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1.
Microb Ecol ; 2020 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-32462391

RESUMEN

Tripartite interactions among insect vectors, midgut bacteria, and viruses may determine the ability of insects to transmit pathogenic arboviruses. Here, we investigated the impact of gut bacteria on the susceptibility of Culicoides nubeculosus and Culicoides sonorensis biting midges for Schmallenberg virus, and of Aedes aegypti mosquitoes for Zika and chikungunya viruses. Gut bacteria were manipulated by treating the adult insects with antibiotics. The gut bacterial communities were investigated using Illumina MiSeq sequencing of 16S rRNA, and susceptibility to arbovirus infection was tested by feeding insects with an infectious blood meal. Antibiotic treatment led to changes in gut bacteria for all insects. Interestingly, the gut bacterial composition of untreated Ae. aegypti and C. nubeculosus showed Asaia as the dominant genus, which was drastically reduced after antibiotic treatment. Furthermore, antibiotic treatment resulted in relatively more Delftia bacteria in both biting midge species, but not in mosquitoes. Antibiotic treatment and subsequent changes in gut bacterial communities were associated with a significant, 1.8-fold increased infection rate of C. nubeculosus with Schmallenberg virus, but not for C. sonorensis. We did not find any changes in infection rates for Ae. aegypti mosquitoes with Zika or chikungunya virus. We conclude that resident gut bacteria may dampen arbovirus transmission in biting midges, but not so in mosquitoes. Use of antimicrobial compounds at livestock farms might therefore have an unexpected contradictory effect on the health of animals, by increasing the transmission of viral pathogens by biting midges.

2.
Math Biosci ; 325: 108366, 2020 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-32387647

RESUMEN

Despite centuries of enormous control efforts, mosquito-borne diseases continue to show upward trend of morbidity. According to WHO reports, malaria caused 438000 deaths in the year 2015 and dengue cases have been increased 30-fold over the last five decades. To control these diseases, it is necessary to understand the transmission dynamics of them among mosquitoes. There are some vertically transmitted mosquito-borne diseases which can also be spread among mosquitoes through sexual contact (e.g., dengue, zika, chikungunya). Recent experimental observations indicate that for virus persistence in mosquito population, the role of venereal transmission cannot be ignored. It is therefore important to investigate which transmission route is more responsible for the persistence of the virus when there is no host. To this aim, we propose and analyze a novel compartmental model considering mosquito population only. To the best of authors knowledge, this is the first attempt to take into account both vertical and sexual transmission of the virus in a mathematical model. Expression representing the basic reproduction number is derived using Jacobian approach. Local stability conditions for disease-free equilibrium and complete infection equilibrium are obtained. Global sensitivity analysis of the system is performed with respect to an epidemiologically important response. While investigating the impact of sexual transmission in presence of vertical transmission, we observed that sexual transmission route has the potential to drive the equilibrium from disease free to endemic states. Further numerical experiments reveal that the virus will have higher half life in fertilized infected female mosquitoes for vertical transmission only than for venereal transmission alone. Furthermore, when both transmission pathways are active, a variety of parameters indicate threshold like behavior of the infection.

3.
Am J Trop Med Hyg ; 2020 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-32431284

RESUMEN

Chikungunya virus (CHIKV) and Zika virus (ZIKV) are arthropod-borne viruses transmitted mainly by Aedes aegypti mosquitoes. These viruses have become endemic in large parts of North, Central, and South America. Arboviruses persistently infect mosquitoes throughout their life span and become infectious (i.e., expectorate infectious virus in saliva) after a period of time called the extrinsic incubation period (EIP). The duration of this infectiousness, however, is not well characterized. This is an important shortcoming because many epidemiological models assume that mosquitoes continue to be infectious for the duration of their life span. To define the duration of infectiousness for CHIKV and ZIKV, mosquitoes were infected orally with these viruses. Every 2 days, legs/wings, midguts, salivary glands, and saliva were collected from 30 to 60 mosquitoes and viral load measured. In CHIKV-infected mosquitoes, infectious virus in saliva peaked early (2-4 dpi), and then decreased rapidly and was rarely observed after 10 dpi. Viral RNA in infected tissues also decreased after the initial peak (4-8 dpi) but did so much less drastically. In ZIKV-infected mosquitoes, the infectious virus in saliva peaked at 12-14 dpi and dropped off only slightly after 14 dpi. In infected tissues, viral RNA increased early during infection, and then plateaued after 6-10 days. Our findings suggest that significant variation exists in the duration of the infectious period for arboviruses that is in part influenced by virus clearance from expectorated saliva.

