RESUMO
Aedes albopictus collected in 2023 in the greater Paris area (Île-de-France) were experimentally able to transmit five arboviruses: West Nile virus from 3 days post-infection (dpi), chikungunya virus and Usutu virus from 7 dpi, dengue virus and Zika virus from 21 dpi. Given the growing number of imported dengue cases reported in early 2024 in France, surveillance of Ae. albopictus should be reinforced during the Paris Olympic Games in July, when many international visitors including from endemic countries are expected.
Assuntos
Aedes , Vírus Chikungunya , Vírus da Dengue , Zika virus , Animais , Aedes/virologia , Humanos , Zika virus/isolamento & purificação , Vírus da Dengue/isolamento & purificação , Vírus Chikungunya/isolamento & purificação , Paris , Mosquitos Vetores/virologia , Vírus do Nilo Ocidental/isolamento & purificação , Arbovírus/isolamento & purificação , Infecções por Arbovirus/transmissão , Flavivirus/isolamento & purificação , França , Dengue/transmissão , Dengue/epidemiologia , Infecção por Zika virus/transmissãoRESUMO
Insecticide resistance has been reported to impact the interactions between mosquitoes and the pathogens they transmit. However, the effect on vector competence for arboviruses still remained to be investigated. We examined the influence of two insecticide resistance mechanisms on vector competence of the mosquito Culex quinquefasciatus for two arboviruses, Rift Valley Fever virus (RVFV) and West Nile virus (WNV). Three Cx. quinquefasciatus lines sharing a common genetic background were used: two insecticide-resistant lines, one homozygous for amplification of the Ester2 locus (SA2), the other homozygous for the acetylcholinesterase ace-1 G119S mutation (SR) and the insecticide-susceptible reference line Slab. Statistical analyses revealed no significant effect of insecticide-resistant mechanisms on vector competence for RVFV. However, both insecticide resistance mechanisms significantly influenced the outcome of WNV infections by increasing the dissemination of WNV in the mosquito body, therefore leading to an increase in transmission efficiency by resistant mosquitoes. These results showed that insecticide resistance mechanisms enhanced vector competence for WNV and may have a significant impact on transmission dynamics of arboviruses. Our findings highlight the importance of understanding the impacts of insecticide resistance on the vectorial capacity parameters to assess the overall consequence on transmission.
Assuntos
Culex/efeitos dos fármacos , Genes de Insetos , Resistência a Inseticidas/genética , Mosquitos Vetores/efeitos dos fármacos , Febre do Nilo Ocidental/transmissão , Vírus do Nilo Ocidental/fisiologia , Animais , Culex/genética , Culex/virologia , Comportamento Alimentar , Feminino , Mosquitos Vetores/genética , Mosquitos Vetores/virologiaRESUMO
Dengue and chikungunya viruses are transmitted by Aedes mosquitoes. In Martinique, an island of the French West Indies, Aedes aegypti is the suspected vector of both arboviruses; there is no Aedes albopictus on the island. During the concomitant outbreak of 2013 - 2015, the authors collected wild A. aegypti populations, and for the first time, detected dengue and chikungunya viruses in field-collected females. This paper demonstrates the mosquito's role in transmission of both dengue and chikungunya on the island, and also highlights a tool that public health authorities can use for preventing outbreaks.
Assuntos
Aedes/virologia , Febre de Chikungunya/epidemiologia , Vírus Chikungunya/isolamento & purificação , Vírus da Dengue/isolamento & purificação , Dengue/epidemiologia , Surtos de Doenças , Animais , Feminino , Humanos , Masculino , Martinica/epidemiologiaRESUMO
BACKGROUND: Dengue viruses (DENV) are comprised in four related serotypes (DENV-1 to 4) and are critically important arboviral pathogens affecting human populations in the tropics. South American countries have seen the reemergence of DENV since the 1970's associated with the progressive re-infestation by the mosquito vector, Aedes aegypti. In French Guiana, DENV is now endemic with the co-circulation of different serotypes resulting in viral epidemics. Between 2009 and 2010, a predominant serotype change occurred from DENV-1 to DENV-4 suggesting a competitive displacement. The aim of the present study was to evaluate the potential role of the mosquito in the selection of the new epidemic serotype. METHODS: To test this hypothesis of competitive displacement of one serotype by another in the mosquito vector, we performed mono- and co-infections of local Ae. aegypti collected during the inter-epidemic period with both viral autochthonous epidemic serotypes and compared infection, dissemination and transmission rates. We performed oral artificial infections of F1 populations in BSL-3 conditions and analyzed infection, dissemination and transmission rates. RESULTS: When two populations of Ae. aegypti from French Guiana were infected with either serotype, no significant differences in dissemination and transmission were observed between DENV-1 and DENV-4. However, in co-infection experiments, a strong competitive advantage for DENV-4 was seen at the midgut level leading to a much higher dissemination of this serotype. Furthermore only DENV-4 was present in Ae. aegypti saliva and therefore able to be transmitted. CONCLUSIONS: In an endemic context, mosquito vectors may be infected by several DENV serotypes. Our results suggest a possible competition between serotypes at the midgut level in co-infected mosquitoes leading to a drastically different transmission potential and, in this case, favoring the competitive displacement of DENV-1 by DENV-4. This phenomenon was observed despite a similar replicative fitness in mono-infections conditions.
