Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 6.171
Filtrar
1.
J Travel Med ; 2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38438165

RESUMEN

BACKGROUND: Vaccination plays a critical role in mitigating the burden associated with yellow fever (YF). However, there is a lack of comprehensive evidence on the humoral response to primary vaccination in the paediatric population, with several questions debated, including the response when the vaccine is administered at early ages, the effect of co-administration with other vaccines, the duration of immunity, and the use of fractional doses, among others. This study summarizes the existing evidence regarding the humoral response to primary YF vaccination in infants and children. METHODS: Studies on the humoral response to primary YF vaccination in children aged 12 years or younger were reviewed. The humoral vaccine response rate (VRR), i.e. the proportion of children who tested positive for vaccine-induced YF-specific neutralizing antibodies, was pooled through random-effects meta-analysis, and categorized based on the time elapsed since vaccination. Subgroup, meta-regression, and sensitivity analyses were performed. RESULTS: A total of 33 articles met the inclusion criteria, with all but one conducted in countries where YF is endemic. A total of 14 028 infants and children entered this systematic review. Within three months following vaccination, the pooled VRR was 91.9% (95%CI 89.8-93.9). A higher VRR observed after 17D-204 at the meta-regression analysis. No significant differences in immunogenicity outcomes were observed based on age, administration route, coadministration with other vaccines, or fractional dosing. Results also indicate a decline in VRR over time. CONCLUSIONS: Primary YF vaccination effectively provides humoral immunity in paediatric population. However, humoral response declines over time, and this decline is observable after the first 18 months following vaccination. A differential response according to the vaccine substrain was also observed. This research has valuable implications for stimulating further research on the primary YF vaccination in infants and children, as well as for informing future policies.

2.
J Am Mosq Control Assoc ; 40(1): 32-49, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38427588

RESUMEN

The sterile insect technique (SIT) and the incompatible insect technique (IIT) are emerging and potentially revolutionary tools for controlling Aedes aegypti (L.), a prominent worldwide mosquito vector threat to humans that is notoriously difficult to reduce or eliminate in intervention areas using traditional integrated vector management (IVM) approaches. Here we provide an overview of the discovery, development, and application of SIT and IIT to Ae. aegypti control, and innovations and advances in technology, including transgenics, that could elevate these techniques to a worldwide sustainable solution to Ae. aegypti when combined with other IVM practices.


Asunto(s)
Aedes , Wolbachia , Animales , Humanos , Control de Mosquitos/métodos , Mosquitos Vectores , Insectos
3.
PLoS One ; 19(3): e0297964, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38437189

RESUMEN

Wolbachia is an endosymbiont bacterium present in many insect species. When Wolbachia-carrying male Aedes aegypti mosquitoes mate with non-carrier females, their embryos are not viable due to cytoplasmic incompatibility. This phenomenon has been exploited successfully for the purpose of controlling mosquito populations and the spread of mosquito-borne illnesses: Wolbachia carriers are bred and released into the environment. Because Wolbachia is not harmful to humans, this method of mosquito control is regarded as a safer alternative to pesticide spraying. In this article, we introduce a mathematical framework for exploring (i) whether a one-time release of Wolbachia carriers can elicit a sustained presence of carriers near the release site, and (ii) the extent to which spatial propagation of carriers may allow them to establish fixation in other territories. While some prior studies have formulated mosquito dispersal models using advection-reaction-diffusion PDEs, the predictive power of such models requires careful ecological mapping: advection and diffusion coefficients exhibit significant spatial dependence due to heterogeneity of resources and topography. Here, we adopt a courser-grained view, regarding the environment as a network of discrete, diffusively-coupled "habitats"-distinct zones of high mosquito density such as stagnant ponds. We extend two previously published single-habitat mosquito models to multiple habitats, and calculate rates of migration between pairs of habitats using dispersal kernels. Our primary results are quantitative estimates regarding how the success of carrier fixation in one or more habitats is determined by: the number of carriers released, sizes of habitats, distances between habitats, and the rate of migration between habitats. Besides yielding sensible and potentially useful predictions regarding the success of Wolbachia-based control, our framework applies to other approaches (e.g., gene drives) and contexts beyond the realm of insect pest control.


