RESUMO
Aedes aegypti is the primary vector of the arboviruses dengue (DENV) and chikungunya (CHIKV). These viruses exhibit key differences in their vector interactions, the latter moving more quicky through the mosquito and triggering fewer standard antiviral pathways. As the global footprint of CHIKV continues to expand, we seek to better understand the mosquito's natural response to CHIKV-both to compare it to DENV:vector coevolutionary history and to identify potential targets in the mosquito for genetic modification. We used a modified full-sibling design to estimate the contribution of mosquito genetic variation to viral loads of both DENV and CHIKV. Heritabilities were significant, but higher for DENV (40%) than CHIKV (18%). Interestingly, there was no genetic correlation between DENV and CHIKV loads between siblings. These data suggest Ae. aegypti mosquitoes respond to the two viruses using distinct genetic mechanisms. We also examined genome-wide patterns of gene expression between High and Low CHIKV families representing the phenotypic extremes of viral load. Using RNAseq, we identified only two loci that consistently differentiated High and Low families: a long non-coding RNA that has been identified in mosquito screens post-infection and a distant member of a family of Salivary Gland Specific (SGS) genes. Interestingly, the latter gene is also associated with horizontal gene transfer between mosquitoes and the endosymbiotic bacterium Wolbachia. This work is the first to link the SGS gene to a mosquito phenotype. Understanding the molecular details of how this gene contributes to viral control in mosquitoes may, therefore, also shed light on its role in Wolbachia.
Assuntos
Aedes , Febre de Chikungunya , Vírus Chikungunya , Dengue , Animais , Vírus Chikungunya/fisiologia , Mosquitos VetoresRESUMO
Multiple Wolbachia strains can block pathogen infection, replication and/or transmission in Aedes aegypti mosquitoes under both laboratory and field conditions. However, Wolbachia effects on pathogens can be highly variable across systems and the factors governing this variability are not well understood. It is increasingly clear that the mosquito host is not a passive player in which Wolbachia governs pathogen transmission phenotypes; rather, the genetics of the host can significantly modulate Wolbachia-mediated pathogen blocking. Specifically, previous work linked variation in Wolbachia pathogen blocking to polymorphisms in the mosquito alpha-mannosidase-2 (αMan2) gene. Here we use CRISPR-Cas9 mutagenesis to functionally test this association. We developed αMan2 knockouts and examined effects on both Wolbachia and virus levels, using dengue virus (DENV; Flaviviridae) and Mayaro virus (MAYV; Togaviridae). Wolbachia titres were significantly elevated in αMan2 knockout (KO) mosquitoes, but there were complex interactions with virus infection and replication. In Wolbachia-uninfected mosquitoes, the αMan2 KO mutation was associated with decreased DENV titres, but in a Wolbachia-infected background, the αMan2 KO mutation significantly increased virus titres. In contrast, the αMan2 KO mutation significantly increased MAYV replication in Wolbachia-uninfected mosquitoes and did not affect Wolbachia-mediated virus blocking. These results demonstrate that αMan2 modulates arbovirus infection in A. aegypti mosquitoes in a pathogen- and Wolbachia-specific manner, and that Wolbachia-mediated pathogen blocking is a complex phenotype dependent on the mosquito host genotype and the pathogen. These results have a significant impact for the design and use of Wolbachia-based strategies to control vector-borne pathogens.
Assuntos
Aedes , Wolbachia , alfa-Manosidase , Animais , Aedes/microbiologia , Aedes/virologia , Aedes/genética , Wolbachia/fisiologia , alfa-Manosidase/metabolismo , alfa-Manosidase/genética , Vírus da Dengue/fisiologia , Arbovírus/fisiologia , Mosquitos Vetores/microbiologia , Mosquitos Vetores/virologia , Mosquitos Vetores/genética , Feminino , Infecções por Arbovirus/transmissão , Proteínas de Insetos/metabolismo , Proteínas de Insetos/genética , Sistemas CRISPR-CasRESUMO
The endocannabinoid (eCB) system represents a promising neurobiological target for novel anxiolytic pharmacotherapies. Previous clinical and preclinical evidence has revealed that genetic and/or pharmacological manipulations altering eCB signaling modulate fear and anxiety behaviors. Water-insoluble eCB lipid anandamide requires chaperone proteins for its intracellular transport to degradation, a process that requires fatty acid-binding proteins (FABPs). Here, we investigated the effects of a novel FABP-5 inhibitor, SBFI-103, on fear and anxiety-related behaviors using rats. Acute intra-prelimbic cortex administration of SBFI-103 induced a dose-dependent anxiolytic response and reduced contextual fear expression. Surprisingly, both effects were reversed when a cannabinoid-2 receptor (CB2R) antagonist, AM630, was co-infused with SBFI-103. Co-infusion of the cannabinoid-1 receptor antagonist Rimonabant with SBFI-103 reversed the contextual fear response yet showed no reversal effect on anxiety. Furthermore, in vivo neuronal recordings revealed that intra-prelimbic region SBFI-103 infusion altered the activity of putative pyramidal neurons in the basolateral amygdala and ventral hippocampus, as well as oscillatory patterns within these regions in a CB2R-dependent fashion. Our findings identify a promising role for FABP5 inhibition as a potential target for anxiolytic pharmacotherapy. Furthermore, we identify a novel, CB2R-dependent FABP-5 signaling pathway in the PFC capable of strongly modulating anxiety-related behaviors and anxiety-related neuronal transmission patterns.
