Navegando por Autor "Melo, Fabrício Freire de"

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Aedes (Stegomyia) albopictus’ dynamics influenced by spatiotemporal characteristics in a Brazilian dengue-endemic risk city.
(2016) Bezerra, Juliana Maria Trindade; Araújo, Raphaela Guedes Pereira; Melo, Fabrício Freire de; Gonçalves, Caroline Macedo; Chaves, Bárbara Aparecida; Silva, Breno de Mello; Silva, Luciana Diniz; Brandão, Silvana Tecles; Secundino, Nagila Francinete Costa; Norris, Douglas; Pimenta, Paulo Filemon Paolucci
Brazil reported the majority of the dengue cases in Americas during the last two decades, where theoccurrence of human dengue cases is exclusively attributed to the Aedes (Stegomyia) aegypti (Linnaeus).Nowadays, other recognized Dengue virus (DENV) vector in Asian countries, Aedes (Stegomyia) albopictus(Skuse), has been detected in more than half of the 5565 Brazilian municipalities. Therefore, the aim of thepresent study was to investigate the presence of, and determine the Ae. albopictus’ dynamics influencedby spatiotemporal characteristics in a dengue-endemic risk city of Belo Horizonte, Minas Gerais State’scapital. Aedes albopictus were collected across four consecutive DENV transmission seasons from 2010 to2014. These mosquitoes were caught in three selected districts, which had been reported in the previousten years as having high mosquito densities and an elevated concentration of human dengue cases dur-ing epidemic seasons. All field-caught Ae. albopictus was individually processed by real-time RT-PCR, toresearch the DENV presence. The third season (p < 0.05) and the Pampulha district (p < 0.05) had the high-est proportions of field-caught Ae. albopictus, respectively. The second season had the highest proportionof DENV-infected field-caught females (p < 0.05), but there was no difference among the proportions ofDENV-infected Ae. albopictus when comparing the collection in the three districts (p = 0.98). Minimum(p = 0.004) and maximum (p < 0.0001) temperature were correlated with the field-caught Ae. albopic-tus in four different periods and districts. In the generalized linear model of Poisson, the field-caughtDENV-infected Ae. albopictus (p = 0.005), East district (p = 0.003), minimum temperature (p < 0.0001) andrelative humidity (p = 0.001) remained associated with the total number of human dengue cases. Ourstudy demonstrated that the number of field-caught DENV-infected Ae. albopictus was inversed corre-lated with the number of human dengue cases. Our study raises the possibility that the DENV circulating inmosquitoes Ae. albopictus is happening in non-epidemic periods, showing that this species may be keep-ing only the presence of the virus in nature. Further long-term studies are necessary to better understandthe role of Ae. albopictus in DENV transmission and or its vectorial competence in Belo Horizonte and inother endemic cities in Brazil and in the New World countries.
Coinfection with Zika Virus (ZIKV) and dengue virus results in preferential ZIKV transmission by vector bite to vertebrate host.
(2018) Chaves, Bárbara Aparecida; Orfanó, Alessandra da Silva; Nogueira, Paula Monalisa; Rodrigues, Nilton Barnabé; Campolina, Thaís Bonifácio; Pimenta, Rafael Nacif; Pires, Ana Clara Araújo Machado; Vieira Junior, Ademir Bentes; Paz, Andréia da Costa; Vaz, Evelyn Beatriz da Costa; Guerra, Maria das Graças Vale Barbosa; Silva, Breno de Mello; Melo, Fabrício Freire de; Norris, Douglas Eric; Lacerda, Marcus Vinícius Guimarães de; Pimenta, Paulo Filemon Paolucci; Secundino, Nagila Francinete Costa
Background. Several tropical cities are permissive to Aedes aegypti and dengue virus (DENV) endemicity and have allowed for invasion and circulation of Zika virus (ZIKV) in the same areas. People living in arbovirus-endemic regions have been simultaneously infected with ≥2 arboviruses. Methods. A. aegypti mosquitoes from Manaus, the capital city of Amazonas State in Brazil, were coinfected with circulating strains of DENV and ZIKV. The coinfected vectors were allowed to bite BALB/c mice. Results. A. aegypti from Manaus is highly permissive to monoinfection and coinfection with DENV and ZIKV and is capable of cotransmitting both pathogens by bite. Coinfection strongly influences vector competence, favoring transmission of ZIKV to the vertebrate host. Conclusions. This finding suggests that A. aegypti is an efficient vector of ZIKV and that ZIKV would be preferentially transmitted by coinfected A. aegypti. Coinfection in the vector population should be considered a new critical epidemiological factor and may represent a major public health challenge.