Asunto(s)
Aedes , Charadriiformes , Wolbachia , Femenino , Humanos , Animales , Masculino , Citoplasma , Citosol
4.
Health Sci Rep ; 7(2): e1924, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38444843

RESUMEN

Background and Aims: The acute tropical infectious disease known as yellow fever (YF) is caused by an arbovirus and is characterized by fever, jaundice, hemorrhage, headache, muscle pain, nausea, vomiting, and fatigue. Angola experienced a yellow fever virus (YFV) outbreak that was documented in December 2015. However, little is known about the outcome of this outbreak. We aimed to demonstrate epidemic features and lessons learned during the YF epidemic in Angola. Methods: A total of 4618 blood samples from suspected YF cases were sent to the Instituto Nacional de Investigação em Saúde (INIS), a national referral and public health laboratory, between December 5, 2015, and December 23, 2016. Sample analyses were conducted using enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR) assays. Blood samples were sent from 16 out of the 18 provinces of Angola. Results: We detected 884 (19.1%) cases that were positive for ELISA, which were confirmed by RT-PCR assay. Considering the positive cases, the incidence among male patients was around three times higher (n = 223; 10.9%) than in female patients (n = 59; 2.6%) in the 20-29 age group, followed by the age group 10-19 with n = 211 (6.8%) in males versus n = 108 (3.3%) in females; and the age group 30-39 had n = 68 (4.8%) in males versus n = 28 (1.8%) in females. The other groups had an incidence below 3.0%. The case fatality ratio for YF was in young adults in the age group 20-29 with n = 39 cases, followed by the age group 10-19 with n = 16 cases, and finally the age group 0-9 with n = 13 cases. The other age groups had several deaths by YF below 10 cases. Conclusions: This study demonstrates features of the YF epidemic that occurred in Angola. Also, it demonstrates that YF causes deaths in young people but is preventable by high vaccine coverage. Thus, public health laboratory surveillance must be strengthened to reduce the possibility of emerging and re-emerging human infections.

5.
bioRxiv ; 2024 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-38463973

RESUMEN

During major, recent yellow fever (YF) epidemics in Brazil, human cases were attributed only to spillover infections from sylvatic transmission with no evidence of human amplification. Furthermore, the historic absence of YF in Asia, despite abundant peridomestic Aedes aegypti and naive human populations, represents a longstanding enigma. We tested the hypothesis that immunity from dengue (DENV) and Zika (ZIKV) flaviviruses limits YF virus (YFV) viremia and transmission by Ae. aegypti . Prior DENV and ZIKV immunity consistently suppressed YFV viremia in experimentally infected macaques, leading to reductions in Ae. aegypti infection when mosquitoes were fed on infected animals. These results indicate that, in DENV- and ZIKV-endemic regions such as South America and Asia, flavivirus immunity suppresses YFV human amplification potential, reducing the risk of urban outbreaks. One-Sentence Summary: Immunity from dengue and Zika viruses suppresses yellow fever viremia, preventing infection of mosquitoes and reducing the risk of epidemics.