Assuntos
Ansiolíticos , Ansiedade , Proteínas de Ligação a Ácido Graxo , Córtex Pré-Frontal , Receptor CB2 de Canabinoide , Animais , Ratos , Tonsila do Cerebelo/efeitos dos fármacos , Tonsila do Cerebelo/metabolismo , Ansiolíticos/metabolismo , Ansiolíticos/farmacologia , Ansiolíticos/uso terapêutico , Ansiedade/tratamento farmacológico , Ansiedade/metabolismo , Canabinoides/metabolismo , Endocanabinoides/metabolismo , Proteínas de Ligação a Ácido Graxo/antagonistas & inibidores , Proteínas de Ligação a Ácido Graxo/metabolismo , Medo/efeitos dos fármacos , Medo/fisiologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Receptor CB1 de Canabinoide/antagonistas & inibidores , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/antagonistas & inibidores , Receptor CB2 de Canabinoide/metabolismoRESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has initiated a global pandemic, and several vaccines have now received emergency use authorization. Using the reference strain SARS-CoV-2 USA-WA1/2020, we evaluated modes of transmission and the ability of prior infection or vaccine-induced immunity to protect against infection in ferrets. Ferrets were semipermissive to infection with the USA-WA1/2020 isolate. When transmission was assessed via the detection of viral RNA (vRNA) at multiple time points, direct contact transmission was efficient to 3/3 and 3/4 contact animals in 2 respective studies, while respiratory droplet transmission was poor to only 1/4 contact animals. To determine if previously infected ferrets were protected against reinfection, ferrets were rechallenged 28 or 56 days postinfection. Following viral challenge, no infectious virus was recovered in nasal wash samples. In addition, levels of vRNA in the nasal wash were several orders of magnitude lower than during primary infection, and vRNA was rapidly cleared. To determine if intramuscular vaccination protected ferrets, ferrets were vaccinated using a prime-boost strategy with the S protein receptor-binding domain formulated with an oil-in-water adjuvant. Upon viral challenge, none of the mock or vaccinated animals were protected against infection, and there were no significant differences in vRNA or infectious virus titers in the nasal wash. Combined, these studies demonstrate direct contact is the predominant mode of transmission of the USA-WA1/2020 isolate in ferrets and that immunity to SARS-CoV-2 is maintained for at least 56 days. Our studies also indicate protection of the upper respiratory tract against SARS-CoV-2 will require vaccine strategies that mimic natural infection or induce site-specific immunity. IMPORTANCE The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) USA-WA1/2020 strain is a CDC reference strain used by multiple research laboratories. Here, we show that the predominant mode of transmission of this isolate in ferrets is by direct contact. We further demonstrate ferrets are protected against reinfection for at least 56 days even when levels of neutralizing antibodies are low or undetectable. Last, we show that when ferrets were vaccinated by the intramuscular route to induce antibodies against SARS-CoV-2, ferrets remain susceptible to infection of the upper respiratory tract. Collectively, these studies suggest that protection of the upper respiratory tract will require vaccine approaches that mimic natural infection.