Assuntos
Aedes/virologia , Coinfecção/transmissão , Vírus da Dengue/patogenicidade , Insetos Vetores/virologia , Animais , Coinfecção/virologia , Dengue/epidemiologia , Vírus da Dengue/imunologia , Guiana Francesa , Humanos , Sorogrupo , América do Sul , Replicação Viral/fisiologiaRESUMO
Interactions between pathogens and their insect vectors in nature are under the control of both genetic and non-genetic factors, yet most studies on mosquito vector competence for human pathogens are conducted in laboratory systems that do not consider genetic and/or environmental variability. Evaluating the risk of emergence of arthropod-borne viruses (arboviruses) of public health importance such as chikungunya virus (CHIKV) requires a more realistic appraisal of genetic and environmental contributions to vector competence. In particular, sources of variation do not necessarily act independently and may combine in the form of interactions. Here, we measured CHIKV transmission potential by the mosquito Aedes albopictus in all combinations of six worldwide vector populations, two virus strains and two ambient temperatures (20°C and 28°C). Overall, CHIKV transmission potential by Ae. albopictus strongly depended on the three-way combination of mosquito population, virus strain and temperature. Such genotype-by-genotype-by-environment (G × G × E) interactions question the relevance of vector competence studies conducted with a simpler set of conditions. Our results highlight the need to account for the complex interplay between vectors, pathogens and environmental factors to accurately assess the potential of vector-borne diseases to emerge.
Assuntos
Aedes/genética , Aedes/virologia , Infecções por Alphavirus/transmissão , Vírus Chikungunya/genética , Insetos Vetores/genética , Insetos Vetores/virologia , Temperatura , Animais , Genótipo , CamundongosRESUMO
Objectives: Our study targets the potential of the local urban mosquito Aedes aegypti to experimentally transmit chikungunya virus (CHIKV), dengue virus (DENV), yellow fever virus (YFV), and Zika virus (ZIKV). Methods: We collected eggs and adults of Ae. aegypti in Medellín, Colombia (from February to March 2020) for mosquito experimental infections with DENV, CHIKV, YFV and ZIKV and viral detection using the BioMark Dynamic arrays system. Results: We show that Ae. aegypti from Medellín was more prone to become infected, to disseminate and transmit CHIKV and ZIKV than DENV and YFV. Conclusions: Thus, in Colombia, chikungunya is the most serious threat to public health based on our vector competence data.
RESUMO
The mosquito-borne disease, Yellow fever (YF), has been largely controlled via mass delivery of an effective vaccine and mosquito control interventions. However, there are warning signs that YF is re-emerging in both Sub-Saharan Africa and South America. Imported from Africa in slave ships, YF was responsible for devastating outbreaks in the Caribbean. In Martinique, the last YF outbreak was reported in 1908 and the mosquito Aedes aegypti was incriminated as the main vector. We evaluated the vector competence of fifteen Ae. aegypti populations for five YFV genotypes (Bolivia, Ghana, Nigeria, Sudan, and Uganda). Here we show that mosquito populations from the Caribbean and the Americas were able to transmit the five YFV genotypes, with YFV strains for Uganda and Bolivia having higher transmission success. We also observed that Ae. aegypti populations from Martinique were more susceptible to YFV infection than other populations from neighboring Caribbean islands, as well as North and South America. Our vector competence data suggest that the threat of re-emergence of YF in Martinique and the subsequent spread to Caribbean nations and beyond is plausible.