6.
Sci Rep ; 14(1): 5422, 2024 03 05.
Artículo en Inglés | MEDLINE | ID: mdl-38443480

RESUMEN

Developing a safe and potent repellent of mosquitoes applicable to human skins is an effective measure against the spread of mosquito-borne diseases. Recently, we have identified that hydrophobic solutions such as low viscosity polydimethylsiloxane (L-PDMS) spread on a human skin prevent mosquitoes from staying on and biting it. This is likely due to the ability of L-PDMS in wetting mosquito legs and exerting a capillary force from which the mosquitoes attempt to escape. Here we show three additional functions of L-PDMS that can contribute to repel Aedes albopictus, by combining physicochemical analysis and behavioral assays in both an arm cage and a virtual flight arena. First, L-PDMS, when mixed with topical repellents and applied on a human skin, enhances the effect of topical repellents in reducing mosquito bites by efficiently transferring them to mosquito legs upon contact. Second, L-PDMS applied to mosquito tarsi compromises visual object tracking during flight, exerting an influence outlasting the contact. Finally, L-PDMS applied to mosquito tarsi acts as an aversive reinforcer in associative learning, making mosquitoes avoid the conditioned odor. These results uncover a multifaceted potential of L-PDMS in altering a sequence of mosquito behaviors from biting a human skin, visual object tracking following takeoff, to the response to an odor linked with L-PDMS.


Asunto(s)
Aedes , Repelentes de Insectos , Humanos , Animales , Repelentes de Insectos/farmacología , Articulación del Tobillo , Humectabilidad
7.
Sci Rep ; 14(1): 5628, 2024 03 07.
Artículo en Inglés | MEDLINE | ID: mdl-38454095

RESUMEN

Vector control is a key intervention against mosquito borne diseases. However, conventional methods have several limitations and alternate strategies are in urgent need. Vector control with endectocides such as ivermectin is emerging as a novel strategy. The short half-life of ivermectin is a limiting factor for its application as a mass therapy tool for vector control. Isoxazoline compounds like fluralaner, a class of veterinary acaricides with long half-life hold promise as an alternative. However, information about their mosquitocidal effect is limited. We explored the efficacy of fluralaner against laboratory reared vector mosquitoes-Aedes aegypti, Anopheles stephensi, and, Culex quinquefasciatus. 24 h post-blood feeding, fluralaner showed a significant mosquitocidal effect with LC50 values in the range of 24.04-49.82 ng/mL for the three different mosquito species tested. Effects on life history characteristics (fecundity, egg hatch success, etc.) were also observed and significant effects were noted at drug concentrations of 20, 25 and 45 ng/mL for Ae. aegypti, An. stephensi, and, Cx. quinquefasciatus respectively. At higher drug concentration of 250 ng/mL, significant mortality was observed within 1-2 h of post blood feeding. Potent mosquitocidal effect coupled with its long half-life makes fluralaner an excellent candidate for drug based vector control strategies.


Asunto(s)
Aedes , Anopheles , Culex , Insecticidas , Isoxazoles , Animales , Ivermectina/farmacología , Insecticidas/farmacología , Mosquitos Vectores , Larva , Extractos Vegetales/farmacología
8.
Parasit Vectors ; 17(1): 117, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38454517

RESUMEN

BACKGROUND: Indoor residual spraying (IRS) capitalizes on the natural behavior of mosquitoes because Aedes aegypti commonly seeks indoor resting sites after a blood meal. This behavior allows mosquitoes to be exposed to insecticide-treated surfaces and subsequently killed. Combinations of deltamethrin and clothianidin with different modes of action have shown promise in IRS, effectively targeting both susceptible and pyrethroid-resistant malaria vectors. However, the effects of this approach on Aedes mosquitoes remain unclear. The present study tested the effects of deltamethrin-clothianidin mixture treatment on behavioral responses and life history traits of Taiwanese and Indonesian populations of Ae. aegypti. METHODS: We adopted an excito-repellent approach to explore the behavioral responses of pyrethroid-resistant Ae. aegypti populations from Indonesia and Taiwan to a deltamethrin-clothianidin mixture used in contact irritancy and non-contact repellency treatments. We further evaluated the life history traits of surviving mosquitoes (i.e., delayed mortality after 7-day post-treatment, longevity, fecundity, and egg hatching) and investigated the potential transgenerational hormetic effects of insecticide exposure (i.e., development rate and survival of immatures and adult mosquitos). RESULTS: All tested field populations of Ae. aegypti displayed strong contact irritancy responses; the percentage of escape upon insecticide exposure ranged from 38.8% to 84.7%. However, repellent effects were limited, with the escape percentage ranging from 4.3% to 48.9%. We did not observe immediate knockdown or mortality after 24 h, and less than 15% of the mosquitoes exhibited delayed mortality after a 7-day exposure period. However, the carryover effects of insecticide exposure on the survival of immature mosquitoes resulted in approximately 25% higher immature mortality than that in the control. By contrast, we further documented stimulated survivor reproduction and accelerated transgenerational immature development resulting from the sublethal effects of the insecticide mixture. In particular, the number of eggs laid by treated (both treatments) female mosquitoes increased by at least 60% compared with that of eggs laid by control female mosquitoes. CONCLUSIONS: IRS with deltamethrin-clothianidin effectively deters Aedes mosquitoes from entering residential areas and thereby reduces mosquito bites. However, the application rate (deltamethrin: 25 mg/m2; clothianidin: 200 mg/m2) may be insufficient to effectively kill Aedes mosquitoes. Insecticide response appears to vary across mosquito species; their behavioral and physiological responses to sublethal doses have crucial implications for mosquito control programs.


