Adelair Helena dos Santos

Ovicidal Activity of Entomopathogenic Hyphomycetes on Aedes aegypti (Diptera: Culicidae) Under Laboratory Conditions

Abstract The ovicidal activity of 21 hyphomycete fungi species against Aedes aegypti (L.) (Diptera: Culicidae) was tested. Fungi with ovicidal activity developed on high numbers of eggs (≥70%) during 25 d of exposure. A clear ovicidal activity with low values of hatch (1.3–40%) was observed after 25 d of incubation with Isaria farinosa (Holm: Fries) Fries, Paecilomyces carneus (Duché & Heim) Brown & Smith, Paecilomyces marquandii (Massee) Hughes, Isaria fumosorosea (Wize), Metarhizium anisopliae (Metschnikoff) Sorokin, Penicillium sp., Paecilomyces lilacinus (Thom) Samson, Beauveria bassiana (Balsamo) Vuillemin, and Evlachovaea kintrischica Borisov & Tarasov. More than 63% of eggs hatched after 25-d exposures to 11 other fungi species deemed as ineffective. These are the first results to show the effects of entomopathogenic fungi against eggs of Ae. aegypti, and they suggest their potential as control agents of this vector.

Impact of moisture on survival of Aedes aegypti eggs and ovicidal activity of Metarhizium anisopliae under laboratory conditions

The effect of relative humidity (43%, 75%, 86% and > 98%) on Aedes aegypti eggs treated with Metarhizium anisopliae or water only was tested for up to a six months exposure at 25 degrees C. Survival of larvae inside eggs was clearly affected by the lowest humidity (43%) tested, and eclosion diminished at all humidities after increasing periods of exposure. M. anisopliae showed to have a strong ovicidal activity only at humidity close to saturation. No difference of activity was found between conidia and hyphal bodies tested. This fungus affected larvae inside eggs and has potential as a control agent of this important vector in breeding sites with high moisture.

Estudo comparativo entre o xenodiagnóstico natural e o artificial, em chagásicos crônicos

In order to study the sensitivity of the xenodiagnosis technique a comparison between natural and artificial xenodiagnosis methods was performed in 57 chronic phase chagasic patients (31 female), with ages ranging from 26 to 83 years. All patients had demonstrable antibodies against Trypanosoma cruzi. Forty first instar nymphs of Dipetalogaster maximus were used for each of both methods and for each patient. The positivity of xenodiagnosis artificial was significantly higher than the routine test method. These results did show that a single application of 40 bugs by the artificial method yielded a similar result than 3 applications of 40 bugs each, by the natural method. The positivity of xenodiagnosis was significantly higher in patients between 56-65 and 66-83 years old than at other ages. Males were predominant in this age group. These results showed the viability of artificial xenodiagnosis and its use in routine laboratory testing.

Occurrence of invertebrate-pathogenic fungi in a Cerrado ecosystem in Central Brazil

Abstract Occurrence of invertebrate-pathogenic fungi in a protected area of the Cerrado region of Brazil is reported. Fungi were baited with triatomines, ticks, aquatic snails or mosquito larvae from substrates or collected from infected insects. The findings underscore the importance to preserve these fungi and to investigate their potential for vector control.

Phenotypic and genotypic profile of pyrethroid resistance in populations of the mosquito Aedes aegypti from Goiânia, Central West Brazil

INTRODUCTION The mosquito Aedes aegypti has evolved resistance to pyrethroid insecticides. The present study evaluated Ae. aegypti from Goiânia for the resistant phenotype and for mutations associated with resistance. METHODS Insecticide dose-response bioassays were conducted on mosquitoes descended from field-collected eggs, and polymerase chain reaction (PCR) was used to genotype 90 individuals at sites implicated in pyrethroid resistance. RESULTS All mosquito populations displayed high levels of resistance to deltamethrin, as well as high frequencies of the 1016Ile kdr and 1534Cys kdrmutations. CONCLUSIONS Aedes aegypti populations in the Goiânia area are highly resistant to deltamethrin, presumably due to high frequencies of kdr(knockdown-resistance) mutations.

BIOLOGIA DO Triatoma costalimai (VERANO & GALVÃO, 1959) (HEMIPTERA, REDUVUDAE)

Estudou-se a biologia do Triatoma costalimai (Verano & Galvao, 1959) (Hemiptera,Reduviidae), especie de habito silvestre, tendo em vista sua capacidade de se desenvolverem ambiente artificial, criacao em grande escala em laboratorio e sua utilizacao nos testesexperimentais da doenca de Chagas. Este triatominco foi encontrado infectado peloTrypanosoma cruz; (cepa cosSalimai), peia primeira vez. por Melo & Borges (1981). Nestetrabalho, realizaram-se os experimentos a temperatura de 28° C, umidade de 75+5% efotoperiodo de 12 horas. A incubacao dos ovos e o seu desenvolvimento completoocorreram em frascos de polietileno de 3,0 x 7,0 cm de diâmetro, com exemplares detriatomineos individualizados. O periodo medio de incubacao dos ovos foi de 21 ± 00 diaspara machos e femeas, com duracao media do ciclo evolutivo de 138,5 dias para machos e136,1 dias para femeas. A duracao dos estadios ninfais foi determinada petas exuviasrecolhidas nas observacoes diarias. A fecundidade e a fertilidade media foram de 75,2 ± 8,5ovos e 90,4%, respectivamente, e o numero medio de postura de 17,4 ± 1,2 com uma mediade 4,1 ±0,3 ovos por postura. A resistencia media ao jejum, na ordem crescente dos estadiosninfais e adultos (macho), foi de 35,8 ± 0,6; 44,8±2,1; 90,6±4,1; 117,4±6,1; 138,1±7,2 e67,5±1,6. O periodo medio de alimentacao dos estadios ninfais para machos foi de 12,0±2,4;6,8±2,1; 3,1±0,6; o,3±2,0; 3,9±0,7 e para femeas de 9,3±1,3; 5,1±1,0; 3,4±0,6; 4,3±0,7;5,7±1,7.

ELIMINAÇÃO DE EPIMASTIGOTAS E TRIPOMASTIGOTAS ESTIMADA ATRAVÉS DA LEITURA DO XENODIAGNÓSTICO, PELO MÉTODO DAS DEJEÇÕES ESPONTÂNEAS

A partir do xenodiagnostico aplicado em 30 pacientes chagasicos cronicos, com parasitem!*!detectavel, avaliou-se a quantidade de epimastigolas e tripomasligotas, eliminados atraves das fezes e daurina dos triatomineos.Nas fezes, a quantidade de epimastigotas foi, significalivamenle maior do que triponiasligoias,e na urina houve uma inversao: a quamidade de tripomastigotas foi significalivamenle maior do queepimasligotas, pelo teste /, ao nivel de 1%.Os experimentos foram realizados numa câmara biologica a temperatura de 28 ± 1*C.umidade relativa de 70 ± 5%, fotoperiodo de 12 horas.