Discrepancies between Aedes aegypti identification in the field and in the laboratory after collection with a sticky trap

Currently, sticky traps are regularly employed to assist in the surveillance of Aedes aegypti infestation. We tested two alternative procedures for specimen identification performed by local health agents: directly in the field, as recommended by certain manufacturers, or after transportation to the laboratory. A total of 384 sticky traps (MosquiTRAP) were monitored monthly during one year in four geographically representative Brazilian municipalities. When the same samples were inspected in the field and in the laboratory, large differences were noted in the total number of mosquitoes recorded and in the number of specimens identified as Ae. aegypti by both procedures. Although field identification has the potential to speed vector surveillance, these results point to uncertainties in the evaluated protocol.

Cocirculation of two dengue virus serotypes in individual and pooled samples of Aedes aegypti and Aedes albopictus larvae / Cocirculação de dois sorotipos do vírus dengue em amostras individuais e pools de larvas de Aedes aegypti e Aedes albopictus

INTRODUCTION: To detect dengue virus, eggs of Aedes sp were collected in the city of Belo Horizonte, Brazil, in 2007. METHODS: Egg samples were subsequently hatched and the larvae were tested for the presence of dengue virus RNA by RT-PCR. RESULTS: Among the Aedes aegypti larvae samples, 163 (37.4 percent) out of 435 were positive, including 32 (10.9 percent) of 293 individual larvae samples concomitantly positive for two serotypes. CONCLUSIONS: Virological surveillance detecting coinfected vectors in the field could represent an important strategy for understanding the numerous factors involved in the transmission and clinical presentation of dengue.

INTRODUÇÃO: Para a detecção do vírus da dengue, ovos de Aedes sp foram coletados em Belo Horizonte, Brasil, em 2007. MÉTODOS: Amostras de ovos eclodiram e suas larvas foram testadas para a presença de RNA do vírus dengue por RT-PCR. RESULTADOS: Das amostras de larvas de Aedes aegypti, 163 (37,4 por cento) de 435 foram positivas, incluindo 32 (10,9 por cento) das 293 amostras individuais que foram concomitantemente positivas para dois sorotipos. CONCLUSÕES: A vigilância virológica de vetores no campo poderia representar uma estratégia importante para a compreensão dos diversos fatores envolvidos na transmissão e apresentação clínica da dengue.