Asunto(s)
Aedes , Guanidinas , Insecticidas , Rasgos de la Historia de Vida , Neonicotinoides , Nitrilos , Piretrinas , Tiazoles , Femenino , Animales , Insecticidas/farmacología , Aedes/fisiología , Indonesia , Resistencia a los Insecticidas , Óvulo , Piretrinas/farmacología , Control de Mosquitos/métodos , Mosquitos Vectores
9.
NPJ Vaccines ; 9(1): 54, 2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38459059

RESUMEN

The re-emergence of yellow fever (YF) urged new mass vaccination campaigns and, in 2017, the World Health Organization approved the use of the fractional dose (FD) of the YF vaccine due to stock shortage. In an observational cross-sectional investigation, we have assessed viremia, antibodies, soluble mediators and effector and memory T and B-cells induced by primary vaccination of volunteers with FD and standard dose (SD). Similar viremia and levels of antibodies and soluble markers were induced early after immunization. However, a faster decrease in the latter was observed after SD. The FD led to a sustained expansion of helper T-cells and an increased expression of activation markers on T-cells early after vaccination. Although with different kinetics, expansion of plasma cells was induced upon SD and FD immunization. Integrative analysis reveals that FD induces a more complex network involving follicular helper T cells and B-cells than SD. Our findings substantiate that FD can replace SD inducing robust correlates of protective immune response against YF.

10.
Int J Med Mushrooms ; 26(3): 41-53, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38505902

RESUMEN

The worldwide scientific community is well aware that mosquitoes are the sole agents responsible for transmitting various dreadful diseases and critical illnesses caused by vector-borne pathogens. The primary objective of this current research was to evaluate the effectiveness of methanol extract from Tricholoma equestre mushroom in controlling the early life stages of Culex quinquefasciatus Say, Anopheles stephensi Liston, and Aedes aegypti (Linnaeus in Hasselquist) mosquitoes. The larvae, pupae and eggs of these mosquitoes were exposed to four different concentrations (62.5 to 500 ppm). After 120 h of treatment, the methanol extract of T. equestre exhibited ovicidal activity ranging from 66% to 80% against the eggs of the treated mosquitoes. It also demonstrated promising larvicidal and pupicidal activity with LC50 values of 216-300 and 230-309 ppm against the early life stages of all three mosquito species. Extensive toxicity studies revealed that the methanol extract from T. equestre had no harmful effects on non-target organisms. The suitability index (SI) or predator safety factor (PSF) indicated that the methanol extract did not harm Poecilia reticulata Peters 1859, (predatory fish), Gambusia affinis S. F. Baird & Girard 1853, dragonfly nymph and Diplonychus indicus Venkatesan & Rao 1871 (water-bug). Gas chromatography-mass spectrometry (GCMS) analysis identified key compounds, including 3-butenenitrile, 2-methyl-(25.319%); 1-butanol, 2-nitro-(18.87%) and oxalic acid, heptyl propyl ester (21.82%) which may be responsible for the observed activity. Furthermore, the formulation based on the methanol extract demonstrated similar effectiveness against all treated mosquitoes at the laboratory level and was found to be non-toxic to mosquito predators. This groundbreaking research represents the first confirmation that methanol extract from T. equestre could be effectively employed in preventing mosquito-borne diseases through mosquito population control programs.