Distinct variation in vector competence among nine field populations of Aedes aegypti from a Brazilian dengue-endemic risk city.
(2014) Gonçalves, Caroline Macedo; Melo, Fabrício Freire de; Bezerra, Juliana Maria Trindade; Chaves, Bárbara Aparecida; Silva, Breno de Mello; Silva, Luciana Diniz; Pessanha, José Eduardo Marques; Arias, Jorge; Secundino, Nagila Francinete Costa; Norris, Douglas; Pimenta, Paulo Filemon Paolucci
Vertical Transmission of Zika Virus (Flaviviridae, Flavivirus) in Amazonian Aedes aegypti (Diptera: Culicidae) delays egg hatching and larval development of progeny.
(2019) Chaves, Bárbara Aparecida; Vieira Junior, Ademir Bentes; Silveira, Karine Renata Dias; Paz, Andréia da Costa; Vaz, Evelyn Beatriz da Costa; Araújo, Raphaela Guedes Pereira; Rodrigues, Nilton Barnabé; Campolina, Thaís Bonifácio; Orfanó, Alessandra da Silva; Pimenta, Rafael Nacif; Villegas, Luis Eduardo Martínez; Melo, Fabrício Freire de; Silva, Breno de Mello; Monteiro, Wuelton Marcelo; Guerra, Maria das Graças Vale Barbosa; Lacerda, Marcus Vinícius Guimarães de; Norris, Douglas Eric; Secundino, Nagila Francinete Costa; Pimenta, Paulo Filemon Paolucci
Zika virus (ZIKV) has emerged as a globally important arbovirus and has been reported from all states of Brazil. The virus is primarily transmitted to humans through the bite of an infective Aedes aegypti (Linnaeus, 1762) or Aedes albopictus (Skuse, 1895). However, it is important to know if ZIKV transmission also occurs from Ae. aegypti through infected eggs to her offspring. Therefore, a ZIKV and dengue virus (DENV) free colony was established from eggs collected in Manaus and maintained until the third–fourth generation in order to conduct ZIKV vertical transmission (VT) experiments which used an infectious bloodmeal as the route of virus exposure. The eggs from ZIKV-infected females were allowed to hatch. The resulting F1 progeny (larvae, pupae, and adults) were quantitative polymerase chain reaction (qPCR) assayed for ZIKV. The viability of ZIKV vertically transmitted to F1 progeny was evaluated by cultivation in C6/36 cells. The effects of ZIKV on immature development of Ae. aegypti was assessed and compared with noninfected mosquitoes. Amazonian Ae. Aegypti were highly susceptible to ZIKV infection (96.7%), and viable virus passed to their progeny via VT. Moreover, eggs from the ZIKV-infected mosquitoes had a significantly lower hatch rate and the slowest hatching. In addition, the larval development period was slower when compared to noninfected, control mosquitoes. This is the first study to illustrate VT initiated by oral infection of the parental population by using mosquitoes, which originated from the field and a ZIKV strain that is naturally circulating in-country. Additionally, this study suggests that ZIKV present in the Ae. aegypti can modify the mosquito life cycle. The data reported here suggest that VT of ZIKV to progeny from naturally infected females may have a critical epidemiological role in the dissemination and maintenance of the virus circulating in the vector.