Evidence of vertical transmission of Zika virus in field-collected eggs of Aedes aegypti in the Brazilian Amazon.

BACKGROUND: Arboviruses are viruses transmitted to humans and other animals by the bite of hematophagous arthropods. Infections caused by chikungunya virus (CHIKV), dengue virus (DENV), Zika virus (ZIKV), and the deadlier yellow fever virus (YFV) are current public health problems in several countries, mainly those located in tropical and subtropical regions. One of the main prevention strategies continues to be vector control, with the elimination of breeding sites and surveillance of infested areas. The use of ovitraps for Aedes mosquitos monitoring has already demonstrated promising results, and maybe be also useful for arboviral surveillance. METHODS: This work aimed to detect natural vertical transmission of arboviruses in Aedes aegypti and Aedes albopictus. Mosquito egg collection was carried out using ovitraps in Itacoatiara, a mid-size city in Amazonas state, Brazil. Collected eggs were allowed to hatch and larvae were tested for CHIKV, DENV, and ZIKV RNA by RT-qPCR. RESULTS: A total of 2,057 specimens (1,793 Ae. aegypti and 264 Ae. albopictus), in 154 larvae pools were processed. Results showed one positive pool for CHIKV and one positive pool for ZIKV. The active ZIKV infection was further confirmed by the detection of the negative-strand viral RNA and nucleotide sequencing which confirmed the Asian genotype. The Infection Rate per 1,000 mosquitoes tested was assessed by Maximum Likelihood Estimation (MLE) with 0.45 and 0.44 for CHIKV and ZIKV, respectively, and by Minimum Infection Rate (MIR) with 0.45 for both viruses. CONCLUSION: To our knowledge, this is the first detection of ZIKV in natural vertical transmission in the Ae. aegypti, a fact that may contribute to ZIKV maintenance in nature during epidemics periods. Furthermore, our results highlight that the use of ovitraps and the molecular detection of arbovirus may contribute to health surveillance, directing the efforts to more efficient transmission blockade.

Bacterial community composition shifts in the gut of Periplaneta americana fed on different lignocellulosic materials.

ABSTRACT: Cockroaches are insects that can accommodate diets of different composition, including lignocellulosic materials. Digestion of these compounds is achieved by the insect's own enzymes and also by enzymes produced by gut symbionts. The presence of different and modular bacterial phyla on the cockroach gut tract suggests that this insect could be an interesting model to study the organization of gut bacterial communities associated with the digestion of different lignocellulosic diets. Thus, changes in the diversity of gut associated bacterial communities of insects exposed to such diets could give useful insights on how to improve hemicellulose and cellulose breakdown systems. In this work, through sequence analysis of 16S rRNA clone libraries, we compared the phylogenetic diversity and composition of gut associated bacteria in the cockroach Periplaneta americana collected in the wild-types or kept on two different diets: sugarcane bagasse and crystalline cellulose. These high fiber diets favor the predominance of some bacterial phyla, such as Firmicutes, when compared to wild-types cockroaches. Our data show a high bacterial diversity in P. americana gut, with communities composed mostly by the phyla Bacteroidetes, Firmicutes, Proteobacteria and Synergistetes. Our data show that the composition and diversity of gut bacterial communities could be modulated by diet composition. The increased presence of Firmicutes in sugarcane bagasse and crystalline cellulose-fed animals suggests that these bacteria are strongly involved in lignocellulose digestion in cockroach guts. BACKGROUND: Cockroaches are omnivorous animals that can incorporate in their diets food of different composition, including lignocellulosic materials. Digestion of these compounds is achieved by the insect's own enzymes and also by enzymes produced by gut symbiont. However, the influence of diet with different fiber contents on gut bacterial communities and how this affects the digestion of cockroaches is still unclear. The presence of some bacterial phyla on gut tract suggests that cockroaches could be an interesting model to study the organization of gut bacterial communities during digestion of different lignocellulosic diets. Knowledge about the changes in diversity of gut associated bacterial communities of insects exposed to such diets could give interesting insights on how to improve hemicellulose and cellulose breakdown systems. METHODOLOGY/PRINCIPAL FINDINGS: We compared the phylogenetic diversity and composition of gut associated bacteria in the cockroach P. americana caught on the wild or kept on two different diets: sugarcane bagasse and crystalline cellulose. For this purpose we constructed bacterial 16S rRNA gene libraries which showed that a diet rich in cellulose and sugarcane bagasse favors the predominance of some bacterial phyla, more remarkably Firmicutes, when compared to wild cockroaches. Rarefaction analysis, LIBSHUFF and UniFrac PCA comparisons showed that gene libraries of wild insects were the most diverse, followed by sugarcane bagasse fed and then cellulose fed animals. It is also noteworthy that cellulose and sugarcane bagasse gene libraries resemble each other. CONCLUSION/SIGNIFICANCE: Our data show a high bacterial diversity in P. americana gut, with communities composed mostly by the phyla Bacteroidetes, Firmicutes, Proteobacteria and Synergistetes. The composition and diversity of gut bacterial communities could be modulated by font of diet composition. The increased presence of Firmicutes in sugarcane bagasse and crystalline cellulose-fed animals suggests that these bacteria are strongly involved in lignocellulose digestion in cockroach guts.