Asunto(s)
Aedes , Agaricales , Anopheles , Culex , Insecticidas , Odonata , Animales , Metanol/farmacología , Mosquitos Vectores , Insecticidas/farmacología , Insecticidas/química , Extractos Vegetales/química , Larva , Hojas de la Planta/química
11.
PLoS Genet ; 20(3): e1011196, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38466721

RESUMEN

Hematophagous mosquitoes require vertebrate blood for their reproductive cycles, making them effective vectors for transmitting dangerous human diseases. Thus, high-intensity metabolism is needed to support reproductive events of female mosquitoes. However, the regulatory mechanism linking metabolism and reproduction in mosquitoes remains largely unclear. In this study, we found that the expression of estrogen-related receptor (ERR), a nuclear receptor, is activated by the direct binding of 20-hydroxyecdysone (20E) and ecdysone receptor (EcR) to the ecdysone response element (EcRE) in the ERR promoter region during the gonadotropic cycle of Aedes aegypti (named AaERR). RNA interference (RNAi) of AaERR in female mosquitoes led to delayed development of ovaries. mRNA abundance of genes encoding key enzymes involved in carbohydrate metabolism (CM)-glucose-6-phosphate isomerase (GPI) and pyruvate kinase (PYK)-was significantly decreased in AaERR knockdown mosquitoes, while the levels of metabolites, such as glycogen, glucose, and trehalose, were elevated. The expression of fatty acid synthase (FAS) was notably downregulated, and lipid accumulation was reduced in response to AaERR depletion. Dual luciferase reporter assays and electrophoretic mobility shift assays (EMSA) determined that AaERR directly activated the expression of metabolic genes, such as GPI, PYK, and FAS, by binding to the corresponding AaERR-responsive motif in the promoter region of these genes. Our results have revealed an important role of AaERR in the regulation of metabolism during mosquito reproduction and offer a novel target for mosquito control.


Asunto(s)
Aedes , Receptores de Esteroides , Animales , Femenino , Humanos , Aedes/genética , Aedes/metabolismo , Ecdisona/metabolismo , Mosquitos Vectores/genética , Receptores Citoplasmáticos y Nucleares/genética , Receptores Citoplasmáticos y Nucleares/metabolismo , Homeostasis/genética , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo
12.
J Am Chem Soc ; 2024 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-38484471

RESUMEN

Mosquito control methods are vital to curtail the spread of life-threatening illnesses, such as dengue fever, malaria, and yellow fever. Vector control technologies must be selective to minimize deleterious effects on our ecosystem. Successful methods that control mosquito larva populations utilize the uniquely high alkaline nature of the midgut. Here, we present novel protected triazabutadienes (pTBD) that are deprotected under basic conditions of the larval midgut, releasing an aryl diazonium ion (ADI) that results in protein modification. The probes contain a bioorthogonal terminal alkyne handle, enabling a selective Cu-click reaction with an azidofluorophore for quantification by SDS PAGE and visualization using fluorescence microscopy. A control TBD, unable to release an ADI, did not label the midgut. We envision our chemical probes will aid in the development of new selective mosquito control methods, thus preventing the spread of mosquito-borne illnesses with minimal impact on other organisms in the ecosystem.

