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1.
J Gen Virol ; 98(11): 2876-2881, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29048274

RESUMEN

During an entomological surveillance for arthropod-borne viruses in the Philippines, we isolated a previously unrecognized virus from female Armigeres spp. mosquitoes. Whole-genome sequencing, genetic characterization and phylogenetic analysis revealed that the isolated virus, designated Armigeres iflavirus (ArIFV), is a novel member of the iflaviruses (genus Iflavirus, family Iflaviridae) and phylogenetically related to Moku virus, Hubei odonate virus 4, slow bee paralysis virus and Graminella nigrifrons virus 1. To our knowledge, this is the first successful isolation of iflavirus from a dipteran insect. Spherical ArIFV particles of approximately 30 nm in diameter contained at least three major structural proteins. ArIFV multiplied to high titres (~109 p.f.u. ml-1) and formed clear plaques in a mosquito cell line, C6/36. Our findings provide new insights into the infection mechanism, genetic diversity and evolution of the Iflaviridae family.


Asunto(s)
Culicidae/virología , Virus de Insectos/clasificación , Virus de Insectos/aislamiento & purificación , Virus ARN/clasificación , Virus ARN/aislamiento & purificación , Animales , Línea Celular , Filipinas , Ensayo de Placa Viral , Proteínas Estructurales Virales/análisis , Virión/química , Virión/ultraestructura
2.
Arch Virol ; 160(12): 2965-77, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26350980

RESUMEN

Among the tick-borne orbiviruses (genus Orbivirus, family Reoviridae), 36 serotypes are currently classified within a single virus species, Great Island virus. In this study, we report the first characterization of a tick-borne orbivirus isolated from the tick Ixodes turdus in Japan, which we identified as a new member of the species Great Island virus. The virus isolate, designated Muko virus (MUV), replicated and induced cytopathic effects in BHK-21, Vero E6, and CCL-141 cells and caused high mortality in suckling mice after intracerebral inoculation. Full genome sequence analysis showed that MUV shared the greatest phylogenetic similarity with Tribec virus in terms of the amino acid sequences of all viral proteins except for outer capsid protein 1 (OC1; VP4 of MUV). Analysis of genome segment 9 in MUV detected an uninterrupted open reading frame that overlaps with VP6 (Hel), which putatively encodes a molecular and functional equivalent of NS4 from Great Island virus. Our study provides new insights into the geographic distribution, genetic diversity, and evolutionary history of the members of the species Great Island virus.


Asunto(s)
Vectores Arácnidos/virología , Ixodes/virología , Orbivirus/genética , Orbivirus/aislamiento & purificación , Infecciones por Reoviridae/virología , Animales , Línea Celular , Genoma Viral , Humanos , Japón , Ratones , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Orbivirus/clasificación , Filogenia , Proteínas Virales/genética
3.
J Med Entomol ; 52(2): 222-9, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26336307

RESUMEN

Superinfection exclusion is generally defined as a phenomenon in which a pre-existing viral infection prevents a secondary viral infection; this has also been observed in infections with mosquito-borne viruses. In this study, we examined the superinfection exclusion of the vertebrate-infecting flaviviruses, Japanese encephalitis virus (JEV) and dengue virus (DENV), by stable and persistent infection with an insect-specific flavivirus, Culex flavivirus (CxFV), in a Culex tritaeniorhynchus Giles cell line (CTR cells). Our experimental system was designed based on the premise that wild Cx. tritaeniorhynchus mosquitoes naturally infected with CxFV are superinfected with JEV by feeding on JEV-infected animals. As a result, we found no evidence of the superinfection exclusion of both JEV and DENV by pre-existing CxFV infection at the cellular level. However, JEV superinfection induced severe cytopathic effects on persistently CxFV-infected CTR cells. These observations imply the possibility that JEV superinfection in CxFV-infected Cx. tritaeniorhynchus mosquitoes has an adverse effect on their fitness.