Assuntos
Aedes , Febre Amarela , Animais , Humanos , Vírus da Febre Amarela/genética , Mosquitos Vetores , Índias Ocidentais , Região do Caribe/epidemiologia , UgandaRESUMO
BACKGROUND: Aedes aegypti is extensively spread throughout South America where it has been responsible for large dengue epidemics during the last decades. Intriguingly, dengue transmission has not been reported in Uruguay and is essentially prevalent in subtropical northern Argentina which borders Uruguay. METHODS: We assessed vector competence for dengue virus (DENV) of Ae. aegypti populations collected in subtropical Argentina (Corrientes) as well as temperate Uruguay (Salto) and Argentina (Buenos Aires) in 2012 using experimental oral infections with DENV-2. Mosquitoes were incubated at 28 °C and examined at 14 and 21 days p.i. to access viral dissemination and transmission. Batches of the Buenos Aires mosquitoes were also incubated at 15 °C and 20 °C. RESULTS: Although mosquitoes from temperate Uruguay and Argentina were competent to transmit DENV, those from subtropical Argentina were more susceptible, displaying the highest virus titters in the head and presenting the highest dissemination of infection and transmission efficiency rates when incubated at 28 °C. Interestingly, infectious viral particles could be detected in saliva of mosquitoes from Buenos Aires exposed to 15 °C and 20 °C. CONCLUSIONS: There is a potential risk of establishing DENV transmission in Uruguay and for the spread of dengue outbreaks to other parts of subtropical and temperate Argentina, notably during spring and summer periods.
Assuntos
Aedes/virologia , Vírus da Dengue/isolamento & purificação , Dengue/transmissão , Insetos Vetores/virologia , Animais , Argentina , Dengue/epidemiologia , Feminino , Masculino , Temperatura , Uruguai , Carga ViralRESUMO
West Nile virus (WNV) and Usutu virus (USUV) are two arthropod-borne viruses that circulate in mainland France. Assessing vector competence has only been conducted so far with mosquitoes from southern France while an increasingly active circulation of WNV and USUV has been reported in the last years. The main vectors are mosquitoes of the Culex genus and the common mosquito Culex pipiens. Here, we measure the vector competence of five mosquito species (Aedes rusticus, Aedes albopictus, Anopheles plumbeus, Culex pipiens and Culiseta longiareolata) present in northeastern France. Field-collected populations were exposed to artificial infectious blood meal containing WNV or USUV and examined at different days post-infection. We show that (i) Cx. pipiens transmitted WNV and USUV, (ii) Ae. rusticus only WNV, and (iii) unexpectedly, Ae. albopictus transmitted both WNV and USUV. Less surprising, An. plumbeus was not competent for both viruses. Combined with data on distribution and population dynamics, these assessments of vector competence will help in developing a risk map and implementing appropriate prevention and control measures.
Assuntos
Aedes , Culex , Flavivirus , Febre do Nilo Ocidental , Vírus do Nilo Ocidental , Animais , França , Mosquitos VetoresRESUMO
Since its detection in 2015 in Brazil, Zika virus (ZIKV) has remained in the spotlight of international public health and research as an emerging arboviral pathogen. In addition to single infection, ZIKV may occur in co-infection with dengue (DENV) and chikungunya (CHIKV) viruses, with whom ZIKV shares geographic distribution and the mosquito Aedes aegypti as a vector. The main mosquito immune response against arboviruses is RNA interference (RNAi). It is unknown whether or not the dynamics of the RNAi response differ between single arboviral infections and co-infections. In this study, we investigated the interaction of ZIKV and DENV, as well as ZIKV and CHIKV co-infections with the RNAi response in Ae. aegypti. Using small RNA sequencing, we found that the efficiency of small RNA production against ZIKV -a hallmark of antiviral RNAi-was mostly similar when comparing single and co-infections with either DENV or CHIKV. Silencing of key antiviral RNAi proteins, showed no change in effect on ZIKV replication when the cell is co-infected with ZIKV and DENV or CHIKV. Interestingly, we observed a negative effect on ZIKV replication during CHIKV co-infection in the context of Ago2-knockout cells, though his effect was absent during DENV co-infection. Overall, this study provides evidence that ZIKV single or co-infections with CHIKV or DENV are equally controlled by RNAi responses. Thus, Ae. aegypti mosquitoes and derived cells support co-infections of ZIKV with either CHIKV or DENV to a similar level than single infections, as long as the RNAi response is functional.
