recSodaliscecropin)have been then microinjected into the L3 larval stage of Glossina palpalis gambiensis flies.The stability of the cloned genes was checked up to the 20th day after microinjection of recSodalis.The rate of fly emergence from untreated pupae was 95%;it was reduced by nearly 50%due to the mechanical injury caused by microinjection.It decreased to nearly 7%when larvae were injected with recSodalisTbgTCTP,which suggests TCTP could have a lethal impact to larvae development.When challenged with T.brucei gambiense,a slightly lower,but statistically non-significant,infection rate was recorded in flies harboring recSodaliscecropin compared to control flies.The effect of recSodalisTbgTCTP could not be measured due to the very low rate of fly emergence after corresponding treatment of the larvae.The results do not allow to conclude on the effect of cecropin or TCTP,delivered by para-transgenesis into the fly's gut,on the fly infection by the trypanosome.Nevertheless,the results are encouraging insofar as the technical approach works on the couple G.p.gambiensis/T.brucei gambiense.The next step will be to optimize the system and test other targets chosen among the ESPs(Excreted-Secreted Proteins)of the trypanosome secretum,or the differentially expressed genes associated with the sensitivity/resistance of the fly to trypanosome infection.
基金supported by the Biogeography,Diversity and Conservation Lab of the University of Malaga,Project PID2021-124063OB-I00 of the Spanish Ministry of Science and Innovation and European Regional Development Fund(ERDF)and by the Leprosy Research Initiative Foundation(Grant#FP25\19)supported by a postdoctoral contract of the Plan Propio de Investigacion,Transferencia y Divulgacion Cientifica of the University of Malaga+7 种基金supported by MOPGA:Visiting Fellowship Program for early career researchers,Campus France,Francesupported by Gordon and Betty Moore Foundation through grant GBMF9258 to the Comunidad de Manejo de Fauna Silvestre en la Amazonia y en Latinoamerica(COMFAUNA)supported UK Research and Innovation’s Global Challenges Research Fund(UKRI GCRF)Trade,Development and the Environment Hub project(ES/S008160/1)supported by the joint NSF-NIH-NIFA Ecology and Evolution of Infectious Disease program(DEB#1911457)benefited from an‘Investissement d’Avenir’Grant managed by Agence Nationale de la Recherche,France(LABEX CEBA:ANR-10-LABX-25-01)supported by Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior—Brasil(CAPES)for a PNPD research fellowship.(88887.717863/2022-00)supported by a Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq)postdoctoral fellowship(150261/2023-3)supported by the Sustainable Landscapes and Livelihoods Programme.
文摘Background Leprosy remains a persistent public health challenge,where human-to-human transmission of Mycobacterium leprae via respiratory droplets is well established.In the tropical Americas,growing evidence implicates armadillos as important zoonotic reservoirs,particularly through direct contact during hunting and handling.However,such transmission has so far been considered rare and highly localised.This study provides a comprehensive spatial analysis of the role of armadillo hunting in human leprosy transmission,quantifying its contribution to disease prevalence and identifying geographic hotspots where interventions could be most effective.Methods Using Brazil’s 326,001 reported leprosy cases from 2013 to 2022,we applied a pathogeographical approach to explore transmission dynamics.We compiled data on 554 hunted armadillos across 175 municipalities and M.leprae prevalence in 376 armadillo individuals from 97 municipalities(mean prevalence=38.5%).These were used to build spatial models assessing hunting-related infection risk and integrated as a variable into a generalised linear model alongside socioeconomic,climatic,and environmental predictors to evaluate their effects on human leprosy prevalence.Results Key predictors of armadillo hunting included higher population density(P<0.001)and firearm availability(P<0.01).Infection in armadillos was negatively correlated with native habitat coverage(coefficient:−2.28;P<0.001),suggesting that environmental degradation can amplify infection risk.The armadillo-hunting infection risk variable—generated by combining armadillo hunting and infection favourability models—emerged as the second strongest predictor of human leprosy prevalence(coefficient:1.69;P<0.001),accounting for~25%of cases nationally and around 40%in deforestation hotspots.Additional positive predictors included greater precipitation seasonality(coefficient:0.82;P<0.001)and malnutrition(coefficient:0.01;P<0.001),while higher population density(coefficient:−0.64;P<0.001),natural habitat coverage(coefficient:−0.50;P<0.001)and socioeconomic status(coefficient:−0.47;P=0.013)were linked to reduced disease prevalence.Conclusions Armadillo hunting seems to play a more significant role in human leprosy transmission than previously recognised.To address this overlooked pathway,targeted interventions should focus on reducing unsafe and illegal hunting,improving communication around zoonotic risks,strengthening disease surveillance in high-risk areas,and conducting genetic studies to confirm wildlife-to-human transmission.Our findings highlight the importance of incorporating wildlife-associated transmission pathways into strategies to reduce disease prevalence and mitigate future outbreaks in tropical regions facing rapid environmental change and persistent poverty.