4.
Glob Public Health ; : 1-13, 2020 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-32436470

RESUMEN

During global health crises, different narratives regarding infectious disease epidemics circulate in traditional media (e.g. news agencies, television channels) and social media. Our study investigated the narratives related to sexual transmission of Zika virus that circulated on Twitter during a public health emergency and analyzed the relationship between information on Twitter and on traditional media. We examined 10,748 tweets posted during the peaks of Twitter activity between January and March 2016. Posts in English, Spanish, French, and Portuguese and websites linked to tweets were manually reviewed and analyzed thematically. During the study period, there were three peaks of Twitter activity related to the sexual transmission of Zika. Most tweets in the first peak (n = 412) had humorous/sarcastic content (55%). Most tweets in the second and third peaks (n = 5,154 and n = 5,182, respectively) disseminated information (>93%). Across languages, textual and visual content on the websites were predominantly placed online by traditional media and highlighted epidemiological narratives published by public health agencies, with little or no mention of the concerns or experiences of individuals most affected by Zika. Prioritising epidemiological/clinical aspects of epidemics may have a depoliticising effect and contribute to overlooking socio-economic determinants of the Zika epidemic and issues related to reproductive justice.

5.
Nat Commun ; 11(1): 2205, 2020 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-32371874

RESUMEN

Flaviviruses, including Zika virus (ZIKV), utilise host mRNA degradation machinery to produce subgenomic flaviviral RNA (sfRNA). In mammalian hosts, this noncoding RNA facilitates replication and pathogenesis of flaviviruses by inhibiting IFN-signalling, whereas the function of sfRNA in mosquitoes remains largely elusive. Herein, we conduct a series of in vitro and in vivo experiments to define the role of ZIKV sfRNA in infected Aedes aegypti employing viruses deficient in production of sfRNA. We show that sfRNA-deficient viruses have reduced ability to disseminate and reach saliva, thus implicating the role for sfRNA in productive infection and transmission. We also demonstrate that production of sfRNA alters the expression of mosquito genes related to cell death pathways, and prevents apoptosis in mosquito tissues. Inhibition of apoptosis restored replication and transmission of sfRNA-deficient mutants. Hence, we propose anti-apoptotic activity of sfRNA as the mechanism defining its role in ZIKV transmission.

6.
Artículo en Inglés | MEDLINE | ID: mdl-32344170

RESUMEN

OBJECTIVES: Infectious Zika viral particles were detected in human milk; however, whether they can be transmitted via breastfeeding remains unknown, so our objective was to clarify this. METHODS: Here, in a natural breastfeeding model, wild-type (C57Bl/6; WT) or interferon α/ß (IFNα/ß) receptor-deficient (A129; KO) murine dams on day 1 post-delivery were infected with Zika virus (ZIKV) intraperitoneally, and the neonates were suckled. In a novel artificial feeding model, WT suckling mice at 1 day old were fed with ZIKV alone or ZIKV and human breast milk mixtures. Thereafter, the virus distribution, clinical progression and neuropathology in the WT or KO neonates were characterized to evaluate the risk of ZIKV transmission through breast milk. RESULTS: In natural breastfeeding, viral RNAs (8/8) and infectious viral particles (7/8) were extensively present in the mammary glands of KO dams. All tested KO neonates (5/5), and none of WT neonates (0/9), were infected with ZIKV. In artificial feeding, 100% of the WT neonates (two groups, 12/12 and 16/16) were infected and developed some signs of neurodegeneration. ZIKV tended to seed and accumulate in the lungs and were subsequently disseminated to other tissues in both 16 naturally suckled and 19 artificially fed infected neonates. As human breast milk was mixed with ZIKV and fed to WT neonates, 45% individuals (9/20) were infected; in the infected neonates, the viral spread to the brain was delayed, and the clinical outcomes were alleviated. CONCLUSIONS: These results demonstrated that suckling mice can be infected with ZIKV through suckling, and breast milk has potential antiviral activity, inhibiting ZIKV infection.