Assuntos
Aedes , Arbovírus , Febre de Chikungunya , Vírus Chikungunya , Coinfecção , Dengue , Infecção por Zika virus , Zika virus , Animais , Zika virus/genética , Vírus Chikungunya/genética , Interferência de RNA , Mosquitos Vetores/genética , Arbovírus/fisiologiaRESUMO
BACKGROUND: Climate change and globalization contribute to the expansion of mosquito vectors and their associated pathogens. Long spared, temperate regions have had to deal with the emergence of arboviruses traditionally confined to tropical regions. Chikungunya virus (CHIKV) was reported for the first time in Europe in 2007, causing a localized outbreak in Italy, which then recurred repeatedly over the years in other European localities. This raises the question of climate effects, particularly temperature, on the dynamics of vector-borne viruses. The objective of this study is to improve the understanding of the molecular mechanisms set up in the vector in response to temperature. METHODS: We combine three complementary approaches by examining Aedes albopictus mosquito gene expression (transcriptomics), bacterial flora (metagenomics) and CHIKV evolutionary dynamics (genomics) induced by viral infection and temperature changes. RESULTS: We show that temperature alters profoundly mosquito gene expression, bacterial microbiome and viral population diversity. We observe that (i) CHIKV infection upregulated most genes (mainly in immune and stress-related pathways) at 20°C but not at 28°C, (ii) CHIKV infection significantly increased the abundance of Enterobacteriaceae Serratia marcescens at 28°C and (iii) CHIKV evolutionary dynamics were different according to temperature. CONCLUSION: The substantial changes detected in the vectorial system (the vector and its bacterial microbiota, and the arbovirus) lead to temperature-specific adjustments to reach the ultimate goal of arbovirus transmission; at 20°C and 28°C, the Asian tiger mosquito Ae. albopictus was able to transmit CHIKV at the same efficiency. Therefore, CHIKV is likely to continue its expansion in the northern regions and could become a public health problem in more countries than those already affected in Europe.
Assuntos
Aedes , Febre de Chikungunya , Vírus Chikungunya , Animais , Humanos , Mudança Climática , Temperatura , Multiômica , Febre de Chikungunya/epidemiologia , Vírus Chikungunya/genéticaRESUMO
Mosquito-borne diseases have a significant impact on humans and animals and this impact is exacerbated by environmental changes. However, in Tunisia, surveillance of the West Nile virus (WNV) is based solely on the surveillance of human neuroinvasive infections and no study has reported mosquito-borne viruses (MBVs), nor has there been any thorough serological investigation of anti-MBV antibodies in horses. This study therefore sought to investigate the presence of MBVs in Tunisia. Among tested mosquito pools, infections by WNV, Usutu virus (USUV), and Sindbis virus (SINV) were identified in Cx. perexiguus. The serosurvey showed that 146 of 369 surveyed horses were positive for flavivirus antibodies using the cELISA test. The microsphere immunoassay (MIA) showed that 74 of 104 flavivirus cELISA-positive horses were positive for WNV, 8 were positive for USUV, 7 were positive for undetermined flaviviruses, and 2 were positive for tick-borne encephalitis virus (TBEV). Virus neutralization tests and MIA results correlated well. This study is the first to report the detection of WNV, USUV and SINV in Cx. perexiguus in Tunisia. Besides, it has shown that there is a significant circulation of WNV and USUV among horses, which is likely to cause future sporadic outbreaks. An integrated arbovirus surveillance system that includes entomological surveillance as an early alert system is of major epidemiological importance.
RESUMO
BACKGROUND: The mosquito Aedes albopictus is undergoing a worldwide expansion with potential consequences on transmission of various arboviruses. This species has been first detected in Lebanon in 2003. METHODS: We performed a phylogenetic study of Lebanese specimens and assessed their host preference by detecting human, cat, dog and chicken immunoglobulins in mosquito blood-meals. Their capacity to transmit arboviruses was investigated by providing infectious blood-meals using an artificial feeding system followed by detection of viral particles in mosquito saliva. RESULTS: Our results suggest that Lebanese strains are part of the recent wave of Ae. albopictus expansion and are related to some European, African and North American strains. They exhibited a host preference towards humans and an important capacity to transmit arboviruses. Indeed, we showed that Ae. albopictus was able to transmit chikungunya (CHIKV), dengue (DENV) and West-Nile (WNV) viruses. At day 10 after an infectious blood-meal at a titer of 108 MID50/ml, 30% of mosquitoes delivered an average of 515 ± 781 viral particles of CHIKV in saliva collected using a forced salivation technique and 55% with an average of 245 ± 304 viral particles when infected with WNV. Whereas DENV was not found in saliva at day 10 post-infection (pi), an average of 174 ± 455 viral particles was detected in 38.1% of mosquitoes tested at day 21 after an infectious blood-meal at a higher titer of 109 MID50/ml. CONCLUSION: These observations suggest that Ae. albopictus around Beirut is a potential vector of the three tested arboviruses.
