Detection of dengue virus serotype 3 by reverse transcription-polymerase chain reaction in Aedes aegypti (Diptera, Culicidae) captured in Manaus, Amazonas

The detection of dengue virus serotypes from Aedes aegypti in Manaus, state of Amazonas was carried out using the reverse transcription-polymerase chain reaction technique. Fourteen pools out 82 (17.1%) were positive for DENV3, providing a minimal infection rate of 2.1% of all analyzed infected female specimens of three different areas of the city

Variation in Aedes aegypti (Linnaeus) (Diptera, Culicidae) infestation in artificial containers in Caxias, state of Maranhão, Brazil

INTRODUCTION: Dengue is a serious public health problem worldwide, with cases reported annually in tropical and subtropical regions. Aedes aegypti (Linnaeus, 1762), the main vector of dengue, is a domiciliary species with high dispersal and survival capacities and can use various artificial containers as breeding sites. We assessed potential container breeding sites of A. aegypti in the municipality of Caxias, Maranhão, Brazil. METHODS: In the initial phase, we analyzed 900 properties in 3 neighborhoods during the dry and rainy seasons (August-October 2005 and February-April 2006, respectively). During the second sampling period, September 2006-August 2007, we used 5 assessment cycles for 300 properties in a single neighborhood. RESULTS: During the dry and rainy seasons, water-storage containers comprised 55.7% (n = 1,970) and 48.5% (n = 1,836) of the total containers inspected, and showed the highest productivity of immature A. aegypti; we found 23.7 and 106.1 individuals/container, respectively, in peridomicile sites. In intradomicile sites, water-storage containers were also the most important breeding sites with 86.4% (n = 973) and 85.6% (n = 900) of all containers and a mean of 7.9 and 108.3 individuals/container in the dry and rainy seaso-October 2006 (1,342). The highest number of positives (70) was recorded in May, mostly (94%) in storage containers. CONCLUSIONS: Storage containers are the principal and most productive A. aegypti breeding sites and are a major contributing factor to the maintenance of this vector in Caxias

Aspectos epidemiológicos do dengue no Município de São Luís, Maranhão, Brasil, 1997-2002 Epidemiological characteristics of dengue in the Municipality of São Luís, Maranhão, Brazil, 1997-2002

Foram notificados 12.008 casos de dengue no período de 1997 a 2002, com picos em 1997 (35,80%) e 1998 (45,80%). A doença predominou na faixa etária de 15-49 anos (72,20%) e na estação chuvosa (83,30%), correlacionando-se positivamente com a precipitação pluviométrica (r = 0,84) e a umidade relativa (r = 0,76), e negativamente com a temperatura (r = -0,78). Não houve diferença significativa (chi2 = 2,319; p > 0,05) no número de casos entre os sexos masculino (49,00%) e feminino (51,00%). Os sete distritos sanitários resultaram positivos: Tirirical (27,00%), Coroadinho (17,00%), Bequimão (16,00%), Cohab (14,00%), Itaqui-Bacanga (11,00%), Centro (8,00%) e Vila Esperança (7,00%). O índice de infestação predial oscilou de 1,01 a 7,15 e o índice de Breteau, de 1,10 a 8,18. Os depósitos mais freqüentes foram: tambor e similares (80,00%), vaso de planta (4,70%), garrafa, lata e plástico (3,60%), pneu (3,30%) e caixa d'água (2,70%); os demais representaram 5,7%. Para Ae. aegyptiforam encontrados 134.631 depósitos positivos, predominando os do tipo B (80,00%), seguidos pelos dos tipos C (4,70%), E (3,60%) e A (3,30%).<br>A total of 12,008 cases of dengue were reported from 1997 to 2002, with peaks in 1997 (35.8%) and 1998 (45.8%). The disease predominated in the 15-49-year age group (72.2%) and during the rainy season (83.3%), showing a positive correlation with the amount of rainfall (r = 0.84) and relative humidity (r = 0.76) and a negative correlation with temperature (r = -0.78). There was no significant difference (chi2 = 2.319; p > 0.05) in the number of cases in males (49%) and females (51%). Dengue was detected in all seven health districts: Tirirical (27%), Coroadinho (17%), Bequimão (16%), Cohab (14%), Itaqui-Bacanga (11%), Centro (8%), and Vila Esperança (7%). The building infestation rate ranged from 1.01 to 7.15, and the Breteau index ranged from 1.10 to 8.18. The most frequent mosquito breeding sites were metal barrels or similar recipients (80.0%), followed by plant vases (4.7%), bottles, cans, and plastics (3.6%), tires (3.3%), water tanks (2.7%), and others (5.7%). In the case of Aedes aegypti, 134,631 positive water deposits were detected, with a predominance of type B (80.0%), followed by types C (4.7%), E (3.6%), and A (3.3%)