7.
Viruses ; 12(4)2020 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-32316394

RESUMEN

Mosquito-borne viruses are emerging or re-emerging globally, afflicting millions of people around the world. Aedes aegypti, the yellow fever mosquito, is the principal vector of dengue, Zika, and chikungunya viruses, and has well-established populations across tropical and subtropical urban areas of the Americas, including the southern United States. While intense arboviral epidemics have occurred in Mexico and further south in the Americas, local transmission in the United States has been minimal. Here, we study Ae. aegypti and Culex quinquefasciatus host feeding patterns and vertebrate host communities in residential environments of South Texas to identify host-utilization relative to availability. Only 31% of Ae. aegypti blood meals were derived from humans, while 50% were from dogs and 19% from other wild and domestic animals. In Cx. quinquefasciatus, 67% of blood meals were derived from chicken, 22% came from dogs, 9% from various wild avian species, and 2% from other mammals including one human, one cat, and one pig. We developed a model for the reproductive number, R0, for Zika virus (ZIKV) in South Texas relative to northern Mexico using human disease data from Tamaulipas, Mexico. We show that ZIKV R0 in South Texas communities could be greater than one if the risk of human exposure to Ae. aegypti bites in these communities is at least 60% that of Northern Mexico communities. The high utilization of non-human vertebrates and low risk of human exposure in South Texas diminishes the outbreak potential for human-amplified urban arboviruses transmitted by Ae. aegypti.

8.
Emerg Infect Dis ; 26(5): 881-890, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32310079

RESUMEN

In 2016, four clusters of local mosquitoborne Zika virus transmission were identified in Miami-Dade County, Florida, USA, generating "red zones" (areas into which pregnant women were advised against traveling). The Miami-Dade County Mosquito Control Division initiated intensive control activities, including property inspections, community education, and handheld sprayer applications of larvicides and adulticides. For the first time, the Mosquito Control Division used a combination of areawide ultralow-volume adulticide and low-volume larvicide spraying to effectively control Aedes aegypti mosquitoes, the primary Zika virus vector within the county. The number of mosquitoes rapidly decreased, and Zika virus transmission was interrupted within the red zones immediately after the combination of adulticide and larvicide spraying.

9.
PLoS Negl Trop Dis ; 14(4): e0008217, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32282830

RESUMEN

BACKGROUND: The Asian bush mosquito Aedes japonicus is invading Europe and was first discovered in Lelystad, the Netherlands in 2013, where it has established a permanent population. In this study, we investigated the vector competence of Ae. japonicus from the Netherlands for the emerging Zika virus (ZIKV) and zoonotic Usutu virus (USUV). ZIKV causes severe congenital microcephaly and Guillain-Barré syndrome in humans. USUV is closely related to West Nile virus, has recently spread throughout Europe and is causing mass mortality of birds. USUV infection in humans can result in clinical manifestations ranging from mild disease to severe neurological impairments. METHODOLOGY/PRINCIPAL FINDINGS: In our study, field-collected Ae. japonicus females received an infectious blood meal with ZIKV or USUV by droplet feeding. After 14 days at 28°C, 3% of the ZIKV-blood fed mosquitoes and 13% of the USUV-blood fed mosquitoes showed virus-positive saliva, indicating that Ae. japonicus can transmit both viruses. To investigate the effect of the mosquito midgut barrier on virus transmission, female mosquitoes were intrathoracically injected with ZIKV or USUV. Of the injected mosquitoes, 96% (ZIKV) and 88% (USUV) showed virus-positive saliva after 14 days at 28°C. This indicates that ZIKV and USUV can efficiently replicate in Ae. japonicus but that a strong midgut barrier is normally restricting virus dissemination. Small RNA deep sequencing of orally infected mosquitoes confirmed active replication of ZIKV and USUV, as demonstrated by potent small interfering RNA responses against both viruses. Additionally, de novo small RNA assembly revealed the presence of a novel narnavirus in Ae. japonicus. CONCLUSIONS/SIGNIFICANCE: Given that Ae. japonicus can experimentally transmit arthropod-borne viruses (arboviruses) like ZIKV and USUV and is currently expanding its territories, we should consider this mosquito as a potential vector for arboviral diseases in Europe.

