Dengue virus in Aedes aegypti and Aedes albopictus in urban areas in the state of Rio Grande do Norte, Brazil: Importance of virological and entomological surveillance.

BACKGROUND: Vector control remains the sole effective method to prevent dengue virus (DENV) transmission, although a vaccine for dengue has recently become available and testing of its efficacy and coverage is being performed in multiple places. Entomological surveillance is a key factor in alerting authorities to possible outbreaks, but until now natural DENV infection of mosquito populations has been scarcely used as an early warning system to monitor fluctuating prevalence of infected mosquitoes. The purpose of this study was to determine the burden of adult and larval/pupae of Aedes aegypti and Aedes albopictus with DENV in urban areas in the state of Rio Grande do Norte, Brazil. METHODOLOGY/PRINCIPAL FINDINGS: Immature insect forms (larvae and pupae) were collected from April 2011 to March 2012, whereas the collection of adults was conducted along 3 years: May 2011 to April 2014. Total RNAs of the samples were extracted and the nested reverse transcriptase PCR assay for detecting and typing DENV was performed. Of the 1333 immature insects collected during the study period, 1186 (89%) were A. aegypti and 147 (11%) A. albopictus. DENV-4 was identified in pools of A. aegypti larvae. The rate of DENV infection in immature A. aegypti was expressed as MIR = 3.37. DENV wasnot detected in immature A. albopictus. A total of 1360 adult female mosquitoes of the Aedes genus were captured from May 2011 to April 2014. Of this total, 1293 were A. aegypti (95%) and 67 were A. albopictus (5%). From the 130 pools studied, 27 (20.7%) were positive for DENV. DENV-1 was identified in 2/27 (7.4%) pools; 1of A. albopictus and 1 of A. aegypti. DENV-2 was identified in only 1/27 (3.7%) A. aegypti pools. DENV-4 was the most prevalent, identified in 24/27 (88.8%) of the positive pools, with 19 being of A. aegypti and 5 of A. albopictus pools. The minimum infection rate for adults of the Aedes genus was 19.8, considering both A. aegypti and A. albopictus. CONCLUSIONS/SIGNIFICANCE: This work represents the most complete study to date on the interaction between dengue viruses and Aedes mosquitoes in the State of Rio Grande do Norte, and raises important questions about a possible role of A. albopictus in the transmission of dengue virus in Brazil.

Seasonal variation of potential flavivirus vectors in an urban biological reserve in northeastern Brazil.

Although yellow fever (YF) has not been reported on the eastern coast of Brazil since 1942, there was a reemergence of dengue fever in Brazil in 1987 due to the reintroduction of Aedes aegypti (L.). To assess areas of potential risk for transmission of vector-borne diseases, a surveillance system was placed in a large Atlantic Forest reserve in Natal, Rio Grande do Norte, Brazil, where in 2004 unexplained epizootics were reported among marmosets. The etiologic agent causing the mortality in marmosets has not been identified. Wyeomyia bourrouli Lutz, Haemagogus leucocelaenus Dyar & Shannon, Ae. aegypti, Aedes albopictus (Skuse), Ochlerotatus scapularis Rondani, Ochlerotatus serratus Theobald, Ochlerotatus taeniorhynchus Wiedemann, Culex quinquefasciatus Say, and Limatus durhami Theobald were collected in the park and in the proximity of the households adjacent to the park. Seasonal abundance fluctuation was significant for Ae. aegypti, Ae. albopictus, Ochlerotatus scapularis (Rondani), and Hg. leucocelaenus. Eggs of Ae. aegypti, Ae. albopictus, and Hg. leucocelaenus were more frequently found at the conclusion of the rainy season. A significant negative correlation between the number ofAe. albopictus collected and temperature was observed (r = -0.50), i.e., for each 10C increase in temperature, the number of specimens collected decreased eight-fold. The findings reported herein reinforce the need for a sustainable arboviral surveillance program in this area to decrease the potential risk of emergence of vector borne diseases as YF.

[Phlebotomine (Diptera: Psychodidae) and leishmaniasis in Rio Grande do Norte State Brazil: anthropic environment responses]. / Flebotomíneos (Diptera: Psychodidae) e leishmanioses no Rio Grande do Norte, Nordeste do Brasil: reflexos do ambiente antrópico.

Natural environmental changes or those resulting from anthropic factors and their impact on infectious diseases have been evaluated in several studies. The objective of this work was to analyze the correlation between the anthropic environment, phlebotomine and leishmaniases in Rio Grande do Norte State, in Northeast Brazil. Information relative to the distribution of vector species in visceral and tegumentary leishmaniasis areas was associated to the record of cases notified by Public Health organs. The analysis suggests associations between the vector species and distribution of the disease with demographic and physionomic characteristics, disorderly growth in the metropolitan area, living conditions and environmental degradation of the Eastern Littoral, the principal area of notified visceral leishmaniasis cases.

Flebotomíneos (Diptera: Psychodidae) e leishmanioses no Rio Grande do Norte, Nordeste do Brasil: reflexos do ambiente antrópico / Phlebotomine (Diptera: Psychodidae) and leishmaniasis in Rio Grande do Norte State Brazil: anthropic environment responses

As alterações ambientais, naturais ou resultantes de ações antrópicas e seu impacto sobre as doenças infecciosas têm sido avaliados em diversos estudos. Com o objetivo de analisar possíveis correlações entre o ambiente antrópico, flebotomíneos (Diptera: Psychodidae) e leishmanioses no Rio Grande do Norte, Nordeste do Brasil, foram associadas informações relativas à distribuição de espécies vetoras em áreas de leishmaniose visceral e tegumentar ao registro de casos notificados pelos órgãos de saúde pública. A análise aponta para a existência de associações entre as espécies vetoras e distribuição da doença com características demográficas, fisionômicas, crescimento desordenado da área metropolitana, condições de vida e degradação ambiental do Litoral Oriental, principal área de notificação de casos de leishmaniose visceral.

Natural environmental changes or those resulting from anthropic factors and their impact on infectious diseases have been evaluated in several studies. The objective of this work was to analyze the correlation between the anthropic environment, phlebotomine and leishmaniases in Rio Grande do Norte State, in Northeast Brazil. Information relative to the distribution of vector species in visceral and tegumentary leishmaniasis areas was associated to the record of cases notified by Public Health organs. The analysis suggests associations between the vector species and distribution of the disease with demographic and physionomic characteristics, disorderly growth in the metropolitan area, living conditions and environmental degradation of the Eastern Littoral, the principal area of notified visceral leishmaniasis cases.