Asunto(s)
Culex/fisiología , Infecciones por Flaviviridae/transmisión , Flavivirus , Sobreinfección , Animales , Línea Celular , Femenino
4.
Arch Virol ; 159(10): 2675-85, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24906523

RESUMEN

An orbivirus was isolated from a sample from the ornithophilic mosquito Culex sasai in Japan. The virus, designated Koyama Hill virus (KHV), replicated to high titer in a mosquito cell line and to a low titer in an avian cell line, but the release of progeny viruses was not observed in mammalian cell lines inoculated with KHV. Electron microscopic examination of KHV-infected mosquito cells showed approximately 70-nm virus particles and viral tubules typical of members of the genus Orbivirus, family Reoviridae. KHV efficiently replicated in Cx. sasai mosquitoes, suggesting a potential vector species for KHV transmission in nature. Full-length viral genome sequencing and phylogenetic analysis revealed that KHV is closely related to Umatilla virus (UMAV) and Stretch Lagoon orbivirus (SLOV). This suggests that KHV is a new member of the species Umatilla virus, an orbivirus species not previously observed in East Asia. The KHV genome segment encoding NS1 contains a notable sequence deletion and heterogeneity compared with a prototype UMAV, which may affect its growth properties and pathogenicity in host cells. These results provide new insights into the genetic diversity and geographic distribution of members of the species Umatilla virus.


Asunto(s)
Orbivirus , ARN Viral/genética , Proteínas no Estructurales Virales/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Culex/virología , Microscopía Electrónica , Datos de Secuencia Molecular , Orbivirus/clasificación , Orbivirus/genética , Orbivirus/aislamiento & purificación , Filogenia , Infecciones por Reoviridae , Análisis de Secuencia de ADN , Replicación Viral/fisiología
5.
J Med Entomol ; 61(3): 741-755, 2024 May 13.
Artículo en Inglés | MEDLINE | ID: mdl-38417093

RESUMEN

Arthropod-derived cell lines serve as crucial tools for studying arthropod-borne viruses (arboviruses). However, it has recently come to light that certain cell lines harbor persistent infections of arthropod-specific viruses, which do not cause any apparent cytopathic effects. Moreover, some of these persistent viral infections either inhibit or promote the growth of arboviruses. Therefore, it is of utmost importance to identify the presence of such persistent viruses and understand their impact on arboviral infections. In this study, we conducted a comprehensive virome analysis of several arthropod-derived cell lines, including mosquito-derived NIID-CTR, Ar-3, MSQ43, NIAS-AeAl-2, CCL-126 cells, and tick-derived IDE8 cells, along with flesh fly-derived NIH-Sape-4 cells. The aim was to determine if these cells were infected with persistent viruses. The results revealed the presence of 15 persistent viruses in NIID-CTR, Ar-3, MSQ43, NIAS-AeAl-2, and IDE8 cells. Among these, 11 were already known arthropod-specific viruses, while the remaining 4 were novel viruses belonging to Orthophasmavirus, Rhabdoviridae, Totiviridae, and Bunyavirales. In contrast, CCL-126 and NIH-Sape-4 cells appeared to be free of viral infections. This study provides valuable insights into the diversity and latency of arthropod-specific viruses within arthropod-derived cell lines. Further investigations are required to explore persistent viral infections in other arthropod-derived cell cultures and their effects on arbovirus replication. Understanding these factors will enhance the accuracy and reliability of experimental data obtained using these cell lines.


Asunto(s)
Viroma , Animales , Línea Celular , Arbovirus/fisiología , Artrópodos/virología , Garrapatas/virología , Culicidae/virología
6.
Arch Virol ; 158(11): 2273-84, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23728735

RESUMEN

In this study, we isolated and characterized an insect nidovirus from the mosquito Culex tritaeniorhynchus Giles (Diptera: Culicidae) in Vietnam, as an additional member of the new family Mesoniviridae in the order Nidovirales. The virus, designated "Dak Nong virus (DKNV)," shared many characteristics with Cavally virus and Nam Dinh virus, which have also been discovered recently in mosquitoes, and these viruses should be considered members of a single virus species, Alphamesonivirus 1. DKNV grew in cultured mosquito cells but could not replicate in the cultured vertebrate cells tested. N-terminal sequencing of the DKNV structural proteins revealed two posttranslational cleavage sites in the spike glycoprotein precursor. DKNV is assumed to be a new member of the species Alphamesonivirus 1, and the current study provides further understanding of viruses belonging to the new family Mesoniviridae.