10.
JAMA ; 323(10): 917, 2020 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-32154863
11.
PLoS Negl Trop Dis ; 14(3): e0007926, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32155143

RESUMEN

The global incidence of arboviral diseases transmitted by Aedes mosquitoes, including dengue, chikungunya, yellow fever, and Zika, has increased dramatically in recent decades. The release of Aedes aegypti carrying the maternally inherited symbiont Wolbachia as an intervention to control arboviruses is being trialled in several countries. However, these efforts are compromised in many endemic regions due to the co-localization of the secondary vector Aedes albopictus, the Asian tiger mosquito. Ae. albopictus has an expanding global distribution following incursions into a number of new territories. To date, only the wMel and wPip strains of Wolbachia have been reported to be transferred into and characterized in this vector. A Wolbachia strain naturally infecting Drosophila simulans, wAu, was selected for transfer into a Malaysian Ae. albopictus line to create a novel triple-strain infection. The newly generated line showed self-compatibility, moderate fitness cost and complete resistance to Zika and dengue infections.


Asunto(s)
Aedes/microbiología , Aedes/virología , Antibiosis , Arbovirus/crecimiento & desarrollo , Wolbachia/crecimiento & desarrollo , Animales , Infecciones por Arbovirus/prevención & control , Transmisión de Enfermedad Infecciosa/prevención & control , Drosophila/microbiología , Femenino , Masculino , Mosquitos Vectores/microbiología , Mosquitos Vectores/virología , Wolbachia/aislamiento & purificación
12.
Viruses ; 12(3)2020 Mar 09.
Artículo en Inglés | MEDLINE | ID: mdl-32182748

RESUMEN

Three autochthonous cases of Zika virus occurred in southern France in August 2019. Diagnosis relied on serology and transcription-mediated amplification. Attempts for virus isolation and ZIKV genome RT-PCR detection remained negative. Since the index case was not identified, we addressed the issue of genotyping and geographical origin by performing hemi-nested PCR and sequencing in the Pr gene. Analysis of 16 genotype-specific Single Nucleotides Polymorphisms identified the Asian genotype and suggested a Southeast Asia origin.

13.
Artículo en Inglés | PAHO-IRIS | ID: phr-51830

RESUMEN

[ABSTRACT]. Objective. To identify studies on the competence of Culex mosquitoes as vectors for the transmission of Zika virus (ZIKV) around the globe. Methods. We performed an integrative review to identify relevant articles on specific experiments to determine whether Culex mosquitoes are vectors for ZIKV. The sources we used for our research were the Brazilian Periódicos CAPES electronic portal (MEDLINE/PubMed, ScienceDirect Journals, Nature Publishing Group, SciELO, Springer Link, and 250 other databases) and gray literature. Results. We identified 344 studies, of which 36 were considered for this review. In 8 studies, infection in salivary glands of Culex quinquefasciatus, Culex restuans, Culex tarsalis, and Culex coronator was detected. Cx. quinquefasciatus was the most studied among those confirmed as potential ZIKV vectors, and only strains of Asian lineages (THA/2014/SV0127-14; SZ01 (2016)) and American lineages (BRPE243 (2015); PRVABC59 (2015)) can infect the salivary glands of Culex mosquitoes. The tested African strains (MR766 and DAK AR 41525) were unable to infect salivary glands. Conclusions. There is still a lack of compelling evidence that indicates Culex spp. are a competent ZIKV vector, but they should remain a target for further monitoring studies, especially regarding ZIKV transmission to other species. Furthermore, studies should not be limited to studying whether their salivary glands are infected.