Assuntos
COVID-19/transmissão , Modelos Animais de Doenças , Reinfecção/prevenção & controle , SARS-CoV-2/fisiologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/administração & dosagem , Furões , Injeções Intramusculares , Nariz/virologia , Reinfecção/imunologia , SARS-CoV-2/imunologia , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/administração & dosagem , Carga ViralRESUMO
Hosts defend themselves against pathogens by mounting an immune response. Fully understanding the immune response as a driver of host disease and pathogen evolution requires a quantitative account of its impact on parasite population dynamics. Here, we use a data-driven modeling approach to quantify the birth and death processes underlying the dynamics of infections of the rodent malaria parasite, Plasmodium chabaudi, and the red blood cells (RBCs) it targets. We decompose the immune response into 3 components, each with a distinct effect on parasite and RBC vital rates, and quantify the relative contribution of each component to host disease and parasite density. Our analysis suggests that these components are deployed in a coordinated fashion to realize distinct resource-directed defense strategies that complement the killing of parasitized cells. Early in the infection, the host deploys a strategy reminiscent of siege and scorched-earth tactics, in which it both destroys RBCs and restricts their supply. Late in the infection, a "juvenilization" strategy, in which turnover of RBCs is accelerated, allows the host to recover from anemia while holding parasite proliferation at bay. By quantifying the impact of immunity on both parasite fitness and host disease, we reveal that phenomena often interpreted as immunopathology may in fact be beneficial to the host. Finally, we show that, across mice, the components of the host response are consistently related to each other, even when infections take qualitatively different trajectories. This suggests the existence of simple rules that govern the immune system's deployment.
Assuntos
Interações Hospedeiro-Parasita/imunologia , Malária/imunologia , Plasmodium chabaudi/patogenicidade , Reticulócitos/parasitologia , Animais , Longevidade , Merozoítos/fisiologia , Camundongos , Modelos Teóricos , Plasmodium chabaudi/imunologia , Reticulócitos/imunologiaRESUMO
Inadequately designed culverts can be physical barriers to fish passage if they increase the velocity of water flow in the environment, alter natural turbulence patterns or fail to provide adequate water depth. They may also act as behavioural barriers to fish passage if they affect the willingness of fish species to enter or pass through the structure due to altered ambient light conditions. To understand how reduced light intensity might affect fish behaviour in culverts, the authors performed a behavioural choice experiment quantifying the amount of time individual fish spent in dark and illuminated areas of a controlled experimental channel. They found that behavioural responses were largely reflective of the species' diel activity patterns; the diurnal species Craterocephalus stercusmuscarum and Retropinna semoni preferred illuminated regions, whereas the nocturnal/crepuscular Macquaria novemaculeata preferred the darkened region of the channel. Bidyanus bidyanus were strongly rheotactic, and their behaviour was influenced more by water flow direction than ambient light level. The authors then determined that a threshold light intensity of only c. 100-200 lx (cf. midday sunlight c. 100,000 lx) was required to overcome the behavioural barrier in c. 70% of the diurnally active C. stercusmuscarum and R. semoni tested. When these values were placed into an environmental context, 15 road-crossing (3.4-7.0 m long) box (c. 1 m × 1 m, height × width) and pipe (c. 1 m diameter) culverts sampled in Brisbane, Australia, recorded light intensities in the centre of the structure that were below the threshold for C. stercusmuscarum and R. semoni movement and could potentially be a barrier to their passage through the structure. Attention is required to better understand the impacts of low light intensity in culverts on fish passage and to prioritize restoration.
Assuntos
Aprendizagem da Esquiva/efeitos da radiação , Ecossistema , Peixes/fisiologia , Luz , Animais , Austrália , Comportamento de Escolha/efeitos da radiaçãoRESUMO
Slowing the evolution of antimicrobial resistance is essential if we are to continue to successfully treat infectious diseases. Whether a drug-resistant mutant grows to high densities, and so sickens the patient and spreads to new hosts, is determined by the competitive interactions it has with drug-susceptible pathogens within the host. Competitive interactions thus represent a good target for resistance management strategies. Using an in vivo model of malaria infection, we show that limiting a resource that is disproportionately required by resistant parasites retards the evolution of drug resistance by intensifying competitive interactions between susceptible and resistant parasites. Resource limitation prevented resistance emergence regardless of whether resistant mutants arose de novo or were experimentally added before drug treatment. Our work provides proof of principle that chemotherapy paired with an "ecological" intervention can slow the evolution of resistance to antimicrobial drugs, even when resistant pathogens are present at high frequencies. It also suggests that a broad range of previously untapped compounds could be used for treating infectious diseases.