Asunto(s)
Culex/virología , Virus de Insectos/clasificación , Virus de Insectos/aislamiento & purificación , Nidovirales/clasificación , Nidovirales/aislamiento & purificación , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Chlorocebus aethiops , Cricetinae , Femenino , Virus de Insectos/genética , Virus de Insectos/crecimiento & desarrollo , Datos de Secuencia Molecular , Nidovirales/genética , Nidovirales/crecimiento & desarrollo , Filogenia , Análisis de Secuencia de ADN , Células Vero , Vietnam , Proteínas Virales/química , Proteínas Virales/genética , Proteínas Virales/metabolismo
7.
J Med Entomol ; 60(2): 408-411, 2023 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-36708061

RESUMEN

Bartonella quintana is a gram-negative bacterium causing trench fever, an illness historically acquired by soldiers during World War I. More recently, outbreaks of trench fever have been reported in those experiencing homelessness in the United States, France, Russia, and Tokyo, as well as in children in Nepal and persons in Ethiopia. Reports of B. quintana infection outside of Tokyo are rare in Japan. The aim of this study was to examine body lice and blood obtained from people staying in shelters in Osaka (2009-2010) for B. quintana via polymerase chain reaction and enzyme-linked immunosorbent assays. Day laborers were defined as homeless individuals and shelter residents in this study. We detected genes of B. quintana in body lice by PCR and antibodies against B. quintana. The positive rate of B. quintana genes was 6/10 (60%) in body lice and the seroprevalence (IgG) of B. quintana was 4/10 (40%). This demonstrates that trench fever was endemic in people staying in shelters in Osaka in 2009-2010.


Asunto(s)
Bartonella quintana , Infestaciones por Piojos , Pediculus , Fiebre de las Trincheras , Animales , Bartonella quintana/genética , Fiebre de las Trincheras/epidemiología , Fiebre de las Trincheras/microbiología , Bartonellaceae , Japón/epidemiología , Estudios Seroepidemiológicos , Infestaciones por Piojos/epidemiología , Pediculus/genética , Pediculus/microbiología
8.
Trop Med Health ; 51(1): 61, 2023 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-37919794

RESUMEN

BACKGROUND: Dengue fever, caused by the dengue virus (DENV), is the most common viral infection transmitted by Aedes mosquitoes (mainly Ae. aegypti and Ae. albopictus) worldwide. Aedes aegypti is not currently established in Japan, and Ae. albopictus is the primary vector mosquito for DENV in the country, but knowledge of its viral susceptibility is limited. Therefore, we aimed to clarify the status of DENV susceptibility by comparing the infection and dissemination dynamics of Japanese Ae. albopictus to all known DENV serotypes with those of Ae. aegypti. METHODS: After propagation of each DENV serotype in Vero cells, the culture supernatants were mixed with defibrinated rabbit blood and adenosine triphosphate, and the mixture was artificially blood-sucked by two colonies of Ae. albopictus from Japan and one colony of Ae. aegypti from a dengue-endemic country (Vietnam). After 14 days of sucking, the mosquito body was divided into two parts (thorax/abdomen and head/wings/legs) and total RNA was extracted from each sample. DENV RNA was detected in these extracted RNA samples using a quantitative RT-PCR method specific for each DENV serotype, and infection and dissemination rates were analyzed. RESULTS: The Japanese Ae. albopictus colonies were susceptible to all DENV serotypes. Its infection and dissemination rates were significantly lower than those of Ae. aegypti. However, the number of DENV RNA copies in Ae. albopictus was almost not significantly different from that in Ae. aegypti. Furthermore, Japanese Ae. albopictus differed widely in their susceptibility to each DENV serotype. CONCLUSIONS: In Japanese Ae. albopictus, once DENV overcame the midgut infection barrier, the efficiency of subsequent propagation and dissemination of the virus in the mosquito body was comparable to that of Ae. aegypti. Based on the results of this study and previous dengue outbreak trends, Ae. albopictus is predicted to be highly compatible with DENV-1, suggesting that this serotype poses a high risk for future epidemics in Japan.