13.
Lancet Glob Health ; 12(4): e563-e571, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38485425

RESUMEN

BACKGROUND: There have been declines in global immunisation coverage due to the COVID-19 pandemic. Recovery has begun but is geographically variable. This disruption has led to under-immunised cohorts and interrupted progress in reducing vaccine-preventable disease burden. There have, so far, been few studies of the effects of coverage disruption on vaccine effects. We aimed to quantify the effects of vaccine-coverage disruption on routine and campaign immunisation services, identify cohorts and regions that could particularly benefit from catch-up activities, and establish if losses in effect could be recovered. METHODS: For this modelling study, we used modelling groups from the Vaccine Impact Modelling Consortium from 112 low-income and middle-income countries to estimate vaccine effect for 14 pathogens. One set of modelling estimates used vaccine-coverage data from 1937 to 2021 for a subset of vaccine-preventable, outbreak-prone or priority diseases (ie, measles, rubella, hepatitis B, human papillomavirus [HPV], meningitis A, and yellow fever) to examine mitigation measures, hereafter referred to as recovery runs. The second set of estimates were conducted with vaccine-coverage data from 1937 to 2020, used to calculate effect ratios (ie, the burden averted per dose) for all 14 included vaccines and diseases, hereafter referred to as full runs. Both runs were modelled from Jan 1, 2000, to Dec 31, 2100. Countries were included if they were in the Gavi, the Vaccine Alliance portfolio; had notable burden; or had notable strategic vaccination activities. These countries represented the majority of global vaccine-preventable disease burden. Vaccine coverage was informed by historical estimates from WHO-UNICEF Estimates of National Immunization Coverage and the immunisation repository of WHO for data up to and including 2021. From 2022 onwards, we estimated coverage on the basis of guidance about campaign frequency, non-linear assumptions about the recovery of routine immunisation to pre-disruption magnitude, and 2030 endpoints informed by the WHO Immunization Agenda 2030 aims and expert consultation. We examined three main scenarios: no disruption, baseline recovery, and baseline recovery and catch-up. FINDINGS: We estimated that disruption to measles, rubella, HPV, hepatitis B, meningitis A, and yellow fever vaccination could lead to 49 119 additional deaths (95% credible interval [CrI] 17 248-134 941) during calendar years 2020-30, largely due to measles. For years of vaccination 2020-30 for all 14 pathogens, disruption could lead to a 2·66% (95% CrI 2·52-2·81) reduction in long-term effect from 37 378 194 deaths averted (34 450 249-40 241 202) to 36 410 559 deaths averted (33 515 397-39 241 799). We estimated that catch-up activities could avert 78·9% (40·4-151·4) of excess deaths between calendar years 2023 and 2030 (ie, 18 900 [7037-60 223] of 25 356 [9859-75 073]). INTERPRETATION: Our results highlight the importance of the timing of catch-up activities, considering estimated burden to improve vaccine coverage in affected cohorts. We estimated that mitigation measures for measles and yellow fever were particularly effective at reducing excess burden in the short term. Additionally, the high long-term effect of HPV vaccine as an important cervical-cancer prevention tool warrants continued immunisation efforts after disruption. FUNDING: The Vaccine Impact Modelling Consortium, funded by Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation. TRANSLATIONS: For the Arabic, Chinese, French, Portguese and Spanish translations of the abstract see Supplementary Materials section.


Asunto(s)
COVID-19 , Hepatitis B , Sarampión , Meningitis , Infecciones por Papillomavirus , Vacunas contra Papillomavirus , Rubéola (Sarampión Alemán) , Enfermedades Prevenibles por Vacunación , Fiebre Amarilla , Humanos , Infecciones por Papillomavirus/prevención & control , Pandemias , COVID-19/epidemiología , COVID-19/prevención & control , Vacunación , Inmunización , Hepatitis B/tratamiento farmacológico
14.
Vaccine ; 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38514353