Assuntos
Resistência a Medicamentos , Interações Hospedeiro-Parasita , Malária , Modelos Biológicos , Mutação , Plasmodium chabaudi/fisiologia , Malária/tratamento farmacológico , Malária/genética , Malária/metabolismoRESUMO
Very little is known about how vector-borne pathogens interact within their vector and how this impacts transmission. Here we show that mosquitoes can accumulate mixed strain malaria infections after feeding on multiple hosts. We found that parasites have a greater chance of establishing and reach higher densities if another strain is already present in a mosquito. Mixed infections contained more parasites but these larger populations did not have a detectable impact on vector survival. Together these results suggest that mosquitoes taking multiple infective bites may disproportionally contribute to malaria transmission. This will increase rates of mixed infections in vertebrate hosts, with implications for the evolution of parasite virulence and the spread of drug-resistant strains. Moreover, control measures that reduce parasite prevalence in vertebrate hosts will reduce the likelihood of mosquitoes taking multiple infective feeds, and thus disproportionally reduce transmission. More generally, our study shows that the types of strain interactions detected in vertebrate hosts cannot necessarily be extrapolated to vectors.
Assuntos
Culicidae/parasitologia , Interações Hospedeiro-Patógeno/fisiologia , Malária/transmissão , Animais , Evolução Biológica , Comportamento AlimentarRESUMO
The evolution of drug resistance, a key challenge for our ability to treat and control infections, depends on two processes: de-novo resistance mutations, and the selection for and spread of resistant mutants within a population. Understanding the factors influencing the rates of these two processes is essential for maximizing the useful lifespan of drugs and, therefore, effective disease control. For malaria parasites, artemisinin-based drugs are the frontline weapons in the fight against disease, but reports from the field of slower parasite clearance rates during drug treatment are generating concern that the useful lifespan of these drugs may be limited. Whether slower clearance rates represent true resistance, and how this provides a selective advantage for parasites is uncertain. Here, we show that Plasmodium chabaudi malaria parasites selected for resistance to artesunate (an artemisinin derivative) through a step-wise increase in drug dose evolved slower clearance rates extremely rapidly. In single infections, these slower clearance rates, similar to those seen in the field, provided fitness advantages to the parasite through increased overall density, recrudescence after treatment and increased transmission potential. In mixed infections, removal of susceptible parasites by drug treatment led to substantial increases in the densities and transmission potential of resistant parasites (competitive release). Our results demonstrate the double-edged sword for resistance management: in our initial selection experiments, no parasites survived aggressive chemotherapy, but after selection, the fitness advantage for resistant parasites was greatest at high drug doses. Aggressive treatment of mixed infections resulted in resistant parasites dominating the pool of gametocytes, without providing additional health benefits to hosts. Slower clearance rates can evolve rapidly and can provide a strong fitness advantage during drug treatment in both single and mixed strain infections.
Assuntos
Adaptação Fisiológica/efeitos dos fármacos , Antimaláricos/farmacologia , Artemisininas/farmacologia , Resistência a Medicamentos/efeitos dos fármacos , Malária/transmissão , Plasmodium chabaudi , Animais , Artesunato , Relação Dose-Resposta a Droga , Malária/patologia , Camundongos , Plasmodium chabaudi/patogenicidade , Plasmodium chabaudi/fisiologiaRESUMO
As Wolbachia pipientis is more widely being released into field populations of Aedes aegypti for disease control, the ability to select the appropriate strain for differing environments is increasingly important. A previous study revealed that longer-term quiescence in the egg phase reduced the fertility of mosquitoes, especially those harboring the wAlbB Wolbachia strain. This infertility was also associated with a greater biting rate. Here, we attempt to quantify the effect of this heightened biting behavior on the transmission potential of the dengue virus using a combination of assays for fitness, probing behavior, and vector competence, allowing repeat feeding, and incorporate these effects in a model of R0. We show that Wolbachia-infected infertile mosquitoes are more interested in feeding almost immediately after an initial blood meal relative to wild type and Wolbachia-infected fertile mosquitoes and that these differences continue for up to 8 days over the period we measured. As a result, the infertile Wolbachia mosquitoes have higher virus prevalence and loads than Wolbachia-fertile mosquitoes. We saw limited evidence of Wolbachia-mediated blocking in the disseminated tissue (legs) in terms of prevalence but did see reduced viral loads. Using a previously published estimate of the extrinsic incubation period, we demonstrate that the effect of repeat feeding/infertility is insufficient to overcome the effects of Wolbachia-mediated blocking on R0. These estimates are very conservative, however, and we posit that future studies should empirically measure EIP under a repeat feeding model. Our findings echo previous work where periods of extensive egg quiescence affected the reproductive success of Wolbachia-infected Ae. aegypti. Additionally, we show that increased biting behavior in association with this infertility in Wolbachia-infected mosquitoes may drive greater vector competence. These relationships require further exploration, given their ability to affect the success of field releases of Wolbachia for human disease reduction in drier climates where longer egg quiescence periods are expected.