9.
Parasit Vectors ; 16(1): 99, 2023 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-36922882

RESUMEN

BACKGROUND: The Getah virus (GETV) is a mosquito-borne Alphavirus (family Togaviridae) that is of significant importance in veterinary medicine. It has been associated with major polyarthritis outbreaks in animals, but there are insufficient data on its clinical symptoms in humans. Serological evidence of GETV exposure and the risk of zoonotic transmission makes GETV a potentially medically relevant arbovirus. However, minimal emphasis has been placed on investigating GETV vector transmission, which limits current knowledge of the factors facilitating the spread and outbreaks of GETV. METHODS: To examine the range of the mosquito hosts of GETV, we selected medically important mosquitoes, assessed them in vitro and in vivo and determined their relative competence in virus transmission. The susceptibility and growth kinetics of GETVs in various mosquito-derived cell lines were also determined and quantified using plaque assays. Vector competency assays were also conducted, and quantitative reverse transcription-PCR and plaque assays were used to determine the susceptibility and transmission capacity of each mosquito species evaluated in this study. RESULTS: GETV infection in all of the investigated mosquito cell lines resulted in detectable cytopathic effects. GETV reproduced the fastest in Culex tritaeniorhynchus- and Aedes albopictus-derived cell lines, as evidenced by the highest exponential titers we observed. Regarding viral RNA copy numbers, mosquito susceptibility to infection, spread, and transmission varied significantly between species. The highest vector competency indices for infection, dissemination and transmission were obtained for Cx. tritaeniorhynchus. This is the first study to investigate the ability of Ae. albopictus and Anopheles stephensi to transmit GETV, and the results emphasize the role and capacity of other mosquito species to transmit GETV upon exposure to GETV, in addition to the perceived vectors from which GETV has been isolated in nature. CONCLUSIONS: This study highlights the importance of GETV vector competency studies to determine all possible transmission vectors, especially in endemic regions.


Asunto(s)
Aedes , Alphavirus , Culex , Humanos , Animales , Alphavirus/genética , Especificidad del Huésped , Mosquitos Vectores
10.
J Virol ; 85(13): 6185-96, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21507977

RESUMEN

Among members of the order Mononegavirales, RNA splicing events have been found only in the family Bornaviridae. Here, we report that a new rhabdovirus isolated from the mosquito Culex tritaeniorhynchus replicates in the nuclei of infected cells and requires RNA splicing for viral mRNA maturation. The virus, designated Culex tritaeniorhynchus rhabdovirus (CTRV), shares a similar genome organization with other rhabdoviruses, except for the presence of a putative intron in the coding region for the L protein. Molecular phylogenetic studies indicated that CTRV belongs to the family Rhabdoviridae, but it is yet to be assigned a genus. Electron microscopic analysis revealed that the CTRV virion is extremely elongated, unlike virions of rhabdoviruses, which are generally bullet shaped. Northern hybridization confirmed that a large transcript (approximately 6,500 nucleotides [nt]) from the CTRV L gene was present in the infected cells. Strand-specific reverse transcription-PCR (RT-PCR) analyses identified the intron-exon boundaries and the 76-nt intron sequence, which contains the typical motif for eukaryotic spliceosomal intron-splice donor/acceptor sites (GU-AG), a predicted branch point, and a polypyrimidine tract. In situ hybridization exhibited that viral RNAs are primarily localized in the nucleus of infected cells, indicating that CTRV replicates in the nucleus and is allowed to utilize the host's nuclear splicing machinery. This is the first report of RNA splicing among the members of the family Rhabdoviridae.


Asunto(s)
Culex/virología , Empalme del ARN , Rhabdoviridae/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Núcleo Celular/metabolismo , Núcleo Celular/virología , Genoma Viral/genética , Intrones , Microscopía Electrónica , Datos de Secuencia Molecular , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Viral/genética , ARN Viral/metabolismo , Rhabdoviridae/clasificación , Rhabdoviridae/ultraestructura , Análisis de Secuencia de ADN , Proteínas Virales/genética , Replicación Viral
11.
Arch Virol ; 157(5): 975-9, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22297417

RESUMEN

Culex flavivirus (CxFV) is an insect-specific flavivirus that has recently been detected in various Culex spp. mosquitoes worldwide. Here, we report the successful construction of a full-length infectious cDNA clone of a Tokyo strain, CxFV-NIID21. The full-length CxFV-NIID21 cDNA was cloned into the low-copy-number plasmid pMW119, which was stably amplified in Escherichia coli. Transfection of a mosquito cell line with in vitro-transcribed RNA from the cDNA clone resulted in the production of recombinant progeny virus with growth properties, cytopathogenicity, and virion morphology similar to the parental virus.


