A study to identify the presence of Aedes Spp. using BG-Sentinel® Traps and larval/pupal surveys in communities around Belmopan, Cayo District.

The knowledge of the presence of Aedes Spp. mosquitoes is very important for the prevention and control of emerging and remerging diseases caused by Arboviruses such as: Yellow fever, Dengue, Chikungunya and Zika. While Chikungunya and Dengue are endemic to Belize, Zika is currently a threat with local transmission having been established in several Caribbean and Central American Countries. The objective of the study is to survey the presence of Ae. aegypti and Ae. albopictus in the communities of San Martin, Salvapan and Las Flores, Belmopan City. The study was conducted from March 14 to April 2, 2016 whereby adult mosquitoes were captured using BG-Sentinel® Traps and larvae/pupae collection surveys were also done. Three hundred meter zone(s) were determined within localities and 1 BG-Sentinel® trap was deployed for 3 days at 24-hour intervals both indoors and outdoors at 2 residences randomly selected in each community. Larvae/Pupae collection surveys were done at 5 private premises within the predetermined zones in each of the three communities. Captured larvae and Pupae were reared for 6 days and adults obtained were used for identification. The identification of adult Ae. aegypti and Ae. albopictus was done using a stereoscopic microscope and pictorial keys that are used for the identification of mosquitoes. The presence of Ae. aegypti was identified in all 3 communities through both adult mosquito and larvae/pupae collections. However, Ae. albopictus was present only in San Martin and Salvapan communities. The presence of Ae. aegypti and/or Ae. albopictus will determine which appropriate vector control interventions are needed considering the different characteristic breeding habitats of these mosquitoes.(AU)

Emergent arboviruses in Brazil

Brazil is a large tropical country (8,514,215km²) with 185,360,000 inhabitants. More than one third of its territory is covered by tropical forests or other natural ecosystems. These provide ideal conditions for the existence of many arboviruses, which are maintained in a large variety of zoonotic cycles. The risk that new arboviruses might emerge in Brazil is related to the existence of large, densely populated cities that are infested by mosquitoes such as Culex and the highly anthropophilic Aedes aegypti. Infected humans or animals may come into these cities from ecological-epidemiological settings where arbovirus zoonoses occur. This study analyzes the risk of emergence of the alphaviruses Mayaro, Venezuelan equine encephalitis, Eastern equine encephalitis and Chikungunya; the flaviviruses yellow fever, Rocio, Saint Louis encephalitis and West Nile; and the orthobunyavirus Oropouche.

O Brasil é país tropical de grande extensão territorial (8.514.215km²) e com 185.360.000 habitantes. Mais de 1/3 deste território é recoberto por florestas tropicais ou outros ecossistemas naturais com condições ideais para a ocorrência de diversas arboviroses as quais são mantidas em uma grande variedade de ciclos zoonóticos. O risco para a emergência de novos arbovirus no Brasil relaciona-se à existência de cidades grandes, populosas e infestadas por mosquitos Culex bem como o altamente antropofílico Aedes aegypti. Nas cidades poderiam ser introduzidos seres humanos ou animais infectados oriundos de sítios eco-epidemiológicos onde existem zoonoses arbovíricas. Neste trabalho, analisa-se o risco de emergência dos alphavirus Mayaro, da encefalite eqüina venezuelana, da encefalite eqüina do leste e Chikungunya, dos flavivirus, da febre amarela, Rocio, da encefalite de Saint Louis e do Nilo Ocidental, e do orthobunyavirus Oropouche.

Historical, Epidemiological and Ecological Aspects of Arboviruses in Argentina: Flaviviridae, Bunyaviridae and Rhabdoviridae

This is a review of the arboviruses in Argentina belonging to families Flaviviridae, Bunyaviridae and Rhabdoviridae. Of the many viruses beloging to these families, the flavivirus St. Louis encephalitis (SLE), has been most intensively studies. SLE virus strains have been recovered from three sources: 2 strains from humans with an undifferentiated, febrile disease; 6 from mosquitoes; and 2 from rodents. The viruses recovered from rodents are attenuated and those from mosquitoes are virulent based on a neuroinvasiveness test in mice; the degree of virulence of the mosquito strains remain to be analyzed. Serological surveys indicate a wide distribution and endemicity of SLE virus in the temperate and subtropical areas (central and northern Argentina), but no data are available from the Andean region or from the South. The virulent SLE virus strains appear to be transmitted between Culex (Cx.) spp., from which they were isolated, and wild birds, based on antibody prevalence. A urban cycle may involve Cx. quinquefasciatus (source of a viral isolate and a competent experimental vector) and abundant birds (house sparrows, doves, and/or chickens), chickens are experimentally competent host species. Despite similarities in the ecology of SLE between Argentina and North America, urban outbreaks of SLE have not recognized. Possible explanations for this discrepancy include virus strain differences in virulence, ecologic factors determining the rate os virus transmission, and the lack of disease recognition and specific laboratory diagnosisof human meningoencephalitis. The transmission cycle of attenuated SLE virus strains isolated from rodents has not been studied. Ilheus virus has been isolated only once from a human being. The available serological data are difficult to interpret due to cross-reactivity with other flaviviruses, and the ecology and medical importance of this agent remain uncertain. Dengue has not been recognized in Argentina since 1916, although its vector, Aedes aegypti, was not eradicated until 1963. Dengue was previously present in coastal localities of Chaco, Corrientes and Misiones Provinces. Within the last few years, Argentina was reinfested by Ae. aegypti. Although no human cases have yet been reported, outbreaks of dengue in bordering countries (Brazil, Paraguay, Bolovia) since 1986, clearly signal that the country in once again at risk of importation and spread of the viruse