Assuntos
Aedes , Vírus da Dengue , Dengue , Comportamento Alimentar , Mosquitos Vetores , Wolbachia , Aedes/microbiologia , Aedes/virologia , Aedes/fisiologia , Animais , Wolbachia/fisiologia , Vírus da Dengue/fisiologia , Mosquitos Vetores/microbiologia , Mosquitos Vetores/virologia , Mosquitos Vetores/fisiologia , Dengue/transmissão , Feminino , Carga Viral , Óvulo/virologia , Óvulo/microbiologiaRESUMO
RATIONALE: The endocannabinoid (eCB) system critically controls anxiety and fear-related behaviours. Anandamide (AEA), a prominent eCB ligand, is a hydrophobic lipid that requires chaperone proteins such as Fatty Acid Binding Proteins (FABPs) for intracellular transport. Intracellular AEA transport is necessary for degradation, so blocking FABP activity increases AEA neurotransmission. OBJECTIVE: To investigate the effects of a novel FABP5 inhibitor (SBFI-103) in the basolateral amygdala (BLA) on anxiety and fear memory. METHODS: We infused SBFI-103 (0.5 µg-5 µg) to the BLA of adult male Sprague Dawley rats and ran various anxiety and fear memory behavioural assays, neurophysiological recordings, and localized molecular signaling analyses. We also co-infused SBFI-103 with the AEA inhibitor, LEI-401 (3 µg and 10 µg) to investigate the potential role of AEA in these phenomena. RESULTS: Acute intra-BLA administration of SBFI-103 produced strong anxiolytic effects across multiple behavioural tests. Furthermore, animals exhibited acute and long-term accelerated associative fear memory extinction following intra-BLA FABP5 inhibition. In addition, BLA FABP5 inhibition induced strong modulatory effects on putative PFC pyramidal neurons along with significantly increased gamma oscillation power. Finally, we observed local BLA changes in the phosphorylation activity of various anxiety- and fear memory-related molecular biomarkers in the PI3K/Akt and MAPK/Erk signaling pathways. At all three levels of analyses, we found the functional effects of SBFI-103 depend on availability of the AEA ligand. CONCLUSIONS: These findings demonstrate a novel intra-BLA FABP5 signaling mechanism regulating anxiety and fear memory behaviours, neuronal activity states, local anxiety-related molecular pathways, and functional AEA modulation.
Assuntos
Ansiolíticos , Complexo Nuclear Basolateral da Amígdala , Animais , Masculino , Ratos , Tonsila do Cerebelo/metabolismo , Ansiolíticos/farmacologia , Ansiolíticos/metabolismo , Extinção Psicológica , Proteínas de Ligação a Ácido Graxo/metabolismo , Proteínas de Ligação a Ácido Graxo/farmacologia , Medo/fisiologia , Ligantes , Fosfatidilinositol 3-Quinases/metabolismo , Fosfatidilinositol 3-Quinases/farmacologia , Ratos Sprague-DawleyRESUMO
Numerous diseases of wildlife have recently emerged due to trade and travel. However, the impact of disease on wild animal populations has been notoriously difficult to detect and demonstrate, due to problems of attribution and the rapid disappearance of bodies after death. Determining the magnitude of avian mortality from West Nile virus (WNV) is emblematic of these challenges. Although correlational analyses may show population declines coincident with the arrival of the virus, strong inference of WNV as a cause of mortality or a population decline requires additional evidence. We show how integrating field data on mosquito feeding patterns, avian abundance, and seroprevalence can be used to predict relative mortality from vector-borne pathogens. We illustrate the method with a case study on WNV in three species of small songbirds, tufted titmouse (Baeolophus bicolor), Carolina wrens (Thryothorus ludovicianus), and northern cardinals (Cardinalis cardinalis). We then determined mortality, infectiousness, and behavioral response of wrens and titmouse following infection with WNV in laboratory experiments and compared them to a previous study on WNV mortality in cardinals. In agreement with predictions, we found titmouse had the highest mortality from WNV infection, with 100% of eleven birds perishing within seven days after infection. Mortality in wrens was significantly lower at 27% (3/11), but still substantial. Viremia profiles indicated that both species were highly infectious for WNV and could play roles in WNV amplification. These findings suggest that WNV may be killing many small-bodied birds, despite the absence of large numbers of dead birds testing positive for WNV. More broadly, they illustrate a framework for predicting relative mortality in hosts from vector-borne disease.