Asunto(s)
Culex/virología , ADN Complementario/genética , Flavivirus/genética , ARN Viral/genética , Animales , Línea Celular , ADN Complementario/metabolismo , Flavivirus/aislamiento & purificación , Flavivirus/fisiología , Plásmidos/genética , Plásmidos/metabolismo , ARN Viral/metabolismo , Especificidad de la Especie
12.
J Med Entomol ; 49(1): 175-82, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22308786

RESUMEN

To investigate the possible spread of West Nile virus (WNV) into Japan, we carried out entomological surveillance for flaviviruses at migratory bird stopover sites in Hokkaido, Japan, during 2003-2006. A total of 3,826 mosquitoes, identified as 15 species in five genera, were collected and 2,465 of these were grouped into 123 pools that were assayed for cytopathic effects on mosquito and mammalian cell cultures and for flavivirus RNA by reverse transcription-polymerase chain reaction using flavivirus universal primer sets for fragments of the NS3 and NS5 genes. Neither WNV nor other mosquito-vertebrate transmitted flaviviruses were detected in mosquitoes collected at any of the sites in Hokkaido, but five Culex flaviviruses and one novel Aedes galloisi flavivirus were identified from Culex pipiens L. s. l. and Aedes galloisi Yamada, respectively. Genetic and phylogenetic analyses based on the partial NS5 nucleotide sequences classified Aedes galloisi flavivirus with the insect flavivirus, but distant from Cell fusing agent, Kamiti river virus, and Culex flaviviruses, showing <74% sequence identities. Polymerase chain reaction-based bloodmeal analysis of 79 females showed that all of the Aedes and Ochlerotatus mosquitoes fed on mammals (deer and humans), whereas, Cx. pipiens s. l. mosquitoes fed on both of avian (ducks and sparrows, 85.7%) and mammalian hosts (dog, 14.3%). We suggest that to date WNV has not become established in Japan.


Asunto(s)
Aedes/virología , Migración Animal , Enfermedades de las Aves/virología , Culicidae/virología , Flavivirus/clasificación , Flavivirus/aislamiento & purificación , Animales , Enfermedades de las Aves/epidemiología , Aves , Ciervos/sangre , Conducta Alimentaria , Femenino , Flavivirus/genética , Humanos , Japón/epidemiología , Filogenia , Vigilancia de la Población
13.
Jpn J Infect Dis ; 75(2): 140-143, 2022 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-34470970

RESUMEN

From August 27 to October 15, 2014, a dengue fever outbreak with 158 autochthonous cases occurred after nearly 70 years of no reports of autochthonous cases in Japan. The most competent mosquito vector for dengue virus (DENV) transmission in Japan is Aedes albopictus. Since A. albopictus is widely distributed throughout Japan, we examined the susceptibility of this species to infection by DENV and the relationship of the endosymbiont Wolbachia (wAlbA and wAlbB) with susceptibility to DENV. The A. albopictus YYG strain, collected from the Yoyogi Park in 2014, the epicenter of the dengue fever outbreak, was found to have lower susceptibility to DENV 1 and 3 than that of the indigenous Japanese strains A. albopictus EBN 201808 (F1 from the field) and A. albopictus ISG 201603. Furthermore, the A. albopictus EBN 201808 strain showed the same susceptibility to DENV3 as the A. albopictus ISG 201603tet strain (Wolbachia-free). Susceptibility to DENV3 was not related to Wolbachia strains wAlbA or wAlbB in the A. albopictus ISG 201603 strain.