基金the financial assistance of the European Union(Grant no.ARISE-PP-FA-072),through the African Research Initiative for Scientific Excellence(ARISE),pilot programme.ARISE is implemented by the African Academy of Sciences with support from the European Commission and the African Union Commission.
文摘We look at the link between climate change and vector-borne diseases in low-and middle-income countries in Africa.The large endemicity and escalating threat of diseases such as malaria and arboviral diseases,intensified by climate change,disproportionately affects vulnerable communities globally.We highlight the urgency of prioritizing research and development,advocating for robust scientific inquiry to promote adaptation strategies,and the vital role that the next generation of African research leaders will play in addressing these challenges.Despite significant challenges such as funding shortages within countries,various pan-African-oriented funding bodies such as the African Academy of Sciences,the Africa Research Excellence Fund,the Wellcome Trust,the U.S.National Institutes of Health,and the Bill and Melinda Gates Foundation as well as initiatives such as the African Research Initiative for Scientific Excellence and the Pan-African Mosquito Control Association,have empowered(or are empowering)these researchers by supporting capacity building activities,including continental and global networking,skill development,mentoring,and African-led research.This article underscores the urgency of increased national investment in research,proposing the establishment of research government agencies to drive evidence-based interventions.Collaboration between governments and scientific communities,sustained by pan-African funding bodies,is crucial.Through these efforts,African nations are likely to enhance the resilience and adaptive capacity of their systems and communities by navigating these challenges effectively,fostering scientific excellence and implementing transformative solutions against climate-sensitive vector-borne diseases.
基金The scoping reviews received funding support from the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases(TDR),Geneva,Switzerland.
文摘Background:More than half of the world’s population currently lives in urban settlements that grow both in size and number.By 2050,approximately 70%of the global population will be living in urban conglomerations,mainly in low-and middle-income countries.Mobility,poverty,different layers of inequalities as well as climate variability and change are some of the social and environmental factors that influence the exposure of human populations in urban settings to vector-borne diseases,which pose eminent public health threats.Accurate,consistent,and evidencebased interventions for prevention and control of vector-borne and other infectious diseases of poverty in urban settings are needed to implement innovative and cost-effective public policy and to promote inclusive and equitable urban health services.Main body:While there is growing awareness of vector-borne diseases epidemiology at the urban level,there is still a paucity of research and action being undertaken in this area,hindering evidence-based public health policy decisions and practice and strategies for active community engagement.This paper describes the collaboration and partnership of the Special Programme for Research and Training in Tropical Diseases(TDR)hosted by the World Health Organization(WHO)and the“VEctor boRne DiseAses Scoping reviews”(VERDAS)Research Consortium as they joined efforts in response to filling this gap in knowledge and evidence by supporting the development of a series of scoping reviews that highlight priority research gaps and policy implications to address vector-borne and other infectious diseases at the urban level.Conclusions:The set of scoping reviews proposed in this special issue presents a critical analysis of the state-of-the-art of research on urban health interventions for the prevention and control of vector-borne and other infectious diseases of poverty.The authors of the 6 reviews highlighted severe gaps in knowledge and identified organizational and theoretical limitations that need to be urgently tackled to improve cities preparedness and vector control response.The more pressing need at present is to ensure that more implementation research on vector-borne diseases in urban settings is conducted,addressing policy and practice implications and calling for more political commitment and social mobilization through adequate citizen engagement strategies.