RESUMO
Jamestown Canyon virus (JCV), a negative-sense arbovirus, is increasingly common in the upper Midwest of the USA. Transmitted by a range of mosquito genera, JCV's primary amplifying host is white-tailed deer. Aedes aegypti is responsible for transmitting various positive-sense viruses globally including dengue (DENV), Zika, chikungunya, and Yellow Fever. Ae. aegypti's distribution, once confined to the tropics, is expanding, in part due to climate change. Wolbachia, an insect endosymbiont, limits the replication of co-infecting viruses inside insects. The release and spread of the symbiont into Ae. aegypti populations have been effective in reducing transmission of DENV to humans, although the mechanism of Wolbachia-mediated viral blocking is still poorly understood. Here we explored JCV infection potential in Ae. aegypti, the nature of the vector's immune response, and interactions with Wolbachia infection. We show that Ae. aegypti is highly competent for JCV, which grows to high loads and rapidly reaches the saliva after an infectious blood meal. The mosquito immune system responds with strong induction of RNAi and JAK/STAT. Neither the direct effect of viral infection nor the energetic investment in immunity appears to affect mosquito longevity. Wolbachia infection blocked JCV only in the early stages of infection. Wolbachia-induced immunity was small compared to that of JCV, suggesting innate immune priming does not likely explain blocking. We propose two models to explain why Wolbachia's blocking of negative-sense viruses like JCV may be less than that of positive-sense viruses, relating to the slowdown of host protein synthesis and the triggering of interferon-like factors like Vago. In conclusion, we highlight the risk for increased human disease with the predicted future overlap of Ae. aegypti and JCV ranges. We suggest that with moderate Wolbachia-mediated blocking and distinct biology, negative-sense viruses represent a fruitful comparator model to other viruses for understanding blocking mechanisms in mosquitoes.
Assuntos
Aedes , Coinfecção , Cervos , Vírus da Encefalite da Califórnia , Wolbachia , Infecção por Zika virus , Zika virus , Animais , Humanos , Mosquitos VetoresRESUMO
The mosquito Aedes aegypti is the primary vector of many disease-causing viruses, including dengue (DENV), Zika, chikungunya, and yellow fever. As consequences of climate change, we expect an increase in both global mean temperatures and extreme climatic events. When temperatures fluctuate, mosquito vectors will be increasingly exposed to temperatures beyond their upper thermal limits. Here, we examine how DENV infection alters Ae. aegypti thermotolerance by using a high-throughput physiological 'knockdown' assay modeled on studies in Drosophila. Such laboratory measures of thermal tolerance have previously been shown to accurately predict an insect's distribution in the field. We show that DENV infection increases thermal sensitivity, an effect that may ultimately limit the geographic range of the virus. We also show that the endosymbiotic bacterium Wolbachia pipientis, which is currently being released globally as a biological control agent, has a similar impact on thermal sensitivity in Ae. aegypti. Surprisingly, in the coinfected state, Wolbachia did not provide protection against DENV-associated effects on thermal tolerance, nor were the effects of the two infections additive. The latter suggests that the microbes may act by similar means, potentially through activation of shared immune pathways or energetic tradeoffs. Models predicting future ranges of both virus transmission and Wolbachia's efficacy following field release may wish to consider the effects these microbes have on host survival.
Assuntos
Aedes/microbiologia , Aedes/fisiologia , Mosquitos Vetores/microbiologia , Mosquitos Vetores/fisiologia , Aedes/virologia , Animais , Vírus da Dengue/fisiologia , Ecossistema , Temperatura Alta , Mosquitos Vetores/virologia , Termotolerância , Wolbachia/fisiologiaRESUMO
West Nile virus (WNV) has caused repeated large-scale human epidemics in North America since it was first detected in 1999 and is now the dominant vector-borne disease in this continent. Understanding the factors that determine the intensity of the spillover of this zoonotic pathogen from birds to humans (via mosquitoes) is a prerequisite for predicting and preventing human epidemics. We integrated mosquito feeding behavior with data on the population dynamics and WNV epidemiology of mosquitoes, birds, and humans. We show that Culex pipiens, the dominant enzootic (bird-to-bird) and bridge (bird-to-human) vector of WNV in urbanized areas in the northeast and north-central United States, shifted its feeding preferences from birds to humans by 7-fold during late summer and early fall, coinciding with the dispersal of its preferred host (American robins, Turdus migratorius) and the rise in human WNV infections. We also show that feeding shifts in Cx. tarsalis amplify human WNV epidemics in Colorado and California and occur during periods of robin dispersal and migration. Our results provide a direct explanation for the timing and intensity of human WNV epidemics. Shifts in feeding from competent avian hosts early in an epidemic to incompetent humans after mosquito infection prevalences are high result in synergistic effects that greatly amplify the number of human infections of this and other pathogens. Our results underscore the dramatic effects of vector behavior in driving the transmission of zoonotic pathogens to humans.