[RESUMEN]. Objetivo. Identificar estudios sobre la competencia de los mosquitos Culex como vectores de la transmisión del virus del Zika en todo el mundo. Métodos. Se realizó una revisión integradora para identificar artículos relevantes sobre experimentos específicos dirigidos a determinar si los mosquitos Culex son vectores del virus del Zika. Se emplearon fuentes obtenidas a partir del portal electrónico de revistas CAPES (MEDLINE/PubMed, ScienceDirect Journals, Nature Publishing Group, SciELO, Springer Link, y otras 250 bases de datos) y la literatura gris. Resultados. Se identificaron 344 estudios, 36 de los cuales fueron considerados para esta revisión. En 8 estudios se detectó infección en las glándulas salivales de Culex quinquefasciatus, Culex restuans, Culex tarsalis y Culex coronator. Cx. quinquefasciatus fue la especie más estudiada entre las confirmadas como potenciales vectores del virus del Zika, y solo las cepas de linajes asiáticos (THA/2014/SV0127-14; SZ01 [2016]) y americanos (BRPE243 [2015]; PRVABC59 [2015]) pueden infectar las glándulas salivales de los mosquitos Culex. Las cepas africanas analizadas (MR766 y DAK AR 41525) no fueron capaces de infectar las glándulas salivales. Conclusiones. Aunque faltan pruebas convincentes que indiquen que las especies de Culex spp. son un vector competente del virus del Zika, estas deben seguir monitoreándose mediante estudios adicionales, especialmente respecto de su capacidad para transmitir el virus del Zika a otras especies. Esta vigilancia no debería limitarse solamente a determinar la infección en las glándulas salivales.


[RESUMO]. Objetivo. Identificar estudos sobre a competência dos mosquitos Culex como vetores da transmissão do vírus Zika em todo o mundo. Métodos. Uma revisão integrativa foi realizada para identificar artigos relevantes sobre experimentos específicos para determinar se os mosquitos Culex são vetores do vírus Zika. As fontes utilizadas na pesquisa foram o portal eletrônico CAPES (MEDLINE/PubMed, ScienceDirect Journals, Nature Publishing Group, Sci-ELO, Springer Link, e outras 250 bases de dados) e a literatura cinza. Resultados. Foram identificados 344 artigos, dos quais 36 foram considerados para esta revisão. Oito artigos relataram infecção nas glândulas salivares de Culex quinquefasciatus, Culex restuans, Culex tarsalis e Culex coronator. Culex quinquefasciatus foi a espécie mais estudada entre as confirmadas como vetores potenciais do vírus Zika. Apenas as linhagens asiáticas (THA / 2014 / SV0127-14; SZ01 [2016]) e americanas (BRPE243 [2015]; PRVABC59 [2015]) podem infectar as glândulas salivares dos mosquitos Culex. As cepas africanas analisadas (MR766 e DAK AR 41525) não foram capazes de infectar as glândulas salivares. Conclusões. Ainda não há evidências convincentes para indicar que os mosquitos Culex são um vetor competente do vírus Zika. Contudo, estudos adicionais de monitoramento devem ser realizados, especialmente no que diz respeito à transmissão do vírus Zika para outras espécies de mosquitos. Além disso, os estudos não devem se limitar a estudar a infecção nas glândulas salivares.


Asunto(s)
Salud Pública , Virus Zika , Mosquitos Vectores , Culex , Salud Pública , Virus Zika , Mosquitos Vectores , Salud Pública , Mosquitos Vectores
14.
Virology ; 543: 34-42, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32056845

RESUMEN

Zika Virus (ZIKV) is a Flavivirus transmitted primarily via the bite of infected Aedes aegypti mosquitoes. Globally, 87 countries and territories have recorded autochthonous mosquito-borne transmission of ZIKV as at July 2019 and distributed across four of the six WHO Regions. Outbreaks of ZIKV infection peaked in 2016 and declined substantially throughout 2017 and 2018 in the Americas region. There is the likely risk for ZIKV to spread to more countries. There is also the potential for the re-emergence of ZIKV in all places with prior reports of the virus transmission. The current status of ZIKV transmission and spread is, however, a global health threat, and from the aforementioned, has the potential to re-emerge as an epidemic. This review summarizes the past and present spread of ZIKV outbreak-2007-2019, the genome, transmission cycle, clinical manifestations, vaccine and antiviral drug advancement.