[Myiasis associated with some socioeconomic factors in five urban areas of the State of Rio de Janeiro]. / Miíases associadas com alguns fatores sócio-econômicos em cinco áreas urbanas do Estado do Rio de Janeiro.

This was a descriptive epidemiological study with the aim of evaluating the occurrence of human myiasis in urban areas of four municipalities in the State of Rio de Janeiro. Seventy-one patients who spontaneously sought attendance at primary healthcare units between October 1999 and October 2003 were examined. The disease was more prevalent among adults, including in individuals more than 51 years old (42.3%), and among children less than 10 years old (33.8%). From all the cases studied, 62% were of low socioeconomic level; 60.6% were male; and 33.8% of the infested individuals were unemployed. In the cases analyzed, the bioagent species were Cochliomyia hominivorax (Coquerel, 1858), Dermatobia hominis (Linnaeus Jr, 1781) and Cochliomyia macellaria (Fabricius, 1775). The results point towards an association between the disease and the patients living and hygiene conditions. This indicates the need for more specific healthcare among more vulnerable groups.

Rhodnius prolixus Malpighian tubules and control of diuresis by neurohormones.

Rhodnius prolixus Malpighian tubules (MTs) are a good model for fluid and ion secretion studies in view of the dramatic postprandial diuresis, which follows its massive blood meals. Ingestion of a blood meal equals to 10-12 times their initial body mass, leads to rapid activation of high output by excretory system, which eliminates 40-50% of the fluid mass. Secretion of ions and water is stimulated 1000-fold by serotonin and diuretic hormone. These hormones cooperate synergistically to activate adenylate cyclase activity from MTs cells, which increase the level of intracellular cAMP. The anti-diuretic hormones have also an important role in the fluid maintenance of Rhodnius prolixus. Several hours after insect feeding occurs a reduction in urine flow, that has been thought to result from a decreased diuretic hormone release or from a novel mechanism of anti-diuresis involving insect cardioacceleratory peptide 2b (CAP2b) and cyclic GMP. In this article it is discussed how the hormone regulation of fluid transport is done in Rhodnius prolixus MTs.

Miíases associadas com alguns fatores sócio-econômicos em cinco áreas urbanas do Estado do Rio de Janeiro / Myiasis associated with some socioeconomic factors in five urban areas of the State of Rio de Janeiro

Trata-se de um estudo epidemiológico descritivo com o objetivo de avaliar a ocorrência de miíases humanas em áreas urbanas de quatro municípios do Estado do Rio de Janeiro. Foram analisados 71 pacientes que procuraram espontaneamente o atendimento em Postos de Saúde, no período de outubro de 1999 a outubro de 2003. Maior prevalência da doença foi encontrada em adultos e idosos acima de 51 anos (42,3 por cento) e em menores de 10 anos (33,8 por cento). Do total dos casos estudados, 62 por cento incluíam-se no nível sócio-econômico baixo; 60,6 por cento eram do sexo masculino e 33,8 por cento dos indivíduos infestados, sem profissão. Nos casos analisados as espécies bioagentes foram Cochliomyia hominivorax (Coquerel, 1858); Dermatobia hominis (Linnaeus Jr, 1781) e Cochliomyia macellaria (Fabricius, 1775). Os resultados apontam para a associação da doença com as condições de vida e de higiene dos pacientes, sinalizando para a necessidade de atenção mais específica à saúde dos grupos mais vulneráveis.