Asunto(s)
Aedes , Virus del Dengue , Dengue , Brotes de Enfermedades , Wolbachia , Aedes/genética , Aedes/virología , Infecciones por Anaplasmataceae/microbiología , Infecciones por Anaplasmataceae/virología , Animales , Dengue/epidemiología , Dengue/inmunología , Dengue/virología , Virus del Dengue/genética , Virus del Dengue/inmunología , Susceptibilidad a Enfermedades , Japón/epidemiología , Serogrupo , Simbiosis , Wolbachia/genética , Wolbachia/virología
14.
Jpn J Infect Dis ; 74(5): 411-415, 2021 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-33518618

RESUMEN

Several outbreaks of trench fever caused by Bartonella quintana occurred in soldiers during World Wars I and II. Although trench fever cases have been decreasing worldwide, the disease was reported among the homeless population in developing and developed countries. The current prevalence of B. quintana infection in Japan is unclear. Blood and body louse (Pediculus humanus humanus) samples were obtained from homeless inpatients with body lice during emergency hospitalization in Tokyo from January 2013 to March 2015. Patients were tested for B. quintana infections using the culture method, polymerase chain reaction, and indirect immunofluorescence assay (IFA). Among the 29 patients tested, the presence of Bartonella spp. was confirmed by genomic sequencing of DNA extracted from two samples from blood culture performed for 15 out of 29 patients and from body louse samples of 20 patients (69%). Immunoglobulin G against B. quintana was detected in 10 patients (34.5%) at a cut-off titer of 1:256 in IFA. B. quintana infection was detected in samples obtained between 2013 and 2015 in Tokyo and needs to be on the list of differential diagnoses performed for febrile homeless individuals.


Asunto(s)
Bartonella quintana/aislamiento & purificación , Personas con Mala Vivienda/estadística & datos numéricos , Pediculus , Fiebre de las Trincheras/diagnóstico , Anciano , Animales , Bartonella quintana/genética , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Japón/epidemiología , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Tokio/epidemiología , Fiebre de las Trincheras/epidemiología
15.
J Med Entomol ; 47(3): 442-50, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20496592

RESUMEN

To evaluate the vectorial capacity of mosquitoes for viruses in Japan, the host-feeding habits of the mosquitoes were analyzed by sequencing polymerase chain reaction-amplified fragments of the cytochrome b and 16S ribosomal RNA regions of the mitochondrial DNA of 516 mosquitoes of 15 species from seven genera that were collected from residential areas during 2003-2006. Culex pipiens L. and Aedes albopictus Skuse were the most commonly collected species in urban and suburban residential areas. Anautogenous Culex pipiens pallens Coquillett was distinguished from the autogenous Cx. pipiens form molestus Forskal using a polymerase chain reaction-based identification method. Both Cx. p. pallens and Cx. p. form molestus exhibited similar host-feeding habits, broadly preferring avian (50.0 and 42.5% of avian, respectively) and mammalian (38.6 and 45.0% of avian, respectively) hosts, such as tree sparrows, ducks, and humans. Conversely, Ae. albopictus exhibited a highly mammalophilic and anthropophilic feeding pattern, with 84.2% feeding on mammalian hosts and 68.5% of these on humans. We concluded that in Japan, Cx. pipiens might play a significant role in the avian-to-mammal transmission of viruses, such as West Nile virus, whereas Ae. albopictus might play a role in the human-human transmission of dengue and Chikungunya viruses.


Asunto(s)
Aedes/fisiología , Culex/fisiología , Culicidae/virología , Aedes/genética , Aedes/virología , Infecciones por Alphavirus/epidemiología , Animales , Aves/parasitología , Virus Chikungunya , Culex/genética , Culex/virología , Cartilla de ADN , Conducta Alimentaria , Humanos , Japón/epidemiología , Reacción en Cadena de la Polimerasa , Densidad de Población , Estaciones del Año , Población Suburbana , Población Urbana
16.
Parasitol Int ; 76: 102034, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31805442