RESUMEN

Studies on yellow fever vaccine (YF) in chronic kidney disease (CKD) patients are scarce. This cross-sectional study aimed to evaluate YF neutralizing antibody seroprevalence and titers in previously vaccinated adults with CKD, on dialysis (D-CKD) or not (ND-CKD), compared to healthy persons. The micro Plaque Reduction Neutralization-Horseradish Peroxidase (µPRN-HP) test was used. Antibody titers were expressed as the reciprocal of the highest dilution that neutralized the challenge virus by 50 % (µPRN50). Seropositivity cut-off was set at ≥ 1:100. We included 153 participants: 46 ND-CKD, 50 D-CKD and 57 healthy adults. Median ages were 58.3, 55 and 52.2 years, respectively. Median time since YF vaccination was 22.3, 18.5 and 48.3 months respectively. There were no statistically significant differences in YF seroprevalence and neutralizing antibodies titers among groups: 100 % of ND-CKD; 96 % of D-CKD and 100 % of healthy participants were seropositive. Geometric mean titers (GMT) were 818.5, 683.0 and 665.5, respectively (p = 0.289).

15.
Environ Microbiol ; 26(3): e16588, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38450576

RESUMEN

Dengue represents an increasing public health burden worldwide. In Africa, underreporting and misdiagnosis often mask its true epidemiology, and dengue is likely to be both more widespread than reported data suggest and increasing in incidence and distribution. Wolbachia-based dengue control is underway in Asia and the Americas but has not to date been deployed in Africa. Due to the genetic heterogeneity of African Aedes aegypti populations and the complexity of the host-symbiont interactions, characterization of key parameters of Wolbachia-carrying mosquitoes is paramount for determining the potential of the system as a control tool for dengue in Africa. The wAlbB Wolbachia strain was stably introduced into an African Ae. aegypti population by introgression, and showed high intracellular density in whole bodies and different mosquito tissues; high intracellular density was also maintained following larval rearing at high temperatures. No effect on the adult lifespan induced by Wolbachia presence was detected. Moreover, the ability of this strain to strongly inhibit DENV-2 dissemination and transmission in the host was also demonstrated in the African background. Our findings suggest the potential of harnessing Wolbachia for dengue control for African populations of Ae. aegypti.


Asunto(s)
Aedes , Dengue , Wolbachia , Animales , Burkina Faso/epidemiología , Wolbachia/genética , Asia , Dengue/prevención & control
16.
Int J Infect Dis ; : 107017, 2024 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-38521450

RESUMEN

Yellow fever (YF) is a potentially lethal viral hemorrhagic fever that can be prevented with the 17D live attenuated YF vaccine. However, this vaccination can cause severe adverse reactions including vaccine-associated YF. Here, we describe the case of a 32-year-old female who was permanently immunosuppressed with an anti-CD20 antibody due to multiple sclerosis. Following YF vaccination, the patient developed, a variety of symptoms such as febrile temperatures, muscle and joint pain, headaches, and dysuria. A vaccine-associated yellow fever with viremia was diagnosed. To avoid a potentially severe course of the disease, sofosbuvir was used as antiviral treatment followed by the resolution of symptoms and serological response. As travelers with chronic diseases and immunosuppression will increasingly engage in long distance travel, this case demonstrates the importance of assessing patient history prior to life vaccinations and points towards a possible therapeutic approach in those suffering from vaccine associated yellow fever.

17.
Multimedia | Recursos Multimedia, MULTIMEDIA-SMS-SP | ID: multimedia-12925

RESUMEN

Live para falar sobre ações de combate ao mosquito Aedes aegypti, transmissor da dengue. A transmissão contou com a presença de Melissa Palmieri, médica e assessora técnica da Vigilância Epidemiológica da Coordenaria de Vigilância em Saúde (Covisa).


Asunto(s)
Dengue/prevención & control , Aedes , Prevención Primaria
18.
Multimedia | Recursos Multimedia | ID: multimedia-12921

RESUMEN

O vídeo ressalta a importância dos cuidados, da mobilização e engajamento da população e do poder público para o combate ao Aedes aegypti, mosquito transmissor da dengue, Chikungunya e Zika.