This was a descriptive epidemiological study with the aim of evaluating the occurrence of human myiasis in urban areas of four municipalities in the State of Rio de Janeiro. Seventy-one patients who spontaneously sought attendance at primary healthcare units between October 1999 and October 2003 were examined. The disease was more prevalent among adults, including in individuals more than 51 years old (42.3 percent), and among children less than 10 years old (33.8 percent). From all the cases studied, 62 percent were of low socioeconomic level; 60.6 percent were male; and 33.8 percent of the infested individuals were unemployed. In the cases analyzed, the bioagent species were Cochliomyia hominivorax (Coquerel, 1858), Dermatobia hominis (Linnaeus Jr, 1781) and Cochliomyia macellaria (Fabricius, 1775). The results point towards an association between the disease and the patientsÆ living and hygiene conditions. This indicates the need for more specific healthcare among more vulnerable groups.

Rhodnius prolixus Malpighian tubules and control of diuresis by neurohormones

Rhodnius prolixus Malpighian tubules (MTs) are a good model for fluid and ion secretion studies in view of the dramatic postprandial diuresis, which follows its massive blood meals. Ingestion of a blood meal equals to 10-12 times their initial body mass, leads to rapid activation of high output by excretory system, which eliminates 40-50 percent of the fluid mass. Secretion of ions and water is stimulated 1000-fold by serotonin and diuretic hormone. These hormones cooperate synergistically to activate adenylate cyclase activity from MTs cells, which increase the level of intracellular cAMP. The anti-diuretic hormones have also an important role in the fluid maintenance of Rhodnius prolixus. Several hours after insect feeding occurs a reduction in urine flow, that has been thought to result from a decreased diuretic hormone release or from a novel mechanism of anti-diuresis involving insect cardioacceleratory peptide 2b (CAP2b) and cyclic GMP. In this article it is discussed how the hormone regulation of fluid transport is done in Rhodnius prolixus MTs.

Os túbulos de Malpighi (TMs) de Rhodnius prolixus são reconhecidos por serem excelentes modelos para o estudo da secreção de fluidos e íons devido a grande diurese que ocorre quando esses animais se alimentam de sangue. O inseto, após alimentação, pode aumentar seu peso corporal inicial em até 10-12 vezes, o que leva a rápida ativação do sistema excretor, que elimina 40-50 por cento do fluido corporal. A secreção de íons e água é estimulada 1000 vezes pela serotonina e pelos hormônios diuréticos. Esses hormônios agem sinergicamente ativando a adenil ciclase das células dos TMs, aumentando os níveis intracelulares de AMPc. Os hormônios anti-diuréticos também têm um importante papel na manutenção dos fluídos corporais do Rhodnius prolixus. Várias horas após a alimentação do inseto ocorre uma redução do fluxo urinário, o que foi sugerido ser decorrente da diminuição da liberação dos hormônios diuréticos ou da anti-diurese envolvendo o peptídeo cardioaceleratório 2b (CAP2b) e o GMPc. Neste artigo é discutida a regulação hormonal do transporte de fluido nos MTs de Rhodnius prolixus.

Morphological and molecular characterization of three species of Anastrepha Schiner and of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae)

Four species of Tephritoidea, three from genus Anastrepha: A. obliqua (Macquart), A. sororcula Zucchi and A. serpentina (Wiedemann), and one from genus Ceratitis, C. capitata (Wiedemann) were compared based on puparium morphology and application of the Heteroduplex Mobility Assay (HMA). Puparia were characterized for the first time using the spiracular posterior plate morphology. Application of HMA allowed the detection of variability in the D2 domain from 28S rRNA gene in all four species (confirmed by sequencing). This is a fast, simple, sensitive and inexpensive assay that was used for the first time in the analysis of two Tephritoidea genera. The detected variability suggests that the tecnique has great potential for rapid determination of infestations with two or more species in the same host fruit.