Assuntos
Culicidae/fisiologia , Culicidae/virologia , Comportamento Alimentar/fisiologia , Febre do Nilo Ocidental/epidemiologia , Vírus do Nilo Ocidental/fisiologia , Animais , Sequência de Bases , Aves/virologia , DNA Viral/genética , Cadeia Alimentar , Humanos , América do Norte/epidemiologia , Fatores de Tempo , População Urbana , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/isolamento & purificação , Zoonoses/epidemiologiaRESUMO
The evolution of Marek's disease virus (MDV, Gallid herpesvirus 2) has threatened the sustainability of poultry farming in the past and its continued evolution remains a concern. Genetic diversity is key to understanding evolution, yet little is known about the diversity of MDV in the poultry industry. Here, we investigate the diversity of MDV on 19 Pennsylvanian poultry farms over a 3-year period. Using eight polymorphic markers, we found that at least twelve MDV haplotypes were co-circulating within a radius of 40 km. MDV diversity showed no obvious spatial clustering nor any apparent clustering by bird line: all of the virus haplotypes identified on the commercial farms could be found within a single, commonly reared bird line. On some farms, a single virus haplotype dominated for an extended period of time, while on other farms the observed haplotypes changed over time. In some instances, multiple haplotypes were found simultaneously on a farm, and even within a single dust sample. On one farm, co-occurring haplotypes clustered into phylogenetically distinct clades, putatively assigned as high and low virulence pathotypes. Although the vast majority of our samples came from commercial poultry farms, we found the most haplotype diversity on a noncommercial backyard farm experiencing an outbreak of clinical Marek's disease. Future work to explore the evolutionary potential of MDV might therefore direct efforts toward farms that harbor multiple virus haplotypes, including both backyard farms and farms experiencing clinical Marek's disease.
RESUMO
The asymmetric unit of the methanol solvate of sodium naproxen, systematic name: sodium (2S)-2-(6-meth-oxy-naphthalen-2-yl)propano-ate methanol sesquisolvate, Na+·C14H13O3 -·1.5CH3OH, comprises two formula units of the mol-ecular salt and three methanol mol-ecules. One of the sodium cations exhibits a coordination number of six and is bonded to three carboxyl-ate O atoms and three methanol OH groups whereas the second sodium cation has a coordination number of seven, defined by five carboxyl-ate O atoms and two methanol OH groups. Both coordination polyhedra around the sodium cations are considerably distorted. The two types of cations are bridged into polymeric chains extending parallel to [010]. This arrangement is stabilized by intrachain O-Hâ¯O hydrogen bonds between methanol ligands as donor and carboxyl-ate O atoms as acceptor groups. The hydro-phobic 6-meth-oxy-naphthyl moieties flank the hydro-philic sodium oxygen chains into ribbons parallel to [010]. There are no noticeable inter-molecular inter-actions between these ribbons. One of the 6-meth-oxy-naphthyl moieties is disordered over two sets of sites in a 0.723â (3):0.277â (3) ratio.