Asunto(s)
Dengue/prevención & control , Infecciones por Arbovirus , Aedes
19.
PLoS One ; 19(2): e0293124, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38324615

RESUMEN

The development of insecticide resistance in mosquitoes of public health importance has encouraged extensive research into innovative vector control methods. Terpenes are the largest among Plants Secondary Metabolites and have been increasingly studied for their potential as insecticidal control agents. Although promising, terpenes are insoluble in water, and they show low residual life which limits their application for vector control. In this study, we developed and evaluated the performances of terpenoid-based nanoemulsions (TNEs) containing myrcene and p-cymene against the dengue vector Aedes aegypti and investigated their potential toxicity against non-target organisms. Our results showed that myrcene and p-cymene showed moderate larvicidal activity against mosquito larvae compared to temephos an organophosphate widely used for mosquito control. However, we showed similar efficacy of TNEs against both susceptible and highly insecticide-resistant mosquitoes from French Guyana, hence suggesting an absence of cross-resistance with conventional insecticides. We also showed that TNEs remained effective for up to 45 days in laboratory conditions. The exposure of zebrafish to TNEs triggered behavioral changes in the fish at high doses but they did not alter the normal functioning of zebrafish organs, suggesting a good tolerability of non-target organisms to these molecules. Overall, this study provides new insights into the insecticidal properties and toxicity of terpenes and terpenoid-based formulations and confirms that TNE may offer interesting prospects for mosquito control as part of integrated vector management.


Asunto(s)
Monoterpenos Acíclicos , Aedes , Alquenos , Cimenos , Dengue , Insecticidas , Animales , Terpenos/farmacología , Pez Cebra , Mosquitos Vectores , Insecticidas/farmacología , Dengue/prevención & control , Larva
20.
Lancet Infect Dis ; 2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38335976

RESUMEN

BACKGROUND: In 2016, outbreaks of yellow fever in Angola and the Democratic Republic of the Congo led to a global vaccine shortage. A fractional dose of 17DD yellow fever vaccine (containing one-fifth [0·1 ml] of the standard dose) was used during a pre-emptive mass campaign in August, 2016, in Kinshasa, Democratic Republic of the Congo among children aged 2 years and older and non-pregnant adults (ie, those aged 18 years and older). 1 year following vaccination, 97% of participants were seropositive; however, the long-term durability of the immune response is unknown. We aimed to conduct a prospective cohort study and invited participants enrolled in the previous evaluation to return 5 years after vaccination to assess durability of the immune response. METHODS: Participants returned to one of six health facilities in Kinshasa in 2021, where study staff collected a brief medical history and blood specimen. We assessed neutralising antibody titres against yellow fever virus using a plaque reduction neutralisation test with a 50% cutoff (PRNT50). Participants with a PRNT50 titre of 10 or higher were considered seropositive. The primary outcome was the proportion of participants seropositive at 5 years. FINDINGS: Among the 764 participants enrolled, 566 (74%) completed the 5-year visit. 5 years after vaccination, 539 (95·2%, 95% CI 93·2-96·7) participants were seropositive, including 361 (94·3%, 91·5-96·2) of 383 who were seronegative and 178 (97·3%, 93·8-98·8) of 183 who were seropositive at baseline. Geometric mean titres (GMTs) differed significantly across age groups for those who were initially seronegative with the lowest GMT among those aged 2-5 years and highest among those aged 13 years and older. INTERPRETATION: A fractional dose of the 17DD yellow fever vaccine induced an immunologic response with detectable titres at 5 years among the majority of participants in the Democratic Republic of the Congo. These findings support the use of fractional-dose vaccination for outbreak prevention with the potential for sustained immunity. FUNDING: Gavi, the Vaccine Alliance through the CDC Foundation. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...