Foram comparadas com base na morfologia do pupário e na técnica de HMA (Heteroduplex Mobility Assay)) quatro espécies de Tephritoidea, três delas pertencentes ao gênero Anastrepha, A. obliqua (Macquart), A. sororcula Zucchi e A. serpentina (Wiedemann) e uma do gênero Ceratitis, C. capitata (Wiedemann). Os pupários foram caracterizados pela primeira vez com base na morfologia da placa espiracular posterior. A aplicação da técnica de HMA possibilitou a detecção de variabilidade no segmento D2 do gene 28S rRNA nas quatro espécies (confirmada por seqüenciamento). Esta é uma técnica rápida, simples, sensível e barata que é aplicada pela primeira vez na análise de dois gêneros de Tephritoidea. A variabilidade observada sugere grande potencial da técnica no caso da determinação da infestação por duas ou mais espécies num mesmo fruto hospedeiro.

Emergence and pupal mortality factors of Anastrepha obliqua (Macq. ) (Diptera: Tephritidae) along the fruiting season of the host Spondias dulcis L. / Emergência e fatores de mortalidade pupal de Anastrepha obliqua (Macq. ) (Diptera: Tephritidae) no período de frutificação do hospedeiro Spondias dulcis L.

A emergência e os fatores de mortalidade pupal de Anastrepha obliqua (Macq.) (Diptera: Tephritidae) durante a frutificação da planta hospedeira Spondias dulcis L. (Anacardiaceae) foram estudados no campo e no laboratório em Sertãozinho, SP. Nas duas condições experimentais, após os períodos de emergência, foram registrados os números de pupários fechados e abertos. Os números de moscas e parasitóides emergidos dos pupários foram registrados. Os pupários fechados foram analisados e, conforme o estado da pupa dentro do pupário, as mesmas foram classificadas em vivas (dormentes) e mortas. Os fatores de mortalidade considerados foram: dessecação, doenças e predação. Foramanalisados 1204 pupários, sendo que de 53% emergiram adultos e 47% permaneceram fechados; do total de pupários fechados, 25,3% eram pupas em estado de dormência e 21,7% eram pupas mortas por predadores, doenças e dessecação. Das pupas em estado de dormência, 17,8% eram moscas e somente 0,2% completaram o estágio pupal; 7,5% continham parasitóides, sendo que 4,7% deles emergiram. Oparasitismo inicial foi de 8,6% e após a emergência das pupas em dormência aumentou para 15,5%. A ação predatória em condições naturais foi acentuada, especialmente quando o tempo de exposição foi prolongado. Em condições de laboratório, a dessecação foi o principal fator de mortalidade pupal. O parasitismo também contribuiu significativamente para a mortalidade pupal enquanto que, as doenças provocadas por patógenos (fungos e bactérias), parecem ter sido menos significativas. Predadores e parasitóides atuaram efetivamente no controle populacional dessa mosca-das-frutas. Entretanto, os fatores que regulam o estado de dormência, ainda devem ser determinados...

The emergence and pupal mortality factors of Anastrepha obliqua (Macq.) (Diptera: Tephritidae) along the fruiting season of the host plant, Spondias dulcis L. (Anarcadiaceae), were studied in Sertãozinho, SP, Brazil, under field and laboratory conditions. Eclosed and uneclosed puparia were recorded in two experimental conditions. The number of emerged flies and parasitoids weredetermined in the eclosed puparia. The uneclosed puparia were inspected and classified into living (dormant) and dead. The following pupal mortality factors were considered: disease, desiccation, predation and parasitism. Out of the total of 1,204 puparia analyzed, 53% emerged and 47% remained uneclosed. Out of the uneclosed puparia, 25.3% contained dormant pupae and 21.7% showed no signs of emergence. Among the dormant pupae, 17.8% were flies, 0.2% of which emerged; 7.5% were parasitoids, 4.7% of them emerged. The initial parasitism was 8.6%, increasing to 15.3% after theemergence of dormant pupae. Predatory activity (natural condition), especially when time of exposure was long, and desiccation (laboratory condition) were the predominant causes of pupal mortality. Variation in mortality caused by parasites and pathogens (bacteria and fungi) seems to play a minor role. Control by predators on fruit fly population is significant. However, the factors, which regulate induction, maintenance and termination of dormancy, are still to be determined. An estimate of the dormancy and of the biotic and abiotic pupal mortality factors are essential to understand the adaptivestrategies of A.obliqua and its parasitoids and to develop effective methods of control in tropical regions.