基金This research project is part of the“Community research studies and interventions for health equity in Burkina Faso”We thank the Canadian Institutes of Health Research(CIHR),who funded the program(ROH-115213).V.Ridde holds a CIHR-funded Research Chair in Applied Public Health(CPP-137901).
文摘Background:The significant malaria burden in Africa has often eclipsed other febrile illnesses.Burkina Faso’s first dengue epidemic occurred in 1925 and the most recent in 2013.Yet there is still very little known about dengue prevalence,its vector proliferation,and its poverty and equity impacts.Methods:An exploratory cross-sectional survey was performed from December 2013 to January 2014.Six primary healthcare centers in Ouagadougou were selected based on previously reported presence of Flavivirus.All patients consulting with fever or having had fever within the previous week and with a negative rapid diagnostic test(RDT)for malaria were invited to participate.Sociodemographic data,healthcare use and expenses,mobility,health-related status,and vector control practices were captured using a questionnaire.Blood samples of every eligible subject were obtained through finger pricks during the survey for dengue RDT using SD BIOLINE Dengue Duo(NS1Ag and IgG/IgM)®and to obtain blood spots for reverse transcription polymerase chain reaction(RT-PCR)analysis.In a sample of randomly selected yards and those of patients,potential Aedes breeding sites were found and described.Larvae were collected and brought to the laboratory to monitor the emergence of adults and identify the species.Results:Of the 379 subjects,8.7%(33/379)had positive RDTs for dengue.Following the 2009 WHO classification,38.3%(145/379)had presumptive,probable,or confirmed dengue,based on either clinical symptoms or laboratory testing.Of 60 samples tested by RT-PCR(33 from the positive tests and 27 from the subsample of negatives),15 were positive.The serotypes observed were DENV2,DENV3,and DENV4.Odds of dengue infection in 15-to-20-year-olds and persons over 50 years were 4.0(CI 95%:1.0–15.6)and 7.7(CI 95%:1.6–37.1)times higher,respectively,than in children under five.Average total spending for a dengue episode was 13771 FCFA[1300–67300 FCFA](1$US=478 FCFA).On average,2.6 breeding sites were found per yard.Potential Aedes breeding sites were found near 71.4%(21/28)of patients,but no adult Aedes were found.The most frequently identified potential breeding sites were water storage containers(45.2%).Most specimens collected in yards were Culex(97.9%).Conclusions:The scientific community,public health authorities,and health workers should consider dengue as a possible cause of febrile illness in Burkina Faso.
基金The Special Programme for Research and Training in Tropical Diseases(TDR)hosted at the World Health Organization(WHO)funded the VERDAS research Consortium,for“VEctor boRne DiseAses Scoping reviews”.
文摘Background:Vector-borne diseases(VBDs)continue to represent a global threat,with“old”diseases like malaria,and“emergent”or“re-emergent”ones like Zika,because of an increase in international trade,demographic growth,and rapid urbanization.In this era of globalization,surveillance is a key element in controlling VBDs in urban settings,but surveillance alone cannot solve the problem.A review of experiences is of interest to examine other solution elements.The objectives were to assess the different means of VBD surveillance in urban environments,to evaluate their potential for supporting public health actions,and to describe the tools used for public health actions,the constraints they face,and the research and health action gaps to be filled.Main body:For this scoping review we searched peer-reviewed articles and grey literature published between 2000 and 2016.Various tools were used for data coding and extraction.A quality assessment was done for each study reviewed,and descriptive characteristics and data on implementation process and transferability were analyzed in all studies.After screening 414 full-text articles,we retained a total of 79 articles for review.The main targets of the articles were arboviral diseases(65.8%)and malaria(16.5%).The positive aspects of many studies fit within the framework of integrated vector management.Public awareness is considered a key to successful vector control programs.Advocacy and legislation can reinforce both empowerment and capacity building.These can be achieved by collaboration within the health sector and with other sectors.Research is needed to develop well designed studies and new tools for surveillance and control.Conclusions:The need for surveillance systems in urban settings in both developing and developed countries was highlighted.Countries face the same challenges relating to human,financial,and structural resources.These findings also constitute a wake-up call for governments,academia,funders,and World Health Organization to strengthen control programs and enhance VBD research in urban environments.