RESUMO
BACKGROUND AND AIMS: Little is known about the long-term economic consequences of smoking during pregnancy. We estimated the association between smoking in pregnancy and the costs of delivering health-care to infants and children in England, and investigated which aspects of care are the key drivers of these costs. METHODS: We used Hospital Episode Statistics (HES) linked with Clinical Practice Research Datalink (CPRD) data in England from January 2003 to January 2015 in children with longitudinal data for at least 1, 5 and 10 years after birth. Poisson regression provided rate ratios (RR) and 95% confidence intervals (CIs) comparing health-care episode rates between those exposed and not exposed to smoking during pregnancy. Linear regression was used to compare estimated costs between groups (£ sterling, 2015 prices) and generalized linear multivariable (GLM) models adjusted for potentially moderating factors. RESULTS: A total of 93 152 singleton pregnancies with the required data were identified. Maternal smoking in pregnancy was associated with higher primary care, prescription and hospital in-patient episode rates, but lower out-patient visit and diagnostic test rates. Adjusting for year of birth, socio-economic deprivation, parity, sex of child and delivery method showed that maternal smoking in pregnancy was associated with increased child health-care costs at 1 year [average cost difference for children of smokers, ß = £91.18, 95% confidence interval (CI) = £47.52-134.83 and 5 years of age (ß = £221.80, 95% CI = £17.78-425.83], but not at 10 years of age (ß = £365.94, 95% CI = -£192.72 to £924.60). CONCLUSION: In England, maternal smoking in pregnancy is associated with increased child health-care costs over the first 5 years of life; these costs are driven primarily by greater hospital in-patient care.
Assuntos
Serviços de Saúde da Criança/economia , Custos de Cuidados de Saúde , Complicações na Gravidez/economia , Fumar/economia , Adulto , Criança , Pré-Escolar , Inglaterra , Feminino , Hospitalização/economia , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Gravidez , Complicações na Gravidez/epidemiologia , Medicamentos sob Prescrição/economia , Medicamentos sob Prescrição/uso terapêutico , Atenção Primária à Saúde/economia , Atenção Primária à Saúde/estatística & dados numéricos , Fumar/epidemiologia , Medicina Estatal , Adulto JovemRESUMO
The feeding behavior of vectors influences the likelihood of pathogen invasion and the exposure of humans to vector-borne zoonotic pathogens. We used multilocus microsatellite genetic typing of an introduced mosquito vector and DNA sequencing of mosquito blood meals to determine the impact of hybrid ancestry on feeding behavior and the emergence of West Nile virus (WNV). The probability of ancestry of Culex pipiens mosquitoes from two bionomically divergent forms, form molestus and form pipiens, influenced the probability that they fed on humans but did not explain a late summer feeding shift from birds to humans. We used a simple model to show that the occurrence of pure form molestus mosquitoes would have decreased the likelihood of WNV invasion (R(0) in bird populations) 3- to 8-fold, whereas the occurrence of pure forms pipiens mosquitoes would have halved human exposure compared with the hybrids that are present. Data and modeling suggest that feeding preferences may be influenced by genetic ancestry and contribute to the emergence of vector-borne pathogens transmitted by introduced species, including malaria, and dengue, Chikungunya, yellow fever, and West Nile viruses.
Assuntos
Culex/genética , Comportamento Alimentar/fisiologia , Insetos Vetores/genética , Zoonoses/transmissão , Animais , Culex/virologia , Humanos , Insetos Vetores/virologia , Repetições de Microssatélites , Vírus do Nilo Ocidental/crescimento & desenvolvimento , Zoonoses/virologiaRESUMO
CONTEXT: The opioid epidemic has included use of traditional drugs and recently newer synthetics. It is critically important to recognize and identify these new drugs both clinically and through appropriately designed toxicology testing. There is little available information on a synthetic gaining popularity, U-47700. CASE DETAILS: A 23-year-old female presented after using "U4" by nasal insufflation and injection. She was cyanotic with respiratory depression and responded to naloxone in the field. She was found to have non cardiogenic pulmonary edema and hemoptysis which improved with BiPAP. Urine and serum samples were analyzed using mass spectrometry, confirming 3,4-dichloro-N-[(1R,2R)-2-(dimethylamino)cyclohexyl]-N-methylbenzamide or U-47700. The sample was further analyzed elucidating metabolism specifics. Drug and metabolite concentrations were subsequently measured in both serum and urine. The parent compound of U-47700 was detected at 394 ng/mL and 228 ng/mL in serum and urine, respectively. Metabolites detected in appreciable amounts included the desmethyl (1964 ng/mL in urine), bisdesmethyl (618 ng/mL), desmethyl hydroxy (447 ng/mL), and bisdesmethyl hydroxy forms (247 ng/mL) of U-47700. DISCUSSION: U-47700 is a potent µ-opioid receptor agonist and has recently been used recreationally, contributing to hospitalizations and likely deaths in the community. This is a case report describing an exposure to U-47700 with subsequent laboratory analysis. Based upon this one case, parent U-47700 appear to be an appropriate marker of use in a serum sample. However, demethylated metabolites appear dominant as urinary markers of U-47700 use.