15.
Vector Borne Zoonotic Dis ; 20(5): 374-379, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31934825

RESUMEN

Zika virus (ZIKV) is an emerging mosquito-borne pathogen belonging to the genus Flavivirus of the family Flaviviridae. Aedes albopictus is widely distributed in China. However, little is known about the vector competence of Ae. albopictus in China. The present study presents the oral susceptibility and vector competence of Ae. albopictus Guangzhou strain to ZIKV. Additionally, vertical transmission of ZIKV is described. The results demonstrated the susceptibility of local Ae. albopictus mosquitoes to ZIKV with an extrinsic incubation period of 6 days. Disseminated infection was observed in Ae. albopictus starting on day 2 postinfection (PI). Starting on day 6 PI, the saliva of Ae. albopictus exhibited ZIKV infection, and the transmission rate was 36.4%. Vertical transmission was observed during the first gonotrophic cycle. The minimum infection rate was observed in third-to-fourth instar larvae.

16.
Cells ; 9(1)2020 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-31947958

RESUMEN

To date, no safe vaccine or antivirals for Zika virus (ZIKV) infection have been found. The pathogenesis of severe Zika, where host and viral factors participate, remains unclear. For the control of Zika, it is important to understand how ZIKV interacts with different host cells. Knowledge of the targeted cellular pathways which allow ZIKV to productively replicate and/or establish prolonged viral persistence contributes to novel vaccines and therapies. Monocytes and endothelial vascular cells are the main ZIKV targets. During the infection process, cells are capable of releasing extracellular vesicles (EVs). EVs are mediators of intercellular communication. We found that mosquito EVs released from ZIKV-infected (C6/36) cells carry viral RNA and ZIKV-E protein and are able to infect and activate naïve mosquito and mammalian cells. ZIKV C6/36 EVs promote the differentiation of naïve monocytes and induce a pro-inflammatory state with tumor necrosis factor-alpha (TNF-α) mRNA expression. ZIKV C6/36 EVs participate in endothelial vascular cell damage by inducing coagulation (TF) and inflammation (PAR-1) receptors at the endothelial surface of the cell membranes and promote a pro-inflammatory state with increased endothelial permeability. These data suggest that ZIKV C6/36 EVs may contribute to the pathogenesis of ZIKV infection in human hosts.

17.
Nat Commun ; 11(1): 260, 2020 01 14.
Artículo en Inglés | MEDLINE | ID: mdl-31937766

RESUMEN

Transmission from an infected mosquito to a host is an essential process in the life cycle of mosquito-borne flaviviruses. Numerous studies have demonstrated that mosquito saliva facilitates viral transmission. Here we find that a saliva-specific protein, named Aedes aegypti venom allergen-1 (AaVA-1), promotes dengue and Zika virus transmission by activating autophagy in host immune cells of the monocyte lineage. The AG6 mice (ifnar1-/-ifngr1-/-) bitten by the virus-infected AaVA-1-deficient mosquitoes present a lower viremia and prolonged survival. AaVA-1 intracellularly interacts with a dominant negative binder of Beclin-1, known as leucine-rich pentatricopeptide repeat-containing protein (LRPPRC), and releases Beclin-1 from LRPPRC-mediated sequestration, thereby enabling the initialization of downstream autophagic signaling. A deficiency in Beclin-1 reduces viral infection in mice and abolishes AaVA-1-mediated enhancement of ZIKV transmission by mosquitoes. Our study provides a mechanistic insight into saliva-aided viral transmission and could offer a potential prophylactic target for reducing flavivirus transmission.


Asunto(s)
Aedes/metabolismo , Autofagia , Infecciones por Flavivirus/transmisión , Flavivirus/fisiología , Proteínas de Insectos/metabolismo , Mosquitos Vectores/metabolismo , Proteínas y Péptidos Salivales/metabolismo , Aedes/virología , Animales , Beclina-1/deficiencia , Beclina-1/metabolismo , Virus del Dengue/fisiología , Infecciones por Flavivirus/virología , Humanos , Proteínas de Insectos/deficiencia , Proteínas de Insectos/genética , Ratones , Mosquitos Vectores/virología , Proteínas de Neoplasias/metabolismo , Unión Proteica , Proteínas y Péptidos Salivales/deficiencia , Proteínas y Péptidos Salivales/genética , Células THP-1 , Replicación Viral , Virus Zika/fisiología
18.
Med Vet Entomol ; 34(1): 116-119, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31120156