基金Valery Ridde holds a CIHR-funded Research Chair in Applied Public Health(CPP-137901).
文摘This paper highlights the critical importance of evidence on vector-borne diseases(VBD)prevention and control interventions in urban settings when assessing current and future needs,with a view to setting policy priorities that promote inclusive and equitable urban health services.Research should produce knowledge about policies and interventions that are intended to control and prevent VBDs at the population level and to reduce inequities.Such interventions include policy,program,and resource distribution approaches that address the social determinants of health and exert influence at organizational and system levels.
基金This work was supported by the Canadian Institutes of Health Research,which funded the program(grant no.ROH-115213)S.O.received a postdoctoral fellowship from the Fonds des Recherches du Québec en Santé.V.R.holds a Canadian Institutes of Health Research–funded Research Chair in Applied Public Health(grant no.CPP-137901).
文摘Background:Several studies highlighted the impact of community-based interventions whose purpose was to reduce the vectors’breeding sites.These strategies are particularly interesting in low-and-middle-income countries which may find it difficult to sustainably assume the cost of insecticide-based interventions.In this case study we determine the spatial distribution of a community-based intervention for dengue vector control using different entomological indices.The objective was to evaluate locally where the intervention was most effective,using spatial analysis methods that are too often neglected in impact assessments.Methods:Two neighbourhoods,Tampouy and Juvenat in Ouagadougou,Burkina Faso,were chosen among five after a survey was conducted,as part of an assessment related to the burden of dengue.As part of the communitybased intervention conducted in Tampouy between August and early October 2016,an entomological survey was implemented in two phases.The first phase consisted of a baseline entomological characterization of potential breeding sites in the neighbourhood of Tampouy as well as in Juvenat,the control area.This phase was conducted in October 2015 at the end of the rainy season.The mosquito breeding sites were screened in randomly selected houses:206 in Tampouy and 203 in Juvenat.A second phase took place after the intervention,in October 2016.The mosquito breeding sites were investigated in the same yards as during the baseline phase.We performed several entomological analyses to measure site productivity as well as before and after analysis using multilevel linear regression.We used Local Indicators of Spatial Association(LISAs)to analyse spatial concentrations of larvae.Results:After the intervention,it is noted that LISAs at Tampouy reveal few aggregates of all types and the suppression of those existing before the intervention.The analysis therefore reveals that the intervention made it possible to reduce the number of concentration areas of high and low values of pupae.Conclusions:The contribution of spatial methods for assessing community-based intervention are relevant for monitoring at local levels as a complement to epidemiological analyses conducted within neighbourhoods.They are useful,therefore,not only for assessment but also for establishing interventions.This study shows that spatial analyses also have their place in population health intervention research.
基金a copy of Network3D,Sonia Kéfi and Dominique Gravel for discussions and comments on the results,Claire Gougat-Barbera for help with the molecular biology experiments,and Joshua S.Weitz and Cesar Flores for discussions about bacteria-phage networks.TP thanks the Canadian Research Chair on Continental Ecosystems Ecology for computational support.MEH thanks the Agence National de la Recherche Scientifique[EvolStress(ANR-09-BLAN-099-01)]the McDonnell Foundation(JSMF 220020294/SCS-Research Award)for financial support.
文摘Introduction:The persistence of generalists and specialists is a topical question in community ecology and results from both ecological and evolutionary processes.At fine taxonomical scales,ecological specialisation,i.e.organisms preferentially exploiting a subset of available habitats,is thought to be a driver promoting niche diversity.It is not clear,however,how different mechanisms interact to shape specialist-generalist coexistence.Methods:We reconstruct the structure of five bacteria-phage networks from soil isolates,and perform an analysis of the relationships between host phylogenetic diversity,parasite specialism,and parasite performance.Results:We show that the co-occurrence of species on a continuum of specialism/generalism is influenced by niche overlap,phage impact on bacterial hosts,and host phylogenetic structure.In addition,using a null-model analysis we show that infection strategies of the phages have more explanatory power than bacterial defenses on key structural features of these antagonistic communities.Conclusions:We report that generalists have more impact on their hosts than specialists,even when the phylogenetic heterogeneity of hosts is controlled for.We discuss our results in the light of their implications for the evolution of biotic interactions.