Clinical and ecoepidemiological situation of human arboviruses in Brazilian Amazonia

The main aspects of clinic manifestations and epidemiological data about human arboviruses in the Brazilian Amazonian region is reviewed. Thirty four types of arboviruses from 183 types isolated in the Amazonia have been associated with human diseases. Four of them are important in public health and are involved with epidemics; they are namely, Dengue (DEN), Mayaro (MAY), Oropouche (ORO) and Yellow Fever (YF) viruses. ORO and DEN are associated with human epidemic diseases in urban areas while MAY and YF in rural areas. Basically, ORO causes a febrile disease, sometimes accompanied with aseptic meningitis. MAY and DEN are associated with rash febrile disease, while YF determines hemorrhagic fever. Thirty other arboviruses are involved with febrile illnesses in a few and sporadic cases. All arboviruses (apart from DEN) are maintained within a sylvatic cycle in the forest, where several species of hemathophagous insects act as vectors and wild vertebrates are involved as hosts. DEN has a cycle where the Aedes aegypti mosquito is the vector and man is the host. With the exception of the four viruses associated with epidemics which determine great economical and social impacts, including death (as in the case of YF), the real involvement of these viruses as systematic agents of human disease is unknown. Further studies are needed to clarify unclear aspects of the epidemiological cycles of these viruses.

Modifications of arbovirus transmission in relation to construction of dams in Brazilian Amazonia

The Amazonian region of Brazil seems to be the world's richest reservoir of arboviruses. To date, 183 different types of arboviruses have been detected in the Amazonian region, accounting for more than one third of the 535 arboviruses reported in the world. Of these, 136 (74.3 per cent) are endemic. The main objective of this paper was to evaluate what the effects of the construction and flooding of dams would be on the transmission and epidemiology of sylvatic arboviruses, in order to define the potential health hazards to which the human population would be subjected. Five areas were surveyed but only one could be thoroughly studied. Comparisons were made between surveys: i) inside the dam region, before, during and after the flooding period; ii) outside the dam region, in an area with a similar climate, landscape and vegetation, during the total time of the studies. The two chosen areas, namely Altamira and Tucuruí, were studied since 1974, and since September, 1982, respectively. The former, and the latter before the outset of flooding (September 6, 1984) were considered as a control or reference for comparisons with data obtained in Tucuruí during flooding and thereafter. The surveys consisted of sampling as many wild vertebrates and haematophagous Diptera as possible. Human sera were collected from febrile cases and random serological surveys. Very few variations seem to have occurred among the three phases of the study, with a maximum of positive serologies during the flooding period, but the differences were not statistically significant. Similarly, in the reference region, the prevalence of antibodies against the four more important arbovirus groups did not vary significantly. The arboviruses were classified under two categories: i) those which showed enhanced transmission and ii) those which showed no apparent modifications in their transmission patterns (referring to the control area). Three new and three already known types in the Anopheles A group of Bunyavirus were favoured by the great proliferation of Anopheles nuneztovari and An. triannulatus which accompanied the flooding of the dam. An epizootic of the Gamboa virus (Bunyavirus, Gamboa serogroup), newly reported in Brazil, was observed one year after the outset of flooding, when the mosquito Aedeomyia squamipennis showed very large populations. Guaroa (Bunyavirus, California group), an endemic arbovirus, showed an epizootic probably as a consequence of the proliferation of anopheline mosquitoes. A temporary proliferation of Culex spp. mosquitoes and the presence of a rich avifauna in the dam area during flooding are probable causes of the enhanced circulation of Turlock (Bunyavirus, Turlock group) and Kwatta-like (Rhabdoviridae, Kwatta group) viruses...

Dengue: aspectos virológicos, históricos, fisiopatológicos e do controle de epidemias / Aspects of dengue: virology, history, physiopathology and control

O autor descreve os 4 tipos de virus do dengue pertencentes à família Flaviviridae, aspectos de seu genoma, proteínas e classificaçäo epidemiológica como arbovirus. Os vetores do dengue e a transmissäo transovariana dos virus por mosquitos säo referidos. Cita a evoluçäo dos conhecimentos sobre a doença desde sua descriçäo por Benjamin Rush em 1780, a descoberta do virus causdador e seu mosquito transmissor. Refere-sae à mudança no comportamento viral com o aparecimento das epidemias de dengue hemorrágico, as teorias visando explicá-lo e os aspectos da fisiopatologia do dengue hemorrágico. Cita as epidemias de dengue brasileiras, na última década, discutindo algumas medidas do controle destas epidemias e problemas encontrados

Uso de células de Aedes albopictus C6/36 na propagaçäo e classificaçäo de arbovirus das famílias Togaviridae, Flaviviridae, Bunyaviridae e Rhabdoviridae / The use of Aedes albopictus C6/36 cells in the propagation and classification of arbovirus of the Togaviridae, Flaviviridae, Bunyaviridae and Rhabdoviridae families

Colônias de células de mosquito Aedes albopicus C6/36 foram infectadas com 23 arbovirus, sendo 19 destes existentes no Brasil, pertencentes às famílias Togavitidae, Flaviviridae, Bunyaviridae e Rhabdoviridae. A Replicaçäo viral foi detectada por imunofluorescência indireta com todos os vírus estudados enquanto que o efeito citopático foi observado durante a infecçäo por alguns deste. No teste de imunofluorescência indireta utilizou-se fluidos ascíticos imunes de camundongos, especificos para os vírus estudados. A replicaçäo viral caracterizada por grande produçäo de antígeno recomenda a utilizaçäo de células C6/36 na propagaçäo e em tentativas de isolamento desses arbovírus. A técnica de imunofluorescência ofereceu subsídios na classificaçäo e identificaçäo de vírus que replicam nestas células