Assuntos
Aedes/fisiologia , Aedes/virologia , Arbovírus/isolamento & purificação , Vetores de Doenças , Comportamento Alimentar , Aedes/classificação , Aedes/genética , Animais , Infecções por Arbovirus/transmissão , Gatos , Galinhas , Surtos de Doenças , Cães , Feminino , Humanos , Líbano , Dados de Sequência Molecular , Medição de Risco , Análise de Sequência de DNARESUMO
One of the most effective vaccines against an arbovirus is the YFV-17D live-attenuated vaccine developed in 1937 against Yellow Fever (YF). This vaccine replicates poorly in mosquitoes and consequently, is not transmitted by vectors. Vaccine shortages, mainly due to constrained productions based on pathogen-free embryonated eggs, led Sanofi to move towards alternative methods based on a state-of-the-art process using continuous cell line cultures in bioreactor. vYF-247 is a next-generation live-attenuated vaccine candidate based on 17D adapted to grow in serum-free Vero cells. For the development of a new vaccine, WHO recommends to document infectivity and replication in mosquitoes. Here we infected Aedes aegypti and Aedes albopictus mosquitoes with vYF-247 vaccine compared first to the YF-17D-204 reference Sanofi vaccines (Stamaril and YF-VAX) and a clinical human isolate S-79, provided in a blood meal at a titer of 6.5 Log ffu/mL and secondly, to the clinical isolate only at an increased titer of 7.5 Log ffu/mL. At different days post-infection, virus replication, dissemination and transmission were evaluated by quantifying viral particles in mosquito abdomen, head and thorax or saliva, respectively. Although comparison of vYF-247 to reference vaccines could not be completed to yield significant results, we showed that vYF-247 was not transmitted by both Aedes species, either laboratory strains or field-collected populations, compared to clinical strain S-79 at the highest inoculation dose. Combined with the undetectable to low level viremia detected in vaccinees, transmission of the vYF-247 vaccine by mosquitoes is highly unlikely.
Assuntos
Aedes , Vacina contra Febre Amarela , Febre Amarela , Chlorocebus aethiops , Animais , Humanos , Vacinas Atenuadas , Células Vero , Mosquitos Vetores , Febre Amarela/prevenção & controle , Antígenos Virais , Vírus da Febre AmarelaRESUMO
The tiger mosquito was introduced to the Eastern region of the Mediterranean basin more than twenty years ago. In Lebanon, it was first observed in 2002 in a limited number of locations mainly from the coastal area of the country. In the absence of national entomological control program, this invasive mosquito became an established species and is now considered in many localities, a source of nuisance because of its human biting behavior. Several entomological surveys were conducted to monitor the geographic spread and the seasonal dynamics of Aedes albopictus by collecting adult stages and by monitoring oviposition activity. Moreover, its susceptibility to the common groups of insecticides was assessed using WHO standard bioassays. Previous vector competence studies revealed that local strains were able to transmit Chikungunya and Dengue viruses. Due to the increased risk of Zika virus introduction in the country, we determined the competence of local populations to transmit this virus. Mapping results showed that Ae. albopictus is mainly spread in the relatively humid western versant of the Mount Lebanon chain reaching 1000m altitude, while it is absent from arid and semi-arid inland areas. Besides, this mosquito is active during 32 weeks from spring till the end of autumn. Local strains of the tiger mosquito are susceptible to pyrethroids and carbamates but resistant to organophosphates and organochlorines. They showed ability to transmit Zika virus; however, only 9% of females were capable to excrete the virus in their saliva at day 28 post infection. Current and previous observations highlight the need to establish a surveillance system in order to control this mosquito and monitor the potential introduction of related diseases.