RESUMEN

The genus Plasmodium is a unicellular eukaryotic parasite that is the causative agent of malaria, which is transmitted by Anopheline mosquito. There are a total of three developmental stages in the production of haploid parasites in the Plasmodium life cycle: the oocyst stage in mosquitoes and the liver and blood stages in mammalian hosts. The Plasmodium oocyst stage plays an important role in the production of the first generation of haploid parasites. Nuclear division is the most important event that occurs during the proliferation of all eukaryotes. However, obtaining the details of nuclear division at the oocyst stage is challenging owing to difficulties in preparation. In this study, we used focused-ion-beam-milling combined with scanning-electron-microscopy to report the 3D architecture during nuclear segregations in oocyst stage. This advanced technology allowed us to analyse the 3D details of organelle segregation inside the oocyst during sporogony formation. It was revealed that multiple nuclei were involved with several centrosomes in one germ nucleus during sporozoite budding (endopolygeny). Our high-resolution 3D analysis uncovered the endopolygeny-like nuclear architecture of Plasmodium in the definitive host. This nuclear segregation was different from that in the blood stage, and its similarity to other apicomplexan parasite nuclear divisions such as Sarcocystis is discussed.


Asunto(s)
División del Núcleo Celular , Núcleo Celular/ultraestructura , Oocistos/ultraestructura , Plasmodium/ultraestructura , Animales , División Celular , Femenino , Imagenología Tridimensional , Macaca/parasitología , Microscopía Electrónica de Rastreo , Oocistos/crecimiento & desarrollo , Plasmodium/crecimiento & desarrollo
17.
Viruses ; 12(2)2020 01 27.
Artículo en Inglés | MEDLINE | ID: mdl-32012771

RESUMEN

Entomological surveillance is one of the tools used in monitoring and controlling vector-borne diseases. However, the use of entomological surveillance for arboviral infection vector control is often dependent on finding infected individuals. Although this method may suffice in highly endemic areas, it is not as effective in controlling the spread of diseases in low endemic and non-endemic areas. In this study, we examined the efficiency of using entomological markers to assess the status and risk of arbovirus infection in Ghana, which is considered a non-endemic country, by combining mosquito surveillance with virus isolation and detection. This study reports the presence of cryptic species of mosquitoes in Ghana, demonstrating the need to combine morphological identification and molecular techniques in mosquito surveillance. Furthermore, although no medically important viruses were detected, the importance of insect-specific viruses in understanding virus evolution and arbovirus transmission is discussed. This study reports the first mutualistic relationship between dengue virus and the double-stranded RNA Aedes aegypti totivirus. Finally, this study discusses the complexity of the virome of Aedes and Culex mosquitoes and its implication for arbovirus transmission.


Asunto(s)
Aedes/virología , Infecciones por Arbovirus/transmisión , Arbovirus/genética , Culex/virología , Mosquitos Vectores/virología , Viroma , Animales , Infecciones por Arbovirus/epidemiología , Arbovirus/aislamiento & purificación , Dengue/epidemiología , Virus del Dengue/genética , Virus del Dengue/patogenicidad , Entomología/métodos , Femenino , Ghana/epidemiología , Masculino , Factores de Riesgo , Enfermedades Transmitidas por Vectores/epidemiología , Enfermedades Transmitidas por Vectores/virología
18.
J Med Entomol ; 46(4): 852-5, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19645288

RESUMEN

In a previous study, the highly pathogenic avian influenza (HPAI) H5N1 viruses were isolated from blow flies collected at the Tamba Town of Kyoto prefecture during the outbreak period in March 2004. In this study, we carried out virus exposure experiments to investigate whether the H5N1 virus would survive in a blow fly, Calliphora nigribarbis. The virus exposure experiments showed that the H5N1 influenza virus was isolated from the crop and intestine of C. nigribarbis for at least 24 h, and the viruses remained viable with titers ranging from 0.5 to 4.63 TCID50. This result suggests that C. nigribarbis could possibly transport the H5N1 virus over a distance of 2 km, which is the distance they can migrate within 24 h.