RESUMEN

Transinfections of the maternally transmitted endosymbiont Wolbachia pipientis can reduce RNA virus replication and prevent transmission by Aedes aegypti, and also have the capacity to invade wild-type populations, potentially reaching and maintaining high infection frequencies. Levels of virus transmission blocking are positively correlated with Wolbachia intracellular density. Despite reaching high densities in Ae. aegypti, transinfections of wAlbA, a strain native to Aedes albopictus, showed no blocking of Semliki Forest Virus in previous intrathoracic injection challenges. To further characterize wAlbA blocking in Ae. aegypti, adult females were intrathoracically challenged with Zika (ZIKV) and dengue viruses, and then fed a ZIKV-containing bloodmeal. No blocking was observed with either virus when challenged by intrathoracic injection. However, when ZIKV was delivered orally, wAlbA-infected females showed a significant reduction in viral replication and dissemination compared with uninfected controls, as well as a complete absence of virus in saliva. Although other Wolbachia strains have been shown to cause more robust viral blocking in Ae. aegypti, these findings demonstrate that, in principle, wAlbA could be used to reduce virus transmission in this species. Moreover, the results highlight the potential for underestimation of the strength of virus-blocking when based on intrathoracic injection compared with more natural oral challenges.

19.
Int J Gynecol Pathol ; 39(2): 157-162, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30789499

RESUMEN

Zika virus (ZIKV) is highly neurotropic after crossing the placenta, inducing teratogenic effects that result in delayed development and microcephaly in infants. The available evidence for vertical transmission of this infection is based on placental studies showing alterations in trophoblastic tissue. However, complete characterization of ZIKV-infected placenta and involved pathways has yet to be fully clarified. This case report of placental ZIKV infection describes morphologic and molecular changes in the placenta. Hyperplasia of placental Hofbauer cells in chorionic villi and numerous histiocyte-like cells in the decidua were observed. The decidua, fibroblasts, and chorion, as well as circulating cells in the intravascular compartment stained positive for ZIKV envelop protein. Deciduitis was present on the maternal surface of the placenta, with a prevalence of lymphocytes associated with vasculitis. A high level of uncommitted CD3 T lymphocytes were present, in addition to CD4 and CD8 cells. Elevated expression of the apoptosis inhibitor, Bcl-2, was observed in syncytiotrophoblasts. These parameters may promote the persistence of ZIKV in placental tissue and transmission to the fetus.

20.
Int J Infect Dis ; 91: 38-43, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31704226

RESUMEN

OBJECTIVE: To evaluate the diagnostic performance of the Inbios (Seattle, US) and Euroimmun (Luebeck, Germany) chikungunya virus (CHIKV) IgM enzyme-linked immunoassays (ELISAs). METHODS: We evaluated the tests' accuracy on sera from 372 patients enrolled in an acute febrile illness surveillance study performed in Salvador, Brazil from Sept/2014 to Jul/2016, a period of simultaneous CHIKV, dengue (DENV), and Zika (ZIKV) virus transmission. We assessed the sensitivity on acute and paired convalescent sera from RT-PCR-confirmed CHIKV cases (collected at median one and 19 days post-onset of symptoms, respectively), and the specificity on sera of RT-PCR-confirmed DENV and ZIKV cases, and on negative patients. RESULTS: The Inbios and Euroimmun tests' sensitivities for acute samples were 4.0% and 10.3%, while for convalescent samples they were 92.4% and 96.9%, respectively. Overall, Inbios IgM ELISA specificities for acute and convalescent samples were 97.7% and 90.5%, respectively, and Euroimmun specificities were 88.5% and 83.9%, respectively. CONCLUSIONS: Both tests presented high sensitivity for convalescent samples. However, the Euroimmun test returned more equivocal results and presented a slightly lower specificity, which might result in a higher rate of false positives if the test is used in scenarios of low CHIKV transmission, when the chance of CHIKV infection is lower.

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