Assuntos
Aedes/fisiologia , Espécies Introduzidas/estatística & dados numéricos , Mosquitos Vetores/fisiologia , Aedes/efeitos dos fármacos , Aedes/virologia , Distribuição Animal , Animais , Vírus da Dengue/genética , Vírus da Dengue/isolamento & purificação , Feminino , Inseticidas/farmacologia , Líbano , Masculino , Mosquitos Vetores/efeitos dos fármacos , Mosquitos Vetores/virologia , Piretrinas/farmacologia , Saliva/virologia , Estações do Ano , Zika virus/genética , Zika virus/isolamento & purificaçãoRESUMO
Mosquitoes are important vectors for many arboviruses. It is becoming increasingly clear that various symbiotic microorganisms (including bacteria and insect-specific viruses; ISVs) in mosquitoes have the potential to modulate the ability of mosquitoes to transmit arboviruses. In this study, we compared the bacteriome and virome (both eukaryotic viruses and bacteriophages) of female adult Aedes aegypti and Culex quinquefasciatus mosquitoes fed with sucrose/water, blood, or blood spiked with Zika virus (ZIKV) or West Nile virus (WNV), respectively. Furthermore, we investigated associations between the microbiota and vector competence. We show that the influence of arboviruses on the mosquito microbiome-and vice versa-is distinct for each combination of arbovirus/mosquito species. The presence of ZIKV resulted in a temporarily increased Aedes ISV diversity. However, this effect was distinct for different ISVs: some ISVs decreased following the blood meal (Aedes aegypti totivirus), whereas other ISVs increased only when the blood contained ZIKV (Guadeloupe mosquito virus). Also, the diversity of the Aedes bacteriome depended on the diet and the presence of ZIKV, with a lower diversity observed for mosquitoes receiving blood without ZIKV. In Cx. quinquefasciatus, some ISVs increased in WNV-infected mosquitoes (Guadeloupe Culex tymo-like virus). Particularly, the presence of Wenzhou sobemo-like virus 3 (WSLV3) was associated with the absence of infectious WNV in mosquito heads, suggesting that WSLV3 might affect vector competence for WNV. Distinct profiles of bacteriophages were identified in Culex mosquitoes depending on diet, despite the lack of clear changes in the bacteriome. Overall, our data demonstrate a complex three-way interaction among arboviruses, resident microbiota, and the host, which is distinct for different arbovirus-mosquito combinations. A better understanding of these interactions may lead to the identification of microbiota able to suppress the ability of arbovirus transmission to humans, and hence improved arbovirus control measures. IMPORTANCE In this study, we first utilized the single mosquito microbiome analysis, demonstrating a complex three-way interaction among arboviruses, resident microbiota, and the host, which is distinct for different arbovirus-mosquito combinations. Some of the previously described "core virus" increased in the mosquitos receiving viral blood meal, like Guadeloupe mosquito virus and Guadeloupe Culex tymo-like virus, suggesting their potential roles in ZIKV and WNV infection. Notably, Wenzhou sobemo-like virus 3 was associated with the absence of infectious WNV in heads of Culex mosquitoes, which might affect vector competence for WNV. A better understanding of these interactions will lead to the identification of microbiota able to suppress the ability of arbovirus transmission to humans, and hence improved arbovirus control measures.
Assuntos
Aedes , Arbovírus , Culex , Microbiota , Vírus , Vírus do Nilo Ocidental , Infecção por Zika virus , Zika virus , Humanos , Animais , Feminino , Mosquitos Vetores , Bactérias , Sacarose , ÁguaRESUMO
Mosquito control is implemented when arboviruses are detected in patients or in field-collected mosquitoes. However, mass screening of mosquitoes is usually laborious and expensive, requiring specialized expertise and equipment. Detection of virus in mosquito saliva using honey-impregnated filter papers seems to be a promising method as it is non-destructive and allows monitoring the viral excretion dynamics over time from the same mosquito. Here we test the use of filter papers to detect chikungunya virus in mosquito saliva in laboratory conditions, before proposing this method in large-scale mosquito surveillance programs. We found that 0.9 cm2 cards impregnated with a 50% honey solution could replace the forced salivation technique as they offered a viral RNA detection until 7 days after oral infection of Aedes aegypti and Aedes albopictus mosquitoes with CHIKV.