Asunto(s)
Dípteros/virología , Subtipo H5N1 del Virus de la Influenza A/fisiología , Insectos Vectores/virología , Animales , Subtipo H5N1 del Virus de la Influenza A/aislamiento & purificación , Intestinos/virología , Factores de Tiempo , Replicación Viral
19.
Parasitol Res ; 105(5): 1351-7, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19629522

RESUMEN

We conducted laboratory experiments to verify molecular techniques of avian malaria parasite detection distinguishing between an infected mosquito (oocysts on midgut wall) and infective mosquito (sporozoites in salivary glands) in parallel with blood-meal identification from individual blood-fed mosquitoes prior to application to field survey for avian malaria. Domestic fowl infected with Plasmodium gallinaceum was exposed to a vector and non-vector mosquito species, Aedes aegypti and Culex pipiens pallens, respectively, to compare the time course of polymerase chain reaction (PCR) detection for parasite between competent and refractory mosquitoes. DNA of the domestic fowl was detectable for at least 3 days after blood feeding. The PCR-based detection of P. gallinaceum from the abdomen and thorax of A. aegypti corresponded to the microscopic observation of oocysts and sporozoites. Therefore, this PCR-based method was considered useful as one of the criteria to assess developmental stages of Plasmodium spp. in mosquito species collected in the field. We applied the same PCR-based method to 21 blood-fed C. sasai mosquitoes collected in Rinshi-no-mori Park in urban Tokyo, Japan. Of 15 blood meals of C. sasai successfully identified, 86.7% were avian-derived, 13.3% were bovine-derived. Plasmodium DNA was amplified from the abdomen of three C. sasai specimens having an avian blood meal from the Great Tit (Parus major), Pale Thrush (Turdus pallidus), and Jungle Crow (Corvus macrorhynchos). This is the first field study on host-feeding habits of C. sasai in relation to the potential role as a vector for avian malaria parasites transmitted in the Japanese wild bird community.


Asunto(s)
Sangre/parasitología , Culex/parasitología , Malaria Aviar/parasitología , Plasmodium/aislamiento & purificación , Aedes/parasitología , Animales , Bovinos , Cuervos/parasitología , ADN Protozoario/química , ADN Protozoario/genética , Femenino , Tracto Gastrointestinal/parasitología , Datos de Secuencia Molecular , Oocistos , Passeriformes/parasitología , Reacción en Cadena de la Polimerasa/métodos , Aves de Corral/parasitología , Saliva/parasitología , Análisis de Secuencia de ADN , Pájaros Cantores/parasitología , Esporozoítos , Tokio
20.
J Agric Food Chem ; 67(29): 8160-8167, 2019 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-31241932

RESUMEN

An increase in the aging population has spurred recent efforts to identify diet and lifestyle changes that help prevent cognitive decline. Several epidemiological investigations and clinical studies have indicated that consuming fermented dairy products prevents cognitive decline. Some peptides from whey including ß-lactolin improve memory impairment; the intake of Camembert cheese has been shown to prevent Alzheimer's in mouse models. To elucidate the molecular mechanisms underlying these preventive effects, we screened peptides from digested casein protein for their ability to improve spatial memory in a scopolamine-induced amnesia mouse model. Administration of KEMPFPKYPVEP peptide from ß-casein at 0.5 mg/kg (54.8 ± 2.5) and 2 mg/kg (57.9 ± 3.7) improved memory impairment in the amnesia mice in comparison with control (44.9 ± 3.4; p = 0.031 and p = 0.042, respectively) and increased dopamine (5.9 ± 3.8 [control] and 12.4 ± 6.2 [KEMPFPKYPVEP peptide]) and norepinephrine (7.7 ± 0.8 [control] and 9.9 ± 2.0 [KEMPFPKYPVEP peptide]) levels in the frontal cortex (p = 0.039 and p = 0.031, respectively). Collectively, our findings suggest that peptides in fermented dairy products prevent cognitive decline and support previously reported observations.


Asunto(s)
Amnesia/tratamiento farmacológico , Caseínas/química , Péptidos/administración & dosificación , Amnesia/metabolismo , Amnesia/psicología , Animales , Productos Lácteos Cultivados/análisis , Modelos Animales de Enfermedad , Dopamina/metabolismo , Lóbulo Frontal/efectos de los fármacos , Lóbulo Frontal/metabolismo , Humanos , Masculino , Memoria/efectos de los fármacos , Ratones , Norepinefrina/metabolismo , Péptidos/química , Escopolamina/efectos adversos , Navegación Espacial/efectos de los fármacos
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