Assuntos
Aedes/virologia , Vírus Chikungunya/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Animais , Vírus Chikungunya/isolamento & purificação , Mel , Papel , RNA Viral/genética , RNA Viral/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa/instrumentação , Saliva/virologia , Manejo de Espécimes/instrumentação , Manejo de Espécimes/métodosRESUMO
Recent expansion of arboviruses such as West Nile (WNV), Usutu (USUV), and tick-borne encephalitis (TBEV) over their natural range of distribution needs strengthening their surveillance. As common viral vertebrate hosts, birds and horses deserve special attention with routine serological surveillance. Here, we estimated the seroprevalence of WNV, USUV and TBEV in 160 migrating/resident birds and 60 horses sampled in Mazandaran, Golestan, North Khorasan, Kordestan provinces and Golestan province of Iran respectively. ELISA results showed that of 220 collected samples, 32 samples (14.54%), including 22 birds and 10 horses, were positive. Microsphere immunoassay results showed that 16.7% (10/60) of horse blood samples collected in Golestan province were seropositive against WNV (7; 11.7%), Flavivirus (2; 3.3%) and seropositive for USUV or WNV (1; 1.7%). Furthermore, micro virus neutralization tests revealed that four of seven ELISA-positive bird blood samples were seropositive against WNV: two Egyptian vultures, and one long-legged buzzard collected in Golestan province as well as a golden eagle collected in North Khorasan province. No evidence of seropositivity with TBEV was observed in collected samples. We showed that WNV, responsible for neuroinvasive infection in vertebrates, is circulating among birds and horses in Iran, recommending a sustained surveillance of viral infections in animals, and anticipating future infections in humans.
Assuntos
Doenças das Aves/epidemiologia , Aves , Doenças dos Cavalos/epidemiologia , Febre do Nilo Ocidental/veterinária , Vírus do Nilo Ocidental/isolamento & purificação , Animais , Animais Selvagens , Doenças das Aves/virologia , Ensaio de Imunoadsorção Enzimática/veterinária , Doenças dos Cavalos/virologia , Cavalos , Irã (Geográfico)/epidemiologia , Prevalência , Estudos Soroepidemiológicos , Febre do Nilo Ocidental/epidemiologia , Febre do Nilo Ocidental/virologiaRESUMO
: Vector competence is an important parameter in evaluating whether a species plays a role in transmission of an arbovirus. Although the protocols are similar, interpretation of results is unique given the specific interactions that exist between a mosquito population and a viral genotype. Here, we assessed the infection (IR), dissemination (DR), and transmission (TR) rates of Cx. pipiens s.l., collected from Iran, for West Nile virus (WNV) lineage 1a. We showed that Cx. pipiens s.l. mosquitoes in Iran were susceptible to WNV with IR up to 89.7%, 93.6%, and 83.9% at 7, 14, and 21 days post-infection (dpi) respectively. In addition, DR and TR reached respectively 92.3% and 75.0% at 21 dpi, and the number of viral particles delivered with saliva reached up to 1.33 × 105 particles. Therefore, an unexpected high risk of WNV dissemination in the region where Cx. pipiens s.l. mosquitoes are well established should be considered carefully and surveillance measures implemented accordingly.
Assuntos
Culex/virologia , Mosquitos Vetores/virologia , Febre do Nilo Ocidental/transmissão , Vírus do Nilo Ocidental/genética , Vírus do Nilo Ocidental/fisiologia , Animais , Feminino , Genótipo , Irã (Geográfico) , RNA Viral/análiseRESUMO
The mosquito Aedes albopictus was detected for the first time in Tunisia in 2018. With its establishment in the capital city of Tunis, local health authorities fear the introduction of new human arboviral diseases, like what happened in Europe with unexpected local cases of chikungunya, dengue and Zika. Even though this mosquito is competent to transmit the arboviruses mentioned above, the transmission level will vary depending on the couple, mosquito population and virus genotype. Here, we assessed the vector competence of Ae. albopictus Tunisia by experimental infections with chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viruses. We found that Ae. albopictus Tunisia was highly competent for CHIKV (transmission efficiency of 25% at 21 post-infection) and to a lesser extent, for ZIKV (8.7%) and DENV (8.3%). Virus was detected in mosquito saliva at day 3 (CHIKV), day 10 (ZIKV) and day 21 (DENV) post-infection. These results suggest that the risk of emergence of chikungunya is the highest imposing a more sustained surveillance to limit Ae. albopictus populations in densely populated urban dwellings and at the entry points of travelers returning from CHIKV-endemic regions.